Abstract:
A processor, to which an endoscope is connectable, for processing signals generated by the endoscope into image data, includes a light source which supplies light to the endoscope connected to the processor to illuminate a target area via the endoscope so that the endoscope can capture an image of the illuminated target area and convert the image into the signals, and an internal memory for storing at least still-image data obtained from the image data.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a processor which processes signals generated by an endoscope connected thereto, and more specifically relates to such a processor whose maintainability and convenience are enhanced.  
       DESCRIPTION OF THE RELATED ART  
       [0002]     A typical endoscope system is generally provided with an endoscope (electronic endoscope), an endoscope processor (hereinafter referred to simply as a “processor”) and a monitor. The endoscope includes an image pick-up device, and is operated to obtain signals of images captured inside the human body via the image pick-up device, and the processor fosters the imaging operation of the endoscope and transforms the signals output from the image pick-up device into image data which is displayed as a visual image on the monitor. In endoscope systems in recent years, a printer for printing image signals obtained by the processor, a personal computer for controlling various processing operations performed by the processor, and an external connection device such as a keyboard designed specially for the endoscope system to input various kinds of data to the processor are connected to the processor.  
         [0003]     In such conventional endoscope systems, the processor incorporates a CPU, various circuits (e.g., a signal-processing circuit), a light source for the endoscope and an internal memory in which information necessary for operations of the CPU and the various circuits is stored. However, the internal memory is not designed so that either still-image data which is obtained through a still-image capturing operation performed by an operator from image data obtained by an imaging operation of the endoscope or historical imaging data is stored in the internal memory. Accordingly, still-image data obtained by a still-image capturing operation is output to an external connection device connected to the processor each time the still-image data is obtained, an animation of the obtained image data is displayed on the monitor, and still images contained in the obtained image data are either printed on a printer in accordance with the still-image data output from the processor or stored in a memory of a personal computer or an external memory device. When such still-image data is stored, historical imaging data, i.e., various kinds of data such as data on an endoscope used for image capture (endoscope data), data on an examined patient or patient ID (patient ID data), data on date of captured images (date data), data on used light source (light source data) and various image parameters are stored in the aforementioned personal computer&#39;s memory or the aforementioned external memory device, which is connected to the processor, separately from the still-image data.  
         [0004]     A technique of storing data of an endoscope connected to a processor in an internal memory integrated into the processor in an electronic endoscope system is disclosed in Japanese unexamined patent publication 2003-132151. This technique makes it possible to reliably record data of an endoscope in use which is necessary to be recorded. However, with such a technique, data other than that of the endoscope such as data of the processor itself, the image data and historical imaging data are not recorded in addition to the data of the endoscope in use.  
         [0005]     In the processor incorporated in such an endoscope system disclosed in the aforementioned patent publication, still-image data and various kinds of data, i.e., historical imaging data obtained when an imaging operation and the like is performed on a patient with the endoscope system, are not stored in an internal memory of the processor as mentioned above. Therefore, when maintenance is performed on the processor, the processor alone cannot obtain usage data of the processor which is necessary for the maintenance. Accordingly, every time maintenance is performed on the processor, the processor inputs or records the historical imaging data into a personal computer or the like, or image data or historical imaging data which is recorded in a personal computer or an external memory that was connected to the processor before has to be read out for reference. Specifically, still-image data obtained in the past cannot be checked solely with the processor and a monitor connected thereto because no still image is recorded in an internal memory of the processor. Therefore, when any still image obtained in the past needs to be checked for maintenance of the processor, the still image must be read out of a personal computer or an external memory which was connected to the processor before. Accordingly, it is difficult to carry out maintenance on the processor solely with the processor; maintenance of the processor needs to be carried out at a site where the processor is set up even with an external connection device such as a computer being connected to the processor, which makes operations for the maintenance complicated and troublesome.  
         [0006]     The aforementioned patent publication does not disclose any system which accesses an internal memory of the processor from an external connection device (e.g., a personal computer) connected thereto to write or read various kinds of data into and from the internal memory. This becomes a cause of inconvenience because if an external connection device is connected to the processor disclosed in the aforementioned patent publication, it is difficult to refer to various kinds of data stored in an internal memory of the processor by reading out the same data from an external connection device, or to modify and re-store the same various kinds of data, and accordingly it is difficult to make effective use of such various kinds of data stored in an internal memory of the processor.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides an endoscope processor which process signals generated by an endoscope connected thereto, wherein more effective use of an internal memory of the processor is achieved while maintainability and convenience of use of the processor are enhanced.  
         [0008]     According to an aspect of the present invention, a processor is provided, to which an endoscope is connectable, for processing signals generated by the endoscope into image data, the processor including a light source which supplies light to the endoscope connected to the processor to illuminate a target area via the endoscope so that the endoscope can capture an image of the illuminated target area and convert the image into the signals, and an internal memory for storing at least still-image data obtained from the image data.  
         [0009]     According to the present invention, when still-image data captured in the past and the historical imaging data thereof need to be referred to upon maintenance of the processor, such still-image data and the historical imaging data thereof which are stored in the processor can be viewed on a personal computer or a monitor which is different from that used when the still image data was captured if the personal computer or the monitor only interfaces with the processor, even in the case where the personal computer used when the still image data was captured is not connected to the processor. Therefore, if only a monitor is simply connected to the processor to be capable of displaying a still image previously captured on the monitor, or if only a printer is simply connected to the processor so that a still image previously captured can be printed on the printer, the processor can perform maintenance thereof on a standalone basis even if a state of the endoscope system in which the processor is connected to a personal computer or a LAN is not maintained. This improves the maintainability of the processor.  
         [0010]     It is desirable for historical imaging data associated with the still-image data to be stored together with the still-image data in the internal memory.  
         [0011]     It is desirable for the still-image data and the historical imaging data which is obtained when the still-image data is captured to be stored in the internal memory to correspond to each other.  
         [0012]     It is desirable for the historical imaging data to include data of the endoscope and data of a patient examined with the endoscope.  
         [0013]     It is desirable for the internal memory to be capable of storing a predetermined number of the still-image data, wherein the oldest still-image data is overwritten with new still-image data in sequence when more than the predetermined number of the still-image data are stored in the internal memory.  
         [0014]     It is desirable for an external connection device to be connectable to the processor to have access to the internal memory from the external connection device.  
         [0015]     It is desirable for an external connection device to be connectable to the processor to have access to the internal memory from the external connection device, and at least the historical imaging data on the examined patient can be written in the internal memory from the external connection device.  
         [0016]     It is desirable for the still-image data and historical imaging data associated therewith which are stored in the internal memory to be read out from the internal memory in response to a request from the external connection device.  
         [0017]     The external device can be a personal computer and/or a keyboard.  
         [0018]     It is desirable for the signals to be processed by the processor to be output as video signals so that the video signals are displayed on a monitor connected to the processor.  
         [0019]     It is desirable for the signals to be processed by the processor to be output as video signals so that the video signals are printed as printed images on a printer connected to the processor.  
         [0020]     It is desirable for the endoscope to include a memory into which data on the endoscope is stored so that the data of the endoscope is output to the processor upon the endoscope being connected to the processor. The internal memory can be an erasable/programmable memory or nonvolatile memory/flash memory.  
         [0021]     In another embodiment, a processor to which an endoscope connectable is provided, including a light source which supplies light to the endoscope connected to the processor to illuminate a target area via the endoscope so that the endoscope can capture an image of the illuminated target area and convert the image into signals, the processor processing the signals into image data, and an internal memory for storing at least still-image data obtained from the image data.  
         [0022]     The present disclosure relates to subject matter contained in Japanese Patent Application No. 2003-373966 (filed on Nov. 4, 2003) which is expressly incorporated herein by reference in its entirety. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]     The present invention will be described below in detail with reference to the accompanying drawings in which:  
         [0024]      FIG. 1  is a diagrammatic representation of an endoscope system according to the present invention;  
         [0025]      FIG. 2  is a schematic block diagram of the endoscope system shown in  FIG. 1 ;  
         [0026]      FIG. 3  is a flow chart of a main routine MAIN of a processor shown in  FIG. 1 ;  
         [0027]      FIG. 4  is a flow chart of a subroutine MEMORY STORAGE NUMBER ASSIGNMENT called from the main routine of  FIG. 3 ;  
         [0028]      FIG. 5  is a flow chart showing a subroutine IMAGE RECORD called from the main routine of  FIG. 3 ;  
         [0029]      FIG. 6  is an explanatory format of the data stored in an internal memory provided in the processor;  
         [0030]      FIG. 7  is a flow chart showing a subroutine DATA READOUT REQUEST called in the main routine shown in  FIG. 3 ; and  
         [0031]      FIG. 8  is a flow chart showing an interrupt routine VERSION UPGRADE. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]     An embodiment of an endoscope system according to the present invention will be hereinafter discussed with reference to  FIG. 1 .  FIG. 1  is a diagrammatic representation of an endoscope system using a processor (endoscope processor)  1  according to the present invention. The endoscope system is provided with a processor  1 , an endoscope (electronic endoscope)  2  and a monitor  3 .  FIG. 2  is a schematic block diagram of the endoscope system shown in  FIG. 1 . The endoscope  2  is detachably connected to the processor  1 . Image signals captured by the endoscope  2  are processed in the processor  1  to be output as video signals so that the video signals are displayed on a monitor  3  connected to the processor  1  or printed as printed images on a printer (video printer)  4  connected to the processor  1 . The endoscope system is provided with a personal computer (external connection device)  5  and a keyboard (external connection device)  6  which serves as an input device for inputting data such as patient ID data to the processor  1 . As will be discussed later, various kinds of data are output from the processor  1  to be input into the personal computer  5 , or the keyboard  6  is operated to input data such as patient ID data into the processor  1 .  
         [0033]     As shown in  FIG. 1 , the endoscope  2  is provided with an insertion portion (insertion tube)  21 , an operation portion  22 , a light guide cable  23  and a connector  24 . The insertion portion  21  is inserted into the body of a patient. The connector  24  is detachably connected to the processor  1 . As shown in  FIG. 2 , the endoscope  2  is provided inside thereof with a light guide  201  which is arranged to pass through the light guide cable  23 , the operation portion  22  and the insertion portion  21 . The light emitted from a light source (lamp)  121  provided in the processor  1  is transmitted through the light guide  201  to illuminate the area in front of the tip end of the insertion portion  21 . A CCD image sensor  203  and a light distribution lens  202  are provided at the distal end portion of the inserting portion  21 . The light emitted from the light source  121  and passed through the light guide  201  is diffused through the light distribution lens  202  to illuminate a wide area inside a body cavity, and this illuminated wide area is photographed by the CCD image sensor  203 . Image signals generated by the CCD image sensor  203  upon the illuminated area being photographed by the CCD image sensor  203  are output to the processor  1  via an image controller  204  provided in the endoscope  2 . The endoscope  2  is provided therein with an electrically erasable/programmable (nonvolatile memory or flash memory) endoscope ROM (EEPROM)  205  into which data such as endoscope data (which will be discussed later) is stored. This endoscope data can be output to the processor  1  upon the endoscope  2  being connected to the processor  1 . The operation of the endoscope  2  is the same as that of a conventional endoscope, and will not be hereinafter discussed in detail. Image signals captured by the endoscope  2  are processed through a signal processing portion  13  provided in the processor  1  so that moving images and still images are displayed on the monitor  3  in accordance with obtained moving-image data and still-image data, respectively.  
         [0034]     The processor  1  is provided with a front panel  11 , a light source portion  12 , the aforementioned signal processing portion  13 , an internal memory  14  and a image-data switching portion  15 , respective operations of which are controlled by a CPU  16  provided in the processor  1 . Regarding the front panel  11 , a front-panel control circuit  111  which is provided in the processor  1  and controlled by the CPU  16  controls the operation of the front panel  11  so that the front panel  11  visually indicates a variety of information related to the front panel  11 , or captures front-panel data input by an operation of the front panel  11  so that the captured front-panel data is stored in the internal memory  14  by the CPU  16 .  
         [0035]     The light source portion  12  is provided with the light source  121 , a light-emitter activating circuit  122 , a dimmer  123 , a light control circuit  124  and a light-emission monitoring circuit  125 . The light-emitter activating circuit  122  operates to activate the light source  121 . The dimmer  123  controls the intensity of the light source  121 . The light-emission monitoring circuit  125  monitors whether the light source  121  is lighting at a desired intensity set by the dimmer  123 . The CPU  16  controls the intensity of the light source  121  in accordance with the results of monitoring by the light-emission monitoring circuit  125  so that the light source  121  stays on at a desired intensity set by the dimmer  123 . Illumination light emitted by the light source  121  is controlled to have a desired intensity via the dimmer  123 , and is subsequently supplied to the endoscope  2  to illuminate the area in front of the end of the insertion portion  21  via the light distribution lens  202  and the light guide  201 . Light-source data obtained in the light-emission monitoring circuit  125  is stored in the internal memory  14  by the CPU  16 .  
         [0036]     The signal processing portion  13  converts analogue image signals, which are generated by the CCD image sensor  203  of the endoscope  2  to be output to the processor  1 , into digital image signals. The signal processing portion  13  also performs various kinds of signal processes for producing image signals in indicating visual images on the monitor  3 . Image signals input from the endoscope  2  are converted into digital signals by an A/D converter  131  to be stored in a moving-image memory  132 , which serves as a frame memory for moving images, and a still-image memory  133 , which serves as a memory for still images which are captured as needed, as appropriate at the correct time. Digital image signals stored in each of the moving-image memory  132  and the still-image memory  133  are translated to desired image data via an image control portion  134  to be input to an image/character composition circuit  135 . In the image/character composition circuit  135 , the input image data is combined with character data output from a patient-ID-data-character indicating circuit  136  to be output as image data combined with characters from the image/character composition circuit  135 . The patient-ID-data-character indicating circuit  136  creates characters which correspond to the patient ID that is input from the keyboard  6  connected to the processor  1 , and outputs character data on the created characters to the image/character composition circuit  135 . It is possible for the image control circuit  134  to generate data corresponding to a combination of moving images and a still image via an operation of the front panel  11 , and for the moving images and still images area to be indicated on the monitor  3 .  
         [0037]     The image-data switching portion  15  is provided with a switch  151  and two D/A converters: a first D/A converter  152  and a second D/A converter  153 . The CPU  16  commands the switch  151  to selectively switch between the image data output from the image/character composition circuit  135  and the image data read out of the internal memory  14  by an internal-memory-data display circuit  141  which is connected to the internal memory  14 . Each of the two D/A converters  152  and  153  converts the input image data that is selected by the switch  151  into analog signals, which are in turn output to the monitor  3  and the printer  4  to be capable of being displayed on the monitor  3  and printed on the printer  4 , respectively.  
         [0038]     The CPU  16  is provided therein with a processor ROM (EEPROM)  161  in which various kinds of data such as programmed software for controlling the operation of CPU  16  are stored. The CPU  16  performs necessary operations in accordance with endoscope insertion data from an endoscope-insertion-detecting circuit  162  which is connected to the CPU  16 .  
         [0039]     The internal memory  14  is constructed as a flash memory or an EEPROM, to which the CPU  16  can write and read out each item of data. The following data (d 1  through d 7 ) can be written in and read out of the internal memory  14 : 
        d 1 : Processor data (including model name and serial number of the processor, repair information, owner information, hardware assembly number and software version number)     d 2 : Endoscope data (including model name and serial number of the endoscope, repair information, owner information, and signal processing data     d 3 : Image parameters (image color information)     d 4 : Light-source data (service life of lamp and the number of light-ups of lamp)     d 5 : Front-panel data (front-panel operational status)     d 6 : Patient ID (including name of patient and patient&#39;s ID number)     d 7 : Image data (still-image data)        
 
         [0047]     Each of these items of data d 1  through d 7  written in the internal memory  14  can be read out of the internal memory  14  by the personal computer  5  to be displayed thereon. Conversely, each of these items of data d 1  through d 7  can be written into the internal memory  14  from the personal computer  5 . A patient ID input via the keyboard  6  can be written into the internal memory  14  as data d 6 .  
         [0048]     Although the personal computer  5  has access to the internal memory  14 , the processor  1  is provided with a protective feature of prohibiting the personal computer  5  from having access to a programmed-software storing area in the processor ROM  161  of the CPU  16  during normal use. In the case that the personal computer  5  makes access to the processor ROM  161 , for instance, the programmed-software storing area can simply be released from protection by operating the front panel  11 .  
         [0049]     A usage pattern of the above described endoscope system will be discussed hereinafter.  
         [0050]      FIG. 3  is a flow chart showing a main routine MAIN (S 100 ) of the processor  1  when the processor  1  starts up the endoscope system. Firstly, upon the power of the processor  1  being turned ON to start up the processor  1 , the CPU  16  reads out and obtains processor data (e.g., model name and serial number of the processor) unique to the processor  1  which is prestored in the processor ROM  161  (step S 101 ). Subsequently, it is determined whether the endoscope  2  is currently connected to the processor  1  (step S 102 ). If the endoscope  2  is currently connected to the processor  1  (if YES at step S 102 ), the processor  1  obtains the endoscope data from the endoscope ROM  205  (step S 103 ). In addition, the processor  1  obtains image parameters which are to be set to correspond to image data that are obtained, together with the endoscope data, by an imaging operation of the endoscope  2  (step S 104 ). Subsequently, the processor  1  obtains light source data from the light-emission monitoring circuit  125  of the light source portion  12  (step S 105 ). Subsequently, it is determined whether the front panel  11  has been operated (control waits for the front panel  11  to be operated) (step S 106 ). If it is determined that the front panel  11  has been operated (if YES at step S 106 ), the CPU  16  obtains front panel data from the operated front panel  11  (step S 107 ), and then it is determined whether data has been entered to the CPU  16  via the keyboard  6  (step S 108 ). If data has been entered (if YES at step S 108 ), the CPU  16  obtains the name of a patient, patient ID, current date and time, which are input in sequence from the keyboard  6  (step S 109 ). Subsequently, the obtained items of information such as patient ID and current date and time are output to the monitor  3  to be displayed thereon as needed together with the image captured by the endoscope  2  (step S 110 ).  
         [0051]     Immediately after the above described series of operations at steps S 101  through S 110  are completed, control enters a subroutine MEMORY STORAGE NUMBER ASSIGNMENT (step S 200 ). In this subroutine, firstly it is determined whether the memory storage number is 0 (zero) as shown in  FIG. 4  (step S 201 ). If the memory storage number is zero (if YES at step S 201 ), the memory storage number is set to 1 (step S 202 ), otherwise (if NO at S 201 ), the memory storage number is increased by one (step S 203 ), and then it is determined whether the memory storage number is greater than a predetermined number Xmax (step S 204 ). The number Xmax is predetermined to correspond to the maximum number of still images which can be stored in the internal memory  14 . The maximum number of still images storable in the internal memory  14  is 36 in this particular embodiment, so that the number Xmax is equal to 36. If it is determined that the memory storage number is equal to or smaller than the number Xmax (if NO at S 204 ), the memory storage number is saved (step S 205 ), and control returns to the main routine. If it is determined that the memory storage number is greater than the number Xmax (if YES at step S 204 ), the memory storage number is reset to 1 so that the first (oldest) still image stored in the internal memory  14  is overwritten with a new still image since thirty-six still images have been already stored in the internal memory  14  (step S 206 ), and subsequently control returns to the main routine.  
         [0052]     Upon completion of the subroutine MEMORY STORAGE NUMBER ASSIGNMENT at step S 200 , it is determined, from a signal output from the image controller  204  of the endoscope  2 , whether a release button (not shown), provided on the endoscope  2 , for capturing a still image of the illuminated area in front of the tip end of the insertion portion  21  of the endoscope  2  has been operated (step S 111 ). If the release button has been operated (if YES at step S 111 ), a subroutine IMAGE RECORD is performed (step S 300 ). Referring to  FIG. 5 , immediately after an image is captured by the endoscope  2  with the endoscope  2  being coupled to the processor  1 , signals generated by the CCD image sensor  203  are input to the processor  1  via the image controller  204  as shown in  FIG. 2 . In the processor  1 , image data is produced from the signals generated by the CCD image sensor  203  via the signal processing portion  13 , and is combined with character data output from the patient-ID-data-character indicating circuit  136  to be output as image data combined with characters from the image/character composition circuit  135  to be input to the image-data switching portion  15 . In the image-data switching portion  15 , the image data which is output to the monitor  3  to be displayed thereon via the switch  151  is switched to the aforementioned character-combined image data by the switch  151  so that the character-combined image data is displayed on the monitor  3 . The still images displayed on the monitor  3  can be printed on the printer  4  as needed. While the combined image data is displayed on the monitor  3 , still-image data d 7  is extracted from the obtained image data to be captured in the still-image memory  133  (step S 301 ). Subsequently, the historical imaging data d 1  through d 6 , which are obtained at steps S 101  through S 110 , the still-image data d 7 , and character data which is to be combined with the still-image data d 7  are captured as integrated data (step S 302 ). The memory storage number obtained via the subroutine MEMORY STORAGE NUMBER ASSIGNMENT at step S 200  is assigned to this integrated data (step S 303 ), and then this integrated data is written into the internal memory  14  (step S 304 ). Subsequently, control returns to the main routine.  
         [0053]     In this manner, two or more of such integrated data, each of which is made by combining the still-image data d 7  with the associated historical imaging data d 1  through d 6 , are stored in the internal memory  14  while the memory storage number is increased one by one. The integrated data is repeatedly stored in the internal memory  14  until the number of still images reaches the number Xmax as shown in  FIG. 6 . When the number of stored still images exceeds the number Xmax, the oldest still-image data (data numbered 1) is erased and rewritten as new still-image data one by one as described in the descriptions of the subroutine MEMORY STORAGE NUMBER ASSIGNMENT at step S 200 . Each data d 1  through d 6  is stored in the internal memory  14  while the aforementioned memory storage number is assigned to the data, and also each data d 1  through d 6  is overwritten with new data d 1  through d 6  in order from oldest data, respectively, while the oldest still-image data is erased and rewritten as new still-image data one by one.  
         [0054]     If the release button is not ON (step S 111 : NO), control skips step S 300  and advances to step S 112 .  
         [0055]     If there is a request for a readout of the data stored in the internal memory  14  for, e.g., maintenance on the processor  1 , after each data d 1  through d 7  has been written into the internal memory  14  (step S 112 ), a subroutine DATA READOUT REQUEST for searching a source of the request is performed (step S 400 ), as shown in  FIG. 7 . In the subroutine DATA READOUT REQUEST, firstly it is determined whether the request has been made from the keyboard  6  (step S 401 ), it is determined whether the request has been made from the external personal computer  5  (step S 402 ), and it is determined whether the request has been made from the front panel  11  (step S 403 ). If it is determined that the request has been made from the keyboard  6 , the personal computer  5  or the front panel  11  (if YES at step S 401 , S 402  or S 403 ), information on the request source is obtained (step S 404 ). If it is determined that the request has been made from neither the keyboard  6 , the personal computer  5  nor the front panel  11  (if NO at each of steps S 401 , S 402  and S 403 ), control returns to the main routine.  
         [0056]     Upon the request source being specified by obtaining information on the request source at step S 404 , desired data stored in the internal memory  14  is output to the request source (step S 405 ). It is possible to specify one data (datum) from among a plurality of items of data (representing a plurality of still images) stored in the internal memory  14  by specifying a type of data to the CPU  16  from the request source. At this time, if the request source requests a specific memory storage number, the data bearing this memory storage number which is stored in the internal memory  14  is output to the request source. If the request source is the personal computer  5  while the personal computer  5  is on a LAN, data stored in the internal memory  14  can be read out from all the personal computers on the LAN.  
         [0057]     When data is output from the internal memory  14 , the data is output to the request source in accordance with the information obtained at step S 404 . At this time, an operation ACK (acknowledge) MONITOR is performed (step S 406 ). This operation is performed whether data communications are properly carried out between the request source and the processor  1  when data is read out of the internal memory  14 . If it is determined that the data communications are properly carried out (if YES at step S 406 ), control returns to the main routine. If it is determined that the data communications are not properly carried out (if NO at step S 406 ), a retry process is performed (step S 407 ) and it is determined whether the retry process is successful (step S 408 ). If the retry process is successful (if YES at step S 408 ), control returns to the main routine. If the retry process is not successful (if NO at step S 408 ), an error message is displayed on the monitor  3  (step S 409 ), and control returns to the main routine. In this case, this error information can be written into the internal memory  14  after the memory storage number obtained in the same manner as in the subroutine at S 200  is assigned to the error information.  
         [0058]     In the main routine S 100 , the data output to the request source is captured by the request source (step S 113 ), so that an associated operation is performed at the request source. Specifically, if the request source is the monitor  3 , the switch  151  operates so that a still image and the historical imaging data thereof are displayed on the monitor  3  in accordance with data obtained from the internal memory  14  via the internal-memory-data display circuit  141 . If the request source is the printer  4 , the switch  151  operates in a similar manner so that a still image with the historical imaging data thereof are printed via the printer  4  in accordance with data obtained from the internal memory  14  via the internal-memory-data display circuit  141 . If the request source is the personal computer  5 , the same data obtained by the internal-memory-data display circuit  141  is recorded in the personal computer  5 .  
         [0059]     Once the process at step S 113  has finished, or if NO at step S 112 , control returns to step S 102 , and steps S 102  through S 113  are repeated while the power of the processor  1  is ON.  
         [0060]     Regarding the data output from the processor  1 , the still-image data d 7  that is stored in the internal memory  14  and the historical imaging data d 1  through d 6  that is stored in the internal memory  14  to be associated with the still-image data d 7  can be output from the processor  1 . This still image data can be stored in the internal memory  14  until the number of stored still images reaches a predetermined number (36 in this particular embodiment), and the oldest still-image data has been overwritten with new still-image data sequentially in order from the oldest data when the number of stored still images exceeds the predetermined number. In the case where the personal computer  5  is connected to the processor  1 , the still-image data d 7  and the associated historical imaging data d 1  through d 6  can be read out sequentially from the internal memory  14  of the processor  1  by the personal computer  5  so that stored still images and the historical imaging data thereof can be seen on the processor  1 , thus being capable of being used effectively at maintenance of the processor  1  and the endoscope  2 .  
         [0061]     When the still-image data d 7  and the historical imaging data d 1  through d 6  need to be retrieved from the processor  1 , such still-image data and the historical imaging data thereof which are stored in the processor  1  can be viewed on a personal computer or a monitor which is different from that used when the still image data was captured, so long as the personal computer or the monitor can interface with the processor  1 . Therefore, if only a monitor is simply connected to the processor  1  to be capable of displaying a still image thereon or if only a printer is simply connected to the processor  1  so that a still image can be printed thereby, the processor  1  can perform maintenance thereof on a standalone basis even if a state of the endoscope system in which the processor  1  is connected to a personal computer or a LAN is not maintained. This improves the maintainability of the processor  1 .  
         [0062]     According to the processor  1  in the above described embodiment of the endoscope system of the present invention, software programs written in the processor ROM  161  in the CPU  16  or the endoscope ROM  205  in the endoscope  2  can be rewritten (reprogrammed) to be upgraded from a personal computer connected to the processor  1 .  FIG. 8  is a flow chart showing an interrupt routine VERSION UPGRADE. In this routine at S 500 , firstly it is determined whether there is a request for rewriting software (step S 501 ). If YES at step S 501 , the storage location of a software program which is to be rewritten is determined in accordance with a command for reprogramming from the personal computer (step S 502 ). Assume here that it is determined at step S 502  that a software program in the processor ROM  161  is to be rewritten, and the storage location thereof is indicated on, e.g., the monitor  3  (step S 503 ). At the same time, from this indication the user confirms the rewrite storage location, and releases protection of the software program by operating the front panel  11  (step S 504 ). Thereafter, a new software program is input to the processor  1  from the personal computer  5  via an operation of the personal computer  5 , and is input to the processor ROM  161  so that the old software program is erased and rewritten as the new software program (step S 505 ). When the old software program is rewritten to be replaced by the new software program, a software version number of the software program written in the processor ROM  161  is also rewritten to a new software version number. Upon completion of the rewriting operation at step S 505 , an operation CHKSUM VERIFICATION is performed (step S 506 ). In this operation, it is determined whether data communication is properly carried out by checking an error checking signal included in the new software program. If it is determined that data communication has been properly carried (if YES at step S 506 ), a rewrite completion message is displayed on, e.g., the monitor  3  and control ends. If data communication has not been properly carried (if NO at step S 506 ), a retry process is performed (step S 507 ), and it is determined whether the retry process is successful (step S 508 ). If the retry process is successful (if OK at step S 508 ), a rewrite completion message is displayed on, e.g., the monitor  3  and control ends. If the retry process is not successful (if NO at step S 508 ), an error message is displayed on, e.g., the monitor  3  (step S 509 ), and control ends.  
         [0063]     If there is no request to rewrite software (NO at step S 501 ), control ends.  
         [0064]     Software programs and data on the endoscope  2  which are written in the endoscope ROM  205  in the endoscope  2  can be rewritten via the processor  1  in a manner similar to the above described manner of rewriting a software program written in the processor ROM  161  in the CPU  16 . A detailed description using a flow chart like the flow chart shown in  FIG. 8  is omitted.  
         [0065]     As can be understood from the above descriptions, the user does not have to take the trouble to go to the installation site of the processor to replace a software-programmed memory provided in the processor by another software-programmed memory since software programs written in the processor can be rewritten to be upgraded via a personal computer or a LAN which is connected to the processor.  
         [0066]     In the processor according to the present invention, the historical imaging data among all the data stored in the internal memory  14  are not limited solely to the historical imaging data d 1  through d 6 , and can be set as appropriate with reference to the usage pattern of the processor. Additionally, in the case where still-image data is stored in the internal memory  14 , historical imaging data, which is stored together with the still-image data, can be different data from the above described specific historical imaging data.  
         [0067]     Obvious changes may be made in the specific embodiment of the present invention described herein, such modifications being within the spirit and scope of the invention claimed. It is indicated that all matter contained herein is illustrative and does not limit the scope of the present invention.