MEASUREMENT SYSTEM, MEASUREMENT APPARATUS, AND INFORMATION PROCESSING APPARATUS

A measurement system includes: a mounting member configured to be mounted on a measurement target portion of a living body and including a plurality of holding units configured to hold a plurality of magnetic sensors such that the plurality of magnetic sensors face the measurement target portion; an image capturing unit configured to capture images of markers arranged in arrangement regions of the plurality of holding units of the mounting member mounted on the measurement target portion, in the measurement target portion; a moving mechanism unit configured to move the image capturing unit relative to the measurement target portion on which the mounting member is mounted; and a derivation unit configured to derive three-dimensional position information on the plurality of magnetic sensors held by the plurality of holding units relative to the measurement target portion, based on the captured images of the markers.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2021-048803, filed on Mar. 23, 2021. The contents of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a measurement system, a measurement apparatus, and an information processing apparatus.

2. Description of the Related Art

A technique for detecting magnetic signals generated from a living body is known. For example, a holding member, such as a helmet, that holds a plurality of magnetic sensors is mounted on a measurement target portion, such as a head portion of a living body, and a magnetic signal at each of positions of the magnetic sensors is measured. Further, a technique for performing signal processing on the magnetic signal at each of the positions of the magnetic sensors and outputting a measurement image that represents the position at which the magnetic signal is generated in the measurement target portion has been known. To detect the position at which the magnetic signal is generated on the living body, it is necessary to identify three-dimensional position information on each of the magnetic sensors with respect to the measurement target portion of the living body.

As a technique for identifying the three-dimensional position information on the magnetic sensors, a technique for identifying the three-dimensional positions of the magnetic sensors by using captured images obtained by a plurality of stereo cameras is disclosed. Further, a technique for providing three-dimensional shape data of a target object viewed from a specific viewpoint by using a camera held by a photographer, and a technique for providing the three-dimensional position information on the magnetic sensors are disclosed.

However, in the method of using the captured images obtained by the stereo cameras, in some cases, it may be difficult to capture images of the magnetic sensors in an environment in which visual fields of the stereo cameras are not fully ensured. Further, in the method of using the camera held by the photographer, in some cases, it may be difficult to fully capture images of the magnetic sensors. Therefore, in the conventional technologies, it is difficult to obtain the three-dimensional position information on the magnetic sensors with high accuracy. In other words, in the conventional technologies, it is difficult to obtain the three-dimensional position information with high accuracy as the measurement positions of the magnetic signals in the measurement target portion of the living body.

Conventional techniques are described in Japanese Patent No. 3907753, Japanese Patent No. 5712640, Japanese Patent No. 5571128, Japanese Unexamined Patent Application Publication No. 2019-164109, “Recording brain activities in unshielded Earth's field with optically pumped atomic

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a measurement system includes a mounting member, an image capturing unit, a moving mechanism unit, and a derivation unit. The mounting member is configured to be mounted on a measurement target portion of a living body and including a plurality of holding units configured to hold a plurality of magnetic sensors such that the plurality of magnetic sensors face the measurement target portion. The image capturing unit is configured to capture images of markers arranged in arrangement regions of the plurality of holding units of the mounting member mounted on the measurement target portion, in the measurement target portion. The moving mechanism unit is configured to move the image capturing unit relative to the measurement target portion on which the mounting member is mounted. The derivation unit is configured to derive three-dimensional position information on the plurality of magnetic sensors held by the plurality of holding units relative to the measurement target portion, based on the captured images of the markers.

DESCRIPTION OF THE EMBODIMENTS

An embodiment has an object to provide a measurement system, a measurement apparatus, and an information processing apparatus that are able to obtain three-dimensional position information with high accuracy as a measurement position of a magnetic signal in a measurement target portion of a living body.

Embodiments of a measurement system, a measurement apparatus, and an information processing apparatus will be described in detail below with reference to the accompanying drawings.

First Embodiment

FIG. 1is a schematic diagram illustrating a measurement system1according to a first embodiment. The measurement system1includes a measurement apparatus10and an information processing apparatus50. The measurement apparatus10and the information processing apparatus50are communicably connected to each other.

The measurement apparatus10is an apparatus that measures a magnetic signal generated from a measurement target portion of a living body B. The living body B is an object that lives. The living body B is, for example, an animal, such as a human being. In the present embodiment, a case in which the living body B is a human being will be described as an example. The measurement target portion is a portion in which a magnetic signal is to be measured in the living body B. In the present embodiment, a case will be described in which the measurement target portion is a head portion H of the living body B.

The measurement apparatus10includes a housing12, a seat portion14, a mounting member16, image capturing units24, and a moving mechanism unit25.

The housing12is a member for holding or supporting various mechanisms in the measurement apparatus10. The seat portion14is a portion on which the living body B sits. The seat portion14is configured as a part of the housing12, for example. A magnetic signal generated from the head portion H is measured while the living body B is sitting on the seat portion14.

The mounting member16is a portion that is mounted on the head portion H of the living body B. The mounting member16includes a plurality of holding units18. The holding units18are members for holding a plurality of magnetic sensors20such that the magnetic sensors20face the head portion H. Holding the magnetic sensors20such that the magnetic sensors20face the head portion H means holding the magnetic sensors20such that measurement surfaces of the magnetic sensors20face the head portion H. In other words, the holding units18hold the magnetic sensors20such that the magnetic sensors20can measure magnetic signals generated from the head portion H. It is preferable that the holding units18are configured to be able to hold the magnetic sensors20such that the magnetic sensors20come into contact with the head portion H. The holding units18hold the magnetic sensors20in a detachably attachable manner.

FIG. 2Ais a schematic diagram of the mounting member16.FIG. 2Bis a schematic diagram of one of the holding units18.

The mounting member16has a shape that conforms to an outer shape of the head portion H that is one example of the measurement target portion. In the present embodiment, the mounting member16has a semispherical shape that conforms to the outer shape of the head portion H that has a spherical shape. In the present embodiment, the mounting member16is configured as a helmet that is worn on the head portion H.

The mounting member16may be formed in any shape as long as the shape conforms to the outer shape of the head portion H. A material of the mounting member16is not specifically limited. For example, the mounting member16may be formed of a hard material member that is made by a three-dimensional (3D) printer or the like, a soft material member that is made with fabric, resin, or the like, etc. The mounting member16may be made, in advance, with a material corresponding to the living body B, measurement contents, or the like.

FIG. 2Aillustrates one example of the mounting member16that is made with a hard material and that is made by a 3D printer or the like. In the mounting member16, the plurality of holding units18for holding the magnetic sensors20are arranged at different positions. The holding units18need not always be arranged over the entire region of the mounting member16as illustrated inFIG. 2Aas long as the holding units18are arranged on the mounting member16. In the present embodiment, a case in which the holding units18are arranged over the entire region of the mounting member16will be described as one example. In this case, it is possible to measure magnetic signals in the entire region of the head portion H on which the mounting member16is mounted or magnetic signals at arbitrary positions in the entire region.

FIG. 2AandFIG. 2Billustrate one example of the mounting member16in which the magnetic sensors20are not held. In the holding units18, sides on an inward side of the mounting member16are sides that face the head portion H and sides on an outward side of the mounting member16are sides on which the magnetic sensors20are inserted. The magnetic sensors20are inserted in the holding units18from the outward side to the inward side of the mounting member16and held by the holding units18, so that the magnetic sensors20are arranged so as to come into contact with or come close to a scalp of the head portion H.

Markers22are arranged in arrangement regions P of the holding units18of the mounting member16mounted on the head portion H, in the head portion H. The markers22may be arranged directly on the scalp of the head portion H or may be arranged on a cap that is put on the head portion H and that fits the head portion H.

The markers22are used to obtain three-dimensional position information on the magnetic sensors20that are held by the holding units18in the arrangement regions P of the markers22. The markers22are not specifically limited as long as the markers22are attachable to the head portion H.

It is not realistic to prepare the mounting member16in accordance with the head portion H of each of subjects as examples of the living body B. Therefore, one or the plurality common mounting members16are shared by a plurality of subjects. In this case, in some cases, a gap may be generated between an inner side of the mounting member16and the scalp of the head portion H because of a difference in a size of the head portion H of the subject and a size of the mounting member16. Therefore, the markers22are arranged in the arrangement regions P that are regions that come into contact with the magnetic sensors20in the head portion H, before the magnetic sensors20are held by the mounting member16. Further, the information processing apparatus50of the present embodiment uses the positions of the markers22as three-dimensional position information on the magnetic sensors20(details will be described later).

It is preferable that the markers22have cross-sectional shapes that conform to a surface of the head portion H when the markers22are arranged on the head portion H. Therefore, as a material and a thickness of each of the markers22, it is preferable to adopt a material and a thickness that allow deformation along an outer surface of the head portion H when the markers22are arranged on the head portion H. Specifically, it is preferable that the markers22has a certain thicknesses. Further, any material that can be bonded or fixed to the head portion H is applicable as the material of the markers22. Furthermore, any material that can easily be removed from the head portion H after completion of image capturing by the image capturing units24is applicable as the material of the markers22.

The markers22may have arbitrary shapes in a direction intersecting a thickness direction as long as the shapes have certain sizes that can be captured by the image capturing units24. For example, the markers22may be formed in arbitrary shapes, such as circular shapes or rectangular shapes, which are formed of curved sides or linear side. The markers22may have any colors as long as the colors are distinguishable on captured images that are captured by the image capturing units24.

The markers22are arranged in the arrangement regions P of the holding units18that hold the magnetic sensors20among the plurality of holding units18of the mounting member16. Therefore, the markers22may be arranged in the arrangement regions P of all of the holding units18provided in the mounting member16, or may be arranged in the arrangement regions P of some of the holding units18.

It is preferable that the holding units18of the mounting member16mounted on the head portion H have shapes such that at least parts of the markers22arranged in the arrangement regions P of the holding units18on the head portion H are not located in the blind areas when the image capturing units24perform image capturing as will be described later. In other words, it is preferable that the mounting member16has a shape that prevents the markers22from being located in the blind areas by the holding units18when the markers22are captured from outside of the mounting member16.

Specifically, in the present embodiment, each of the holding units18includes an opening18A in at least a part of a region that faces the head portion H in the holding unit18when the mounting member16is mounted on the head portion H. Further, each of the holding units18includes openings18D on side walls18C that connect the opening18A located in an inward direction of the mounting member16and an opening18B located in an outward direction of the mounting member16in the holding unit18. Therefore, the mounting member16is able to prevent the markers22from being shadowed by the holding units18and located in the blind areas of the image capturing units24when the markers22are captured from a camera viewpoint outside the mounting member16. In other words, the mounting member16is able to prevent missing of the markers22in captured images that are captured by the image capturing units24(to be described later) when image capturing is performed when the mounting member16is mounted on the head portion H.

Meanwhile, each of the holding units18need not always be formed in the shape as illustrated inFIG. 2B, but may be formed in any shape as long as it is possible to prevent the markers22from being located in the blind areas by the holding units18.

In some cases, there may be a difference between the size of the head portion H and the size of the mounting member16depending on a living body B as a subject. In this case, the holding units18may further include configurations that can hold the magnetic sensors20while the magnetic sensors20come into contact with the scalp of the head portion H.

FIG. 3is a schematic diagram illustrating an example of the magnetic sensors20. The magnetic sensors20are held by the holding units18of the mounting member16such that the magnetic sensors20come into contact with or come close to the head portion H.

Each of the magnetic sensors20is, for example, a room-temperature magnetic sensor. The room-temperature magnetic sensor is a magnetic sensor for which a cooling mechanism is not needed. Examples of the room-temperature magnetic sensor include a magneto resistive sensor and an atomic magnetic sensor. Examples of the atomic magnetic sensor include an optically pumped atomic magnetic sensor. Any magnetic sensor may be selected in accordance with a measurement purpose and may be used as the magnetic sensors in the measurement apparatus10.

In the measurement apparatus10of the present embodiment, a plurality of cancel coils21are arranged around the magnetic sensors20. The cancel coils21are one example of environmental magnetic field reduction coils for reducing residual magnetic fields. The magneto resistive sensor or the atomic magnetic sensor operates under a residual magnetic field equal to or less than a certain level. Therefore, the cancel coils21form magnetic field regions in which the magnetic sensors20are operable.

FIG. 3illustrates a configuration in which a cancel coil21A is arranged on a side of each of the magnetic sensors20facing the head portion H and a cancel coil21B is arranged on the opposite side. Meanwhile, the number of the cancel coils21may be arbitrary as long as the residual magnetic fields at which the magnetic sensors20are operable or less can be obtained. Therefore, the number of the cancel coils21arranged for each of the magnetic sensors20is not limited to two, and may be adjusted in accordance with a usage environment or characteristics of the magnetic sensors20.

In the information processing apparatus50to be described later, values of currents that flow through the cancel coils21are optimized in accordance with output of a magnetic field sensor that is used to measure an effect of reduction of environmental magnetism by the cancel coils21. Through this process, the information processing apparatus50adjusts a magnetic field to a desired magnetic field (details will be described later).

Referring back toFIG. 1, explanation is continued. The moving mechanism unit25will be described below.

The moving mechanism unit25is a moving mechanism that moves the image capturing units24relative to the head portion H of the living body B on which the mounting member16is mounted. The moving mechanism unit25is a mechanical unit that moves the image capturing units24such that the image capturing units24move around the head portion H.

The image capturing units24capture images of the markers22arranged in the arrangement regions P of the holding units18. In the present embodiment, a device that obtains a captured image including distance information is used as the image capturing units24. The image capturing units24are, for example, cameras of a time-of-flight (ToF) system, stereo cameras, or the like. The ToF system is a system to obtain a distance by applying infrared light to a measurement object and calculating a time taken by reflected light to return. The stereo camera is a camera that obtains depth information as the distance information by using an interval between two cameras and disparity information on images obtained by the two respective cameras. A camera that can obtain three-dimensional position information with necessary accuracy may be selected as the image capturing units24.

FIG. 4is an enlarged schematic diagram of the moving mechanism unit25. The moving mechanism unit25includes a support member26and a rotation driving unit28. The support member26includes a support member26A and a shaft26B.

The support member26A is a member that supports the image capturing units24such that the image capturing units24face the head portion H. Supporting the image capturing units24such that the image capturing units24face the head portion H means supporting the image capturing units24such that lens surfaces of the image capturing units24face the head portion H. In other words, the support member26A supports the image capturing units24such that the image capturing units24are able to capture images of the markers22on the head portion H.

In the present embodiment, the support member26A has a shape that is extended from a top portion of the mounting member16along the outer shape of the mounting member16. The top portion of the mounting member16is arranged at a position corresponding to a parietal region of the head portion H when the mounting member16is mounted on the head portion H. As described above, in the present embodiment, the mounting member16has a semispherical shape. Therefore, in the present embodiment, the support member26A has a circular arc shape that conforms to the semispherical outer shape of the mounting member16. It is preferable that a curvature of the support member26A substantially matches a curvature of the outer shape of the mounting member16.

The support member26A supports the plurality of image capturing units24at different positions in an extending direction thereof.

Specifically, the support member26A having the circular arc shape supports the plurality of image capturing units24at intervals along the extending direction of the support member26A. In the present embodiment, the support member26A supports an image capturing unit24A, an image capturing unit24B, and an image capturing unit24C. An arrangement direction of the plurality of image capturing units24matches the extending direction of the support member26A. Further, the plurality of image capturing units24are arranged in advance such that visual fields of the image capturing units24located adjacent to each other in the arrangement direction partly overlap with each other. Meanwhile, the number of the image capturing units24supported by the support member26A is not limited to three.

One end portion of the support member26A in the extending direction is supported by the shaft26B. One end portion of the support member26A in a bending direction is adjusted in advance so as to be located at a position corresponding to the parietal region of the head portion H. In other words, one end portion of the support member26A in the extending direction is adjusted in advance so as to be located at a position corresponding to the top portion of the semispherical mounting member16that is mounted on the head portion H.

The shaft26B is a linear bar-shaped member. One end portion of the shaft26B is connected to the support member26A, and the other end portion is connected to the housing12via the rotation driving unit28.

The rotation driving unit28rotates the support member26A about the head portion H as a rotation center. Specifically, in the present embodiment, the rotation driving unit28rotates the support member26A about the shaft26B as a rotation axis. Therefore, the shaft26B and the support member26A are driven to rotate in a direction of arrow R. Further, the rotation driving unit28rotates the support member26A in an angular range of more than 360 degrees.

The shaft26B is a shaft extended along a virtual axis F that passes through a position of the support member26A facing the top portion of the mounting member16and that passes through the top portion of the mounting member16. Therefore, the image capturing units24supported by the support member26A rotate around the head portion H on which the mounting member16is mounted. Further, by causing the image capturing units24to capture images during the rotation, images of the entire region of the mounting member16are captured.

In the present embodiment, when the image capturing units24capture images of the mounting member16, the image capturing is performed in a state in which the markers22are set in the arrangement regions P of the holding units18on the head portion H and the mounting member16is mounted on the head portion H. Therefore, the plurality of image capturing units24that rotate around the head portion H along with the rotation of the support member26A are able to obtain captured images in which the markers22and the mounting member16set on the head portion H are captured at various angles.

FIG. 5is a schematic diagram illustrating examples of captured images30. InFIG. 5, captured images30A1to30A4are examples of the captured images30that are captured by the image capturing unit24A. Captured images30B1to30B4are examples of the captured images30that are captured by the image capturing unit24B. Captured images30C1to30C4are examples of the captured images30that are captured by the image capturing unit24C.

Further, the captured image30A1, the captured image30B1, and the captured image30C1are examples of the captured images30that are obtained when the image capturing units24are located in front of a face of the head portion H of the living body B who is sit on the seat portion14. The captured image30A2, the captured image30B2, and the captured image30C2are examples of the captured images30that are obtained when the image capturing units24are located at positions rotated by 45 degrees from the front of the face of the head portion H of the living body B who sits on the seat portion14. The captured image30A3, the captured image30B3, and the captured image30C3are examples of the captured images30that are obtained when the image capturing units24are located at positions rotated by 90 degrees from the front of the face of the head portion H of the living body B who sits on the seat portion14. The captured image30A4, the captured image30B4, and the captured image30C4are examples of the captured images30that are obtained when the image capturing units24are located at positions rotated by 135 degrees from the front of the face of the head portion H of the living body B who sits on the seat portion14.

Referring back toFIG. 1, explanation is continued. The image capturing units24output the captured images30to the information processing apparatus50.

The information processing apparatus50controls the moving mechanism unit25. Further, the information processing apparatus50derives the three-dimensional position information on the magnetic sensors20held by the holding units18with respect to the head portion H by using the captured images30acquired from the measurement apparatus10. Furthermore, the information processing apparatus50generates an image that represents a measurement result from the derived three-dimensional position information and the magnetic signal of the head portion H obtained from each of the magnetic sensors20.

FIG. 6is an exemplary functional block diagram of the measurement system1.

The measurement apparatus10includes the rotation driving unit28, the image capturing units24, the magnetic sensors20, the cancel coils21, and a magnetic field sensor23. The magnetic field sensor23is a sensor that measures a magnetic field around the magnetic sensors20.

The information processing apparatus50includes a communication unit52, a user interface (UI) unit54, a storage unit56, and a processing unit60. The communication unit52, the UI unit54, the storage unit56, and the processing unit60are communicably connected to one another.

The communication unit52communicates with an external information processing apparatus via a network or the like. In the present embodiment, the communication unit52communicates with the measurement apparatus10.

The UI unit54has an input function to receive an operation instruction from a user and a display function to display various kinds of information. The input function is, for example, a keyboard, a pointing device, a microphone, or the like. The display function is, for example, a display, a projection apparatus, or the like. Meanwhile, the UI unit54may be a touch panel that has the input function and the display function.

The storage unit56stores therein various kinds of information.

The processing unit60performs information processing. The processing unit60includes a first determination unit60A, a drive control unit60B, a captured image acquisition unit60C, a derivation unit60D, a second determination unit60E, a magnetic field adjustment unit60F, a measurement result acquisition unit60G, an image generation unit60H, and an output unit60I. The first determination unit60A, the drive control unit60B, the captured image acquisition unit60C, the derivation unit60D, the second determination unit60E, the magnetic field adjustment unit60F, the measurement result acquisition unit60G, the image generation unit60H, and the output unit60I are implemented by a single or a plurality of processors, for example. For example, each of the units as described above may be implemented by causing a processor, such as a central processing unit (CPU), to execute a program, in other words, by software. Each of the units as described above may be implemented by a processor, such as a dedicated integrated circuit (IC), in other words, by hardware. Each of the units as described above may be implemented by both of software and hardware. If the plurality of processors are used, each of the processors may implement one of the units or may implement two or more of the units.

Further, at least one of the units as described above may be mounted on a cloud computing server that performs a process on cloud computing.

The first determination unit60A determines whether the mounting member16that does not hold the magnetic sensors20is mounted on the head portion H.

For example, a user, such as a person who is responsible for measurement, mounts the mounting member16from which all of the magnetic sensors20are detached onto the head portion H of the subject who is sitting on the seat portion14of the measurement apparatus10, and inputs information indicating mounting completion. For example, as illustrated inFIG. 1, the mounting member16is mounted on the head portion H of the living body B as the subject who is sitting on the seat portion14. Meanwhile, it is preferable to fix the mounting member16to the head portion H with a band member or the like to prevent the mounting member16from moving from the head portion H even if the head portion H of the subject slightly moves. Furthermore, if hair of the head portion H of the subject may disturb the measurement, it is preferable to put a cap that fits the head portion H onto the head portion H to reduce a thickness of the hair and thereafter mount the mounting member16on the head portion H.

The user operates the UI unit54to input the information indicating mounting completion. The first determination unit60A determines whether the information indicating mounting completion is received from the UI unit54to determine whether the mounting member16that does not hold the magnetic sensors20is mounted the head portion H.

Further, the first determination unit60A determines whether the markers22are arranged in the arrangement regions P of the head portion H. The user arranges the markers22in the arrangement regions P of the holding units18of the mounting member16on the head portion H. It is sufficient for the user to arrange the markers22in the arrangement regions P of the holding units18that are adopted as targets to which the magnetic sensors20are mounted among the plurality of holding units18arranged in the mounting member16. Then, after arranging the markers22, the user operates the UI unit54to input information indicating completion of arrangement of the markers22. The first determination unit60A determines whether the information indicating completion of arrangement of the markers22is received from the UI unit54to determine whether the markers22are arranged in the arrangement regions P on the head portion H.

Meanwhile, in some cases, only a partial region of the mounting member16may be adopted as a region in which a magnetic signal is to be measured on the head portion H. In this case, it is sufficient to arrange the markers22in the arrangement regions P of the holding units18that are adopted as targets for holding the magnetic sensors20among the plurality of holding units18arranged in the mounting member16.

Furthermore, at this time, the image capturing units24may capture images of magnetic markers that are separately arranged on the head portion H, in addition to capturing images of the markers22that are used to obtain the three-dimensional position information on the magnetic sensors20. The magnetic markers may be used for positional alignment when a magnetoencephalograph (MEG) image that is generated based on magnetic signals of the magnetic sensors20, a separately captured magnetic resonance imaging (MRI) image of the head portion H, and the like are synthesized. In this case, the user may further set the magnetic markers on the head portion H.

The drive control unit60B controls drive of the rotation driving unit28. The drive control unit60B rotates the rotation driving unit28such that an angular range in which the support member26A rotates is equal to or larger than 360 degrees. Through the control by the drive control unit60B, the support member26A that supports the plurality of image capturing units24rotates in the angular range of more than 360 degrees by using the shaft26B as the rotation axis. If rotation drive of the support member26A is started due to the control by the rotation driving unit28, the image capturing units24start to capture images. Meanwhile, the image capturing units24may start to capture images due to control by the processing unit60.

For example, the rotation driving unit28stops rotation of the support member26A every time the support member26A rotates by a predetermined angle. The image capturing unit24A and the image capturing unit24B arranged on the support member26A simultaneously or sequentially capture images of the head portion H on which the mounting member16is mounted, every time the rotation of the support member26A is stopped. Therefore, by repetition of a series of processes including rotation of the support member26A by the predetermined angle, stop of the rotation of the support member26A, and image capturing by the image capturing units24, images of all of the arranged markers22are captured.

Meanwhile, in some cases, the captured images30in which some parts of the markers22are hidden by the holding units18may be obtained when the images of the markers22are captured. However, as described above with reference toFIG. 2B, the openings18D are arranged on the side walls18C of the holding units18. Therefore, at least parts of the markers22are captured by the image capturing units24. In other words, it is possible to increase the number of pixels of the markers22to be captured as compared to a configuration in which the openings18D are not arranged.

The captured image acquisition unit60C acquires the captured images30captured by the image capturing units24. By causing the image capturing units24to perform image capturing during rotation of the support member26A, it is possible to obtain the plurality of captured images30as illustrated inFIG. 5, for example.

As illustrated inFIG. 5, in some cases, the captured images30in which the markers22are hidden by shadows caused by the mounting member16or the configurations of the holding units18rather than the visual fields of the image capturing units24and some parts of the markers22are missing may be obtained. However, the image capturing units24rotate around the mounting member16mounted on the head portion H along with the rotation of the support member26A that supports the image capturing units24. Therefore, as illustrated inFIG. 5, along with the rotation, the marker22that is lost in an image captured at a rotation position is captured without being lost at another rotation position. The drive control unit60B adjusts angular intervals of rotation angles at which the image capturing units24capture images, so that it is possible to reduce missing areas of the markers22.

Meanwhile, if a configuration for obtaining the captured images30that are captured while the image capturing units24rotate around the head portion H once is adopted, it is sufficient to set the rotation angle of the support member26to reach 360 degrees in conjunction with a viewing angle of each of the image capturing units24. Further, if a configuration for obtaining the captured images30that are captured while the image capturing units24rotate around the head portion H more than once is adopted, it is sufficient to set the rotation angle of the support member26to reach 360 degrees or more in conjunction with the viewing angle of each of the image capturing units24.

Furthermore, if the magnetic sensors20are held by only some of the holding units18arranged in the mounting member16, the markers22are arranged in only the arrangement regions P of the some of the holding units18on the head portion H. In this case, the rotation angle of the support member26may be set to reach 360 degrees or less in conjunction with the viewing angle of each of the image capturing units24.

In other words, it is sufficient for the drive control unit60B to rotate the support member26by a rotation angle that is needed to derive accurate three-dimensional position coordinate information on the markers22arranged on the head portion H.

Referring back toFIG. 6, explanation is continued. The derivation unit60D derives the three-dimensional position information on the magnetic sensors20held by the holding units18with respect to the head portion H, on the basis of the captured images30of the markers22.

The derivation unit60D extracts the markers22from the captured images30that are obtained by capturing images of the mounting member16in various angular directions and that include the distance information. Meanwhile, it is assumed that the information processing apparatus50measures, in advance, an absolute three-dimensional position coordinate of at least one of the markers22by using a three-dimensional digitizer or the like.

Then, the derivation unit60D derives the three-dimensional position information on each of the extracted markers22by using the iterative closest point (ICP) algorithm. The ICP algorithm is a method of obtaining a solution that minimizes an error function through iterative calculation by using a portion that is redundantly measured among a plurality of distance images.

The derivation unit60D obtains, from the three-dimensional position information on an outline of any of the markers22, a position of center of gravity of the marker22as the three-dimensional position coordinate of the marker22. Meanwhile, the derivation unit60D may first derive the three-dimensional position information on the outline from a continuous curve or a continuous straight line that forms the outline of the marker22, and thereafter obtain the position of the center of gravity of the marker22as the three-dimensional position coordinate of the marker22. Further, the derivation unit60D may obtain the position of the center of gravity in accordance with the shape of the magnetic sensor20from three-dimensional position information on outline of several points of the marker22, and adopt the position of the center of gravity as the three-dimensional position coordinate of the marker22. Furthermore, it may be possible to obtain an identifiable point, such as a position of a top point of a side that forms the outline of the marker22, instead of the position of the center of gravity, as the three-dimensional position coordinate of the marker22.

Then, the derivation unit60D obtains the three-dimensional position coordinate of each of the other markers22from relative position information on the other markers22, with reference to the obtained three-dimensional position coordinate of the marker22.

Positional alignment with a real space may be performed by obtaining a three-dimensional position coordinate in the real space on the basis of a relative three-dimensional position coordinate with respect to the marker22that is used as a reference, by using a three-dimensional digitizer.

As described above, the markers22have shapes, such as circular shapes or rectangular shapes, that are formed of straight lines or curved lines and that have thicknesses. Therefore, in some cases, all or a part of the markers22are not captured due to shadows caused by the configurations of the holding units18when the image capturing units24capture images. However, in the present embodiment, the holding units18include the openings18D and the captured image acquisition unit60C acquires the plurality of captured images30for each of the markers22. Therefore, the derivation unit60D is able to accurately derive the three-dimensional position information on each of the markers22.

Further, if a magnetic marker is included in any of the captured images30, a three-dimensional position coordinate of each of the magnetic markers arranged on the head portion H may be derived in the same manner.

The second determination unit60E determines whether holding of the magnetic sensors20by the holding units18is completed.

For example, after deriving the three-dimensional position information on each of the markers22, the derivation unit60D performs power control of turning off power of each of the rotation driving unit28and the image capturing units24, and the derivation unit60D displays information indicating completion of derivation of the three-dimensional position on the UI unit54. If the information indicating completion of derivation of the three-dimensional position is displayed on the UI unit54, the user removes the markers22from the head portion H of the living body B, and sets the magnetic sensors20on the mounting member16at the positions of the markers22. In this case, the magnetic sensors20are mounted such that a gap between each of the magnetic sensors20and the scalp of the head portion H is reduced to nearly zero, in other words, the magnetic sensors20come into contact with the scalp of the head portion H.

Meanwhile, when the magnetic sensors20are set to the holding units18, it is preferable to perform setting such that the mounting member16is not moved relative to the head portion H. After all of the magnetic sensors20that are holding targets are held by the holding units18, the user operates the UI unit54to input information indicating completion of holding of the magnetic sensors20. Upon receiving the information indicating the completion of the holding, the second determination unit60E determines that the holding of the magnetic sensors20by the holding units18is completed.

The magnetic field adjustment unit60F adjusts a magnetic field. The magnetic field adjustment unit60F performs feedback control of causing electrical currents to flow through the cancel coils21and setting current values of the cancel coils21such that a magnetic field measurement result of the magnetic field sensor23reaches a desired environmental magnetic field or less.

The measurement result acquisition unit60G acquires a magnetic signal that is measured under an environment at a predetermined environmental magnetic field or less, from each of the magnetic sensors20held by the holding units18.

The image generation unit60H generates an image that represents a measurement result by using the three-dimensional position information on each of the magnetic sensors20that is derived by the derivation unit60D and the magnetic signal that is obtained by each of the magnetic sensors20and acquired by the measurement result acquisition unit60G.

For example, the image generation unit60H generates an MEG image that represents a position of the head portion H at which the magnetic signal is generated, by using the three-dimensional position information on each of the magnetic sensors20and the magnetic signal obtained by each of the magnetic sensors20.

Further, the image generation unit60H may further generate an image in which the MEG image and an MRI image of the head portion H that is separately captured are synthesized by using, for positional alignment, the three-dimensional position information on the magnetic marker included in the captured image30acquired by the captured image acquisition unit60C.

Meanwhile, in the present embodiment, a case will be described in which the measurement target portion is the head portion H, for example. Therefore, a case will be described in which the image generation unit60H generates an MEG image, for example. However, it is sufficient for the image generation unit60H to generate an image corresponding to the measurement target portion of the living body B. For example, the image generation unit60H may generate a magnetocardiograph (MCG) image, a magnetospinography (MSG) image, or the like in accordance with the measurement target portion.

The output unit60I outputs the image that represents the measurement result and that is generated by the image generation unit60H to the UI unit54. Further, the output unit60I may output an image that represents the measurement result to an external information processing apparatus via the communication unit52.

A flow of information processing performed by the information processing apparatus50of the present embodiment will be described below.

FIG. 7is a flowchart illustrating an example of the flow of the information processing performed by the information processing apparatus50of the present embodiment.

The first determination unit60A determines whether the mounting member16that does not hold the magnetic sensors20is mounted on the head portion H (Step S100). The first determination unit60A repeats negative determination until it is determined that the information indicating mounting completion is received from the UI unit54(NO at Step S100). If the first determination unit60A determines that the information indicating mounting completion is received from the UI unit54(YES at Step S100), the process goes to Step S102.

At Step S102, the first determination unit60A determines whether the markers22are arranged in the arrangement regions P (Step S102). The first determination unit60A repeats negative determination until it is determined that the information indicating completion of arrangement of the markers22is received from the UI unit54(NO at Step S102). If it is determined that the information indicating completion of arrangement of the markers22is received (YES at Step S102), the process goes to Step S104.

At Step S104, the drive control unit60B controls drive of the rotation driving unit28(Step S104). The drive control unit60B causes the rotation driving unit28to stop rotation of the support member26A every time the support member26A rotates by the predetermined angle. Then, the drive control unit60B causes an image of the head portion H, on which the markers22are arranged and the mounting member16is mounted, to be captured every time the rotation of the support member26A is stopped. Therefore, by repetition of a series of processes including rotation of the support member26A by the predetermined angle, stop of the rotation of the support member26A, and image capturing by the image capturing units24, images of all of the arranged markers22are captured.

The captured image acquisition unit60C acquires the captured images30that are captured by the image capturing units24through the drive control performed at Step S104(Step S106). For example, the captured image acquisition unit60C acquires the plurality of captured images30as illustrated inFIG. 5.

The derivation unit60D derives the three-dimensional position information on the magnetic sensors20held by the holding units18with respect to the head portion H, on the basis of the captured images30of the markers22acquired at Step S106(Step S108).

The second determination unit60E determines whether holding of the magnetic sensors20by the holding units18is completed (Step S110). The second determination unit60E repeats negative determination until it is determined that the information indicating completion of the holding is received from the UI unit54(NO at Step S110). If it is determined that the information indicating the completion of the holding completion is received (YES at Step S110), the process goes to Step S112.

At Step S112, the magnetic field adjustment unit60F adjusts the magnetic field (Step S112). The magnetic field adjustment unit60F performs feedback control of causing electrical currents to flow through the cancel coils21and setting current values of the cancel coils21such that a magnetic field measurement result of the magnetic field sensor23reaches a desired environmental magnetic field or less.

The measurement result acquisition unit60G acquires the measurement results from the magnetic sensors20(Step S114). The measurement result acquisition unit60G acquires, as the measurement result, the magnetic signal measured by each of the magnetic sensors20under an environment at the predetermined environmental magnetic field through the process at Step S112, form each of the magnetic sensors20held by the holding units18(Step S114).

The image generation unit60H generates an image that represents the measurement result by using the three-dimensional position information on each of the magnetic sensors20that is derived at Step S108and the magnetic signal that is obtained by each of the magnetic sensors20and that is acquired at Step S114(Step S116). For example, the image generation unit60H generates an MEG image that represents a position of the head portion H at which the magnetic signal is generated, by using the three-dimensional position information on each of the magnetic sensors20and the magnetic signal obtained by each of the magnetic sensors20. Further, the image generation unit60H may further generate an image in which the MEG image and an MRI image of the head portion H that is separately captured are synthesized.

The output unit60I outputs the image that represents the measurement result and that is generated at Step S116to at least one of the UI unit54and an external information processing apparatus (Step S118). Then, the routine is finished.

As described above, the measurement system1of the present embodiment includes the mounting member16, the image capturing units24, the moving mechanism unit25, and the derivation unit60D. The mounting member16is mounted on the head portion H that is one example of the measurement target portion of the living body B, and includes the plurality of holding units18for holding the plurality of magnetic sensors20such that the magnetic sensors20face the head portion H. The image capturing units24capture images of the markers22that are arranged in the arrangement regions P of the holding units18of the mounting member16mounted on the head portion H, on the head portion H. The moving mechanism unit25moves the image capturing units24relative to the head portion H on which the mounting member16is mounted. The derivation unit60D derives the three-dimensional position information on the magnetic sensors20held by the holding units18with respect to the head portion H, on the basis of the captured images30of the markers22.

In this manner, in the measurement system1of the present embodiment, the moving mechanism unit25moves the image capturing units24relative to the head portion H on which the mounting member16is mounted. The image capturing units24capture images of the markers22arranged in the arrangement regions P of the holding units18of the mounting member16that is mounted on the head portion H.

Therefore, in the measurement system1of the present embodiment, it is possible to automatically capture images of the markers22, which are arranged in the arrangement regions P of the holding units18on the head portion H, in various directions. Further, the derivation unit60D derives the three-dimensional position information on the magnetic sensors20held by the holding units18with respect to the head portion H, on the basis of the captured images30of the markers22. Therefore, in the measurement system1of the present embodiment, even if at least a part of the markers22in the single captured image30is lost, it is possible to accurately derive the three-dimensional position information on the markers22by using the captured images30that are captured in various directions.

Consequently, in the measurement system1of the present embodiment, it is possible to obtain the three-dimensional position information with high accuracy as the measurement position of the magnetic signal in the measurement target portion of the living body B.

Furthermore, in the measurement system1of the present embodiment, an image, such as an MEG image, that represents the measurement result is generated by using the three-dimensional position information on each of the magnetic sensors20that is accurately derived and the magnetic signal that is obtained by each of the magnetic sensors20. Therefore, in the measurement system1of the present embodiment, it is possible to provide a highly-accurate image that represents a position at which the magnetic signal is generated in the measurement target portion, such as the head portion H.

Moreover, the holding units18of the present embodiment have shapes such that at least parts of the markers22arranged in the arrangement regions P on the head portion H are not located in blind areas of the image capturing units24. Therefore, the derivation unit60D is able to derive the three-dimensional position information on the markers22with higher accuracy, on the basis of the captured images30of the markers22.

Meanwhile, in the present embodiment, the case has been described, as one example, in which the measurement apparatus10includes the seat portion14and the subject as the living body B is subjected to measurement of the magnetic signal while the subject is sitting on the seat portion14. However, the measurement apparatus10may measure the magnetic signal of the subject in a standing position or in a supine position. In the case of the standing position, the same configuration as illustrated inFIG. 1is applicable. In the case of the supine position, it is sufficient to provide a board, such as a bed, on which the subject can lie down instead of the seat portion14. Furthermore, in this case, a configuration in which the mounting member16is fixed to the housing12, the head portion H of the subject is inserted in the mounting member16with movement of the subject, and the mounting member16is mounted on the head portion H may be applicable.

Second Embodiment

In a second embodiment, a configuration in which a moving mechanism unit25B different from the first embodiment is provided as the moving mechanism unit25will be described. Meanwhile, in the present embodiment, the same functional components as those of the first embodiment as described above are denoted by the same reference symbols and detailed explanation thereof will be omitted.

FIG. 8is a schematic diagram of a measurement system1B according to the present embodiment. The measurement system1B includes a measurement apparatus10B and an information processing apparatus62. The measurement apparatus10B and the information processing apparatus62are communicably connected to each other.

The measurement apparatus10B has the same configuration as the measurement apparatus10of the first embodiment except that the measurement apparatus10B includes the moving mechanism unit25B instead of the moving mechanism unit25. Therefore, differences from the first embodiment as described above will be described in detail below.

The moving mechanism unit25B is, similarly to the moving mechanism unit25, a moving mechanism that moves the image capturing units24relative to the head portion H of the living body B on which the mounting member16is mounted. In the present embodiment, the moving mechanism unit25B rotates and moves the image capturing units24in a direction along a central axis that is a rotation axis of the rotation.

FIG. 9is an enlarged schematic diagram of the moving mechanism unit25B. The moving mechanism unit25B includes a support member36, the rotation driving unit28, and a movement driving unit29. The support member36includes a support member36A and a shaft36B.

The support member36A is a member that supports the image capturing units24such that the image capturing units24face the head portion H. In other words, the support member36A supports the image capturing units24such that the image capturing units24are able to capture images of the markers22on the head portion H.

In the present embodiment, the support member36A has a shape that is extended from the top portion of the mounting member16along the outer shape of the mounting member16. As described above, the mounting member16has a semispherical shape. Therefore, in the present embodiment, the support member36A has a circular arc shape that conforms to the semispherical outer shape of the mounting member16. It is preferable that a curvature of the support member36A approximately matches a curvature of the outer shape of the mounting member16.

In the present embodiment, the support member36A has a shape that is extended from the top portion of the mounting member16and is branched in two opposing directions toward an opening, in which the head portion H is inserted, along the outer shape of the mounting member16. Further, the support member36A supports the image capturing units24at opposing positions across the mounting member16.

In the present embodiment, the support member36A holds an image capturing unit24D in one end portion in an extending direction of the support member36A having a circular arc shape, and holds an image capturing unit24E at the other end portion in the extending direction. The image capturing unit24D and the image capturing unit24E are one example of the image capturing units24.

Each of the image capturing unit24D and the image capturing unit24E is held so as to be able to change an image capturing direction at each of the positions held by the support member36A. Specifically, as illustrated inFIG. 9, each of the image capturing unit24D and the image capturing unit24E is held so as to be able to change the image capturing direction to a direction D1along a rotation axis F and a direction D2that intersects with the direction D1. Specifically, a direction driving unit31is arranged in each of the image capturing unit24D and the image capturing unit24E. The direction driving unit31changes the image capturing direction of each of the image capturing unit24D and the image capturing unit24E along the direction D1and the direction D2.

The shaft36B is a linear bar-shaped member. One end portion of the shaft36B is connected to the support member36A, and the other end portion is connected to the housing12via the rotation driving unit28and the movement driving unit29.

The rotation driving unit28rotates the support member36A about the head portion H as a rotation center. Specifically, in the present embodiment, the rotation driving unit28rotates the support member36A about the shaft36B as a rotation axis. Therefore, the shaft36B and the support member36A are driven to rotate in the direction of arrow R. The rotation driving unit28rotates the support member36A in an angular range of more than 360 degrees.

The shaft36B is a shaft extended along the virtual axis F that passes through a position of the support member36A facing the top portion of the mounting member16and that passes through the top portion of the mounting member16. Therefore, the image capturing units24supported by the support member36A rotate around the head portion H on which the mounting member16is mounted. Further, by causing the image capturing units24to capture images during the rotation, images of the entire region of the mounting member16are captured.

Furthermore, in the present embodiment, the movement driving unit29moves the support member36A in a direction along the rotation axis of the rotation of the support member36A. Specifically, the movement driving unit29moves the support member36A in an extending direction of the shaft36B that serves as the rotation axis of the support member36A. In other words, in the example illustrated inFIG. 9, the movement driving unit29moves the support member36A along a direction of arrow X.

FIG. 10is an exemplary functional block diagram of the measurement system1B.

The measurement apparatus10B includes the rotation driving unit28, the image capturing units24, the magnetic sensors20, the cancel coils21, the magnetic field sensor23, the movement driving unit29, and the direction driving unit31.

The information processing apparatus62includes the communication unit52, the UI unit54, the storage unit56, and a processing unit64. The communication unit52, the UI unit54, the storage unit56, and the processing unit64are communicably connected to one another. The information processing apparatus62is the same as the processing unit60of the first embodiment as described above except that the information processing apparatus62includes the processing unit64instead of the processing unit60.

The processing unit64includes the first determination unit60A, a drive control unit64B, the captured image acquisition unit60C, the derivation unit60D, the second determination unit60E, the magnetic field adjustment unit60F, the measurement result acquisition unit60G, the image generation unit60H, and the output unit60I. The processing unit64is the same as the processing unit60of the first embodiment as described above except that the processing unit64includes the drive control unit64B instead of the drive control unit60B.

The drive control unit64B controls drive of the rotation driving unit28, the movement driving unit29, and the direction driving unit31. The drive control unit64B rotates the rotation driving unit28such that an angular range in which the support member36A rotates is equal to or larger than 180 degrees. Further, the drive control unit64B controls the movement driving unit29such that the support member36A moves along the extending direction of the shaft36B. Furthermore, the drive control unit64B controls the direction driving unit31such that the image capturing directions of the image capturing units24are changed.

Therefore, the image capturing unit24D and the image capturing unit24E that are the two image capturing units24arranged at both end portions in the extending direction of the support member36A rotate about the shaft26B as the rotation axis, move along an extending direction of the shaft26B, and capture images of the markers22on the mounting member16while changing the image capturing directions.

FIG. 11Ais a diagram for explaining an example of a movement pattern of one of the image capturing units24under the control of the drive control unit64B.FIG. 11Aillustrates an example of the movement pattern of the image capturing unit24D.

As illustrated inFIG. 11A, for example, the drive control unit64B controls the rotation driving unit28and the movement driving unit29such that the image capturing unit24D moves to a position A, a position A′, a position B′, a position B, a position C, a position C′, a position D′, and a position D in this order.

Specifically, the drive control unit64B controls the rotation driving unit28such that the position of the image capturing unit24D is moved from the position A to the position A′ by 180 degrees in a clockwise direction. Then, the drive control unit64B controls the movement driving unit29such that the image capturing unit24D is moved from the position A′ to the position B′ in an extending direction of the rotation axis of the shaft36B. Subsequently, the drive control unit64B controls the rotation driving unit28such that the image capturing unit24D is rotated from the position B′ to the position B by 180 degrees in a counterclockwise direction. Furthermore, the drive control unit64B controls the movement driving unit29such that the image capturing unit24D is moved from the position B to the position C in the extending direction of the rotation axis of the shaft36B. Then, the drive control unit64B controls the rotation driving unit28such that the image capturing unit24D is rotated from the position C to the position C′ by 180 degrees in the clockwise direction. Moreover, the drive control unit64B controls the movement driving unit29such that the image capturing unit24D moves from the position C′ to the position D′ in the extending direction of the rotation axis of the shaft36B. Then, the drive control unit64B controls the rotation driving unit28such that the image capturing unit24D is rotated from the position D′ to the position D by 180 degrees in the counterclockwise direction.

By the rotation drive and the movement drive of the support member36A, the image capturing unit24E that is arranged in the other end portion of the support member36A follows the same movement pattern on a back surface side of the mounting member16.

Further, the drive control unit64B causes the image capturing units24to acquire the captured images30by performing image capturing every time the support member36A rotates by the predetermined angle and moves in the extending direction of the shaft36B.

Furthermore, the drive control unit64B causes the image capturing units24to acquire the captured images30in each of the image capturing directions while changing the image capturing direction of the image capturing unit24D every time the support member36A moves in the extending direction of the shaft36B.

Therefore, the image capturing units24capture images of all of the markers22arranged on the head portion H.

FIG. 11Bis a diagram for explaining another example of the movement pattern of one of the image capturing units24under the control of the drive control unit64B.FIG. 11Billustrates an example of the movement pattern of the image capturing unit24D.

As illustrated inFIG. 11B, for example, the drive control unit64B controls the rotation driving unit28and the movement driving unit29such that the image capturing unit24D moves to the position A, the position B′, the position B, the position C, and the position D′ in this order. In other words, the drive control unit64B moves the support member36A along the extending direction of the shaft36B while rotating the support member36A.

By the rotation drive and the movement drive of the support member36A, the image capturing unit24E that is arranged in the other end portion of the support member36A follows the same movement pattern on the back surface side of the mounting member16.

Further, the drive control unit64B also controls the direction driving unit31while rotating and moving the support member36A.

Then, the drive control unit64B causes the support member36A to rotate and move, and causes the image capturing units24to capture the captured images30at different positions and in different image capturing directions while causing the direction driving unit31to change the image capturing directions of the image capturing units24. Meanwhile, at the time of image capturing by the image capturing units24, the rotation drive and the movement drive of the support member36A and the drive of the direction driving unit31are performed in a standstill state.

Therefore, the image capturing units24capture images of all of the markers22arranged on the head portion H.

FIG. 11Cis a diagram for explaining another example of the movement pattern of one of the image capturing units24under the control of the drive control unit64B.FIG. 11Cillustrates an example of the movement pattern of the image capturing unit24D.

As illustrated inFIG. 11C, for example, the drive control unit64B controls the rotation driving unit28and the movement driving unit29such that the image capturing unit24D repeats a series of movement patterns such that the image capturing unit24D first moves from the position A to the position D along the extending direction of the shaft36B, and thereafter the image capturing unit24D is rotated by the predetermined angle and moves in an opposite direction of the extending direction of the shaft36B.

By the rotation drive and the movement drive of the support member36A, the image capturing unit24E that is arranged in the other end portion of the support member36A follows the same movement pattern on the back surface side of the mounting member16.

Further, the drive control unit64B also controls the direction driving unit31while rotating and moving the support member36A.

Then, the drive control unit64B causes the image capturing units24to capture the captured images30at different positions and in different image capturing directions while rotating and moving the support member36A and causing the direction driving unit31to change the image capturing directions of the image capturing units24.

Therefore, the image capturing units24capture images of all of the markers22arranged on the head portion H.

Meanwhile, the movement pattern of the shaft36B, in other words, the image capturing units24, by the drive control unit64B is not limited to the examples illustrated inFIG. 11AtoFIG. 11C. It is sufficient for the drive control unit64B to select a movement pattern that is appropriate for measurement of the head portion H, and use the selected movement pattern to control the rotation driving unit28, the movement driving unit29, and the direction driving unit31.

If a configuration for obtaining the captured images that are captured while the image capturing units24rotate around the head portion H once is adopted, it is sufficient to set a rotation angle of the support member36to reach 180 degrees in conjunction with the viewing angle of each of the image capturing units24. Further, if a configuration for obtaining the captured images30that are captured while the image capturing units24rotate around the head portion H more than once is adopted, it is sufficient to set the rotation angle of the support member36to reach 180 degrees or more in conjunction with the viewing angle of each of the image capturing units24. It is sufficient for the drive control unit64B to rotate the support member36by a rotation angle that is needed to accurately obtain the three-dimensional position coordinates of the markers22.

A flow of information processing performed by the information processing apparatus62of the present embodiment will be described below.

FIG. 12is a flowchart illustrating an example of the of the information processing performed by the information processing apparatus62of the present embodiment.

The information processing apparatus62performs processes at Step S200and Step S202in the same manner as the processes performed by the information processing apparatus50at Step S100and Step S102.

Subsequently, the drive control unit64B performs drive control (Step S204). At Step S204, the drive control unit64B controls the rotation driving unit28, the movement driving unit29, and the direction driving unit31such that the support member36A rotates about the shaft36B as the rotation axis, the support member36A moves in the extending direction of the shaft26B, and the image capturing directions are changed. Therefore, the image capturing units24acquire the captured images30every time the support member36A rotates by the predetermined angle, the support member36A moves in the extending direction of the shaft36B, and the image capturing directions are changed.

Then, the information processing apparatus62performs processes from Step S206to Step S218in the same manner as the processes performed by the information processing apparatus50of the first embodiment at Step S106to Step S118, and the routine is finished.

As described above, in the measurement system1B of the present embodiment, the drive control unit64B causes the support member36A that supports the image capturing units24to rotate about the shaft36B as the rotation axis, and moves the support member36A in the extending direction of the shaft36B. Therefore, in the present embodiment, it is possible to acquire the captured images30of all of the markers22arranged on the head portion H.

Therefore, the measurement system1B of the present embodiment is able to acquire the three-dimensional position information with high accuracy, as the measurement position of the magnetic signal in the measurement target portion of the living body B, in the same manner as the embodiment as described above.

Third Embodiment

In the second embodiment as described above, the case in which the support member36of the moving mechanism unit25B is supported by the housing12has been described. In a third embodiment, a case in which the support member36is supported by the mounting member16will be described.

FIG. 13is a schematic diagram illustrating an example of a moving mechanism unit25C. The moving mechanism unit25C is mounted on a measurement apparatus10C of a measurement system1C of the present embodiment. Meanwhile, the measurement apparatus10C of the present embodiment is the same as the measurement apparatus10and the measurement apparatus10B of the embodiments as described above except that the measurement apparatus10C includes the moving mechanism unit25C instead of the moving mechanism unit25and the moving mechanism unit25B of the embodiments as described above. Therefore, detailed explanation of mechanisms other than the moving mechanism unit25C will be omitted.

The moving mechanism unit25C is a moving mechanism that moves the image capturing units24relative to the head portion H of the living body B on which the mounting member16is mounted, similarly to the moving mechanism unit25B. In the present embodiment, the moving mechanism unit25C rotates the image capturing units24.

The moving mechanism unit25C includes a support member37, the rotation driving unit28, and the direction driving unit31. The support member37includes a support member37A and a shaft37B.

The support member37A is a member that supports the image capturing units24such that the image capturing units24face the head portion H. In other words, the support member37A supports the image capturing units24such that the image capturing units24are able to capture images of the markers22on the head portion H.

In the present embodiment, the support member37A has a shape that is extended from the top portion of the mounting member16along the outer shape of the mounting member16. As described above, the mounting member16has a semispherical shape. Therefore, the support member37A has a circular arc shape that conforms to the semispherical outer shape of the mounting member16. It is preferable that a curvature of the support member37A approximately matches the curvature of the outer shape of the mounting member16.

The support member37A has a shape that is extended from the top portion of the mounting member16and is branched in two opposing directions toward an opening, in which the head portion H is inserted, along the outer shape of the mounting member16. Further, the support member37A supports the plurality of image capturing units24in an extending direction of the support member37A. In the present embodiment, the support member37A supports image capturing units24F to24K as the image capturing units24. The image capturing unit24F and the image capturing unit24K are arranged at one end portion and the other end portion in the extending direction of the support member37A. The image capturing unit24H and the image capturing unit24I are arranged on end portions of the support member37A on the shaft37B side. The image capturing unit24G is arranged between the image capturing unit24F and the image capturing unit24H on the support member37A. Further, the image capturing unit24J is arranged between the image capturing unit24I and the image capturing unit24K on the support member37A.

The shaft37B is a linear bar-shaped member. One end portion of the shaft37B is connected to the support member37A, and the other end portion is connected to the mounting member16. Therefore, in the present embodiment, the support member37is supported by the mounting member16.

The rotation driving unit28rotates the support member37A about the head portion H as a rotation center. Specifically, in the present embodiment, the rotation driving unit28rotates the support member37A about the shaft37B as a rotation axis. Therefore, the shaft37B and the support member37A are driven to rotate in the direction of arrow R. The rotation driving unit28rotates the support member37A in an angular range of more than 360 degrees.

The shaft37B is a shaft that passes through a position of the support member37A facing the top portion of the mounting member16and that passes through the top portion of the mounting member16. Therefore, the image capturing units24supported by the support member37A rotate around the head portion H on which the mounting member16is mounted. Further, by causing the image capturing units24to capture images during the rotation, images of the entire region of the mounting member16are captured.

For example, the rotation driving unit28stops rotation of the support member37A every time the support member37A rotates by a predetermined angle. The plurality of image capturing units24F to24K arranged on the support member37A simultaneously or sequentially capture images of the head portion H on which the mounting member16is mounted, every time the rotation of the support member37A is stopped. Therefore, by repetition of a series of processes including rotation of the support member37A by the predetermined angle, stop of the rotation of the support member37A, and image capturing by the image capturing units24, images of all of the arranged markers22are captured.

Meanwhile, a weight may be applied to the head portion H of the subject when the configuration in which the mounting member16holds the support member37is adopted. In this case, it may be possible to adopt a configuration in which the support member37is separately supported by a frame to prevent a weight from being applied to the head portion H.

FIG. 10is a functional block diagram of the measurement system1C of the present embodiment.

The measurement system1C includes the measurement apparatus10C and an information processing apparatus62C. The measurement apparatus10C and the information processing apparatus62C are communicably connected to each other. The functional configuration of the measurement apparatus10C is the same as that of the measurement apparatus10B except that the measurement apparatus10C does not include the movement driving unit29. The information processing apparatus62C is the same as the information processing apparatus62except that the information processing apparatus62C includes a processing unit65instead of the processing unit64. The processing unit65is the same as the processing unit64except that the processing unit65includes a drive control unit65B instead of the drive control unit64B.

Explanation will be given below with reference toFIG. 13. The drive control unit65B controls drive of the rotation driving unit28, similarly to the drive control unit60B of the first embodiment. The drive control unit65B rotates the rotation driving unit28such that an angular range in which the support member37A rotates is equal to or larger than 360 degrees. Through the control by the drive control unit65B, the support member37A that supports the plurality of image capturing unit24rotates in the angular range of more than 360 degrees by using the shaft37B as the rotation axis. If rotation drive of the support member37A is started due to the control by the rotation driving unit28, the image capturing units24start to capture images.

For example, the rotation driving unit28stops rotation of the support member37A every time the support member37A rotates by a predetermined angle. The plurality of image capturing units24F to24K arranged on the support member37A simultaneously or sequentially capture images of the head portion H on which the mounting member16is mounted, every time the rotation of the support member37A is stopped. Therefore, by repetition of a series of processes including rotation of the support member37A by the predetermined angle, stop of the rotation of the support member37A, and image capturing by the image capturing units24, images of all of the arranged markers22are captured.

Further, the drive control unit65B may further cause the direction driving unit31to change the image capturing directions of the image capturing units24. Therefore, the drive control unit65B stops the rotation of the support member37A every time the support member37A rotates by the predetermined angle. Then, the drive control unit65B controls the direction driving unit31every time the rotation of the support member37A is stopped. Through the control as described above, it is sufficient for the drive control unit65B to control the image capturing units24and the direction driving unit31so as to obtain the captured images30in a plurality of different image capturing directions that are achieved by rotation as indicated by D1and D2in the figure.

Therefore, it is possible to acquire the captured images30of all of the markers22arranged on the head portion H.

Consequently, the measurement system1C of the present embodiment is able to obtain the three-dimensional position information with high accuracy, as the measurement position of the magnetic signal in the measurement target portion of the living body B, similarly to the embodiments as described above.

Fourth Embodiment

In the second embodiment, the case has been described in which the support member36A is supported by the shaft36B at a position corresponding to the rotation axis. However, the support member36A may be supported by shafts at both end portions in the extending direction of the support member36A.

FIG. 14is a schematic diagram illustrating an example of a moving mechanism unit25D of the present embodiment. The moving mechanism unit25D is mounted on a measurement apparatus10D of a measurement system1D of the present embodiment. Meanwhile, the measurement apparatus10D of the present embodiment has the same configuration as those of the measurement apparatus10, the measurement apparatus10B, and the measurement apparatus10C of the embodiments as described above except that the measurement apparatus10D includes the moving mechanism unit25D instead of the moving mechanism unit25, the moving mechanism unit25B, and the moving mechanism unit25C of the embodiments as described above. Therefore, detailed explanation of mechanisms other than the moving mechanism unit25D will be omitted.

The moving mechanism unit25D is a moving mechanism that moves the image capturing units24relative to the head portion H of the living body B on which the mounting member16is mounted. In the present embodiment, the moving mechanism unit25D rotates the image capturing units24.

The moving mechanism unit25D includes a support member38, the rotation driving unit28, and the direction driving unit31. The support member38includes a support member38A and a shaft38B.

The support member38A is a member that supports the image capturing units24such that the image capturing units24face the head portion H. In other words, the support member36A supports the image capturing units24such that the image capturing units24are able to capture images of the markers22on the head portion H.

In the present embodiment, the support member38A has a shape that is extended from the top portion of the mounting member16along the outer shape of the mounting member16. As described above, the mounting member16has a semispherical shape. Therefore, the support member38A has a circular arc shape that conforms to the semispherical outer shape of the mounting member16. It is preferable that a curvature of the support member38A approximately matches the curvature of the outer shape of the mounting member16.

The support member38A has a shape that is extended from the top portion of the mounting member16and is branched in two opposing directions toward an opening, in which the head portion H is inserted, along the outer shape of the mounting member16. Further, the support member38A supports the plurality of image capturing units24in an extending direction of the support member38A. In the present embodiment, the support member38A supports the plurality of image capturing units24at predetermined intervals from one end portion to the other end portion in the extending direction of the support member38A.FIG. 14illustrates a mode in which the support member38A supports image capturing units24L to24Q.

The shaft38B is a linear bar-shaped member. One end portion of the shaft38B is connected to one end of the support member38A in the extending direction, and the other end portion is connected to the housing12via the rotation driving unit28.

The rotation driving unit28rotates the support member38A about the shaft38B as the rotation axis in an angular range of more than 180 degrees. Specifically, if the rotation driving unit28rotates, rotation motion is transmitted to the shaft38B, so that the support member38A rotates about the shaft38B as the rotation axis in an angular range of more than 180 degrees. Therefore, the image capturing units24supported by the support member38A move from the face side of the head portion H on which the mounting member16is mounted to the back side of the head.

FIG. 10is a functional block diagram of the measurement system1D of the present embodiment.

The measurement system1D includes the measurement apparatus10D and an information processing apparatus62D. The measurement apparatus10D and the information processing apparatus62D are communicably connected to each other. The functional configuration of the measurement apparatus10D is the same as that of the measurement apparatus10B except that the measurement apparatus10D does not include the movement driving unit29. The information processing apparatus62D is the same as the information processing apparatus62except that the information processing apparatus62D includes a processing unit67instead of the processing unit64. The processing unit67is the same as the processing unit64except that the processing unit67includes a drive control unit67B instead of the drive control unit64B.

Explanation will be given below with reference toFIG. 14. The drive control unit67B controls drive of the rotation driving unit28, similarly to the drive control unit60B of the first embodiment. The drive control unit67B rotates the rotation driving unit28such that an angular range in which the support member38A rotates is equal to or larger than 180 degrees. Through the control by the drive control unit67B, the support member38A that support the plurality of image capturing units24rotates in the angular range of more than 180 degrees by using the shaft38B as the rotation axis. If rotation drive of the support member38A is started due to the control by the rotation driving unit28, the image capturing units24start to capture images.

For example, the rotation driving unit28stops rotation of the support member38A every time the support member38A rotates by a predetermined angle. The plurality of image capturing units24L to24Q arranged on the support member38A simultaneously or sequentially capture images of the head portion H on which the mounting member16is mounted, every time the rotation of the support member38A is stopped. Therefore, by repetition of a series of processes including rotation of the support member38A by the predetermined angle, stop of the rotation of the support member38A, and image capturing by the image capturing units24, images of all of the arranged markers22are captured.

Further, the drive control unit67B may further cause the direction driving unit31to change the image capturing directions of the image capturing units24. Therefore, the drive control unit67B stops the rotation of the support member38A every time the support member38A rotates by the predetermined angle. Then, the drive control unit67B controls the direction driving unit31every time the rotation of the support member38A is stopped. Through the control as described above, it is sufficient for the drive control unit67B to control the image capturing units24and the direction driving unit31so as to obtain the captured images30in a plurality of different image capturing directions that are achieved by rotation as indicated by D1and D2in the figure.

Therefore, it is possible to acquire the captured images30of all of the markers22arranged on the head portion H.

Consequently, the measurement system1D of the present embodiment is able to obtain the three-dimensional position information with high accuracy, as the measurement position of the magnetic signal in the measurement target portion of the living body B, similarly to the embodiments as described above.

Fifth Embodiment

The configuration of the support member that supports the image capturing units24is not limited to the embodiments as described above.

FIG. 15is a schematic diagram illustrating an example of a moving mechanism unit25E of a fifth embodiment. The moving mechanism unit25E is mounted on a measurement apparatus10E of a measurement system1E of the present embodiment. Meanwhile, the measurement apparatus10E of the present embodiment has the same configuration as those of the measurement apparatus10, the measurement apparatus10B, the measurement apparatus10C, and the measurement apparatus10D as described above except that the measurement apparatus10E includes the moving mechanism unit25E instead of the moving mechanism unit25, the moving mechanism unit25B, the moving mechanism unit25C, and the moving mechanism unit25D of the embodiments as described above.

The moving mechanism unit25E is a moving mechanism that moves the image capturing units24relative to the head portion H of the living body B on which the mounting member16is mounted. In the present embodiment, the moving mechanism unit25E moves the image capturing units24.

The moving mechanism unit25E includes a support member39, the direction driving unit31, and the movement driving unit29. The support member39includes a support member39A, a support member39B, a support member39C, and a support member39D.

The support member39is a member that supports the image capturing units24such that the image capturing units24face the head portion H. In other words, the support member39supports the image capturing units24such that the image capturing units24are able to capture images of the markers22on the head portion H.

The support member39A and the support member39B are arm-shaped members that surround the head portion H, on which the mounting member16is mounted, in a front-back direction. The support member39C and the support member39D are arm-shaped members that surround the head portion H, on which the mounting member16is mounted, in a left-right direction.

An image capturing unit24R, an image capturing unit24U, and an image capturing unit24S, as the image capturing units24, are mounted on the support member39C, a support member39E, and the support member39D, respectively. The support member39C, the support member39D, and the support member39E are configured with linear members, and the image capturing units24are arranged on the respective linear members in one-to-one correspondence. An image capturing unit24T and the image capturing unit24U, as the image capturing units24, are arranged on the support member39A and the support member39B, respectively. Each of the support member39A and the support member39B is configured with a linear member and another linear member that is perpendicular to the support member39E, and each of the image capturing unit24T and the image capturing unit24U is arranged on one of the two linear members that are arranged in a facing manner.

In the present embodiment, the direction driving unit31and the movement driving unit29are arranged on each of the image capturing units24.

FIG. 10is a functional block diagram of the measurement system1E of the present embodiment.

The measurement system1E includes the measurement apparatus10E and an information processing apparatus62E. The measurement apparatus10E and the information processing apparatus62E are communicably connected to each other. The functional configuration of the measurement apparatus10E is the same as that of the measurement apparatus10B. The information processing apparatus62E is the same as the information processing apparatus62except that the information processing apparatus62E includes a processing unit69instead of the processing unit64. The processing unit69is the same as the processing unit64except that the processing unit69includes a drive control unit69B instead of the drive control unit64B.

Explanation will be given below with reference toFIG. 15. The drive control unit69B controls drive of the direction driving unit31and the movement driving unit29. For example, the drive control unit69B controls the movement driving unit29arranged on each of the image capturing units24such that each of the image capturing units24moves along an extending direction of the linear member on which each of the image capturing units24is arranged. Further, the drive control unit69B controls the direction driving unit31and the image capturing units24so as to obtain the captured images30in a plurality of different image capturing directions that are archived by rotation as indicated by D1and D2in the figure, every time the image capturing units24move in a predetermined distance.

Meanwhile, the drive control unit69B may sequentially move the position of each of the image capturing units24. Further, the drive control unit69B may simultaneously move the positions of the plurality of image capturing units24and cause the image capturing units24to simultaneously capture the captured images30every time the image capturing units24are moved in the predetermined distance. Furthermore, the drive control unit69B may control the image capturing units24such that the plurality of image capturing units24sequentially obtain the captured images every time the image capturing units24are moved in the predetermined distance.

Therefore, in the present embodiment, it is possible to acquire the captured images30of all of the markers22arranged on the head portion H.

Consequently, the measurement system1E of the present embodiment is able to obtain the three-dimensional position information with high accuracy, as the measurement position of the magnetic signal in the measurement target portion of the living body B, similarly to the embodiments as described above.

Hardware configurations of the information processing apparatus50and the information processing apparatus62of the embodiments as described above will be described below.

FIG. 16is a diagram illustrating one example of hardware configurations of the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E of the embodiments as described above.

Each of the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E of the embodiments as described above includes a control device, such as a CPU11A, storage devices, such as a read only memory (ROM)11B and a random access memory (RAM)11C, a hard disk drive (HDD), an interface (I/F)11D that is connected to a network and performs communication, and a bus11E for connecting each of the units.

A program executed by each of the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E of the embodiments as described above is provided by being incorporated in the ROM11B or the like in advance.

The program executed by each of the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E of the embodiments as described above may be recorded in a computer-readable recording medium, such as a compact disk read only memory (CD-ROM), a flexible disk (FD), a compact disk recordable (CD-R), or a digital versatile disk (DVD), in a computer-installable or computer-executable file format, and may be provided as a computer program product.

Furthermore, the program executed by each of the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E of the embodiments as described above may be stored in a computer connected to a network, such as the Internet, and may be provided by download via the network. Moreover, the program executed by each of the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E of the embodiments as described above may be provided or distributed via a network, such as the Internet.

The program executed by each of the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E of the embodiments as described above may cause a computer to function as each of the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E as described above. The computer may be implemented by causing the CPU11A to read the program from the computer-readable storage medium onto a main storage device, and execute the program.

Furthermore, the information processing apparatus50, the information processing apparatus62, the information processing apparatus62C, the information processing apparatus62D, and the information processing apparatus62E may be implemented as virtual machines that operate on a cloud computing system.

According to one aspect of the present invention, it is possible to obtain three-dimensional position information with high accuracy, as a measurement position of a magnetic signal in a measurement target portion of a living body.