Patent Publication Number: US-2018035876-A1

Title: Image pickup apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of PCT/JP2016/052164 filed on Jan. 26, 2016 and claims benefit of Japanese Application No. 2015-124907 filed in Japan on Jun. 22, 2015, the entire contents of which are incorporated herein by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image pickup apparatus, in particular to an image pickup apparatus including an image pickup device driven by a clock set independently of and asynchronously with a clock in a connected video processor. 
     2. Description of the Related Art 
     Conventionally, in a medical field and an industrial field, an endoscope including an image pickup device configured to observe a subject has been widely used. In addition, a technology of configuring an endoscope system in which a signal processor called a video processor which performs various kinds of signal processing relating to the endoscope is freely attachably and detachably connected to the endoscope is also known. 
     In the endoscope system as described above, a conventional endoscope receives supply of a predetermined clock from a connected video processor, and drives a loaded image pickup device by the supplied clock. In this case, synchronization of the endoscope and the video processor is kept at a rate of the clock described above. 
     On the other hand, video processors of different drive frequencies for each type are present. For example, for the video processor corresponding to an NTSC standard and the video processor corresponding to a PAL standard, the drive frequencies are different from each other. 
     In the conventional endoscope, even in a case where the endoscope is connected to the video processors of the different drive frequencies, there are no problems in particular even when a drive clock from the video processor is received as it is and used in respective circuits inside the endoscope, a drive circuit of the image pickup device in particular. 
     That is, in the case of receiving supply of the clock from the video processors of the different drive frequencies such as the NTSC standard and the PAL standard, even though frequencies of the supplied clock are different from each other, such a difference of the frequencies is not a big trouble in the respective circuits loaded on the conventional endoscope. 
     On the other hand, in recent years, pixels have been increased more and more in the image pickup device loaded on the endoscope, and acceleration and quality improvement are demanded more regarding drive of the image pickup device. That is, for the clock that drives the image pickup device, a performance of higher quality is demanded. 
     Then, in consideration of the situation, in recent years, an endoscope provided with a high quality clock generation portion independent of a clock generation portion in a video processor is proposed (Japanese Patent Application Laid-Open Publication No. 2014-033788). 
     SUMMARY OF THE INVENTION 
     An image pickup apparatus of one aspect of the present invention is the image pickup apparatus connectable to a processor including a first clock generation portion configured to generate a predetermined first clock and a first vertical synchronizing signal generation portion configured to generate a predetermined first vertical synchronizing signal, and includes: a second clock generation portion configured to generate a second clock to drive an image pickup device, which is set independently of and asynchronously with the first clock; a second vertical synchronizing signal generation portion configured to receive the first vertical synchronizing signal and generate a second vertical synchronizing signal including a period synchronized at least at a frame rate with the first vertical synchronizing signal, according to the second clock and the first vertical synchronizing signal; a sensor synchronization control signal generation portion configured to generate a sensor synchronization control signal capable of clock synchronous communication by a serial communication standard, according to the second clock and the second vertical synchronizing signal; and the image pickup device for which internal vertical synchronizing drive timing is set according to the sensor synchronization control signal, and which is configured to pick up an image of an object according to the internal vertical synchronizing drive timing. 
     An image pickup apparatus of one aspect of the present invention is the image pickup apparatus connectable to a processor including a first clock generation portion configured to generate a predetermined first clock and a first vertical synchronizing signal generation portion configured to generate a predetermined first vertical synchronizing signal, and includes: a second clock generation portion configured to generate a second clock to drive an image pickup device, which is set independently of and asynchronously with the first clock; a second vertical synchronizing signal generation portion configured to receive the first vertical synchronizing signal and generate a second vertical synchronizing signal including a period synchronized at least at a frame rate with the first vertical synchronizing signal, according to the first clock and the first vertical synchronizing signal; a sensor synchronization control signal generation portion configured to generate a sensor synchronization control signal capable of clock synchronous communication by a serial communication standard, according to the first clock and the second vertical synchronizing signal; and the image pickup device for which internal vertical synchronizing drive timing is set according to the sensor synchronization control signal, and which is configured to pick up an image of an object according to the internal vertical synchronizing drive timing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a schematic configuration of an endoscope system including an image pickup apparatus (endoscope) relating to a first embodiment of the present invention; 
         FIG. 2  is a timing chart illustrating a relation between a vertical synchronizing signal supplied from a video processor and a vertical synchronizing signal generated on an endoscope side, in the endoscope relating to the first embodiment; 
         FIG. 3  is a timing chart illustrating a relation between a vertical synchronizing signal inputted to a sensor synchronization control signal generation circuit and a vertical synchronizing signal inside a CMOS sensor in the endoscope relating to the first embodiment; 
         FIG. 4  is a block diagram illustrating a schematic configuration when a video processor of another drive frequency is connected to the endoscope, in the endoscope system including the image pickup apparatus (endoscope) relating to the first embodiment; 
         FIG. 5  is a block diagram illustrating a schematic configuration of an endoscope system including an image pickup apparatus (endoscope) relating to a second embodiment of the present invention; 
         FIG. 6  is a timing chart illustrating a clock and a vertical synchronizing signal supplied to a sensor synchronization control signal generation circuit in the endoscope relating to the second embodiment; 
         FIG. 7  is a timing chart illustrating a relation between the vertical synchronizing signal inputted to the sensor synchronization control signal generation circuit and the vertical synchronizing signal inside the CMOS sensor in the endoscope relating to the second embodiment; 
         FIG. 8  is a block diagram illustrating a schematic configuration of an endoscope system including an image pickup apparatus (endoscope) relating to a third embodiment of the present invention; and 
         FIG. 9  is a block diagram illustrating a schematic configuration of an endoscope system including an image pickup apparatus (endoscope) relating to a fourth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Hereinafter, embodiments of the present invention will be described. 
     In addition, the invention is not limited by the embodiments. Further, in description of the drawings, same signs are attached to same parts. 
       FIG. 1  is a block diagram illustrating a schematic configuration of an endoscope system including an image pickup apparatus of a first embodiment of the present invention. 
     Note that, the embodiments illustrated below are described with an endoscope including an image pickup device as an example of the image pickup apparatus. 
     As illustrated in  FIG. 1 , an endoscope system  1  mainly includes an endoscope  2  configured to pick up an in-vivo image of an object by inserting a distal end portion into a body cavity of a subject and output an image signal of the object image, a video processor  3  configured to execute predetermined image processing on the image signal outputted from the endoscope  2  and generally control an operation of the entire endoscope system  1 , and a non-illustrated light source device configured to generate illumination light to be emitted from a distal end of the endoscope  2 . 
     First, the video processor  3  is, in the present embodiment, a video processor corresponding to an NTSC standard for example, including a processor drive clock A generation circuit  31  configured to generate and output a predetermined drive clock A, and a vertical synchronizing signal A generation circuit  32  configured to generate and output a predetermined vertical synchronizing signal A. 
     In addition, the endoscope  2  includes an image pickup device (CMOS sensor)  21  configured to receive the object image and photoelectrically convert the object image to an electric signal and execute predetermined image processing on the electric signal, a sensor drive clock C generation circuit  23  configured to generate a drive clock (drive clock C) to be supplied to required circuits inside the endoscope  2  in addition to the image pickup device  21 , a sensor synchronization control signal generation circuit  24  configured to generate a sensor synchronization control signal to be supplied to the image pickup device  21 , and a synchronizing signal reception circuit  25  configured to receive the vertical synchronizing signal A from the video processor  3  and output a vertical synchronizing signal C to be supplied to the sensor synchronization control signal generation circuit  24 . 
     For the image pickup device  21 , in the present embodiment, a CMOS (complementary metal oxide semiconductor) image sensor (CIS) is adopted. Hereinafter, the image pickup device  21  is also described as a CMOS sensor  21 . 
     In the present embodiment, the CMOS sensor  21  receives the drive clock C generated in the sensor drive clock C generation circuit  23 , and is driven. 
     In addition, the CMOS sensor  21  includes a register  22  which can be accessed from an outside (in the present embodiment, accessed by the sensor synchronization control signal), and holds setting data for generating a predetermined drive pulse. 
     The sensor drive clock C generation circuit  23  generates the drive clock C independently of the clock in the video processor  3 . The sensor drive clock C generation circuit  23  is configured by a crystal oscillator for example, and outputs to required circuits inside the endoscope  2  including the sensor synchronization control signal generation circuit  24  and the synchronizing signal reception circuit  25  in addition to the CMOS sensor  21 . 
     Note that, in the present embodiment, a center frequency of the drive clock C is set at a frequency higher than the clock A in the video processor  3 , and is set asynchronously with the clock A. 
     Here, as described above, in the present embodiment, the clock A supplied from the video processor  3  and the clock C in the sensor drive clock C generation circuit  23  are asynchronously set, that is, a configuration is such that synchronization is not attained at a clock rate. 
     Therefore, in a case of such a configuration, for example in the case of counting a time period corresponding to one frame using the clock A of a frequency A in the video processor  3  and counting the time period using the clock C of a frequency C on a side of the endoscope  2 , both time periods are slightly different due to a deviation of the mutual clock generation circuits. 
     Then, when the side of the video processor  3  and the side of the endoscope  2  uniquely continue counting, a difference may become non-negligible. Specifically, drive timing of the CMOS sensor  21  on the side of the endoscope  2  may deviate from vertical synchronizing timing in the video processor  3 . 
     In this case, in the video processor  3  to which an image pickup signal from the CMOS sensor  21  of the endoscope  2  is inputted, a failure may occur when performing image processing relating to the image pickup signal or when executing a light adjustment function of a light source. 
     Note that the light adjustment function of the light source described above includes not only control of a light emission intensity but also control of changeover timing of a color of illumination light or timing in the case of intermittent light emission. In addition, the control timing of the light source needs to be determined according to drive timing of the CMOS sensor  21 . 
     In consideration of a situation described above, an object of the present invention is to prevent occurrence of the failure described above by surely operating synchronization at a frame rate between the endoscope  2  and the video processor  3 . 
     Hereinafter, a characteristic configuration of the present invention will be described. 
     Returning to  FIG. 1 , the sensor synchronization control signal generation circuit  24  is driven by the clock C generated in the sensor drive clock C generation circuit  23 , and generates and outputs the sensor synchronization control signal to be supplied to the register  22  in the CMOS sensor  21 . 
     Note that the sensor synchronization control signal generation circuit  24  and the CMOS sensor  21  are connected by communication by a clock synchronous serial communication standard so called I 2 C (inter-integrated circuit). 
     In addition, for the CMOS sensor  21 , the drive timing is determined based on the vertical synchronizing timing indicated from the sensor synchronization control signal generation circuit  24 . 
     The synchronizing signal reception circuit  25  receives the vertical synchronizing signal A from the video processor  3 , is driven by the clock C generated in the sensor drive clock C generation circuit  23 , and generates and outputs the vertical synchronizing signal C to be supplied to the sensor synchronization control signal generation circuit  24 . 
     Action of First Embodiment 
     Next, an action of the first embodiment will be described. 
       FIG. 2  is a timing chart illustrating a relation between the vertical synchronizing signal A supplied from the video processor  3  and the vertical synchronizing signal C generated on the side of the endoscope  2 , in the endoscope relating to the first embodiment, and  FIG. 3  is a timing chart illustrating a relation between the vertical synchronizing signal C inputted to the sensor synchronization control signal generation circuit  24  and the vertical synchronizing signal inside the CMOS sensor  21  in the endoscope relating to the first embodiment. 
     As illustrated in  FIG. 2 , the vertical synchronizing signal A from the video processor  3  received in the synchronizing signal reception circuit  25  is synchronized with the clock A generated in the processor drive clock A generation circuit  31  in the video processor  3 . 
     On the other hand, in the present embodiment, the clock C independent of the clock A in the video processor  3  is generated in the sensor drive clock C generation circuit  23  as described above, and the synchronizing signal reception circuit  25  generates the vertical synchronizing signal C synchronized with the clock C from the vertical synchronizing signal A, based on the clock C. 
     Thereafter, the synchronizing signal reception circuit  25  outputs the newly generated vertical synchronizing signal C to the sensor synchronization control signal generation circuit  24 . 
     The sensor synchronization control signal generation circuit  24  which receives the vertical synchronizing signal C transmits the sensor synchronization control signal to the register  22  which is a synchronization control register of the CMOS sensor  21  based on the vertical synchronizing signal C, as illustrated in  FIG. 3 . 
     The CMOS sensor  21  receives the sensor synchronization control signal based on the vertical synchronizing signal C in the register  22 , and thereafter, generates the vertical synchronizing signal inside the sensor. 
     As described above, in the first embodiment, in the endoscope  2  including the CMOS sensor  21  driven by the clock C set independently of and asynchronously with the clock A in the connected video processor  3 , while the clock C and the clock A are not synchronized at the clock rate, the synchronization at the frame rate is surely attained though slightly gentle between the CMOS sensor  21  and the video processor  3 , and thus the endoscope that can drive the CMOS sensor  21  by the clock C of higher quality than the connected video processor  3 , and does not obstruct image processing or a light source light adjustment function in the connected video processor  3  can be provided. 
     Note that, as described above, the center frequency of the drive clock C is set at a frequency higher than the drive clock A in the video processor  3  in the present embodiment, but regardless of the frequency, may be same as the center frequency of the clock A as long as being asynchronous with the drive clock A. 
     In addition, as long as being asynchronous with the drive clocks in the plurality of other video processors connectable to the endoscope  2 , the center frequency of the drive clock C may be the same as the center frequency of one of the drive clocks relating to the plurality of video processors. 
     For example, as illustrated in  FIG. 4 , it is assumed that the endoscope  2  of the present embodiment is connected to another video processor  103  different from the video processor  3 . 
     At the time, the video processor  103  includes a processor drive clock B generation circuit  131  configured to generate a drive clock B different from the drive clock A, and a vertical synchronizing signal B generation circuit  132  configured to generate a vertical synchronizing signal B different from the vertical synchronizing signal A. 
     In this case, the endoscope  2  of the present embodiment generates the drive clock C independently of and asynchronously with the clock B in the video processor  103  as described above in the sensor drive clock C generation circuit  23 , and the center frequency of the drive clock C may be the same as the center frequency of the clock B as long as being asynchronous with the drive clock B. 
     Second Embodiment 
     Next, a second embodiment of the present invention will be described. 
       FIG. 5  is a block diagram illustrating a configuration of an endoscope system including an image pickup apparatus (endoscope) relating to the second embodiment of the present invention. 
     Since the configuration of the endoscope system including the image pickup apparatus of the second embodiment is basically similar to the configuration of the first embodiment, only the difference from the first embodiment will be described here and the other detailed description is omitted. 
     As illustrated in  FIG. 5 , an endoscope system  101  mainly includes an endoscope  102  configured to output the image signal of the object image similarly to the above description, the video processor  3  connectable to the endoscope  102  and capable of outputting the clock A similarly to the first embodiment, and the non-illustrated light source device similarly to the above description. 
     In the second embodiment as well, the video processor  3  includes the processor drive clock A generation circuit  31  configured to generate and output the predetermined drive clock A, and a vertical synchronizing signal A generation circuit  32  configured to generate and output the predetermined vertical synchronizing signal A. 
     The endoscope  102  includes a CMOS sensor  121  configured similarly to the first embodiment, a sensor drive clock C generation circuit  123  configured to generate a sensor drive clock (drive clock C) to be supplied to the CMOS sensor  121 , a sensor synchronization control signal generation circuit  124  configured to generate the sensor synchronization control signal to be supplied to the CMOS sensor  121 , and a synchronizing signal reception circuit  125  configured to receive the vertical synchronizing signal A from the video processor  3  and output the vertical synchronizing signal A to the sensor synchronization control signal generation circuit  124 . 
     Here, in the image pickup apparatus (endoscope  2 ) of the first embodiment described above, not only the CMOS sensor  21  is driven by the clock C generated in a clock generation portion (sensor drive clock C generation circuit  23 ) inside the endoscope but also the sensor synchronization control signal generation circuit  24  and the synchronizing signal reception circuit  25  are driven by the clock C. 
     In addition, in the first embodiment, the synchronizing signal reception circuit  25  receives the vertical synchronizing signal A which is an external clock from the video processor  3 , and newly generates and outputs the vertical synchronizing signal C based on the clock C. 
     Further, in the first embodiment, the sensor synchronization control signal generation circuit  24  outputs the sensor synchronization control signal to the register  22  in the CMOS sensor  21  based on the vertical synchronizing signal C. 
     In contrast, the sensor drive clock C generation circuit  123  in the image pickup apparatus (endoscope  102 ) of the second embodiment generates the drive clock C independently of and asynchronously with the clock A in the video processor  3  similarly to the first embodiment, and the CMOS sensor  121  is driven by the clock C which is the clock generated in the clock generation portion inside the endoscope. 
     On the other hand, in the second embodiment, the sensor synchronization control signal generation circuit  124  and the synchronizing signal reception circuit  125  are driven by the external clock, that is, the clock A generated in the processor drive clock A generation circuit  31  in the connected video processor  3  differently from the first embodiment. 
     In addition, in the second embodiment, the synchronizing signal reception circuit  125  receives the vertical synchronizing signal A which is the external clock from the video processor  3 , and also outputs the vertical synchronizing signal A synchronized with the clock A to the sensor synchronization control signal generation circuit  124 . 
     Further, the sensor synchronization control signal generation circuit  124  outputs the sensor synchronization control signal to a register  122  in the CMOS sensor  121  based on the inputted vertical synchronizing signal A. 
     Then, in the second embodiment, the CMOS sensor  121  receives the sensor synchronization control signal based on “the vertical synchronizing signal A” in the register  122 , and generates the vertical synchronizing signal inside the sensor. 
     In this way, in the second embodiment, while the CMOS sensor  121  is driven by “the clock C” asynchronously with “the clock A” and the synchronization is not attained at the clock rate with the video processor  3 , the CMOS sensor  121  generates the vertical synchronizing signal inside the sensor based on “the vertical synchronizing signal A” from the video processor  3 . 
     Action of Second Embodiment 
     Next, the action of the second embodiment will be described. 
       FIG. 6  is a timing chart illustrating the clock (clock A) and the vertical synchronizing signal (vertical synchronizing signal A) supplied to the sensor synchronization control signal generation circuit in the endoscope relating to the second embodiment, and  FIG. 7  is a timing chart illustrating a relation between the vertical synchronizing signal inputted to the sensor synchronization control signal generation circuit and the vertical synchronizing signal inside the CMOS sensor in the endoscope relating to the second embodiment. 
     As illustrated in  FIG. 6 , while the vertical synchronizing signal A from the video processor  3  received in the synchronizing signal reception circuit  125  is synchronized with the clock A generated in the processor drive clock A generation circuit  31  in the video processor  3 , in the second embodiment, the synchronizing signal reception circuit  125  is driven by the clock A from the video processor  3  as described above so that the vertical synchronizing signal to be outputted is the received vertical synchronizing signal A as it is. 
     In the second embodiment, the synchronization control signal generation circuit  124  transmits the sensor synchronization control signal to the register  122  which is a synchronization control register of the CMOS sensor  121  based on the vertical synchronizing signal A, as illustrated in  FIG. 7 . 
     Note that, in the present embodiment, the communication (I2C) of register control is the communication asynchronous with the sensor drive clock C, but it is possible to receive the sensor synchronization control signal based on the vertical synchronizing signal A. 
     That is, while the clock of high quality is demanded for the clock to be supplied to the CMOS sensor  21 , demanded quality can be lower than the quality relating to the clock for communication control relating to the register control as described above so that, in the configuration of the present embodiment as well, the CMOS sensor  21  can receive the sensor synchronization control signal based on the vertical synchronizing signal A. 
     Then, the CMOS sensor  121  receives the sensor synchronization control signal based on the vertical synchronizing signal A in the register  122 , and thereafter, generates the vertical synchronizing signal inside the sensor. 
     As described above, in the second embodiment as well, similarly to the first embodiment, in the endoscope  102  including the CMOS sensor  121  driven by the clock C set independently of and asynchronously with the clock A in the connected video processor  3 , while the clock C and the clock A are not synchronized at the clock rate, the synchronization at the frame rate is surely attained between the CMOS sensor  121  and the video processor  3 , and thus the endoscope that can drive the CMOS sensor  121  by the clock C of the higher quality than the connected video processor  3 , and does not obstruct the image processing or the light source light adjustment function in the connected video processor  3  can be provided. 
     Note that, in the second embodiment as well, similarly to the first embodiment, the center frequency of the drive clock C is set at the frequency higher than the drive clock A in the video processor  3 , but regardless of the frequency, may be same as the center frequency of the clock A as long as being asynchronous with the drive clock A. 
     In addition, it is similar to the first embodiment that, as long as being asynchronous with the drive clocks in the plurality of other video processors connectable to the endoscope  102 , the center frequency of the drive clock C may be the same as the center frequency of one of the drive clocks relating to the plurality of video processors. 
     Third Embodiment 
     Next, a third embodiment of the present invention will be described. 
       FIG. 8  is a block diagram illustrating a configuration of an endoscope system including an image pickup apparatus (endoscope) relating to an eighth embodiment of the present invention. 
     Both of the image pickup apparatuses (endoscopes) of the first and second embodiments described above adopt the CMOS sensor as the image pickup device, but a CCD image sensor is loaded as an image pickup device in the third embodiment. 
     As illustrated in  FIG. 8 , an endoscope system  201  relating to the third embodiment mainly includes an endoscope  202  configured to pick up an in-vivo image of an object by inserting the distal end portion into a body cavity of a subject and output an image signal of the object image, a video processor  203  configured to execute predetermined image processing on the image signal outputted from the endoscope  202  and generally control an operation of the entire endoscope system  201 , and a non-illustrated light source device configured to generate illumination light to be emitted from a distal end of the endoscope  202 . 
     The video processor  203  is, in the third embodiment as well, a video processor corresponding to the NTSC standard for example, including the processor drive clock A generation circuit  31  configured to generate and output the predetermined drive clock A, and the vertical synchronizing signal A generation circuit  32  configured to generate and output the predetermined vertical synchronizing signal A. 
     The endoscope  202  includes an image pickup device (CCD image sensor)  221  configured to receive the object image and photoelectrically convert the object image to an electric signal and execute predetermined image processing on the electric signal, a sensor drive clock D generation circuit  223  configured to generate a drive clock (drive clock D) to be supplied to the image pickup device  221 , a CCD drive signal generation circuit  224  configured to generate a vertical drive signal and a horizontal drive signal to be supplied to the image pickup device  221 , and a synchronizing signal reception circuit  225  configured to receive the vertical synchronizing signal A from the video processor  203 , be driven by the drive clock C, and output a synchronizing signal D to be supplied to the CCD drive signal generation circuit  224 . 
     For the image pickup device  221 , in the present embodiment, a CCD (charge coupled device) image sensor is adopted. Hereinafter, the image pickup device  221  is also described as a CCD image sensor  221 . 
     The sensor drive clock D generation circuit  223  generates the drive clock D independently of the clock A in the video processor  203 , similarly to the first and second embodiments. The sensor drive clock D generation circuit  223  is configured by a crystal oscillator for example, and outputs to the synchronizing signal reception circuit  225  in addition to the CCD drive signal generation circuit  224 . 
     Note that, in the present embodiment as well, the center frequency of the drive clock D is set at the frequency higher than the clock A in the video processor  203 , and is set asynchronously with the clock A. 
     That is, in the third embodiment as well, the clock A supplied from the video processor  203  and the clock D in the sensor drive clock D generation circuit  223  are asynchronously set, that is, the configuration is such that the synchronization is not attained at the clock rate. 
     The synchronizing signal reception circuit  225  generates the synchronizing signal D synchronized with the clock D from the vertical synchronizing signal A based on the clock D, and outputs the synchronizing signal D to the CCD drive signal generation circuit  224 . 
     The CCD drive signal generation circuit  224  supplies the vertical drive signals described above based on the synchronizing signal D to the CCD image sensor  221 . 
     Action of Third Embodiment 
     Next, the action of the third embodiment will be described. 
     The vertical synchronizing signal A from the video processor  203  received in the synchronizing signal reception circuit  225  is synchronized with the clock A generated in the processor drive clock A generation circuit  31  in the video processor  203 . 
     On the other hand, in the third embodiment as well, the clock D independent of the clock A in the video processor  203  is generated in the sensor drive clock D generation circuit  223  similarly to the first embodiment, and the synchronizing signal reception circuit  225  generates a synchronizing signal D synchronized with the clock D from the vertical synchronizing signal A based on the clock D. 
     Thereafter, the synchronizing signal reception circuit  225  outputs the synchronizing signal D to the CCD drive signal generation circuit  224 , and the CCD drive signal generation circuit  224  which receives the synchronizing signal D transmits the vertical drive signal described above to the CCD image sensor  221  based on the synchronizing signal D. 
     As described above, in the third embodiment as well, in the endoscope  202  including the CCD image sensor  221  driven by the clock D set independently of and asynchronously with the clock A in the connected video processor  203 , while the clock D and the clock A are not synchronized at the clock rate, the synchronization at the frame rate is surely attained though slightly gentle between the CCD image sensor  221  and the video processor  203 , and thus the endoscope that can drive the CCD image sensor  221  by the clock D of the higher quality than the connected video processor  203 , and does not obstruct image processing or a light source light adjustment function in the connected video processor  203  can be provided. 
     Fourth Embodiment 
     Next, a fourth embodiment of the present invention will be described. 
       FIG. 9  is a block diagram illustrating the configuration of an endoscope system including an image pickup apparatus (endoscope) relating to the fourth embodiment of the present invention. 
     The image pickup apparatus (endoscope  2 ) of the first embodiment described above supplies the clock C generated in the clock generation portion (sensor drive clock C generation circuit  23 ) inside the endoscope to required circuits inside the endoscope  2  in addition to the CMOS sensor  21 . 
     In contrast, the image pickup apparatus (endoscope  302 ) of the fourth embodiment includes various circuits  26  (excluding the sensor synchronization control signal generation circuit  24  and the synchronizing signal reception circuit  25 ) operated by the clock A in the connected video processor  3 . 
     In this way, since the configuration of an endoscope system  301  including the image pickup apparatus of the fourth embodiment is basically similar to the first embodiment except for the point described above, the detailed description of the other configuration is omitted. 
     As described above, in the image pickup apparatus (endoscope) of the fourth embodiment, even in the case of partially including the circuit operated at the clock A in the connected video processor  3 , the effect similar to the effect of the first embodiment described above is demonstrated. 
     The present invention is not limited to the embodiments described above, and can be variously changed and modified or the like without changing a subject matter of the present invention. 
     According to the present invention, it is possible to provide an image pickup apparatus capable of not causing troubles in image processing or light adjustment of a light source and coping with various video processors of different clock frequencies, in the image pickup apparatus including an image pickup device driven by a clock set independently of and asynchronously with a clock in a connected video processor.