Patent Publication Number: US-2020297231-A1

Title: Information processing device, information processing method, recording medium storing program code, and biomedical-signal measuring system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2019-051313, filed on Mar. 19, 2019, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     Embodiments of the present disclosure relate to an information processing device, an information processing method, a recording medium storing program code, and a biomedical-signal measuring system. 
     Background Art 
     When brain surgery or the like is to be performed, a target site that is an affected site of the brain to be removed and sites to be conserved without removal need to be specified. The sites to be conserved include, for example, the visual area, auditory area, somatosensory area, motor area, and the language area of the brain. When some of such sites to be conserved is removed by mistake, the corresponding ability, including, for example, perception and movement, is impaired. For this reason, specifying a target site or sites to be conserved is crucial in performing brain surgery or the like. In order to scan the brain for activity in advance of such brain surgery or the like, physical phenomena inside the brain are measured using, for example, magneto-encephalography, electro-encephalography (EEG), functional Magnetic Resonance Imaging (fMRI), or functional near-infrared spectroscopy (fNIRS). Regarding the fMRI and fNIRS methods, biomedical signals are obtained by measuring the blood flow inside the brain. However, in view of the nature of such blood flow, the precision of the brain-activity measurement is limited. By contrast, magneto-encephalography measures the magnetic field caused by the electrical activity inside the brain, and the electro-encephalography (EEG) can measure the electrical activity inside the brain and obtain the biomedical signals in waveform. In order to analyze such a biomedical signal, methods are known in the art in which the source of the biomedical signal is estimated, and a dipole of the source is obtained based on a signal from the source of the biomedical signal or time-frequency analysis is performed on the biomedical signal. 
     Such technologies are known in the art in which a dipole is estimated and the result of dipole estimation is superimposed on an image indicating the shape of the brain measured by magnetic resonance imaging (MRI). 
     SUMMARY 
     Embodiments of the present disclosure described herein provide an information processing device, an information processing method, a recording medium storing a program for causing a computer to execute the information processing method, and a biomedical-signal measuring system. The information processing device includes circuitry to control a display to superimpose a first image indicative of an estimated site or portion of a live subject on a biological image of the live subject, and control the display to superimpose a second image indicative of a result of analysis on the biological image. 
     The result of the analysis indicating activity of the live subject. The information processing method includes controlling a display to superimpose a first image indicative of an estimated site or portion of a live subject on a biological image of the live subject, and controlling the display to superimpose a second image indicative of a result of analysis on the biological image. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of embodiments and the many attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. 
         FIG. 1  is schematic diagram illustrating a biomedical-signal measuring system according to embodiments of the present disclosure. 
         FIG. 2  is a diagram illustrating a hardware configuration of an information processing device according to embodiments of the present disclosure. 
         FIG. 3  is a block diagram illustrating a functional configuration of an information processing device according to embodiments of the present disclosure. 
         FIG. 4  is a diagram illustrating a starting screen displayed on an information processing device, according to embodiments of the present disclosure. 
         FIG. 5  is a diagram illustrating a measurement and collection screen according to embodiments of the present disclosure. 
         FIG. 6  is a diagram illustrating a magnified view of an area of a measurement and collection screen on the left side, according to embodiments of the present disclosure. 
         FIG. 7  is a diagram illustrating a magnified view of an area of a measurement and collection screen on the right side, according to embodiments of the present disclosure. 
         FIG. 8  is a diagram illustrating a state immediately after an annotation is input, according to embodiments of the present disclosure. 
         FIG. 9  is a diagram illustrating an updated annotation list according to embodiments of the present disclosure. 
         FIG. 10  is a flowchart of the measurement and collection processes performed by an information processing device, according to embodiments of the present disclosure. 
         FIG. 11  is a diagram illustrating a time-frequency analysis screen according to embodiments of the present disclosure. 
         FIG. 12  is a diagram illustrating a heat map in which the range is expressed in decibels, according to embodiments of the present disclosure. 
         FIG. 13  is a diagram illustrating a state where a specific position is designated on a heat map, according to embodiments of the present disclosure. 
         FIG. 14  is a diagram illustrating a state where three peaks are indicated on a heat map from a peak list, according to embodiments of the present disclosure. 
         FIG. 15  is a diagram illustrating a state where the display mode of each peak is changed on a heat map according to the data of each peak, according to embodiments of the present disclosure. 
         FIG. 16  is a diagram illustrating a state where a specific area is designated on a heat map, according to embodiments of the present disclosure. 
         FIG. 17  is a diagram illustrating a state where a plurality of specific areas are designated on a heat map, according to embodiments of the present disclosure. 
         FIG. 18  is a diagram illustrating a state where another three-dimensional image and three-view head image are added to a time-frequency analysis screen, according to embodiments of the present disclosure. 
         FIG. 19  is a diagram illustrating a three-dimensional image on a time-frequency analysis screen, according to embodiments of the present disclosure. 
         FIG. 20  is a diagram in which the state of the brain, which corresponds to the position designated on a heat map, is displayed in the center on a three-dimensional image, according to embodiments of the present disclosure. 
         FIG. 21  is a diagram in which the state of the brain, which corresponds to the range designated on a heat map, is displayed in the center on a three-dimensional image, according to embodiments of the present disclosure. 
         FIG. 22  is a diagram in which line segments are used to indicate to what time and frequency on a heat map each one of the images of a brain displayed as a three-dimensional image corresponds, according to embodiments of the present disclosure. 
         FIG. 23  is a diagram in which rectangular areas are used to indicate to what time and frequency on a heat map each one of the images of a brain displayed as a three-dimensional image corresponds, according to embodiments of the present disclosure. 
         FIG. 24A  and  FIG. 24B  are diagrams illustrating how the display on a three-dimensional image and the display of the rectangular regions on a heat map move as the three-dimensional image is dragged, according to embodiments of the present disclosure. 
         FIG. 25A  and  FIG. 25B  are diagrams illustrating how the display on a three-dimensional image and the display of the rectangular regions on a heat map move as one of the brain images on the three-dimensional image is clicked, according to embodiments of the present disclosure. 
         FIG. 26A ,  FIG. 26B , and  FIG. 26C  are diagrams illustrating how the viewpoints of all brain images in the same row are changed when one of the viewpoints of the brain displayed on a three-dimensional image is changed, according to embodiments of the present disclosure. 
         FIG. 27A ,  FIG. 27B , and  FIG. 27C  are diagrams illustrating how the viewpoints of all the brain images in all the rows are changed when one of the viewpoints of the brain displayed on a three-dimensional image is changed, according to embodiments of the present disclosure. 
         FIG. 28A ,  FIG. 28B , and  FIG. 28C  are diagrams illustrating in detail how the viewpoint is changed in  FIG. 27A ,  FIG. 27B , and  FIG. 27C . 
         FIG. 29A ,  FIG. 29B , and  FIG. 29C  are another set of diagrams illustrating how the viewpoints of all the brain images in all the rows are changed when one of the viewpoints of the brain displayed on a three-dimensional image is changed, according to embodiments of the present disclosure. 
         FIG. 30A ,  FIG. 30B , and  FIG. 30C  are diagrams illustrating the details of how the viewpoint is changed as in  FIG. 29A ,  FIG. 29B , and  FIG. 29C . 
         FIG. 31  is a diagram illustrating a state in which a comment is added to a three-dimensional image, according to embodiments of the present disclosure. 
         FIG. 32  is a diagram illustrating a three-view head image on a time-frequency analysis screen, according to embodiments of the present disclosure. 
         FIG. 33  is a diagram illustrating a cut model that is displayed as a three-dimensional image on a three-view head image, according to embodiments of the present disclosure. 
         FIG. 34  is a diagram illustrating the peak selected from a peak list in a three-view head image, according to embodiments of the present disclosure. 
         FIG. 35  is a diagram illustrating the peak selected from a peak list and the peaks that are temporally close to each other around the selected peak, in a three-view head image, according to embodiments of the present disclosure. 
         FIG. 36  is a diagram illustrating a state in which the peak selected from a peak list and the peaks that are temporally close to each other around the selected peak are indicated with varying colors, in a three-view head image, according to embodiments of the present disclosure. 
         FIG. 37  is a diagram illustrating a state in which a result of dipole estimation is superimposed on the three-dimensional images on a three-view head image, according to embodiments of the present disclosure. 
         FIG. 38A ,  FIG. 38B ,  FIG. 38C , and  FIG. 38D  are diagrams each illustrating a state in which a result of measuring a plurality of objects (heat map) is superimposed on the three-dimensional images of a three-view head image, according to embodiments of the present disclosure. 
         FIG. 39  is a diagram illustrating a state before the viewpoint is changed for the three-dimensional images in a three-view head image, according to embodiments of the present disclosure. 
         FIG. 40  is a diagram illustrating a dialog box displayed when the viewpoint of the three-dimensional images in a three-view head image is changed, according to embodiments of the present disclosure. 
         FIG. 41  is a diagram illustrating a setting in which the changes in viewpoint made on a three-dimensional image are applied to the viewpoint of the three-dimensional images in the first row of three-dimensional view, according to embodiments of the present disclosure. 
         FIG. 42  is a diagram illustrating a state in which the changes in viewpoint of a three-dimensional image in a three-view head image are applied to the viewpoint of the three-dimensional images in the first row of three-dimensional view, according to embodiments of the present disclosure. 
         FIG. 43  is a diagram illustrating a setting in which the changes in viewpoint made on a three-dimensional image are reflected in the three-dimensional images in the first and second rows of three-dimensional view, according to embodiments of the present disclosure. 
         FIG. 44  is a diagram illustrating a state in which the changes in the viewpoint of a three-dimensional image of a three-view head image are reflected in the first and second rows of three-dimensional view, according to embodiments of the present disclosure. 
         FIG. 45  is a diagram illustrating a setting in which the changes in viewpoint made on a three-dimensional image are symmetrically reflected in the three-dimensional images in the first and second rows of three-dimensional view, according to embodiments of the present disclosure. 
         FIG. 46  is a diagram illustrating a state in which the changes in the viewpoint of a three-dimensional image of a three-view head image are symmetrically reflected in the three-dimensional images in the first and second rows of three-dimensional view, according to embodiments of the present disclosure. 
         FIG. 47  is a diagram illustrating a setting in which new three-dimensional images in which the changes in viewpoint made on a three-dimensional image are reflected are added to three-dimensional view in a separate row, according to embodiments of the present disclosure. 
         FIG. 48  is a diagram illustrating a state in which new three-dimensional images in which the changes in viewpoint made on a three-dimensional image of a three-view head image are reflected are added to three-dimensional view in a separate row, according to embodiments of the present disclosure. 
         FIG. 49  is a diagram illustrating the setting of a peak list, according to embodiments of the present disclosure. 
         FIG. 50  is a diagram illustrating a spatial peak according to embodiments of the present disclosure. 
         FIG. 51  is a diagram illustrating a peak in time and a peak in frequency, according to embodiments of the present disclosure. 
         FIG. 52  is a diagram illustrating how a specific peak is selected from a drop-down peak list, according to embodiments of the present disclosure. 
         FIG. 53  is a diagram illustrating a state in which the peak selected from a pull-down peak list is reflected in a heat map, three-dimensional view, and a three-view head image, according to embodiments of the present disclosure. 
         FIG. 54A  and  FIG. 54B  are diagrams illustrating how the viewing of a heat map and a three-dimensional image are played back by operations on a replay control panel, according to embodiments of the present disclosure. 
         FIG. 55A  and  FIG. 55B  are diagrams illustrating how the viewing of a heat map and a three-dimensional image are returned on a frame-by-frame basis by operations on a replay control panel, according to embodiments of the present disclosure. 
         FIG. 56A  and  FIG. 56B  are diagrams illustrating how the viewing of a heat map and a three-dimensional image are advanced on a frame-by-frame basis by operations on a replay control panel, according to embodiments of the present disclosure. 
         FIG. 57  is a diagram illustrating from what viewpoint the images are to be initially displayed with respect to a peak, according to embodiments of the present disclosure. 
         FIG. 58  is a diagram illustrating from what viewpoint the images are to be initially displayed with respect to a pair of peaks, according to embodiments of the present disclosure. 
         FIG. 59  is a diagram illustrating a state in which the images of the brain viewed from the viewpoints as illustrated in  FIG. 58  are displayed as the initial display in three-dimensional view. 
         FIG. 60A ,  FIG. 60B ,  FIG. 60C , and  FIG. 60D  are diagrams illustrating how a lumbar signal is transmitted to the upper side in chronological order, according to embodiments of the present disclosure. 
         FIG. 61  is a diagram illustrating a state of a time-frequency analysis screen in which a drop-down menu of dipole list is displayed, according to embodiments of the present disclosure. 
         FIG. 62  is a diagram illustrating how dipoles are displayed on a time-frequency analysis screen as a result of dipole selection when such dipoles do not exist on a currently-displayed sectional views, according to embodiments of the present disclosure. 
         FIG. 63  is a diagram illustrating a state of a time-frequency analysis screen in which a sectional view on which a dipole exists is displayed together with the selected dipole, according to embodiments of the present disclosure. 
         FIG. 64  is a diagram illustrating how dipoles are displayed when a plurality of dipoles are selected on a time-frequency analysis screen, according to embodiments of the present disclosure. 
         FIG. 65  is a diagram illustrating a time-frequency analysis and dipole display screen according to embodiments of the present disclosure. 
         FIG. 66  is a schematic diagram of storing a plurality of results of time-frequency analysis and superimposing a result of time-frequency analysis and a dipole on a time-frequency analysis and dipole display screen, according to embodiments of the present disclosure. 
         FIG. 67  is a flowchart of storing a plurality of results of time-frequency analysis and superimposing a result of time-frequency analysis and a dipole on a time-frequency analysis and dipole display screen, according to embodiments of the present disclosure. 
         FIG. 68  is a diagram illustrating a state in which a time-frequency analysis and dipole display screen includes a slider that indicates the degree of reliability, according to a modification of the above embodiment. 
     
    
    
     The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. 
     DETAILED DESCRIPTION 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes” and/or “including”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     In describing example embodiments shown in the drawings, specific terminology is employed for the sake of clarity. However, the present disclosure is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have the same structure, operate in a similar manner, and achieve a similar result. 
     In the following description, illustrative embodiments will be described with reference to acts and symbolic representations of operations (e.g., in the form of flowcharts) that may be implemented as program modules or functional processes including routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types and may be implemented using existing hardware at existing network elements or control nodes. Such existing hardware may include one or more central processing units (CPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), computers or the like. These terms may be collectively referred to as processors. 
     Unless specifically stated otherwise, or as is apparent from the discussion, terms such as “processing” or “computing” or “calculating” or “determining” or “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical, electronic quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. 
     Some embodiments of an information processing device, an information processing method, a non-transitory recording medium storing a program, and a biomedical-signal measuring system according to the present disclosure will be described below in detail with reference to the drawings. Note that numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the disclosure of the present disclosure may be practiced otherwise than as specifically described herein. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims. 
       FIG. 1  is schematic diagram illustrating a biomedical-signal measuring system  1  according to embodiments of the present disclosure. 
     A schematic configuration of the biomedical-signal measuring system  1  according to the present embodiment is described with reference to  FIG. 1 . 
     The biomedical-signal measuring system  1  (an example of an information processing system) measures various kinds of biomedical signals of a test subject such as magneto-encephalography (MEG) signals and electro-encephalography (EEG) signals, and displays the results of measurement. The biomedical signals to be measured are not limited to the magneto-encephalography (MEG) signals and electro-encephalography (EEG) signals as above, but may be, for example, any electrical signal that is caused by cardiac activity (i.e., any electrical signal that can be expressed in an electrocardiogram (ECG)). As illustrated in  FIG. 1 , the biomedical-signal measuring system  1  includes a measurement device  3  that measures at least one biomedical signal of a test subject, a server  40  that stores at least one biomedical signal measured by the measurement device  3 , and an information processing device  50  that analyzes at least one biomedical signal stored on the server  40 . In the present embodiment, as illustrated in  FIG. 1 , the server  40  and the information processing device  50  are described as separate units. However, no limitation is indicated thereby. For example, at least some of the functions of the server  40  may be implemented by the information processing device  50 . 
     In the present embodiment as illustrated in  FIG. 1 , a test subject (person to be measured) lies on a measurement table  4  on his or her back with electrodes (or sensors) attached to his or her head to measure the electrical brain waves, and puts his or her head into a hollow  32  of a Dewar  31  of the measurement device  3 . The Dewar  31  is a container of liquid helium that can be used at very low temperatures, and a number of magnetic sensors for measuring the brain magnetism are disposed on the inner surface of the hollow  32  of the Dewar  31 . The measurement device  3  collects the electrical signals and the magnetic signals through the electrodes and the magnetic sensors, respectively, and outputs data including the collected electrical signals and magnetic signals to the server  40 . Note that such collected electrical signals and magnetic signals may be referred to simply as “measurement data” in the following description of the present embodiment. The measurement data recorded on the server  40  is read and displayed by the information processing device  50 , and is analyzed by the information processing device  50 . As known in the art, the Dewar  31  equipped with magnetic sensors and the measurement table  4  is inside a magnetically shielded room. However, for the sake of explanatory convenience, the illustration of such a magnetically shielded room is omitted in  FIG. 1 . 
     The information processing device  50  synchronizes and displays the waveform of the magnetic signals obtained through the multiple magnetic sensors and the waveform of the electrical signals obtained through the multiple electrodes on the same time axis. The electrical signals indicate the inter-electrode voltage value obtained for the electrical activity of nerve cells (i.e., the flow of ionic charge caused at the dendrites of neurons during synaptic transmission). Moreover, the magnetic signals indicate minute changes in electric field caused by the electrical activity of the brain. The magnetic field that is generated by the brain is detected by a high-sensitivity superconducting quantum interference device (SQUID). These electrical signals and magnetic signals are examples of biomedical signals. 
       FIG. 2  is a diagram illustrating a hardware configuration of the information processing device  50  according to the present embodiment. 
     A hardware configuration of the information processing device  50  according to the present embodiment is described with reference to  FIG. 2 . 
     As illustrated in  FIG. 2 , the information processing device  50  is provided with a central processing unit (CPU)  101 , a random access memory (RAM)  102 , a read only memory (ROM)  103 , an auxiliary memory  104 , a network interface (I/F)  105 , an input device  106 , and a display device  107 , and these elements are interconnected through a bus  108 . 
     The CPU  101  controls the entire operation of the information processing device  50 , and performs various kinds of information processing. Moreover, the CPU  101  executes an information displaying program stored in the ROM  103  or the auxiliary memory  104 , to control the display of a measurement and collection screen  502  (see, for example,  FIG. 5 ) and the analyzing screen (see, for example, a time-frequency analysis screen  601  in  FIG. 11 ). 
     The RAM  102  is used as a work area of the CPU  101 , and may be a volatile memory in which a desired control parameter or data are stored. The ROM  103  is a nonvolatile memory in which a basic input and output program or the like is stored. For example, the ROM  103  may store the above-described information displaying program. 
     The auxiliary memory  104  may be, for example, a hard disk drive (HDD) or a solid state drive (SSD). The auxiliary memory  104  stores, for example, a control program to control the operation of the information processing device  50 , various kinds of data used to operate the information processing device  50 , and files. 
     The network interface  105  is a communications interface used to communicate with a device such as the server  40  in the network. For example, the network interface  105  is implemented by a network interface card (NIC) that complies with the transmission control protocol (TCP)/Internet protocol (IP). 
     The input device  106  is, for example, a user interface such as a touch panel, a keyboard, a mouse, and an operation key. The display device  107  is a device for displaying various kinds of information thereon. For example, the display device  107  is implemented by the display function of a touch panel, a liquid crystal display (LCD), or an organic electroluminescence (EL). The measurement and collection screen  502  and the time-frequency analysis screen  601  are displayed on the display device  107 , and the screen of the display device  107  is updated in response to input and output operation through the input device  106 . 
     The hardware configuration of the information processing device  50  as illustrated in  FIG. 2  is given by way of example, and different kinds of devices may further be provided. It is assumed that the information processing device  50  as illustrated in  FIG. 2  is configured by hardware such as a personal computer (PC). However, no limitation is intended thereby, and the information processing device  50  may be a mobile device such as a tablet PC. In such a configuration, the network interface  105  is satisfactory as long as it is a communication interface with radio communication capability. 
       FIG. 3  is a block diagram illustrating a functional configuration of the information processing device  50  according to the present embodiment. 
     A configuration of the functional blocks of the information processing device  50  according to the present embodiment is described with reference to  FIG. 3 . 
     As illustrated in  FIG. 3 , the information processing device  50  includes a collection and display controller  201 , an analysis display controller  202 , a peak-list controller  203  (peak controller), a communication unit  204 , a sensor information acquisition unit  205 , an analyzer  206  (calculator), a storage unit  207 , an input unit  208 , an analytical-result storage control unit  221 , and a superimposition display control unit  222 . 
     The collection and display controller  201  is a functional unit that controls the visual display when the data output from a sensor is being collected, using methods as will be described below with reference to  FIG. 5  to  FIG. 10 . 
     The analysis display controller  202  is a functional unit that controls the visual display of, for example, the signal strength of the biomedical signal computed and obtained by the analyzer  206  based on the sensor data (electrical signals or magnetic signals) obtained by the sensor information acquisition unit  205 , using methods as will be described below with reference to  FIG. 11  to  FIG. 60D . As illustrated in  FIG. 3 , the analysis display controller  202  includes a heat-map display control unit  211 , a three-dimensional display control unit  212 , a sectional-view control unit  213 , and a viewing control unit  214 . 
     As will be described later in detail with reference to, for example,  FIG. 11 , the heat-map display control unit  211  is a functional unit that controls the visual display of the heat map  611  of the time-frequency analysis screen  601 . The three-dimensional display control unit  212  is a functional unit that controls the visual display of the three-dimensional view  612  of the time-frequency analysis screen  601 . The sectional-view control unit  213  is a functional unit that controls the visual display of the three-view head image  613  on the time-frequency analysis screen  601 . The viewing control unit  214  is a functional unit that controls the viewing in accordance with the operation of or input to a replay control panel  615  on the time-frequency analysis screen  601 . 
     The peak-list controller  203  is a functional unit that extracts a peak in signal strength that meets a specified condition and registers the extracted peak in a peak list  614  on the time-frequency analysis screen  601 , as will be described later in detail with reference to, for example,  FIG. 11 . 
     The communication unit  204  is a functional unit that performs data communication with, for example, the measurement device  3  or the server  40 . The communication unit  204  is implemented by the network interface  105  illustrated in  FIG. 2 . 
     The sensor information acquisition unit  205  is a functional unit to obtain sensor information (i.e., an electrical signal or magnetic signal) from the measurement device  3  or the server  40  through the communication unit  204 . The analyzer  206  is a functional unit that analyzes the sensor data (measured and obtained signal) obtained by the sensor information acquisition unit  205  to compute and obtain a signal that indicates the signal strength at various parts inside the brain (such a signal may also be referred to as a biomedical signal in the following description). 
     The storage unit  207  is a functional unit that stores, for example, the data of a biomedical signal that indicates the signal strength computed and obtained by the analyzer  206 . The storage unit  207  is implemented by the RAM  102  or the auxiliary memory  104  as illustrated in  FIG. 2 . 
     The input unit  208  is a functional unit that accepts an input operation of annotation to be added to the sensor information and various kinds of input operations for the time-frequency analysis screen  601 . The input unit  208  is implemented by the input device  106  as illustrated in  FIG. 2 . 
     The analytical-result storage control unit  221  is a functional unit that controls, on the screen that is controlled by the analysis display controller  202 , the storing operation of data including, for example, the specified site of the brain, time, frequency, peak list, and parameters for display, into the storage unit  207 . 
     The superimposition display control unit  222  is a functional unit that controls visual display in which a dipole and a result of time-frequency analysis (heat map) are superimposed, using a method as will be described below with reference to  FIG. 65 . The superimposition display control unit  222  includes a dipole display control unit  231  (an example of a first display controller) and a heat-map display control unit  232  (an example of a second display controller). 
     The dipole display control unit  231  is a functional unit that controls the display operation of the selected dipole on a time-frequency analysis and dipole display screen  901  as will be described later in detail with reference to, for example,  FIG. 65 . The heat-map display control unit  232  is a functional unit that controls, on the time-frequency analysis and dipole display screen  901 , the display operation of the heat map that indicates the distribution of the signal strength of biomedical signals at the time and frequency indicated by the selected result of time-frequency analysis. 
     The collection and display controller  201 , the analysis display controller  202 , the peak-list controller  203 , the sensor information acquisition unit  205 , the analyzer  206 , the analytical-result storage control unit  221 , and the superimposition display control unit  222  as described above may be implemented as the CPU  101  launches a program stored in a memory such as the ROM  103  into the RAM  102  and executes the program. Note also that some of or all of the collection and display controller  201 , the analysis display controller  202 , the peak-list controller  203 , the sensor information acquisition unit  205 , and the analyzer  206  may be implemented by hardware circuitry such as a field-programmable gate array (FPGA) or an application specific integrated circuit (ASIC), in place of a software program. 
     The functional units as illustrated in  FIG. 3  merely indicate functions schematically, and no limitation is intended by such configurations. For example, a plurality of functional units that are illustrated as independent functional units in  FIG. 3  may be configured as a single functional unit. Alternatively, the function of a single functional unit as illustrated in  FIG. 3  may be divided into a plurality of functions implemented by a plurality of functional units. 
       FIG. 4  is a diagram illustrating a starting screen displayed on the information processing device  50 , according to the present embodiment. The operations on the starting screen  501  are described below with reference to  FIG. 4 . 
     On the starting screen  501 , selection keys “measurement and collection” and “analysis” are displayed. When the brain wave and brain magnetism are to be measured, in many cases, the person who measures and collects the data and the person who analyzes the data are different. For example, when the “measurement and collection” key is selected by a measurement engineer (technician), the data measured by the measurement device  3  is sequentially stored on the server  40 , and is read and displayed by the information processing device  50 . On the other hand, when the “analysis” key is selected by a doctor after the measurement and collection is done, the recorded measurement data is read and analyzed. 
       FIG. 5  is a diagram illustrating a measurement and collection screen  502  according to the present embodiment. 
     As illustrated in  FIG. 5 , a measurement and collection screen  502  includes an area  511   a  on which the signal waveforms of measured biomedical signals (i.e., magnetic signals and electrical signals in the present embodiment) are displayed, and an area  511   b  on which monitoring data other than the signal waveform is displayed. The area  511   a  on which signal waveform is displayed is arranged on the left side of the screen when viewed from the technician, and the area  511 B on which monitoring data other than the signal waveform is displayed is arranged on the right side of the screen when viewed from the technician. Accordingly, there is an economy of motion between the movement of the mouse from the area  511   a  on the left side of the screen to the area  511   b  on the right side of the screen and the motion of the line of sight of a technician that follows the movement of a waveform (detected in real time and dynamically displayed from the left side of the screen to the right side of the screen), thereby providing improved efficiency. 
     In the area  511 B of the display screen, a monitoring window  512  is displayed to monitor the state of a subject during measurement. By displaying the live image of the subject while he/she is being measured, the reliability of the check and judgment of a signal waveform can be improved as will be described later in detail. Note that  FIG. 5  illustrates a case in which the entirety of the measurement and collection screen  502  is displayed on the display screen of a single monitoring display (i.e., the display device  107 ). However, no limitation is indicated thereby, and the area  511   a  on the left side of the screen and the area  511   b  on the right side of the screen may separately be displayed by two or more monitoring displays. 
       FIG. 6  is a diagram illustrating a magnified view of an area of the measurement and collection screen  502  on the left side, according to the present embodiment. 
     The area  511   a  includes a first display area  530  in which the time data of signal detection is displayed in the horizontal direction of the screen, and second display areas  521  to  523  in which a plurality of signal waveforms based on the signal detection are displayed in parallel across the screen. 
     In the example as illustrated in  FIG. 6 , the time data that is displayed in the first display area  530  is a time line including the time indication given along a time axis  531 . However, no limitation is indicated thereby, and such a time line may only be a band-like or belt-like axis where no time (time in numbers) is displayed, or may only be the time (time in numbers) where no axis is given. Alternatively, a one time line may be displayed by displaying the time axis  531  under the second display area  523  in addition to the first display area  530  on the topside of the screen. 
     In the area  511   a , a plurality of signal waveforms obtained by a plurality of similar kinds of sensors or various kinds of signal waveforms obtained by a group of a plurality of different kinds of sensors are displayed in a synchronous manner along the same time axis  531 . In the example as illustrated in  FIG. 6 , the waveforms of a plurality of magneto-encephalography (MEG) signals obtained from the right side of the head of a subject and the waveforms of a plurality of magneto-encephalography (MEG) signals obtained from the left side of the head of a subject are displayed parallel to each other in the second display area  521  and the second display area  522 , respectively. In the second display area  523 , the waveforms of a plurality of electro-encephalography (EEG) signals are displayed in parallel. These waveforms of a plurality of electro-encephalography (EEG) signals correspond to the voltage signals measured between pairs of electrodes. Each of these waveforms of a plurality of signals is displayed in association with the identification number or channel number of the sensor through which the signal is obtained. 
     Once measurement is started and the readings from each sensor are collected, as time passes a signal waveform is displayed moving from left to right in each of the second display areas  521  to  523  in the area  511   a . A vertical line  532  indicates the measurement time (present time), and moves from the left side to the right side of the screen. Once the signal waveform display reaches the right end of the area  511   a  (i.e., until the right end of the time axis  531 ), the signal waveform gradually disappears from the left end of the screen to the right. Then, new signal waveforms are displayed at disappearing positions in sequence from the left side to the right side, and the vertical line  532  also moves from the left end of the screen to the right. Together with the above changes on the display, the lapse of time is also displayed in the horizontal first display area  530  along the time axis  531  as the measurement progresses. The measurement and collection continues until the stop key  539  is touched or clicked. 
     In the present embodiment, when the technician (i.e., a person who collects the data) notices, for example, irregularities in waveform and a singular point of amplitude on the signal waveform during the data recording, he/she can mark a problematic point or area on the signal waveform. The point or area of such a problematic point or area to be marked can be specified by moving a mouse cursor or clicking with a mouse. The specified point or area is highlighted on the signal waveforms of the second display areas  521  to  523 , and the specified result is displayed along the time axis  531  of the first display area  530  in a relevant point in time or time range. The marking information including the display along the time axis  531  is stored together with the signal waveform data. The specified point corresponds to particular time, and the specified area corresponds to a certain area including the particular time. 
     In the example illustrated in  FIG. 6 , an area including at least one channel is specified at a time t 1  in the second display area  523 , and the span of time including the time t 1  is highlighted at the mark  523   a - 1 . In association with the display of the mark  523   a - 1 , an annotation  530   a - 1  that indicates the result of specification is displayed at the corresponding point in time in the first display area  530 . At a time t 2 , another point in waveform or an area around that point is marked in the second display area  523 , and a mark  523   a - 2  is highlighted at that point (the time t 2 ) or in the area around that point (the time t 2 ) (where at least one of a time range or a plurality of waveforms is indicated). At the same time, an annotation  530   a - 2  is displayed at the corresponding point in time (time range) in the first display area  530 . Note that the term “annotation” indicates that related information is given to certain data as an annotation. An annotation according to the present embodiment is displayed at least based on the specified time data in association with the position at which the waveform is displayed based on the time data. When a plurality of channels are, the annotation according to the present embodiment displayed in association with the corresponding channel information. 
     The annotation  530   a - 1  that is added to the first display area  530  at the time t 1  includes, for example, an annotation identification number and the waveform-attribute information. In the present embodiment, an icon that indicates the attributes of the waveform and the text data saying “strong spike” are displayed together with the annotation number “1.” 
     Once the technician specifies another point in waveform or an area around that point in waveform at the time t 2 , the mark  523   a - 2  is highlighted at the specified point, and an annotation number “2” is displayed at the corresponding point in time in the first display area  530 . Further, a pop-up window  535  for selecting the attribute is displayed at the highlighted point. The pop-up window  535  includes selection keys  535   a  for selecting the various kinds of attribute, and an input box  535   b  through which a comment or additional information is input. On the selection keys  535   a , the causes of irregularities in waveform such as fast activity, eye motion, body motion, and spike are indicated as the attributes of waveform. As the technician can check the state of the subject through the monitoring window  512  of the area  511   b  in the screen, he/she can appropriately select the attribute indicating the causes of irregularities in waveform. For example, when a spike occurs in a waveform, the technician can determine whether such a spike shows symptoms of epilepsy or caused by the body motion (such as a sneeze) of the subject. 
     The same operations are also performed at the time t 1 . In  FIG. 6 , as the selection key  535   a  of “spike” is selected in the pop-up window  535  and “strong spike” is input to the input box  535   b , the annotation  530   a - 1  is displayed in the first display area  530 . Due to such a display mode, when a large number of signal waveforms are displayed along the same time axis  531  in a synchronous manner, a point of interest or region of interest of the signal waveforms can visually be recognized and identified easily, and the basic information at a point of interest can easily be figured out. 
     Some of or all of the annotation  530   a - 1 , for example, at least one of an attribute icon and a text data may be displayed in the proximity of the mark  523   a - 1  on the signal waveforms in the second display area  523 . When such an annotation is added directly over the signal waveforms, the ability to check the shape of the waveforms may be impaired. For this reason, when an annotation is displayed over the signal waveforms in the second display areas  521  to  523 , it is desired that display or non-display of such an annotation be selectable. 
     The counter box  538  displays the cumulative number of spike annotations. In the present embodiment, every time “spike” is selected, the counter value in the counter box  538  is incremented. Accordingly, the analyst can instantly figure out the total number of spikes selected until now (as indicated by the vertical line  532 ) since the recording has started. 
       FIG. 7  is a diagram illustrating a magnified view of an area of the measurement and collection screen  502  on the right side, according to the present embodiment. 
     In  FIG. 7 , a state at the same time as illustrated in  FIG. 6  (the point in time indicated by the vertical line  532 ) is illustrated. In the monitoring window  512  of the area  511   b , the live image of a state in which a subject lies on the measurement table  4  and the head of the subject is inside the measurement device  3  is displayed. In the area  511   b , the magnetoencephalogram distribution maps  541  and  542 , the brain-wave distribution map  550 , and the annotation list  560 , each of which corresponds to one of the signal waveforms in the second display areas  521 ,  522 , and  523 , are displayed. The annotation list  560  is a list of annotations of the signal waveforms as illustrated in  FIG. 6 . Every time the point or area on the signal waveforms is specified in the second display areas  521  to  523  and annotated, the associated information is sequentially added to the annotation list  560 . When information is added to the annotation list  560  on the measurement and collection screen  502 , such information is displayed, for example, in descending order where new data is displayed on an upper side). However, no limitation is intended thereby. For example, the annotation list  560  may be displayed in ascending order. The annotation list  560  is displayed such that the relation with the annotation displayed in the first display area  530  along the time axis  531  will be clear to the analyst. Alternatively, the display order may be changed, or information may be sorted according to the type of item. 
     In the example as illustrated in  FIG. 7 , the time data that correspond to the annotation number “1” and the added annotation are listed in the annotation list  560 . As the annotation, an attribute icon that indicates “spike” and the text saying “strong spike” are recorded. When the mark  523   a - 1  is highlighted, the time data that correspond to the annotation number “2” is listed. In the present embodiment, the term “annotation” may be considered to be a group of information including an annotation number, time data, and annotation, or may be considered to be only the annotation. Additionally, the term “annotation” may be considered to be a group of information including annotation and an annotation number or time data. 
     A selection box  560   a  to choose show/hide is arranged near the annotation list  560 . When “hide” is selected in the selection box  560   a , the annotation other than a highlighting mark on the signal waveforms is hidden from view in the second display areas  521  to  523 . However, the display of the annotation in the first display area  530  along the time axis  531  is maintained. Due to such a configuration, the annotation becomes recognizable without impairing the recognizability of signal waveforms. 
       FIG. 8  is a diagram illustrating a state immediately after an annotation is input, according to the present embodiment. 
     More specifically,  FIG. 8  illustrates a screen displayed immediately after “spike” is selected from the pop-up window  535  at the time t 2  and a text “normal spike” is input. When “OK” key is selected from the pop-up window  535  as illustrated in  FIG. 6 , the pop-up window  535  closes and an annotation  530   a - 2  is displayed at the corresponding point in time in the first display area  530  as illustrated in  FIG. 8 . In association with the annotation number “2,” an attribute icon that indicates “spike” and text data saying “normal spike” are displayed. At the same time, the value in the counter box  538  is incremented. Moreover, an attribute icon  526 - 2  is displayed near the highlighted mark  523   a - 2 . In the present embodiment, the attribute icon  526 - 1  is also displayed near the mark  523   a - 1 . However, as described above, the attribute icons  526 - 1  and  526 - 2  may be displayed or hidden in a selective manner. The annotation includes annotation A 1  including the mark  523   a - 1  and the attribute icon  526 - 1  and annotation A 2  including the mark  523   a - 2  and the attribute icon  526 - 2 . 
       FIG. 9  is a diagram illustrating an updated annotation list according to the present embodiment. 
     The annotation list  560  is updated as the annotation that corresponds to the mark  523   a - 2  is added to the area  511   a  on the left side of the measurement and collection screen  502 . As a result, a memo saying “normal spike” is added to the annotation number “2.” 
     Every time a desired point or area on the signal waveforms is specified in the area  511  a during the measurement, the specified point is highlighted, and the annotation is displayed in the first display area  530  along the time axis  531 . In the area  511   b , the annotation is sequentially added to the annotation list  560 . 
     It is not always necessary to display an annotation number in the annotation list  560  and the area  511   a  where signal waveforms are displayed, and the display of an annotation number may be omitted. Any information can be used as identification information as long as the added annotation can be recognized by that information. For example, an attribute icon, attribute texts (e.g., “strong spike”), and time in the proximity of the time axis  531  may be displayed in association with each other. Further, a file number (i.e., the number displayed in the item “File” as illustrated in  FIG. 9 ) may be displayed along with the area  511   a.    
     When the stop key  539  (see  FIG. 8 ) is selected (touched or clicked) and the measurement is terminated, the highlighted portion specified in the second display areas  521  to  523  is stored in association with the signal waveform. The annotation that is displayed at the corresponding point in time in the first display area  530  is also stored in association with the annotation number and the time. Relevant information such as the counter value in the counter box  538  and the items in the annotation list  560  is also stored. By storing the above display information, even if the technician and the analyst are different, the analyst can easily recognize and analyze a problematic portion. 
       FIG. 10  is a flowchart of the measurement and collection processes performed by the information processing device  50 , according to the present embodiment. 
     The measurement and collection that is performed by the information processing device  50  according to the present embodiment below with reference to  FIG. 10 . 
     When “measurement and collection” is selected on the starting screen  501  as illustrated in  FIG. 4  (step S 11 ), the measurement is started, and the display is controlled in a synchronous manner along a time axis where the waveforms of a plurality of signals are equivalent to each other (step S 12 ). In the present embodiment, the term “a plurality of signal waveforms” includes both the signal waveform detected by a plurality of sensors of the same kind and the multiple signal waveforms detected by a plurality of various kinds of sensors. In the present embodiment, the waveforms of biomedical signals consist of the waveform of the magnetic signals obtained through a plurality of magnetic sensors from the right side of the head of a subject, the waveform of the magnetic signals obtained through a plurality of magnetic sensors from the left side of the head of the subject, and the waveform of the electric signals obtained through electrodes for measuring the electrical brain waves of the subject. However, no limitation is intended thereby. The sensors may be selected not just between the right and left groups of sensors, but may be selected from any part of the brain such as a parietal region, a frontal lobe, and a temporal lobe. When sensors at a parietal region are selected in “MEG Window Control  1 ” as illustrated in, for example,  FIG. 7 , the sensors other than sensors at a parietal region are selected in “MEG Window Control  2 .” 
     The information processing device  50  determines whether any designation is made as a point of interest or region of interest in the displayed signal waveform (step S 13 ). When such designation is made as a point of interest or a range of interest (YES in the step S 13 ), the display is controlled to highlight the designated point in the display areas of signal waveform (i.e., the second display areas  521  to  523 ), and to display the results of selection in a relevant point in time of the time-axis field (i.e., the first display area  530 ) (step S 14 ). The result of designation includes data indicating that the designation has been made or the identification information of the designation. Then, whether or not there is a request to input an annotation is determined at the same time as when the results of designation are displayed in the time-axis field or before or after the results of designation are displayed in the time-axis field (step S 15 ). When there is a request to input an annotation (YES in the step S 15 ), the input annotation is displayed in a relevant point in time of the time-axis field, and the input annotation is added to the annotation list so as to be displayed therein (step S 16 ). Then, whether or not a measurement termination command has been input is determined (step S 17 ). On the other hand, when no point of interest or range of interest is designated (NO in the step S 13 ) and when there is no request to input an annotation (NO in the step S 15 ), the process proceeds to a step S 17 , and whether or not the measurement is completed is determined. Steps S 13  to S 16  are repeated until the measurement is completed (YES in the S 17 ). 
     Due to the above information displaying method, the measurement and collection screen  502  can be provided in which the visibility of the signal data is high when signals are collected from a plurality of sensors. 
       FIG. 11  is a diagram illustrating a time-frequency analysis screen  601  according to the present embodiment. 
     The analyzing operations that are performed on the time-frequency analysis screen  601 , which is displayed on the information processing device  50 , are described below with reference to  FIG. 11 . 
     When an “analysis” key is touched or clicked on the starting screen  501  as described above with reference to  FIG. 4 , the analyzer  206  analyzes the sensor information (i.e., an electrical signal or magnetic signal) that is collected by the above measurement and collection processes that are performed on the measurement and collection screen  502 , and computes and obtains a biomedical signal that indicates the signal strength at varying points inside the brain (an example of a biological site or a source). As a method of calculating the signal strength, for example, spatial filtering is known in the art. However, no limitation is indicated thereby, and any other method may be adopted. When an “analysis” key is selected on the starting screen  501  as described above with reference to  FIG. 4 , the analysis display controller  202  controls the display device  107  to display the time-frequency analysis screen  601  as illustrated in  FIG. 11 . As illustrated in  FIG. 11 , an analyzing screen switching list  605 , a heat map  611 , a three-dimensional view  612 , a three-view head image  613 , a peak list  614 , and a replay control panel  615  are displayed the time-frequency analysis screen  601 . An object of the analysis and measurement that is performed using the time-frequency analysis screen  601  is to mark and display critical sites of the brain for human to live, such as a visual area, auditory area, somatosensory area, motor area, and a language area. A peak-list setting key  614   a  that is displayed on the right side of the peak list  614  is used to display a window to configure the conditions for a peak to be registered in the peak list  614 . How the conditions for a peak to be registered in the peak list  614  are configured by touching or clicking the peak-list setting key  614   a  will be described later in detail. The display and operation of the heat map  611 , the three-dimensional view  612 , the three-view head image  613 , the peak list  614 , and the replay control panel  615  will be described later in detail. 
     The analyzing screen switching list  605  is used to make a selection from among various kinds of analyzing screens. In addition to or in place of the time-frequency analysis screen  601  according to the present embodiment where analysis is performed in regard to time and frequency based on a biomedical signal, the analyzing screens selectable from the analyzing screen switching list  605  may include, for example, an analyzing screen where dipole estimation is performed to estimate or analyze a site indicative of epilepsy or the like based on a biomedical signal. In the present embodiment, analyzing operations on the time-frequency analysis screen  601  are described. 
     Some operations to be made on the heat map  611  of the time-frequency analysis screen  601  are described with reference to  FIG. 13  to  FIG. 18 . 
       FIG. 13  is a diagram illustrating a state where a specific position is designated on a heat map, according to the present embodiment. 
       FIG. 14  is a diagram illustrating a state where three peaks are indicated on a heat map from a peak list, according to the present embodiment. 
       FIG. 15  is a diagram illustrating a state where the display mode of each peak is changed on a heat map according to the data of each peak, according to the present embodiment. 
       FIG. 16  is a diagram illustrating a state where a specific area is designated on a heat map, according to the present embodiment. 
       FIG. 17  is a diagram illustrating a state where a plurality of specific areas are designated on a heat map, according to the present embodiment. 
       FIG. 18  is a diagram illustrating a state where another three-dimensional image and three-view head image are added to the time-frequency analysis screen  601 , according to the present embodiment. 
     Time-frequency decomposition is performed on the biomedical signals computed and obtained by the analyzer  206 , each of which indicates the signal strength at a position inside the brain, and as illustrated in  FIG. 11 , the heat map  611  is an figure in which the horizontal axis and the vertical axis indicate the time (i.e., the time elapsed since a triggering time) and the frequency, respectively, and the distribution of the signal strength of the biomedical signals, which is specified by the time and frequency, is expressed by color. In the example as illustrated in  FIG. 11 , the signal strength is indicated by the variations with reference to, for example, a prescribed reference value. In the present embodiment, a prescribed reference value is, for example, 0% as the average of the signal strength when no stimulus is given to a test subject. In the present embodiment, illustration is made based on the premise that the average of the signal strength varies between 0±100%. However, no limitation is intended thereby. When the average of the signal strength varies beyond 100%, the range in the illustration may be changed to, for example, 200%. Alternatively, for example, decibels (dB) may be adopted in place of the percentage (%) as in the heat map  611  as illustrated in  FIG. 12 , which is a diagram illustrating a heat map in which the range is expressed in decibels, according to embodiments of the present disclosure. For example, when some sort of stimulation is given to the test subject (for example, physical shock is given to the test subject, an arm of the test subject is moved, the test subject is made to listen to some spoken words, or the test subject is made to listen to a sound) at time 0 millisecond (ms), the heat map  611  indicates, at the later time, the state of activity of the brain after that stimulation is given to the test subject, and indicates, at the time earlier than the time 0 ms, the state of activity of the brain before that stimulation is given to the test subject. The display operation on the heat map  611  is controlled by the heat-map display control unit  211 . 
     As illustrated in  FIG. 13 , a desired position (point) on the heat map  611  can be specified as the analyst performs an operation or input (clicking or tapping operation) to the input unit  208 . As illustrated in  FIG. 13 , for example, the heat-map display control unit  211  controls the display to display the specified position like the specified point  621 . In  FIG. 13 , the specified point  621  is indicated by a white-colored rectangle. However, no limitation is intended thereby, and the specified point  621  may be indicated in any other display modes. 
     On the heat map  611  as illustrated in  FIG. 13 , the position specified by the operation of or input to the input unit  208  is indicated. However, no limitation is indicated thereby, and the heat map and some peak positions at the time and frequency that the item of peak data selected from among the peaks registered in the peak list  614  indicates may be displayed. For example, the top N peak positions with reference to the peak selected from the peak list  614  may be displayed on the heat map  611 .  FIG. 14  is a diagram illustrating an example in which the positions of the top three peaks are indicated, according to the present embodiment. How the peak positions are to be indicated may be determined based on the settings. For example, in addition to or in place of the above setting, the settings may be switched between the setting in which no peak is to be indicated or the setting in which peaks whose signal strength is equal to or higher than M are indicated. 
     As illustrated in  FIG. 15 , the display mode of the multiple peaks displayed on the heat map  611  may be changed according to the attribute information of those peaks.  FIG. 15  is a diagram illustrating an example in which a number is given to each of the indicated peaks and the colors of each portion in which a number is indicated are changed so as to be different from each other, according to the present embodiment. 
     When a particular position is specified on the heat map  611  as described above, the distribution of the signal strength of the biomedical signals of the time and frequency corresponding to the specified position is displayed as a heat map. Note that this heat map is different from the heat map on the heat map  611 . As illustrated in  FIG. 11 , for example, the distribution of the signal strength of the biomedical signals of the time and frequency corresponding to the specified position is displayed like sites  712   a - 1  to  712   a - 5  and  712   b - 1  to  712   b - 5  on the images of the brain in the three-dimensional view  612 , and the distribution of the signal strength of the biomedical signals of the time and frequency corresponding to the specified position is displayed like the sites  713   a - 1 ,  713   a - 2 ,  713   b ,  713   c , and  713   d  on the images of the brain in the three-view head image  613 . More specifically, the distribution of the signal strength of the biomedical signals of the time and frequency corresponding to the position specified on the heat map  611  is displayed as a red-to-blue heat map. 
     As illustrated in  FIG. 16 , an area on the heat map  611  can be specified by a dragging operation or swiping operation made by the analyst to the input unit  208 . As illustrated in  FIG. 16 , for example, the heat-map display control unit  211  controls the display to display the specified area like a specified area  622  in a rectangular shape having the dimension determined by dragging operation or the like. In  FIG. 16 , the specified area  622  is indicated by a rectangular region that is empty. However, no limitation is intended thereby. The shape of the specified area  622  may be any shape including a circular shape, indicated in any other display modes, and the specified area  622  may be indicated in any other display modes. 
     When a specific area is specified on the heat map  611  as described above, the distribution of the average of the signal strength of the biomedical signals of the time and frequency included in the specified area is displayed as a heat map. Note that this heat map is different from the heat map on the heat map  611 . As illustrated in  FIG. 11 , for example, the distribution of the signal strength of the biomedical signals of the time and frequency corresponding to the specified position is displayed like sites  712   a - 1  to  712   a - 5  and  712   b - 1  to  712   b - 5  on the images of the brain in the three-dimensional view  612 , and the distribution of the signal strength of the biomedical signals of the time and frequency corresponding to the specified position is displayed like the sites  713   a - 1 ,  713   a - 2 ,  713   b ,  713   c , and  713   d  on the images of the brain in the three-view head image  613 . 
     In addition to the specified area  622  that has already been specified, as illustrated in  FIG. 17 , an additional area may be specified like a specified area  623  by an additional operation made on the input unit  208  by the analyst (for example, a dragging operation by right-clicking or a new swiping operation). In such a case, as illustrated in  FIG. 18 , a three-dimensional view  612   a  and a three-view head image  613   a  are displayed as the three-dimensional image and three-view head image that correspond to the newly-specified area  623 , respectively. Then, the distribution of the average signal strength of the biomedical signals corresponding to the time and frequency included in the specified area  623  is displayed on the brain images of the three-dimensional view  612  and the three-view head image  613   a  as a heat map. Note that this heat map is different from the heat map on the heat map  611 . When the information about multiple specifying operations is received through the heat map  611 , the three-dimensional view  612  and the three-view head image  613  that correspond to the above information about specifying operations are displayed in descending order of time of receipt (in the direction from top to bottom).  FIG. 18  illustrates an example in which the specified area  622  is selected and then the specified area  623  is selected. Due to such manner of presentation, the analyst can easily and intuitively figure out the situation. Alternatively, when the information about multiple selecting operations is received through the heat map  611 , the three-dimensional view  612  and the three-view head image  613  that correspond to the above information about specifying operations are displayed in ascending order of time of receipt (in the direction from bottom to top). In such a configuration, the three-dimensional view  612  and the three-view head image  613  that correspond to the latest selected area are displayed directly below the heat map  611 . Accordingly, the shift of the line of vision of the analyzer to the heat map  611 , the three-dimensional view  612 , and the three-view head image  613  can be reduced. When a plurality of points are specified on the heat map  611 , not only areas such as the specified areas  622  and  623  but also a plurality of points such as the specified point  621  may be specified. When a plurality of positions (points or areas) are specified on the heat map  611  as described above, the multiple distributions of the signal strength of the biomedical signals of the time and frequency corresponding to the specified positions can be compared with each other. 
       FIG. 19  is a diagram illustrating the three-dimensional view  612  on the time-frequency analysis screen  601 , according to the present embodiment. 
       FIG. 20  is a diagram in which the state of the brain, which corresponds to the position designated on the heat map  611 , is displayed in the center on the three-dimensional view  612 , according to the present embodiment. 
       FIG. 21  is a diagram in which the state of the brain, which corresponds to the area designated on the heat map  611 , is displayed in the center on the three-dimensional view  612 , according to the present embodiment. 
       FIG. 22  is a diagram in which line segments are used to indicate to what time and frequency on the heat map  611  each one of the images of the brain displayed as the three-dimensional view  612  corresponds, according to the present embodiment. 
       FIG. 23  is a diagram in which rectangular areas are used to indicate to what time and frequency on the heat map  611  each one of the images of the brain displayed as the three-dimensional view  612  corresponds to, according to the present embodiment. 
       FIG. 24A  and  FIG. 24B  are diagrams illustrating how the display on the three-dimensional view  612  and the display of the rectangular regions on the heat map  611  move as the three-dimensional view  612  is dragged, according to the present embodiment. 
       FIG. 25A  and  FIG. 25B  are diagrams illustrating how the display on the three-dimensional view  612  and the display of the rectangular regions on the heat map  611  move as one of the brain images on the three-dimensional view  612  is clicked, according to the present embodiment. 
     Basic display operation of the three-dimensional view  612  on the time-frequency analysis screen  601  is described below with reference to  FIG. 19  to  FIG. 25B . 
     As illustrated in  FIG. 19 , the three-dimensional view  612  is a view of the three-dimensional images (3D image) of the brain from a prescribed viewpoint, and the position (point or area) designated on the heat map  611  or the signal strength of the biomedical signal that corresponds to the peak selected from the peak list  614  is superimposed on the three-dimensional view  612  as a heat map. As illustrated in  FIG. 19 , in the same row of the three-dimensional view  612 , three-dimensional images of a brain from the same viewpoint are displayed. In the example as illustrated in  FIG. 19 , the three-dimensional images of the brain as displayed in the display area  612 - 1  in the upper row of the three-dimensional view  612  are viewed from a viewpoint on the left side of the brain, and the three-dimensional images of the brain as displayed in the display area  612 - 2  in the lower row of the three-dimensional view  612  are viewed from a viewpoint on the right side of the brain. The display operation of the three-dimensional view  612  is controlled by the three-dimensional display control unit  212 . 
     As illustrated in  FIG. 19 , the three-dimensional view  612  consists of three-dimensional images of a brain viewed from two viewpoints, and such three-dimensional images of a brain are displayed in two rows. However, no limitation is intended thereby, and three-dimensional images of a brain may be displayed in any other numbers of rows. The number of rows may be changed as desired. For example, when the language area of the brain is to be measured, the difference between right and left sides of the brain is crucial information. For this reason, the three-dimensional images of the brain that are viewed from two different viewpoints, consisting of a viewpoint on the right side of the brain and a viewpoint on the left side of the brain, are to be displayed in two rows. Some example associations between an object to be measured and desired viewpoints are depicted in a first table given below. The object to be measured includes the stimulation given to a test subject during the measurement (such stimulation is given by a stimulator and the rows in No. 1 to No. 4 of the first table are relevant) and the motion made by the test subject (see No. 5 of the first table), and indicates the items from which selection is to be made on the measurement and collection screen  502  when collection is to be performed. Once the object to be measured is selected, the three-dimensional view  612  of the brain that is viewed from the corresponding viewpoint is displayed. The term viewpoint indicates the direction with the origin located at the front of the test subject. As a matter of course, the number of rows may be edited in a separate manner. The three-dimensional view  612  as illustrated in  FIG. 19  corresponds to No. 2 in the first table. For the sake of explanatory convenience, it is assumed in the following description that the three-dimensional view  612  consists of two rows (images viewed from two viewpoints). 
     
       
         
           
               
               
               
             
               
                 FIRST TABLE 
               
               
                   
               
               
                   
                 OBJECT TO BE 
                   
               
               
                 No. 
                 MEASURED 
                 VIEWPOINT 
               
               
                   
               
             
            
               
                 1 
                 VISUAL 
                 REAR (VIEWPOINT TO VIEW 
               
               
                   
                 PERCEPTION 
                 OCCIPITAL REGION FROM BACK 
               
               
                   
                   
                 OF OCCIPITAL REGION) ONE ROW 
               
               
                 2 
                 AUDITORY 
                 RIGHT (VIEWPOINT TO VIEW RIGHT 
               
               
                   
                 SENSATION 
                 TEMPORAL REGION FROM OUTSIDE 
               
               
                   
                   
                 RIGHT TEMPORAL REGION) AND 
               
               
                   
                   
                 LEFT (VIEWPOINT TO VIEW LEFT 
               
               
                   
                   
                 TEMPORAL REGION FROM OUTSIDE 
               
               
                   
                   
                 LEFT TEMPORAL REGION) ONE ROW 
               
               
                   
                   
                 FOR RIGHT, ONE ROW FOR LEFT 
               
               
                 3 
                 LANGUAGE 
                 RIGHT AND LEFT 
               
               
                 4 
                 SOMATIC 
                 TOP 
               
               
                   
                 SENSATION 
               
               
                 5 
                 MOTION 
                 TOP 
               
               
                   
               
            
           
         
       
     
     When the specified point  621  is specified on the heat map  611  as illustrated in  FIG. 20 , the three-dimensional display control unit  212  sets the time that corresponds to the specified point  621  to the center of the display area of the three-dimensional view  612 , and controls the display to display on the three-dimensional view  612  the heat map of the signal strength on the brain at the times before and after the time that corresponds to the specified point  621 . In the example as illustrated in  FIG. 20 , the time 560 ms is specified on the heat map  611 . Accordingly, the intervals at which the brains are displayed are set to 5 ms, and the images of the brain at 550, 555, 560, 565, and 570 ms around 560 ms are displayed on the three-dimensional view  612 . However, no limitation is indicated thereby, and the intervals at which the images of the brain are displayed may be edited to, for example, 10 ms or 25 ms. 
     As illustrated in  FIG. 21 , when an area (i.e., the specified area  622 ) is specified on the heat map  611 , the heat map of signal strength where the signal strength within that selected area is averaged may be displayed on the three-dimensional view  612 . In such a configuration, the times of the neighboring three-dimensional images displayed on the three-dimensional view  612  may be adjusted according to the selected range of time. As illustrated in  FIG. 21 , for example, when the range of time of the specified area  622  is between 450 and 600 ms and the intervals at which the neighboring three-dimensional images are displayed on the three-dimensional view  612  is set to 150 ms, the range of time of the three-dimensional image that is displayed in the center of the three-dimensional view  612  is 450 to 600 ms. Moreover, the range of time of the three-dimensional image on the left side of the three-dimensional image in the center of the three-dimensional view  612  is 300 to 450 ms, and the range of time of the three-dimensional image on the right of the three-dimensional image in the center of the three-dimensional view  612  is 600 to 750 ms. The heat map that is displayed on each three-dimensional image indicates the average in each range of time. 
     The association between the positions or ranges on the heat map  611  and the multiple three-dimensional images on the three-dimensional view  612  is described below with reference to  FIG. 22  and  FIG. 23 . First of all, as illustrated in  FIG. 22 , when a specified point  621 - 1  is specified on the heat map  611 , the three-dimensional image of the brain, which corresponds to the time and frequency of the specified point  621 - 1 , is displayed on the three-dimensional view  612 . In this configuration, the three-dimensional images of the brain at the times before and after the time that corresponds to the specified point  621 - 1  are displayed around the above three-dimensional image of the brain. In the example as illustrated in  FIG. 22 , the images of the brain that correspond to five points in time are displayed. Accordingly, the heat-map display control unit  211  control the display to display the points that correspond to the respective points in time of the brain on the heat map  611  as corresponding points  621 - 2  to  621 - 5 , respectively. In such a configuration, the positions in frequency of the corresponding points  621 - 2  to  621 - 5  are made consistent with the position in frequency of the specified point  621 - 1 . Further, as illustrated in  FIG. 22 , the heat-map display control unit  211  controls the display to display line segments  631 - 1  to  631 - 5  that connect the specified point  621 - 1  and the corresponding points  621 - 2  to  621 - 5  on the heat map  611  and the corresponding three-dimensional images of the brain on the three-dimensional view  612 . Due to this configuration, to what positions on the heat map  611  the states of the brain as displayed on the three-dimensional view  612  correspond to can be checked instantly. In the example as illustrated in  FIG. 22 , line segments are adopted. However, no limitation is indicated thereby, and any other ways of association may be adopted. For example, the marks of the specified point  621 - 1  and the corresponding points  621 - 2  to  621 - 5  may be associated with the colors of the background of the images of the brain in the three-dimensional view  612 . In such a case, the specified point  621 - 1  that is specified by the analyst is to be displayed in a mode distinguishable from the corresponding points  621 - 2  to  621 - 5 . 
     When a specified area  622 - 1  is specified as a specific area on the heat map  611 , firstly, as illustrated in  FIG. 23 , the three-dimensional image of the brain, which corresponds to the time and frequency on the specified area  622 - 1 , is displayed in the three-dimensional view  612 . In this configuration, the three-dimensional images of the brain at the ranges of time before and after the range of time that corresponds to the specified area  622 - 1  are displayed around the above three-dimensional image of the brain. In the example as illustrated in  FIG. 23 , the images of the brain that correspond to five ranges of time are displayed. Accordingly, the heat-map display control unit  211  control the display to display the ranges that correspond to the respective ranges of time of the brain on the heat map  611  as related areas  622 - 2  to  622 - 5 , respectively. In such a case, the specified area  622 - 1  that is specified by the analyst is to be displayed in a mode distinguishable from the related areas  622 - 2  to  622 - 5 . For example, the color of the rectangular frame of the specified area  622 - 1  may be differentiated from the other frames. Further, as illustrated in  FIG. 23 , the three-dimensional display control unit  212  controls the display to display rectangles similar to the specified area  622 - 1  and the related areas  622 - 2  to  622 - 5  on the heat map  611  to surround the corresponding three-dimensional images of the brain in the three-dimensional view  612 . Due to this configuration, to what ranges on the heat map  611  the states of the brain as displayed in the three-dimensional view  612  correspond to can be checked instantly. When the specified area  622 - 1  is specified as a specific area on the heat map  611 , the frames of the specified area  622 - 1  and the related areas  622 - 2  to  622 - 5  may be displayed, and frames  722 - 1  to  722 - 5  and the heat maps may be displayed in the three-dimensional view  612 . 
     Operations where the display in the three-dimensional view  612  is moved to the right and left sides when a dragging operation, swiping operation, or a cursor-movement key operation is performed in the three-dimensional view  612  are described below with reference to  FIG. 24A ,  FIG. 24B ,  FIG. 25A , and  FIG. 25B .  FIG. 24A  and  FIG. 24B  are diagrams illustrating a state in which the three-dimensional images in the three-dimensional view  612  are moved to the right side by a dragging operation, swiping operation, or a cursor-movement key operation performed in the three-dimensional view  612 , according to the present embodiment. In such a case, as illustrated in  FIG. 24A  and  FIG. 24B , as a result of the movement, the display of time is updated in accordance with the brains that are currently displayed, and a rectangle is displayed to indicate that the three-dimensional image of the brain displayed in the center of the three-dimensional view  612  is selected. Further, the three-dimensional display control unit  212  moves the display of the specified area  622 - 1  and the related areas  622 - 2  to  622 - 5  on the heat map  611  in accordance with the movement of the three-dimensional images in the three-dimensional view  612 . 
     As illustrated in  FIG. 25A  and  FIG. 25B , when one of the three-dimensional images other than the three-dimensional image in the center of the three-dimensional view  612  is clicked or tapped by the analyst, the operated three-dimensional image of the brain moves to the center of the three-dimensional view  612 . In the actual implementation, only the overlapping heat map may be moved and the positions of the images of the brain may remain the same. In such a case, as illustrated in  FIG. 25A  and  FIG. 25B , as a result of the movement, the display of time is updated in accordance with the brains that are currently displayed, and a rectangle is displayed to indicate that the three-dimensional image of the brain displayed in the center of the three-dimensional view  612  is selected. Further, the three-dimensional display control unit  212  moves the display of the specified area  622 - 1  and the related areas  622 - 2  to  622 - 5  on the heat map  611  in accordance with the movement of the three-dimensional images in the three-dimensional view  612 . 
     As described above, the display in the three-dimensional view  612  can be moved as desired. Due to such a configuration, the changes in the state of the brain across the time can quickly be recognized. 
     Operations in which the viewpoint of a desired three-dimensional image of the three-dimensional view  612  on the time-frequency analysis screen  601  is changed are described below with reference to  FIG. 26A  to  FIG. 31 . 
       FIG. 26A ,  FIG. 26B , and  FIG. 26C  are diagrams illustrating how the viewpoints of all brain images in same row are changed when one of the viewpoints of the brain displayed in the three-dimensional view  612  is changed, according to the present embodiment. 
       FIG. 27A ,  FIG. 27B , and  FIG. 27C  are diagrams illustrating how the viewpoints of all the brain images in all the rows are changed when one of the viewpoints of the brain displayed in the three-dimensional view  612  is changed, according to the present embodiment. 
       FIG. 28A ,  FIG. 28B , and  FIG. 28C  are diagrams illustrating in detail how the viewpoint is changed in  FIG. 27A ,  FIG. 27B , and  FIG. 27C , according to the present embodiment. 
       FIG. 29A ,  FIG. 29B , and  FIG. 29C  are another set of diagrams illustrating how the viewpoints of all the brain images in all the rows are changed when one of the viewpoints of the brain displayed in the three-dimensional view  612  is changed, according to the present embodiment. 
       FIG. 30A ,  FIG. 30B , and  FIG. 30C  are diagrams illustrating the details of how the viewpoint is changed as in  FIG. 29A ,  FIG. 29B , and  FIG. 29C , according to the present embodiment. 
       FIG. 31  is a diagram illustrating a state in which a comment is added to the three-dimensional view  612 , according to the present embodiment. 
     The viewpoint of the brains that are displayed as three-dimensional images in the three-dimensional view  612  can be changed as manipulated by the analyst (for example, a dragging operation or a swiping operation). Some patterns of a method of reflecting the changes made in the viewpoint of a specific three-dimensional image of the brain in the three-dimensional view  612 , in the other three-dimensional images, are described below. 
     Firstly, cases in which the viewpoint of the other three-dimensional images in the same row is changed in a similar manner when the viewpoint of a specific three-dimensional images is changed are described. As illustrated in  FIG. 26A , it is assumed that the analyst has performed an operation on the three-dimensional view  612  displayed in two rows to change the viewpoint of the three-dimensional image at the right end (such a three-dimensional image may be referred to as a target three-dimensional image in the following description) from among the multiple three-dimensional images of the brain as displayed in the display area  612 - 1 . In such a case, as illustrated in  FIG. 26B , as manipulated by the analyst, the three-dimensional display control unit  212  changes the viewpoint of the target three-dimensional images with the viewpoint from the left side of the brain so as to display the three-dimensional images of the brain viewed from a rear side. In so doing, the viewpoint of the heat maps that are superimposed on the images of the brain is also changed in a similar manner. Then, as illustrated in  FIG. 26C , the three-dimensional display control unit  212  changes the viewpoint of the other three-dimensional images of the brain in the same row as the target three-dimensional images (in the display area  612 - 1 ) in a similar manner to the target three-dimensional image. Due to this configuration, the changes that are made in the viewpoint of a specific three-dimensional image (i.e., the target three-dimensional image) are automatically reflected in the other three-dimensional images in the same row. Accordingly, the operability or efficiency improves, and the changes in activity among the images of the brain that viewed from the same viewpoint and are temporally close to each other can easily be checked. When the analyst wishes to change the viewpoint of a three-dimensional image, for example, he or she may manipulate mouse to move the cursor onto the three-dimensional image whose viewpoint is to be changed, and may perform, for example, dragging or clicking operation. Alternatively, the analyst may designate a parameter in a pop-up window. 
     Secondly, cases in which the viewpoint of the other three-dimensional images is changed in a similar manner when the viewpoint of a specific three-dimensional images is changed are described. As illustrated in  FIG. 27A , it is assumed that the analyst has performed an operation on the three-dimensional view  612  displayed in two rows to change the viewpoint of the target three-dimensional image at the right end from among the multiple three-dimensional images of the brain as displayed in the display area  612 - 1 . In such a case, as illustrated in  FIG. 27B , as manipulated by the analyst, the three-dimensional display control unit  212  changes the viewpoint of the target three-dimensional images with the viewpoint from the left side of the brain so as to display the three-dimensional images of the brain viewed from a rear side. Then, as illustrated in  FIG. 27C , the three-dimensional display control unit  212  changes the viewpoint of the other three-dimensional images of the brain in the same row as the target three-dimensional images (in the display area  612 - 1 ) in a similar manner to the target three-dimensional image. In other words, the three-dimensional display control unit  212  changes the viewpoint of the other three-dimensional images of the brain as displayed in the display area  612 - 1  on the left side of the brain as illustrated in  FIG. 28A  so as to display the three-dimensional images of the brain viewed from a rear side, as illustrated in  FIG. 28B . Further, as illustrated in  FIG. 27C , the three-dimensional display control unit  212  changes the viewpoint of the three-dimensional images in the other row (display area  612 - 2 ) different from the row of the target three-dimensional image, in a similar manner to the target three-dimensional image. In other words, as illustrated in  FIG. 28C , the three-dimensional display control unit  212  changes the viewpoint of the three-dimensional images of the brain as displayed in the display area  612 - 2  on the right side of the brain as illustrated in  FIG. 28A , so as to display the three-dimensional images of the brain viewed from a front side. If the processing capability is well above the actual load, the processes in  FIG. 28A  to  FIG. 28C  may be performed at high speed, as if the viewpoints of all the images of the brain appear to change at the same time. On the other hand, if the processing capability is poor, the viewpoints of the other images may be changed when the change in viewpoint is determined (i.e., the timing at which the user releases a key of the mouse when the viewpoint is changed, for example, by rotating the image of the brain by dragging operation) after only the viewpoint of the image that is moved by the user is changed. In so doing, the respective viewpoints of the heat maps that are superimposed on the images of the brain are also changed in a similar manner. Due to this configuration, the changes that are made in the viewpoint of a specific three-dimensional image (i.e., the target three-dimensional image) are automatically reflected in the other three-dimensional images in the same row and the other rows. Accordingly, the operability or efficiency improves, and the changes in activity among the images of the brain that are temporally close to each other can easily be checked. 
     Furthermore, cases are described in which, when the viewpoint of a specific three-dimensional images is changed, the viewpoint of the other three-dimensional images in the same row is changed in a similar manner and the viewpoint of the three-dimensional images in the other row is changed in a corresponding manner. More specifically, the viewpoint is changed to be symmetrical to the center plane of the brain (symmetry plane). As illustrated in  FIG. 29A , it is assumed that the analyst has performed an operation on the three-dimensional view  612  displayed in two rows to change the viewpoint of the target three-dimensional image at the right end from among the multiple three-dimensional images of the brain as displayed in the display area  612 - 1 . In such a case, as illustrated in  FIG. 29B , as manipulated by the analyst, the three-dimensional display control unit  212  changes the viewpoint of the target three-dimensional images with the viewpoint from the left side of the brain, so as to display the three-dimensional images of the brain viewed from a left-frontal side. Then, as illustrated in  FIG. 29C , the three-dimensional display control unit  212  changes the viewpoint of the other three-dimensional images of the brain in the same row as the target three-dimensional images (in the display area  612 - 1 ) in a similar manner to the target three-dimensional image. In other words, the three-dimensional display control unit  212  changes the viewpoint of the other three-dimensional images of the brain as displayed in the display area  612 - 1  on the left side of the brain as illustrated in  FIG. 30A  so as to display the three-dimensional images of the brain viewed from a left-frontal side, as illustrated in  FIG. 30B . Further, as illustrated in  FIG. 29C , the three-dimensional display control unit  212  changes the viewpoint of the three-dimensional images in the other row (display area  612 - 2 ) different from the row of the target three-dimensional image, in a corresponding manner to the target three-dimensional image. In other words, the three-dimensional display control unit  212  changes the viewpoint of the three-dimensional images of the brain as displayed in the display area  612 - 2  on the right side of the brain as illustrated in  FIG. 30A  to be symmetrical to the center plane of the brain (symmetry plane) as illustrated in  FIG. 30C . In other words, the three-dimensional display control unit  212  changes the viewpoint so as to display the three-dimensional images of the brain viewed from a right-frontal side of the brain. In so doing, the respective viewpoints of the heat maps that are superimposed on the images of the brain are also changed in a similar manner. Due to this configuration, the changes that are made in the viewpoint of a specific three-dimensional image (i.e., the target three-dimensional image) are automatically reflected in the other three-dimensional images in the same row. Moreover, corresponding changes in viewpoint are reflected in the three-dimensional images in the other rows. Accordingly, the operability or efficiency improves. Furthermore, the images of the brain in multiple rows can be compared with each other, and thus the changes in activity among the images of the brain that are viewed from a corresponding viewpoint and are temporally close to each other can be checked. 
     Any one of the three methods of reflecting changes in other three-dimensional images as described above may be adopted, or which one of these methods is to be adopted to reflect changes may be switched by editing the settings. 
     As described above with reference to  FIG. 26A  to  FIG. 30C , the first target three-dimensional image that is to be manipulated by the analyst to change its viewpoint in the present embodiment is the three-dimensional image at the right end of the display area  612 - 1 . However, no limitation is intended thereby, and any one of the three-dimensional images in the display area  612 - 1  or the display area  612 - 2  may be operated. A group of three-dimensional images included in the display area  612 - 1  and a group of three-dimensional images included in the display area  612 - 2  correspond to shape images and third images, respectively. 
     In the above description, the viewpoint of a specific three-dimensional image of the brain in the three-dimensional view  612  is changed, and operations in which such a change in viewpoint is reflected in other three-dimensional images are described. However, no limitation is indicated thereby, and the display mode that is to be changed for a three-dimensional image is not limited to viewpoint. For example, the display mode that is to be changed for a three-dimensional image may be, for example, changes in size, changes in brightness, or changes in transparency. Such changes may be reflected in other three-dimensional images without departing from the spirit or scope of the disclosure of the above changes in viewpoint. 
     After some changes are made on the three-dimensional images in the three-dimensional view  612  as described above, as illustrated in  FIG. 31 , the analyst may operate the input unit  208  to add a memo (for example, a comment  635  as depicted in  FIG. 31 ) onto a specific three-dimensional image. Due to such a configuration, comments on an active site of the brain that the analyst (for example, a doctor) is concerned about can be recorded in association with the relevant three-dimensional image, and can be applied to, for example, neurosurgery or a conference on such disorder of the brain. 
     Basic display operation of the three-view head image  613  on the time-frequency analysis screen  601  is described below with reference to  FIG. 32  to  FIG. 38D . 
       FIG. 32  is a diagram illustrating the three-view head image  613  on the time-frequency analysis screen  601 , according to the present embodiment. 
       FIG. 33  is a diagram illustrating a cut model that is displayed as a three-dimensional image on the three-view head image  613 , according to the present embodiment. 
       FIG. 34  is a diagram illustrating the peak selected from the peak list  614  in the three-view head image  613 , according to the present embodiment. 
       FIG. 35  is a diagram illustrating the peak selected from the peak list  614  and the peaks that are temporally close to each other around the selected peak, in the three-view head image  613 , according to the present embodiment. 
       FIG. 36  is a diagram illustrating a state in which the peak selected from the peak list  614  and the peaks that are temporally close to each other around the selected peak are indicated with varying colors, in the three-view head image  613 , according to the present embodiment. 
       FIG. 37  is a diagram illustrating a state in which a result of dipole estimation is superimposed on the three-dimensional image  644  of the three-view head image  613 , according to the present embodiment. 
       FIG. 38A ,  FIG. 38B ,  FIG. 38C , and  FIG. 38D  are diagrams each illustrating a state in which a result of measuring a plurality of objects (heat map) is superimposed on the three-dimensional image  644  of the three-view head image  613 , according to the present embodiment. 
     As illustrated in  FIG. 32 , the three-view head image  613  includes the three-dimensional image  644  and three sectional views viewed from a desired point of the brain from three directions (such three sectional views may be collectively referred to as a three-view image in the following description). In the example as illustrated in  FIG. 32 , the three-view head image  613  includes a sectional view  641  orthogonal to the forward and backward directions of the brain, a sectional view  642  orthogonal to the right and left directions of the brain, and a sectional view  643  orthogonal to the up-and-down directions of the brain as the three sectional views viewed from a desired point of the brain in three directions. In the sectional view  641 , a reference line  645   a  and a reference line  645   b  that pass through the above-desired point are drawn. In the sectional view  642 , the reference line  645   a  and a reference line  645   c  that pass through the above-desired point are drawn. In the sectional view  643 , the reference line  645   b  and a reference line  645   d  that pass through the above-desired point are drawn. A heat map that indicates the distribution of the signal strength of the biomedical signal of the time and frequency that correspond to the position (point or area) designated on the heat map  611 , which is different from the heat map  611 , is superimposed on each one of the sectional views  641  to  643 . The display operation on the three-view head image  613  is controlled by the sectional-view control unit  213 . 
     The reference line  645   a  defines the position in the up-and-down directions with reference to the above-desired point of the brain, and thus is drawn as a continuous line across the sectional view  641  and the sectional view  642 . The reference line  645   b  defines the position in the right and left directions with reference to the above-desired point of the brain, and thus is drawn as a continuous line across the sectional view  641  and the sectional view  643 . On the sectional view  642 , the reference line  645   c  defines the position in the forward and backward directions with reference to the above-desired point of the brain. On the sectional view  643 , the reference line  645   d  defines the position in the forward and backward directions with reference to the above-desired point of the brain. The sectional views  641  to  643  in the three-view head image  613  are arranged as above as illustrated in  FIG. 32  because the reference line  645   a  and the reference line  645   b  can be drawn in a continuous manner across a plurality of sectional views. However, no limitation is intended thereby, and the sectional views  641  to  643  may be arranged in any desired manner. In such a configuration, a reference line that passing through a desired point of the brain may be drawn in each one of the sectional views. Alternatively, no reference line may be drawn in the sectional views. In such a configuration, for example, a mark that indicates the desired point of the brain may be displayed on each one of the sectional views. 
     The three-dimensional image  644  is a three-dimensional image of the brain, and as will be described later, the viewpoints of the three-dimensional images of the brain that are drawn in the three-dimensional view  612  are changed in accordance with the operation made to the three-dimensional image  644 . A heat map that indicates the distribution of the signal strength of the biomedical signal of the time and frequency that correspond to the position (point or area) designated on the heat map  611 , which is different from the heat map  611 , is superimposed on the three-dimensional image  644 . Note also that the function of the three-dimensional image  644  is not limited to display a three-dimensional image of the brain viewed from a desired point of the brain. For example, as illustrated in  FIG. 33 , the three-dimensional image  644  may be a cut-model image obtained by extracting a partial image of the brain in three-dimensional directions around the position of the brain specified in the three-view head image  613 . 
     The peak that is selected from among the peaks registered in the peak list  614  is identified on the three-view head image  613  as illustrated in  FIG. 32 , and as illustrated in  FIG. 34 , a peak point  646  that indicates the above-selected peak may be displayed on the three-dimensional image  644 . For example, the top N peak positions with reference to the peak selected from the peak list  614  may be displayed on the three-dimensional image  644 .  FIG. 35  is a diagram illustrating an example in which the positions of the top three peaks (i.e., the peak points  646 ,  646   a , and  646   b ) are indicated, according to the present embodiment. Alternatively, the peaks at times before and after the peak selected from the peak list  614  may be displayed in  FIG. 35  as the peak points  646 ,  646   a , and  646   b  in place of the above top three peaks. In other words, the track of the peaks may be displayed. How the peak positions are to be indicated may be determined based on the settings. For example, in addition to or in place of the above setting, the settings may be switched between the setting in which no peak is to be indicated or the setting in which peaks whose signal strength is equal to or higher than M are indicated. 
     As illustrated in  FIG. 36 , the display mode of the multiple peaks displayed on the three-dimensional image  644  may be changed according to the attribute information of those peaks.  FIG. 36  is a diagram illustrating an example in which the colors of the indicated peaks are changed so as to be different from each other, according to the present embodiment. 
     As illustrated in  FIG. 37 , the sectional-view control unit  213  may control the display to superimpose a dipole  647  that is obtained as a result of dipole estimation on the three-dimensional image  644 , in, for example, a different analyzing screen. Due to such a configuration, the relative positions of the heat map on the three-dimensional image  644  that indicates sites to be conserved and the dipole that indicates the affected sites (target sites) can be figured out, and such information can be used for, for example, surgery. 
     On one of the sectional views of the three-view head image  613 , a desired point of the brain in the three-dimensional space can be specified by a clicking or tapping operation performed on the input unit  208  by the analyst. Once a particular position is specified on the three-view images as described above, the distribution of the signal strength of the biomedical signals of the time and frequency corresponding to the specified position is reflected in the heat map  611 . 
     On one of the sectional views of the three-view head image  613 , a specific area of the brain in the three-dimensional space can be designated by a dragging operation or swiping operation made by the analyst to the input unit  208 . Once a desired area is specified on the three-view images as described above, the distribution of the average signal strength of the biomedical signals of the time and frequency corresponding to the specified area is reflected in the heat map  611 . 
     Alternatively, the analyst may switch the sectional views (slices) of the three-view image without specifying a desired point or area. In so doing, for example, the analyst may operate the center wheel of a mouse that serves as the input unit  208  to switch the sectional views (slices) of the three-view image. In such a configuration, the reference lines that are drawn in a three-view image (for example, the reference lines  645   a  to  645   d  as illustrated in  FIG. 37 ) indicate a specified position of the brain. For this reason, when the sectional views (slices) are switched, the reference lines are hidden from view. 
     In the heat map that is drawn on the three-dimensional image  644  (and the three-view images), which is a contour map that indicates the differences in signal strength, results of stimulation such as activation at varying sites of the brain may be superimposed on top of one another. For example, after a result of performing language stimulation during the measurement and a result of performing visual stimulation during the measurement are obtained, as illustrated in  FIG. 38C , the sectional-view control unit  213  may superimpose a heat map where the language area is activated as illustrated in  FIG. 38A  and a heat map where the visual area is activated as illustrated in  FIG. 38B  on top of one another. Due to such a configuration as above, it becomes identifiable as illustrated in  FIG. 38C  that the sites indicated on the heat map where superimposition has been performed are sites to be conserved. Such superimposition may be implemented as follows. Assuming that the currently-displayed result of measurement indicates the language area, it may be configured such that a different result of measurement (for example, the result of measurement indicating the visual area) is selectable from a menu. When superimposition is to be performed, the reaction time to the stimulation may vary depending on the object. In view of such circumstances, if the time lag is configurable when an object is added, superimposition can be performed more precisely. Further, the three-dimensional image as illustrated in  FIG. 38C , which is obtained as a result of superimposing a heat map on a three-dimensional image of the brain, may be highlighted in an inverse manner as illustrated in  FIG. 38D . Due to this configuration, a removable site, which is not among the sites to be conserved, can be indicated in the reversed manner. 
     In the present embodiment, the sectional view in the three-view head image  613  includes three cross sections taken from three different directions. However, no limitation is intended thereby, and the sectional view in the three-view head image  613  may be a single cross section taken from one specific direction or two or four or more cross sections taken from different directions. 
     With reference to  FIG. 39  to  FIG. 48 , operations in the time-frequency analysis screen  601  are described in which the changes in viewpoint made on the three-dimensional image  644  of the three-view head image  613  are reflected in the three-dimensional images of the three-dimensional view  612 . 
       FIG. 39  is a diagram illustrating a state before the viewpoint is changed for the three-dimensional image  644  of the three-view head image  613 , according to the present embodiment. 
       FIG. 40  is a diagram illustrating a dialog box displayed when the viewpoint of the three-dimensional image  644  of the three-view head image  613  is changed, according to the present embodiment. 
       FIG. 41  is a diagram illustrating a setting in which the changes in viewpoint made on the three-dimensional image  644  are applied to the viewpoint of the three-dimensional images in the first row of the three-dimensional view  612 , according to the present embodiment. 
       FIG. 42  is a diagram illustrating a state in which the changes in viewpoint of the three-dimensional image  644  in the three-view head image  613  are applied to the viewpoint of the three-dimensional images in the first row of the three-dimensional view  612 , according to the present embodiment. 
       FIG. 43  is a diagram illustrating a setting in which the changes in viewpoint made on the three-dimensional image  644  are reflected in the three-dimensional images in the first and second rows of the three-dimensional view  612 , according to the present embodiment. 
       FIG. 44  is a diagram illustrating a state in which the changes in the viewpoint of the three-dimensional image  644  of the three-view head image  613  are reflected in the first and second rows of the three-dimensional view  612 , according to the present embodiment. 
       FIG. 45  is a diagram illustrating a setting in which the changes in viewpoint made on the three-dimensional image  644  are symmetrically reflected in the three-dimensional images in the first and second rows of the three-dimensional view  612 , according to the present embodiment. 
       FIG. 46  is a diagram illustrating a state in which the changes in the viewpoint of the three-dimensional image  644  of the three-view head image  613  are symmetrically reflected in the three-dimensional images in the first and second rows of the three-dimensional view  612 , according to the present embodiment. 
       FIG. 47  is a diagram illustrating a setting in which new three-dimensional images in which the changes in viewpoint made on the three-dimensional image  644  are reflected are added to the three-dimensional view  612  in a separate row, according to the present embodiment. 
       FIG. 48  is a diagram illustrating a state in which new three-dimensional images in which the changes in viewpoint made on the three-dimensional image  644  of the three-view head image  613  are reflected are added to the three-dimensional view  612  in a separate row, according to the present embodiment. 
     In a similar manner to the three-dimensional view  612 , the viewpoint of the image of the brain displayed on the three-dimensional image  644  of the three-view head image  613  can be changed as manipulated by the analyst (for example, a dragging operation or a swiping operation). In such cases, the changes in the viewpoint of the brain in the three-dimensional image  644  may be reflected in the viewpoint of the three-dimensional images of the brain displayed in the three-dimensional view  612 . Some patterns of reflection methods or application methods are described below. 
     Once the three-dimensional image  644  of the three-view head image  613  displayed on the time-frequency analysis screen  601 , as illustrated in  FIG. 39 , is manipulated by the analyst (for example, a dragging operation or a swiping operation), the sectional-view control unit  213  controls the display to display the dialog box  650  as illustrated in  FIG. 40 . The dialog box  650  appears when the viewpoint of the brain in the three-dimensional image  644  is changed, and is a window used to determine how such changes in viewpoint are to be reflected in the three-dimensional view  612 . For example, when a key “Do not make changes in three-dimensional view” is clicked or tapped in the present embodiment, the viewpoint of the three-dimensional images in the three-dimensional view  612  is not changed. In the present embodiment, as illustrated in  FIG. 40 , it is assumed that the analyst changes the viewpoint of the three-dimensional image  644  viewed from the viewpoint on the left side of the brain so as to display the three-dimensional images of the brain viewed from a rear side. 
     Firstly, as illustrated in  FIG. 41 , a case is described in which the key “Reflect changes in row of three-dimensional view” in the dialog box  650  is clicked or tapped. In response to this operation, the sectional-view control unit  213  controls the display to display a dialog box  651  as illustrated in  FIG. 41  to determine how such changes in viewpoint are to be reflected in the three-dimensional view  612 . As illustrated in  FIG. 41 , the analyst selects the first row of the three-dimensional view  612  as the row in which changes are to be reflected and then the selects “Apply same viewpoint to three-dimensional images” in the dialog box  651 . In such a case, as illustrated in  FIG. 42 , the three-dimensional display control unit  212  controls the display to display the three-dimensional images in the first row (upper row) of the three-dimensional view  612  to have the viewpoint same as the changed viewpoint of the three-dimensional image  644 . 
     Next, a case is described in which, after the viewpoint is changed as illustrated in  FIG. 40 , the analyst clicks or taps the key “Reflect changes in row of three-dimensional view” in the dialog box  650  as illustrated in  FIG. 43 , and the analyst selects the first and second rows of the three-dimensional view  612  as the row in which changes are to be reflected and then selects “Change viewpoints of three-dimensional images accordingly” in the dialog box  651 . In such a case, as illustrated in  FIG. 44 , the three-dimensional display control unit  212  controls the display to reflect the changes in viewpoint made on the three-dimensional image  644  in the three-dimensional images in the first row of the three-dimensional view  612 , which originally have the same viewpoint as the three-dimensional image  644 . In other words, as illustrated in  FIG. 44 , changes are reflected so as to display the three-dimensional images of the brain viewed from a rear side. Further, as illustrated in  FIG. 44 , the three-dimensional display control unit  212  controls the display to reflect the changes in viewpoint made on the three-dimensional image  644  in the three-dimensional images in the second row of the three-dimensional view  612 , which originally have the viewpoint on the right side of the brain. In other words, as illustrated in  FIG. 44 , the viewpoint is changed so as to display the three-dimensional images of the brain viewed from a front side. Note also that the selection made in the dialog box  651  by clicking or tapping the key “Reflect changes in row of three-dimensional view” may be set to the initial state. Upon that selection, for example, a “View link” or “Release view link” key may be arranged to display the result of selection. Due to such a configuration, repetitive selecting operation can be omitted or simplified. 
     Next, as illustrated in  FIG. 46 , a case is described in which the viewpoint of the three-dimensional image  644  viewed from the viewpoint on the left side of the brain is changed by the analyst so as to display the three-dimensional images of the brain viewed from a left-frontal side. Upon these changes, as illustrated in  FIG. 45 , the analyst clicks or taps the key “Reflect changes in row of three-dimensional view” in the dialog box  650 , and then selects the first and second rows of the three-dimensional view  612  as the row in which changes are to be reflected and selects “Change viewpoints of three-dimensional images symmetrically” in the dialog box  651 . In such a case, as illustrated in  FIG. 46 , the three-dimensional display control unit  212  controls the display to reflect the changes in viewpoint made on the three-dimensional image  644  in the three-dimensional images in the first row of the three-dimensional view  612 , which originally have the same viewpoint as the three-dimensional image  644 . In other words, as illustrated in  FIG. 46 , the viewpoint is changed so as to display the three-dimensional images of the brain viewed from a left-frontal side of the brain. Further, as illustrated in  FIG. 46 , the three-dimensional display control unit  212  controls the display to symmetrically reflect the changes in viewpoint made on the three-dimensional image  644  in the three-dimensional images in the second row of the three-dimensional view  612 , which originally have the viewpoint on the right side of the brain. As illustrated in  FIG. 46 , the viewpoint of the three-dimensional images in the second row of the three-dimensional view  612  is changed to be symmetrical to the center plane of the brain (symmetry plane). In other words, the viewpoint of the three-dimensional images in the second row of the three-dimensional view  612  is changed so as to display the three-dimensional images of the brain viewed from a right-frontal side of the brain. 
     Next, a case is described in which, after the viewpoint is changed as illustrated in  FIG. 40 , the analyst selects “Apply same viewpoint to three-dimensional images” in a dialog box  652  displayed by clicking or tapping the key “Add new row in three-dimensional view” in the dialog box  650  as illustrated in  FIG. 47 . In such a case, as illustrated in  FIG. 48 , as a result of the changes in viewpoint made on the three-dimensional image  644 , the three-dimensional display control unit  212  controls the display to add the three-dimensional images of the brain with the same viewpoint as a new row in a display area  612 - 3  of the three-dimensional view  612 . In other words, as illustrated in  FIG. 48 , three-dimensional images of the brain viewed from a rear side are displayed in a new row of the display area  612 - 3 . 
     As described above, in accordance with the various kinds of settings, the changes in viewpoint made on the three-dimensional image  644  in the three-view head image  613  can be reflected in the viewpoint of the three-dimensional images of the brain that are arranged in the three-dimensional view  612  in a chronological order. Due to such a configuration, changes in viewpoint similar to the changes in viewpoint made on the three-dimensional image  644  do not have to be made on the three-dimensional view  612  in a repetitive manner. Due to this configuration, the operability or efficiency improves. Furthermore, the changes in the state of the brain can be checked on the three-dimensional view  612  in chronological order with the viewpoint same as the viewpoint as changed in the three-dimensional image  644  or with the viewpoint corresponding to the viewpoint as changed in the three-dimensional image  644 . 
     The above methods of reflecting changes in viewpoint in each one of the images of the brain displayed in the three-dimensional view  612 , which are set or determined in the dialog boxes  650  to  652  as illustrated in  FIG. 41 ,  FIG. 43 ,  FIG. 45 , and  FIG. 47 , are given by way of example, and any other ways or methods of reflection may be set or adopted. 
     Operations in which changes in viewpoint are reflected in the three-dimensional images of the three-dimensional view  612  when the viewpoint of the brain in the three-dimensional image  644  is changed are described as above. However, no limitation is indicated thereby, and the display mode that is to be changed for the three-dimensional image  644  is not limited to viewpoint. For example, the display mode that is to be changed for the three-dimensional image  644  may be, for example, changes in size, changes in brightness, or changes in transparency. Such changes may be reflected in the three-dimensional images of the three-dimensional view  612  without departing from the spirit or scope of the disclosure of the above changes in viewpoint. 
     Basic operation of the peak list  614  on the time-frequency analysis screen  601  is described below with reference to  FIG. 49  to  FIG. 53 . 
       FIG. 49  is a diagram illustrating the setting of the peak list  614 , according to the present embodiment. 
       FIG. 50  is a diagram illustrating a spatial peak according to the present embodiment. 
       FIG. 51  is a diagram illustrating a peak in time and a peak in frequency according to the present embodiment. 
       FIG. 52  is a diagram illustrating how a specific peak is selected from the drop-down peak list  614 , according to the present embodiment. 
       FIG. 53  is a diagram illustrating a state in which the peak selected from the drop-down peak list  614  is reflected in the heat map  611 , the three-dimensional view  612 , and the three-view head image  613 , according to the present embodiment. 
     In the peak list  614 , the peaks in signal strength that meet a specified condition, which are extracted by the peak-list controller  203 , are registered. As illustrated in  FIG. 49 , the peak-list controller  203  controls the display to display a pull-down list  656 , indicating a list of signal strengths registered as the peak list  614  is pulled down. 
     The above conditions for a peak in regard to the signal strength, which is extracted by the peak-list controller  203 , can be configured by clicking or tapping the peak-list setting key  614   a . Once the peak-list setting key  614   a  is clicked or tapped, the peak-list controller  203  controls the display to display a dialog box  655  where the conditions for a peak in regard to the extracted signal strength can be configured. 
     In the dialog box  655 , first of all, how the peak data registered in the peak list  614  is to be sorted can be configured. When “Sort values of peaks in descending order” is selected in a dialog box  655 , the peak-list controller  203  sorts the peaks of the signal strength in the peak data registered in the peak list  614  in descending order. By contrast, when “Sort levels of peaks (difference in height between top and bottom) in descending order” is selected in the dialog box  655 , the peak-list controller  203  sorts the peak data registered in the peak list  614  in descending order of the difference between the signal strength at the peak point and the signal strength at the bottom of the peak. 
     Further, in the dialog box  655 , what type of peak data is to be registered (listed) in the peak list  614  can be configured. When “All spatial peaks” is selected in the dialog box  655 , the peak-list controller  203  extracts the spatial peaks, in the entirety of the brain, at each time and each frequency on the plane of time and frequency, and registers the extracted spatial peaks in the peak list  614 . The term “spatial peaks” in the present embodiment indicates the peaks of signal strength of a biomedical signal of the time and frequency of interest in the entirety of the brain, and the signal strength in the peak spot  801  is greater than that of the area around that peak spot, like a peak spot  801  as illustrated in  FIG. 50 . 
     When “All peaks in time/frequency” is selected in the dialog box  655 , the peak-list controller  203  extracts all the peaks in time and frequency from varying points of the plane of time and frequency in the entirety of the brain and registers the extracted peaks in the peak list  614 . The term “peaks in time and frequency” in the present embodiment indicate the peaks of signal strength of a biomedical signal at a site of interest in the brain on the plane of time and frequency, like a peak spot  802  as illustrated in  FIG. 51 , and the signal strength in the peak spot  802  is greater than that of the area around that peak spot. 
     When “Spatial peaks in designated time/frequency” is selected in the dialog box  655 , the peak-list controller  203  extracts the spatial peaks at the time and frequency specified on the plane of time and frequency in the entirety of the brain, and registers the extracted spatial peaks in the peak list  614 . Note also that the specified time and frequency is not limited to a point, and the time and frequency may be selected or specified by an area or range. 
     When “Peaks in time/frequency at designated position” is selected in the dialog box  655 , the peak-list controller  203  extracts all the peaks in time and frequency on the plane of time and frequency at the specified site of the brain, and registers the extracted peaks in the peak list  614 . Note also that the designated position is not limited to a point, and the position may be selected or specified by an area or range. For example, when a peak on a visual area is to be extracted, the entirety of the occipital region of the brain may be specified. By so doing, a peak can easily be extracted as desired. 
     Next, operations are described that are performed when a specific item of peak data is selected from the peak list  614  in which several items of peak data are registered. When a specific item of peak data (for example, “95%/9 ms/70 Hz, voxel: 1736” as depicted in  FIG. 52 ) is selected by the analyst from the pull-down list  656  of the peak list  614 , the heat-map display control unit  211  controls the display to display the heat map  611  that corresponds to a desired point of the brain indicated by the selected item of peak data. In such a configuration, as described above with reference to  FIG. 14 , the heat-map display control unit  211  may specifically indicate on the heat map  611  the peak that is indicated by the selected item of peak data. 
     Moreover, the three-dimensional display control unit  212  controls the display to display the three-dimensional image of the brain of the time and frequency that the selected item of peak data indicates in the center of each row of the three-dimensional view  612 , and further controls the display to display the three-dimensional images of the brain at times before and after the time indicated by the selected peak data in the three-dimensional view  612 . In such cases, the heat maps that are superimposed on the multiple three-dimensional images of the brain in the three-dimensional view  612  may correspond to the signal strength of the biomedical signal with the frequency that the selected item of peak data indicates. 
     The sectional-view control unit  213  controls the display to display three-view images that go through the position of the brain indicated by the selected item of peak data, in the three-view head image  613 . Further, the sectional-view control unit  213  may control the display to superimpose the heat map, which corresponds to the signal strength of the biomedical signal with the time and frequency that the selected item of peak data indicates, on the image of the brain in the three-dimensional image  644 . As illustrated in  FIG. 53 , the sectional-view control unit  213  may controls the display to display a cut-model image, which is obtained by extracting a partial image of the brain in three-dimensional directions around the position of the brain indicated by the selected peak data, on the three-dimensional image  644 . 
     As described above, a specific item of peak data is selected from the peak data registered in the peak list  614 , and the heat map  611 , the three-dimensional view  612 , and the three-view head image  613  that correspond to the selected item of peak data are displayed accordingly. Due to such a configuration, to what position, time, and frequency of the brain the selected peak belongs can instantly be recognized. Further, the states of signal strength at the selected peak and at the time and frequency around the selected peak can be figured out, and the states of signal strength on the brain at the peak and around the peak can also be figured out on the heat map  611 . 
     The operations when the replay control panel  615  on the time-frequency analysis screen  601  is manipulated are described below with reference to  FIG. 54A  to  FIG. 56B . 
       FIG. 54A  and  FIG. 54B  are diagrams illustrating how the viewing of the heat map  611  and the three-dimensional view  612  are viewed by operations on the replay control panel  615 , according to the present embodiment. 
       FIG. 55A  and  FIG. 55B  are diagrams illustrating how the viewing of the heat map  611  and the three-dimensional view  612  are returned on a frame-by-frame basis by operations on the replay control panel  615 , according to the present embodiment. 
       FIG. 56A  and  FIG. 56B  are diagrams illustrating how the heat map  611  and the three-dimensional view  612  are advanced on a frame-by-frame basis by operations on the replay control panel  615 , according to the present embodiment. 
     The replay control panel  615  is a user interface manipulated by the analyst to view the states of the heat map  611 , the three-dimensional view  612 , and the three-view head image  613  as time elapses. 
     For example, when the analyst touches or clicks the “replay” key on the replay control panel  615 , as illustrated in  FIG. 54A  and  FIG. 54B , the viewing control unit  214  instructs the heat-map display control unit  211  to move the specified area  622 - 1  specified on the heat map  611  and the related areas  622 - 2  to  622 - 5  around the specified area  622 - 1  in the right direction (i.e., the direction in which the time advances) as time elapses. As the specified area  622 - 1  and the related areas  622 - 2  to  622 - 5  are moved on the heat map  611 , the viewing control unit  214  instructs the three-dimensional display control unit  212  to switch to the display of the three-dimensional images of the brain that correspond to the relevant multiple areas, as illustrated in  FIG. 54A  and  FIG. 54B . As the specified area  622 - 1  is moved on the heat map  611  moves, the viewing control unit  214  instructs the sectional-view control unit  213  to display the heat map of the signal strength that corresponds to the range of time and frequency of the moving specified area  622 - 1  on the three-view images and the three-dimensional image  644 . 
     When the analyst touches or clicks the “Frame-by-frame return” key on the replay control panel  615 , as illustrated in  FIG. 55A  and  FIG. 55B , the viewing control unit  214  instructs the heat-map display control unit  211  to move the specified area  622 - 1  specified on the heat map  611  and the related areas  622 - 2  to  622 - 5  around the specified area  622 - 1  in the left direction (i.e., the direction in which the time returns) by a certain length of time. As the specified area  622 - 1  and the related areas  622 - 2  to  622 - 5  are moved on the heat map  611 , the viewing control unit  214  instructs the three-dimensional display control unit  212  to switch to the display of the three-dimensional images of the brain that correspond to the relevant multiple areas, as illustrated in  FIG. 55A  and  FIG. 55B . As the specified area  622 - 1  is moved on the heat map  611  moves, the viewing control unit  214  instructs the sectional-view control unit  213  to display the heat map of the signal strength that corresponds to the range of time and frequency of the moved specified area  622 - 1  on the three-view images and the three-dimensional image  644 . 
     When the analyst touches or clicks the “frame-by-frame advance” key on the replay control panel  615 , as illustrated in  FIG. 56A  and  FIG. 56B , the viewing control unit  214  instructs the heat-map display control unit  211  to move the specified area  622 - 1  specified on the heat map  611  and the related areas  622 - 2  to  622 - 5  around the specified area  622 - 1  in the right direction (i.e., the direction in which the time advances) by a certain length of time. As the specified area  622 - 1  and the related areas  622 - 2  to  622 - 5  are moved on the heat map  611 , the viewing control unit  214  instructs the three-dimensional display control unit  212  to switch to the display of the three-dimensional images of the brain that correspond to the relevant multiple areas, as illustrated in  FIG. 56A  and  FIG. 56B . As the specified area  622 - 1  is moved on the heat map  611  moves, the viewing control unit  214  instructs the sectional-view control unit  213  to display the heat map of the signal strength that corresponds to the range of time and frequency of the moved specified area  622 - 1  on the three-view images and the three-dimensional image  644 . 
     When the analyst touches or clicks the “stop” key on the replay control panel  615 , the viewing control unit  214  instructs each one of the heat-map display control unit  211 , the three-dimensional display control unit  212 , and the sectional-view control unit  213  to terminate its display operation on the heat map  611 , the three-dimensional view  612 , and the three-view head image  613 . 
     When the analyst touches or clicks the “move to head” key on the replay control panel  615 , the viewing control unit  214  instructs the heat-map display control unit  211  to move the specified area  622 - 1  specified on the heat map  611  to the head of the time. As the specified area  622 - 1  is moved on the heat map  611  moves, the viewing control unit  214  instructs the three-dimensional display control unit  212  to switch to the display of the three-dimensional images of the brain that correspond to the specified area  622 - 1 . As the specified area  622 - 1  is moved on the heat map  611  moves, the viewing control unit  214  instructs the sectional-view control unit  213  to display the heat map of the signal strength that corresponds to the range of time and frequency of the moved specified area  622 - 1  on the three-view images and the three-dimensional image  644 . 
     When the analyst touches or clicks the “move to end” key on the replay control panel  615 , the viewing control unit  214  instructs the heat-map display control unit  211  to move the specified area  622 - 1  specified on the heat map  611  to the end of the time. As the specified area  622 - 1  is moved on the heat map  611  moves, the viewing control unit  214  instructs the three-dimensional display control unit  212  to switch to the display of the three-dimensional images of the brain that correspond to the specified area  622 - 1 . As the specified area  622 - 1  is moved on the heat map  611  moves, the viewing control unit  214  instructs the sectional-view control unit  213  to display the heat map of the signal strength that corresponds to the range of time and frequency of the moved specified area  622 - 1  on the three-view images and the three-dimensional image  644 . 
     Due to the viewing and displaying operation as described above, the changes over time in the distribution (heat map) of the signal strength indicated on the three-view head image  613  and the three-dimensional view  612  can be checked in moving images, and for example, the movement of the peaks over time can visually be checked. 
     How the heat map  611 , the three-dimensional view  612 , and the three-view head image  613  are initially displayed when the time-frequency analysis screen  601  is started (opened) according to the present embodiment are described below with reference to  FIG. 57  to  FIG. 59 . 
       FIG. 57  is a diagram illustrating from what viewpoint the images are to be initially displayed with respect to a peak, according to the present embodiment. 
       FIG. 58  is a diagram illustrating from what viewpoint the images are to be initially displayed with respect to a pair of peaks, according to the present embodiment. 
       FIG. 59  is a diagram illustrating a state in which the images of the brain viewed from the viewpoints as illustrated in  FIG. 58  are displayed in the three-dimensional view  612  as the initial display. 
     Some patterns of what kind of images are to be initially displayed as the heat map  611 , the three-dimensional view  612 , and the three-view head image  613  when the analyst started (opened) the time-frequency analysis screen  601  are described below. 
     For example, the analysis display controller  202  calculates the time and frequency and the position inside the brain where the signal strength is maximized throughout the entire range of time and frequency in the entirety of the brain. In such a case, the heat-map display control unit  211  controls the display to display the heat map  611  at the position inside the brain calculated by the analysis display controller  202 . Moreover, the three-dimensional display control unit  212  controls the display to display the three-dimensional image of the brain, which corresponds to the time and frequency calculated by the analysis display controller  202 , where the signal strength is maximized, in the three-dimensional view  612 . The sectional-view control unit  213  controls the display to display three-view images that go through the position inside the brain calculated by the analysis display controller  202  in the three-view head image  613 , and superimposes the heat map of time and frequency calculated by the analysis display controller  202 , where the signal strength is maximized, on the three-view images and the three-dimensional image  644 . 
     The analysis display controller  202  may calculate the position inside the brain where the average of signal strength is maximized throughout the entire range of time and frequency. In such a case, the heat-map display control unit  211  controls the display to display the heat map  611  at the position inside the brain calculated by the analysis display controller  202 . Moreover, the three-dimensional display control unit  212  controls the display to display the three-dimensional image of the brain, which corresponds to the time and frequency on the displayed heat map  611  where the signal strength is maximized, on the three-dimensional view  612 . The sectional-view control unit  213  controls the display to display three-view images that go through the position inside the brain calculated by the analysis display controller  202  in the three-view head image  613 , and superimposes the heat map of the time and frequency, where the signal strength is maximized in the displayed heat map  611 , on the three-view images and the three-dimensional image  644 . 
     Alternatively, the analysis display controller  202  may compute and obtain the time and frequency where the average of the signal strength is maximized in the entirety of the brain. In such a case, the three-dimensional display control unit  212  controls the display to display the three-dimensional image of the brain that corresponds to the time and frequency calculated by the analysis display controller  202  on the three-dimensional view  612 . The heat-map display control unit  211  computes and obtains the position inside the brain, which is displayed on the three-dimensional images of the three-dimensional view  612 , where the signal strength is maximized in the heat map that corresponds to the time and frequency calculated by the analysis display controller  202 , and controls the display to display the heat map  611  at the computed and obtained position. The sectional-view control unit  213  controls the display to display three-view images that go through the position inside the brain calculated by the heat-map display control unit  211  in the three-view head image  613 , and superimposes the heat map of the time and frequency calculated by the analysis display controller  202  on the three-view images and the three-dimensional image  644 . 
     Moreover, the three-dimensional display control unit  212  may control the display to display the heat map  611  at a position inside the brain indicated by the first item of peak data in the peak data registered in the peak list  614 . Moreover, the three-dimensional display control unit  212  controls the display to display the three-dimensional image of the brain, which corresponds to the time and frequency indicated by the first item of peak data in the peak data registered in the peak list  614 , on the three-dimensional view  612 . The sectional-view control unit  213  controls the display to display three-view images that go through the position inside the brain indicated by the first item of peak data in the peak data registered in the peak list  614 , in the three-view head image  613 , and superimposes the heat map of the time and frequency indicated by the selected item of peak data, on the three-view images and the three-dimensional image  644 . 
     Moreover, the three-dimensional display control unit  212  may control the display to display the heat map  611  at the position inside the brain that is preset depending on an object to be measured (for example, a visual area, auditory area, somatosensory area, motor area, and a language area are the preset parameters). Moreover, the three-dimensional display control unit  212  controls the display to display the three-dimensional image of the brain, which corresponds to the time and frequency that is preset depending on an object to be measured (for example, a visual area, auditory area, somatosensory area, motor area, and a language area), on the three-dimensional view  612 . The sectional-view control unit  213  controls the display to display three-view images that are preset depending on an object to be measured (for example, a visual area, auditory area, somatosensory area, motor area, and a language area) and go through the position inside the brain in the three-view head image  613 , and superimposes the heat map of the time and frequency indicated by the selected item of peak data, on the three-view images and the three-dimensional image  644 . 
     The initial viewpoint of the three-dimensional images of the brain in the three-dimensional view  612  and the three-dimensional image  644  on the three-view head image  613  that are displayed when the analyst started (opened) the time-frequency analysis screen  601  is described below. 
     For example, the viewpoint that is preset depending on an object to be measured (for example, a visual area, auditory area, somatosensory area, motor area, and a language area) may be employed for the initial viewpoint. In such a configuration, the number of rows (viewpoints) in the three-dimensional view  612  is also preset in advance. For example, when the three-dimensional view  612  consists of two rows, two viewpoints need to be preset in advance. For example, when the language areas are to be measured, the viewpoints on the right and left sides of the brain are preset in advance. 
     A viewpoint from which the peak that is registered in the forefront of the peak list  614  can be observed most clearly may be employed for the initial viewpoint. More specifically as illustrated in  FIG. 57 , a viewpoint P 0  may be set on a straight line  811  that connects the center of the brain and a peak, as the initial viewpoint. 
     A viewpoint that is determined based on a peak whose predetermined parameter in the peak list  614  (for example, the value of the peak (signal strength) or the level of the peak as illustrated in  FIG. 50 ) exceeds a prescribed threshold may be employed for the initial viewpoint. For example, when there are two peaks that have exceeded the threshold, the three-dimensional view  612  may be displayed in two rows, and as illustrated in  FIG. 58 , viewpoints P 1  and P 2  may be set as the initial viewpoints on straight lines  812  and  813  that connect the center of the brain and the respective peaks. An example of such a configuration as above is illustrated in  FIG. 59  in which the three-dimensional images of the brain viewed from the viewpoint P 1  are displayed in the upper row of the three-dimensional view  612  and the three-dimensional images of the brain viewed from the viewpoint P 2  are displayed in the lower row of the three-dimensional view  612 . 
     As described above, in the above embodiment of the present disclosure, the heat map  611  indicating the time and frequency of a biomedical signal at a specific site of the brain or in a specific area of the brain is displayed. Moreover, the three-dimensional images indicative of the activity of the brain at times before and after the above time are displayed around the three-dimensional image on which a heat map indicative of the activity of the brain at the point designated on the heat map  611  or in the area designated on the heat map  611  is superimposed. In other words, some still images (i.e., three-dimensional images) that indicate the activity of the brain are advanced or returned on a frame-by-frame basis in the above embodiment of the present disclosure. Due to this configuration, still images that indicate the activity of the brain can appropriately and promptly be extracted, and the activity of the brain can easily be analyzed. Further, a conference or discussion can take place based on those images in an effective manner. 
     In the above embodiment of the present disclosure, once a specific item of peak data is selected from the peak data registered in the peak list  614 , the heat map  611 , the three-dimensional view  612 , and the three-view head image  613  that correspond to the selected item of peak data are displayed. Due to such a configuration, to what position, time, and frequency of the brain the selected peak belongs can instantly be recognized. Further, the states of signal strength at the selected peak and at the time and frequency around the selected peak can be figured out, and the states of signal strength on the brain at the peak and around the peak can also be figured out on the heat map  611 . 
     The viewpoint of the brain can be changed as desired in the three-dimensional view  612 , and the changes based on the changed viewpoint of the brain can be reflected in the images of the brain in the same row or in a different row. Due to this configuration, the changes that are made in the viewpoint of a specific three-dimensional image (i.e., the target three-dimensional image) are automatically reflected in the other three-dimensional images, and the operability or efficiency improves. Furthermore, the images of the brain in multiple rows can be compared with each other, and thus the changes in activity among the images of the brain that are viewed from a corresponding viewpoint and are temporally close to each other can easily be checked. As the viewpoint of the brain that is drawn as three-dimensional images can be changed as desired, a firing point that cannot be viewed from one viewpoint can be checked. 
     As described above, in accordance with the various kinds of settings, the changes in viewpoint made on the three-dimensional image  644  in the three-view head image  613  can be reflected in the viewpoint of the three-dimensional images of the brain that are arranged in the three-dimensional view  612  in a chronological order. Due to such a configuration, changes in viewpoint similar to the changes in viewpoint made on the three-dimensional image  644  do not have to be made on the three-dimensional view  612  in a repetitive manner. Accordingly, the operability or efficiency improves. Furthermore, the changes in the state of the brain can be checked on the three-dimensional view  612  in chronological order with the viewpoint same as the viewpoint as changed in the three-dimensional image  644  or with the viewpoint corresponding to the viewpoint as changed in the three-dimensional image  644 . 
     In the above embodiment of the present disclosure, a biomedical signal of the brain, which is an example of a biological site, is considered. However, no limitation is intended thereby, and it can be applied to the biomedical signals of a biological site such as a spinal cord and muscles. For example, in the case of lumber spine (lumbar vertebra), the three-dimensional view  612  that is used as an image of the brain may be displayed as illustrated in  FIG. 60A ,  FIG. 60B ,  FIG. 60C , and  FIG. 60D .  FIG. 60A ,  FIG. 60B ,  FIG. 60C , and  FIG. 60D  illustrates how a lumbar signal is transmitted to the upper side in chronological order. 
     The processes of superimposing marks indicative of analytical results on a biological image are described below with reference to  FIG. 61  to  FIG. 64 . 
       FIG. 61  is a diagram illustrating a state of the time-frequency analysis screen  601  in which a drop-down menu of dipole list is displayed, according to the present embodiment. 
       FIG. 62  is a diagram illustrating how dipoles are displayed on the time-frequency analysis screen  601  as a result of dipole selection when such dipoles do not exist on the currently-displayed sectional views, according to the present embodiment. 
       FIG. 63  is a diagram illustrating a state of the time-frequency analysis screen  601  in which a sectional view on which a dipole exists is displayed together with the selected dipole, according to the present embodiment. 
       FIG. 64  is a diagram illustrating how dipoles are displayed when a plurality of dipoles are selected on the time-frequency analysis screen  601 , according to the present embodiment. 
     Operations in which a dipole that indicates a result of dipole estimation and a heat map that indicates the distribution of the signal strength of the biomedical signal are superimposed on top of one another on the time-frequency analysis screen  601  are described below with reference to  FIG. 61  to  FIG. 64 . 
     Firstly, the purpose of superimposing, on the time-frequency analysis screen  601 , a dipole that indicates a result of dipole estimation and a heat map that indicates the distribution of the signal strength of biomedical signals is described below. Some methods of preventing epilepsy by performing surgery to remove a portion of the brain that is considered to be a source of epilepsy from an epilepsy patient are known in the art. In such methods, it is important to remove a source of epilepsy in an unfailing manner. However, on the other hand, if a site or portion of the brain that is in charge of normal activities is removed, there is some concern that the life after the surgery may be interfered. For this reason, it is crucial to remove a source of epilepsy in an unfailing manner while maintaining a site or portion of the brain that is in charge of normal activities. 
     A site or portion of the brain that is considered to be a source of epilepsy and a site or portion of the brain that is used in normal activities are specified using measurement methods such as magneto-encephalography (MEG) and electro-encephalography (EEG). As a method of analyzing the biomedical signals that are obtained by the MEG or EEG, dipole estimation or time-frequency analysis is known in the art. Epilepsy does not occur at regular time intervals, and the source of such epilepsy is not always the same. For this reason, when a site or portion of the brain that is considered to be a source of epilepsy is estimated, dipole estimation is performed on each case of epilepsy to estimate the source (an example of an estimated site or portion of the brain). By contrast, when a site or portion of the brain that is used in normal activities is to be estimated, it is desired that a plurality of results of stimulation be superimposed on top of one another using time-frequency analysis, to reduce the influence of noise as much as possible. For example, when an active site or portion of the brain for the sense of touch is to be specified, electrical stimulation is given to a finger or the like, and the brain activity in response to the given electrical stimulation is measured. The brain activity is measured a plurality of times, and the results of such brain-activity measurement are statistically analyzed. Due to such a configuration, an active site or portion of the brain (an area of the brain that is activated in response to the sense of touch) can be estimated with reliability despite an external cause such as noise. An active site or portion of the brain for the visual perception, auditory sensation, language, or the like can be estimated using a similar method. In other words, dipole estimation is performed to estimate a site or portion of the brain that is considered to be a source of epilepsy, and such an estimated site or portion of the brain is considered as a candidate for removal. The time-frequency analysis is performed to clarify a site or portion of the brain that is used in normal activities, and such a site or portion of the brain is excluded from the candidate for removal. Due to such a configuration, a site of portion of the brain, which is considered to be responsible for epilepsy, can be removed in the surgery with improved safety and reliability. 
     Operations in which a dipole that indicates a result of dipole estimation and a heat map that indicates the distribution of the signal strength of the biomedical signal are superimposed on top of one another on the time-frequency analysis screen  601  are described below in detail with reference to  FIG. 61  to  FIG. 64 . The time-frequency analysis screen  601  as illustrated in  FIG. 61  includes a dipole list  616  that indicates a list of estimated dipoles and a storage key  617  used to store, for example, the specified site of the brain, time, frequency, peak list, and parameters for display. 
     As the three-dimensional view  612  is hidden from view on the time-frequency analysis screen  601  as illustrated in  FIG. 61 ,
 
Due to the use of such a hidden area, the display area of the heat map  611  increases. This indicates that the display layout as illustrated in  FIG. 61  is enabled, for example, if any of the heat map  611 , the three-dimensional view  612 , and the three-view head image  613  can be hidden from view by adjusting the setting.
 
     A specified point  661  is specified on the heat map  611  of the time-frequency analysis screen  601  as illustrated in  FIG. 61 . Accordingly, a heat map that indicates the of the signal strength of the biomedical signal of the time and frequency corresponding to the position by the specified point  661  is superimposed on each one of the multiple three-dimensional images on the three-view head image  613  (i.e., the sectional views  641  to  643  and the three-dimensional image  644 ) (an example of a biological image). As the input unit  208  is manipulated by the analyst, the analysis display controller  202  controls the display to display a drop-down menu  616   a  of the dipole list  616 . The drop-down menu  616   a  indicates a list of dipoles that have been estimated for the same patient. The analyst can manipulate the input unit  208  to select one of the dipoles included in the list of the drop-down menu  616   a . In such a configuration, it is desired that a plurality of dipoles be selectable. The time-frequency analysis screen  601  as illustrated in  FIG. 61  indicates a state in which two dipoles are selected from the list of dipoles in the displayed drop-down menu  616   a.    
     In the present embodiment, when the analyst selects a dipole from the drop-down menu  616   a  to control the display to display the selected dipole (i.e., the first image) on the three-view head image  613 , in most cases, any of the sectional views (i.e., the sectional views  641  to  643 ) that are displayed at that time in the three-view head image  613  is different from the sectional view (slice) that includes the selected dipole. For this reason, when a dipole is to be displayed only on the sectional view (slice) that actually includes that dipole, in most cases, no dipole is displayed on the sectional views (i.e., the sectional views  641  to  643 ) (some examples of a sectional image) that are displayed at that time in the three-view head image  613 . 
     As a first method to deal with such circumstances as above, a method is known in the art for displaying a dipole on one of the sectional views that are displayed in the three-view head image  613  even if no dipole actually exists on any of those sectional views when a dipole is selected. However, when such a method is adopted, the accurate position of the dipole cannot be determined. For this reason, the sectional-view control unit  213  should change the way of presenting the dipole between a case in which the dipole exists on one of the sectional views that are actually displayed in the three-view head image  613  and a cases in which the dipole exists on a sectional view different from the currently-displayed sectional views. For example, when the dipole exists on a sectional view currently-displayed on three-view head image  613 , the sectional-view control unit  213  (an example of a first display control unit) controls the to display the dipole in a strong color, as will be described later in detail with reference to  FIG. 63 . Moreover, when the dipole exists on a sectional view different from any of the sectional views displayed in the three-view head image  613 , the sectional-view control unit  213  controls the display to display dipoles in a pale color, as illustrated in  FIG. 62 . In the present embodiment, reference lines  645   a  to  645   d  that indicate positions on the images of the brain that are displayed in the three-view head image  613  may be referred to as a cursor. 
     In the time-frequency analysis screen  601  according to the present embodiment as illustrated in  FIG. 62 , the sectional-view control unit  213  (an example of a second display control unit) controls the display to display a dipole  648   a , which does not exist in the sectional view  641  of the three-dimensional view  612 , in a pale color. Moreover, the sectional-view control unit  213  controls the display to display in sites  681   a  and  682  a heat map that indicates the distribution of the signal strength of the biomedical signal of the time and frequency corresponding to the position specified by the specified point  661 . In this configuration, the dipole  648   a  does not exist on the sectional view  641 , but the sectional-view control unit  213  controls the display to display the dipole  648   a  on the position on the sectional view  641  that corresponds to the point on the plane orthogonal to the brain in the forward and backward directions where the dipole  648   a  exists. In a similar manner, the sectional-view control unit  213  controls the display to display a dipole  648   b , which does not exist in the sectional view  642  of the three-dimensional view  612 , in a pale color. Moreover, the sectional-view control unit  213  controls the display to display in a site  681   b  a heat map that indicates the distribution of the signal strength of the biomedical signal of the time and frequency corresponding to the position specified by the specified point  661 . In this configuration, the dipole  648   b  does not exist on the sectional view  642 , but the sectional-view control unit  213  controls the display to display the dipole  648   b  on the position on the sectional view  642  that corresponds to the point on the plane orthogonal to the brain in the right and left directions where the dipole  648   b  exists. Further, the sectional-view control unit  213  controls the display to display a dipole  648   c , which does not exist in the sectional view  643  of the three-dimensional view  612 , in a pale color. Moreover, the sectional-view control unit  213  controls the display to display in a site  681   c  a heat map that indicates the distribution of the signal strength of the biomedical signal of the time and frequency corresponding to the position specified by the specified point  661 . In this configuration, the dipole  648   c  does not exist on the sectional view  643 , but the sectional-view control unit  213  controls the display to display the dipole  648   c  on the position on the sectional view  643  that corresponds to the point on the plane orthogonal to the brain in the up-and-down directions where the dipole  648   c  exists. As a matter of course, the dipoles  648   a  to  648   c  that are displayed in the three-view head image  613  of  FIG. 62  are not separate and different dipoles, but are the same dipoles. 
     As a second method to deal with the circumstances as above, a method is known in the art for switching, as a result of dipole selection, from the sectional views (slices) of the three-view head image  613  to new sectional views (slices) each of which includes a dipole. In other words, when a dipole is selected from the drop-down menu  616   a  of the time-frequency analysis screen  601  as illustrated in  FIG. 61 , the sectional-view control unit  213  controls the display to display the sectional views each of which includes a dipole as the sectional views  641  to  643 , respectively, as in the three-view head image  613  as illustrated in  FIG. 63 . However, in such a configuration, if the cursor is also moved towards the multiple sectional views that are newly displayed as the sectional views  641  to  643  of the three-view head image  613 , the display of the heat map  611  may also be changed in an unintentional manner in synchronization with the position of the cursor. In the present embodiment, the brain activity at the particular time and frequency that have already been specified (an example of the activities of a live subject) and the relative positions of the dipoles are to be checked. For this reason, changes are undesired in the display status of the heat map  611  in which the time and frequency have already been specified. In order to handle such a situation, the sectional-view control unit  213  switches only the sectional views (slices) of the three-view head image  613  without changing the position of the cursor. In order to check a heat map on the three-view head image  613 , which indicates the distribution of the signal strengths of the brain activity, without moving the cursor (maintaining the display status of the currently-displayed heat map  611  as it is without a change) as described above, the sectional views (slices) of the three-view head image  613  need to be switched without moving the cursor. In such a configuration, when a particular dipole is selected but that dipole does not exist at the position of the brain indicated by the cursor that was displayed on the three-view head image  613  before the selection was made, it is considered that the position of the brain indicated on the three-view head image  613  (the position of the dipole) is different from the position of the brain indicated by the cursor. Accordingly, the cursor that is displayed on the three-view head image  613  is hidden from view. 
     In the time-frequency analysis screen  601  according to the present embodiment as illustrated in  FIG. 63 , the sectional-view control unit  213  controls the display to display a sectional view on which a dipole exists, as the sectional view  641  of the three-dimensional view  612 . Moreover, the sectional-view control unit  213  may control the display to display such a dipole as a dipole  648   a  of a strong color. Moreover, the sectional-view control unit  213  controls the display to display in sites  683   a  and  684   a  a heat map that indicates the distribution of the signal strength of the biomedical signal of the time and frequency corresponding to the position specified by the specified point  661 . In a similar manner, the sectional-view control unit  213  controls the display to display a sectional view on which a dipole exists, as the sectional view  642  of the three-dimensional view  612 . Moreover, the sectional-view control unit  213  may control the display to display such a dipole as a dipole  648   b  of a strong color. Moreover, the sectional-view control unit  213  controls the display to display in a site  683   c  a heat map that indicates the distribution of the signal strength of the biomedical signal of the time and frequency corresponding to the position specified by the specified point  661 . Further, the sectional-view control unit  213  controls the display to display a sectional view on which a dipole exists, as the sectional view  643  of the three-dimensional view  612 . Moreover, the sectional-view control unit  213  may control the display to display such a dipole as a dipole  648   c  of a strong color. Moreover, the sectional-view control unit  213  controls the display to display in sites  683   c  and  684   c  a heat map that indicates the distribution of the signal strength of the biomedical signal of the time and frequency corresponding to the position specified by the specified point  661 . 
     No matter which one of the first and second methods that are used to deal with the circumstances as above may be adopted, as described above, the analyst may operate the center wheel of a mouse that serves as the input unit  208  to switch the sectional views (slices) of the three-view head image  613  from the state of the time-frequency analysis screen  601  as illustrated in  FIG. 62  or  FIG. 63 . 
     When a plurality of dipoles are selected from the pull-down  616   a  as illustrated in  FIG. 61 , the sectional-view control unit  213  controls the display to display two kinds of dipoles (i.e., dipoles  648   a  to  648   c  and dipoles  649   a  to  649   c ) on the three-view head image  613  as illustrated in  FIG. 64 . In such a case, the sectional-view control unit  213  may control the display to display, for example, the sectional views in which the selected dipoles (i.e., the dipoles  648   a  to  648   c  in the present embodiment) displayed on the upper side of the drop-down menu  616   a  exist as the sectional views  641  to  643 , respectively. In such a configuration where the sectional-view control unit  213  control the display to display a plurality of dipoles on the three-view head image  613 , it is desired that the colors of those dipoles be different from each other. For example, the sectional-view control unit  213  may control the display to display the dipoles (dipoles  648   a  to  648   c ) that do not exist in the sectional views  641  to  643  of the three-view head image  613  in blue, and the sectional-view control unit  213  may control the display to display the dipoles (i.e., the dipoles  649   a  to  649   c ) that do not exist in the sectional views  641  to  643  in green. Alternatively, the sectional-view control unit  213  may control the display to match the color of the area of the selected dipoles in the dipole list  616  to the color of the dipoles displayed in the three-view head image  613 . 
     As described above, a dipole and a result of time-frequency analysis (a heat map that indicates the distribution of the signal strength of the biomedical signal at the time and frequency specified on the heat map  611 ) may be superimposed on the time-frequency analysis screen  601 . Due to this configuration, whether or not the source of epilepsy is included in the range or area of the brain that is used in normal activities can easily be determined. Moreover, as a dipole and a result of time-frequency analysis are display in an appropriate manner, analysis can easily be performed. 
     As described above with reference to  FIG. 61  to  FIG. 64 , when the scope of the brain (a site of the brain, time, and a frequency) that is used in normal activities is specified on the time-frequency analysis screen  601 , the analyst can store the data by clicking or tapping the storage key  617 . In other words, when the storage key  617  is clicked or tapped as the input unit  208  is manipulated by the analyst, the analytical-result storage control unit  221  controls the storage unit  207  to store, for example, the specified site of the brain, time, frequency, peak list, and parameters for display. Due to this configuration, the data of, for example, the specified site of the brain, time, frequency, peak list, and parameters for display (such items of data may be referred to as analysis data in the following description) can be stored for each type of normal activities (stimulation) (for example, visual perception, hearing, language, or somatic sensation). Accordingly, the heat map of signal strength of each type of normal activities (stimulation) can be superimposed on top of one another based on these multiple items of analysis data. Such superimposition and display operations are described below. 
       FIG. 65  is a diagram illustrating a time-frequency analysis and dipole display screen  901  according to the present embodiment. 
       FIG. 66  is a schematic diagram of processes in which a result of time-frequency analysis and a dipole are superimposed on the time-frequency analysis and dipole display screen  901  upon storing a plurality of results of time-frequency analysis, according to the present embodiment. 
     Operations in which a dipole and a heat map of a plurality of signal strengths of normal activities (stimulation) are superimposed on the time-frequency analysis and dipole display screen  901  are described below with reference to  FIG. 65  and  FIG. 66 . 
     In order to display the time-frequency analysis and dipole display screen  901  as illustrated in  FIG. 65 , for example, the time-frequency analysis and dipole display screen  901  needs to be selected by the analyst from an analyzing screen switching list  605  of the time-frequency analysis screen  601 . In response to this operation, the superimposition display control unit  222  controls the display to display the time-frequency analysis and dipole display screen  901 . 
     As illustrated in  FIG. 65 , the time-frequency analysis and dipole display screen  901  includes a three-view head image  913 , a peak list  914 , a dipole list  916 , and a time-frequency analysis result list  918 . 
     In the peak list  914 , the peak list that corresponds to the result of time-frequency analysis selected in the time-frequency analysis result list  918  is merged and displayed. The dipole list  916  indicates a list of the dipoles that have already been estimated in the dipole estimation. In the time-frequency analysis result list  918 , a list of analysis data such as the specified site of the brain, a time, a frequency, a peak list, and parameters for display is displayed for each type of the normal activities (stimulation) (for example, visual perception, hearing, language, or somatic sensation), which is stored in the storage unit  207  by the analytical-result storage control unit  221  as manipulated by the analyst on the above time-frequency analysis screen  601 . In other words, as illustrated in  FIG. 66 , the analysis data of each type of normal activities (stimulation) is stored in the storage unit  207 , and the time-frequency analysis and dipole display screen  901  controls the display to display as a list a plurality of items of analysis data stored in the storage unit  207  in the time-frequency analysis result list  918 . In  FIG. 66 , the time-frequency analysis screen  601  when the analysis data of first type of activity (for example, visual perception) is obtained from among several types of normal activities is illustrated as a time-frequency analysis screen  601   a . Moreover, in  FIG. 66 , the time-frequency analysis screen  601  when the analysis data of second type of activity (for example, auditory sensation) is obtained from among several types of normal activities is illustrated as a time-frequency analysis screen  601   b . Further, in  FIG. 66 , the time-frequency analysis screen  601  when the analysis data of third type of activity (for example, language) is obtained from among several types of normal activities is illustrated as a time-frequency analysis screen  601   c . Due to this configuration, a summary of the analysis data that is stored for each type of normal activities (stimulation) can be checked on the time-frequency analysis screen  601 . In the example of  FIG. 65 , the name of the activity (stimulation, the time, and the frequency are listed and displayed. 
     The three-view head image  913  has functions similar to those of the three-view head image  613  of the time-frequency analysis screen  601 , and includes sectional views  941  to  943  (an example of a sectional image) and a three-dimensional image  944 . The dipole that is selected from the dipole list  916  and the result of time-frequency analysis that is selected from the time-frequency analysis result list  918  (i.e., a heat map that indicates the distribution of the signal strength of the biomedical signal at the specified time and frequency that corresponds to the activity of the brain selected from the time-frequency analysis result list  918 ) are superimposed on the three-view head image  913 . A plurality of dipoles are selectable from the dipole list  916  in a similar manner to the dipole list  616  on the time-frequency analysis screen  601 , and the dipole display control unit  231  controls the display to display a plurality of dipoles that are selected from the dipole list  916  on the three-view head image  913 . In order to secure the viewability of the dipoles, for example, the dipole display control unit  231  may add a border to each of the dipoles, or may control the display to display the dipoles with the color selected from the color options displayed when dipoles are selected from the dipole list  916 . Such measures to secure the viewability of the dipoles may also be performed on the above three-view head image  613  of the time-frequency analysis screen  601  in a similar manner to the above. 
     Further, a plurality of results of the time-frequency analysis may be selected from the time-frequency analysis result list  918  on the time-frequency analysis and dipole display screen  901 . In such a case, the heat-map display control unit  232  controls the display as follows to superimpose a heat map that represents a plurality of results of the time-frequency analysis, which is selected from the time-frequency analysis result list  918 . 
     For example, the heat-map display control unit  232  may maintain the color of each pixel that is originally used in the drawing of a heat map. In such a configuration, when there are a plurality of nontransparent results (i.e., a plurality of sites or portions of the brain where no activity is detected), the heat-map display control unit  232  may color such a site or portion of the brain with, for example, a color on a upper side (or on a lower side) in the time-frequency analysis result list  918 , or an average color. Alternatively, the heat-map display control unit  232  may color such a site or portion of the brain with, for example, a color whose absolute value of one or a plurality of pixel values is the largest, or a pixel with the highest degree of reliability on the heat-map side. Due to such a configuration, no image is superimposed on a transparent site or portion of the brain (i.e., a site or portion of the brain where no activity is detected), and the display status is maintained as it is. As the pixel value of a heat map, for example, the largest value or the largest value of absolute values, the value obtained by performing normalization on each one of the heat maps with the largest value among all the pixel values or the largest value among the absolute values of all the pixel values, or the value with the highest degree of reliability may be used. In such a configuration, a color map that arranged on the bottom-right side of the three-view head image  913  may be used to adjust the assignment of pixel value and color. 
     As described above, at least one dipole and a plurality of results of the time-frequency analysis (a heat map that indicates the distribution of the signal strength of the biomedical signal at the specified time and frequency that corresponds to the activity of the brain selected from the time-frequency analysis result list  918 ) can be superimposed on the time-frequency analysis and dipole display screen  901 . Due to this configuration, whether or not the source of epilepsy is included in the range or area of the brain that is used in a plurality of types of normal activities can easily be determined. Moreover, as a dipole and a result of time-frequency analysis are display in an appropriate manner, analysis can easily be performed. 
       FIG. 67  is a flowchart of storing a plurality of results of time-frequency analysis and superimposing a result of time-frequency analysis and a dipole on the time-frequency analysis and dipole display screen  901 , according to the present embodiment. 
     With reference to  FIG. 67 , a flow of processes in the information processing device  50  are described below in which a plurality of results of the time-frequency analysis are stored through the time-frequency analysis screen  601  and those results of time-frequency analysis and a dipole are superimposed on the time-frequency analysis and dipole display screen  901 . 
     In a step S 21 , the analyst specifies the target activity of the brain (stimulation) (for example, visual perception, hearing, language, or somatic sensation) of the time-frequency analysis. Then, the process shifts to the processes in a step S 22 . 
     In a step S 22 , the analyst manipulates a cursor on the three-view head image  613  of the time-frequency analysis screen  601  to specify the position of the brain that corresponds to the specified activity of the brain, and the target time and frequency (i.e., the position on the heat map  611 ) at the specified position of the brain are specified on the heat map  611  that indicates the distribution of the signal strength of the biomedical signals, where the horizontal axis and the vertical axis indicate the time and the frequency, respectively. Then, the process shifts to step S 23 . 
     In a step S 23 , the analyst selects the already-estimated dipole from the dipole list  616 , and controls the display to display the selected dipole on the three-view head image  613 , on an as-needed basis. Then, while checking the heat map indicating the signal strength of the biomedical signals of the time and frequency corresponding to the position specified on the heat map  611 , which is displayed on each sectional view of the three-view head image  613 , the analyst specifies the position of the brain, the time, and the frequency that correspond to the finally-specified activity of the brain (stimulation), and touches or clicks the storage key  617 . When the storage key  617  is clicked or tapped, the analytical-result storage control unit  221  controls the storage unit  207  to store, for example, the specified site of the brain, time, frequency, peak list, and parameters for display, as the analysis data. Then, the process shifts to step S 24 . 
     When there is another target activity of the brain (stimulation) for analysis (“YES” in a step S 24 ), the process returns to the processes in the step S 21 . When there is no target activity of the brain (stimulation) (“NO” in the step S 24 ), the process shifts to the processes in a step S 25 . 
     When the time-frequency analysis and dipole display screen  901  is selected by the analyst from the analyzing screen switching list  605  of the time-frequency analysis screen  601 , the superimposition display control unit  222  controls the display to change the screen to the time-frequency analysis and dipole display screen  901  (step S 25 ). Then, the process shifts to a step S 26 . 
     In a step S 26 , the analyst selects at least one dipole from the dipole list  916  of the time-frequency analysis and dipole display screen  901 . Then, the process shifts to a step S 27 . 
     Further, the analyst selects a plurality of results of the time-frequency analysis from the time-frequency analysis result list  918  of the time-frequency analysis and dipole display screen  901  (step S 27 ). In some embodiments, the analyst may select one result of time-frequency analysis from the time-frequency analysis result list  918 . Then, the process shifts to the processes in a step S 28 . 
     In response to this operation, the dipole display control unit  231  controls the display to superimpose the at least one dipole selected from the dipole list  916  on the three-view head image  913  (step S 28 ). As described above, the heat-map display control unit  232  controls the display to superimpose a heat map that represents a plurality of results of the time-frequency analysis, which is selected from the time-frequency analysis result list  918 . 
     Due to the processes in the steps S 21  to S 28  as described above, a plurality of results of the time-frequency analysis are stored through the time-frequency analysis screen  601  of the information processing device  50 , and a plurality of results of the time-frequency analysis and a dipole are superimposed on the time-frequency analysis and dipole display screen  901 . 
       FIG. 68  is a diagram illustrating a state in which the time-frequency analysis and dipole display screen  901  includes a slider  919  that indicates the degree of reliability, according to a modification of the above embodiment. 
     The time-frequency analysis and dipole display screen  901  according to the present modification of the above embodiment is described below with reference to  FIG. 68 . 
     When the result of the dipole estimation is compared with the result of the time-frequency analysis, it is desired that such a comparison be based on objective and statistical data as much as possible. Regarding the dipole estimation, for example, a method in which a reliability volume is displayed is known in the art. As the reliability volume is indicated by the probability that a dipole is included in the range of that reliability volume (degree of reliability), preferably, the displayed probability is adjustable. In view of such circumstances, the time-frequency analysis and dipole display screen  901  as illustrated in  FIG. 68  includes the slider  919  by which the reliability in the reliability volume can be adjusted. The dipole that is selected from the dipole list  916  is displayed on the sectional view  941 , the sectional view  942 , and the sectional view  943  of the three-view head image  913  as a dipole  648   a , a dipole  648   b , and a dipole  648   c , respectively. On the three-view head image  913 , the dipole display control unit  231  controls the display to display a range  671   a , a range  671   b , and a range  671   c  on the sectional view  941 , the sectional view  942 , and on the sectional view  943 , respectively, as a range of the reliability volume. 
     In parallel with that, the result of the time-frequency analysis is also obtained by performing measurement a number of times. Accordingly, not only the values of several points but also the degree of reliability (risk) of each of those values can be obtained. The display can be switched using the obtained degree of reliability. The time-frequency analysis and dipole display screen  901  as illustrated in  FIG. 68  includes a slider  920  that is used to adjust the coloring range in a similar manner. In this configuration, the pixels where the values are considered to be inappropriate according to the specified level of risk are not colored. As described above, the results can be viewed in a more objective manner by switching the display according to the statistical plausibility. 
     In the above embodiment of the present disclosure and its modifications, when at least some of the multiple functional units of the biomedical-signal measuring system  1  is implemented by executing a program, such a program may be incorporated in advance in a read only memory (ROM) or the like. The program to be executed by the biomedical-signal measuring system  1  according to the above embodiment of the present disclosure and its modifications may be installed for distribution in any desired computer-readable recording medium such as a compact disc, a read-only memory (CD-ROM), a flexible disk (FD), a compact disc-recordable (CD-R), and a digital versatile disk (DVD) in a file format installable or executable by a computer. The program that is executed in the biomedical-signal measuring system  1  according to the above embodiment of the present disclosure and its modifications may be provided upon being stored in a computer connected to a network such as the Internet and downloaded through the network. A program to be executed by the biomedical-signal measuring system  1  according to the above embodiment of the present disclosure and its modifications may be provided or distributed through a network such as the Internet. A program to be executed by the biomedical-signal measuring system  1  according to the above embodiment of the present disclosure and its modifications has module structure including at least one of the above-described functional units. Regarding the actual hardware related to the program, the CPU  101  reads and executes the program from the memory as described above (e.g., the ROM  103 ) to load the program onto the main memory (e.g., the RAM  102 ) to implement the above multiple functional units. 
     Note that numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the disclosure of the present disclosure may be practiced otherwise than as specifically described herein. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims. 
     Each of the functions of the described embodiments may be implemented by one or more processing circuits or circuitry. Processing circuitry includes a programmed processor, as a processor includes circuitry. A processing circuit also includes devices such as an application specific integrated circuit (ASIC), digital signal processor (DSP), field programmable gate array (FPGA), and conventional circuit components arranged to perform the recited functions.