Patent Document

BACKGROUND OF THE INVENTION  
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an electronic endoscope, and more particularly to the configuration of an electronic endoscope apparatus in which a scope not equipped with a timing generator and a scope equipped with a timing generator can be connected to a processor unit which is an image processing apparatus. 
         [0003]    2. Description of the Related Art 
         [0004]    An electronic endoscope apparatus is able to display on a monitor an image of an object to be observed as, for example, the object illuminated with light is imaged by a charge coupled device (CCD) which is a solid-state imaging device mounted in a scope (electronic endoscope), and an imaging signal from this CCD is supplied to a processor unit (main unit) and is subjected to predetermined signal processing in an image processing circuit within this processor unit. This type of electronic endoscope apparatus is so configured that a plurality of scopes in which types of the aforementioned CCDs and imaging methods (signal processing methods) are different can be connected to the processor unit. 
         [0005]      FIG. 4  shows a configuration of the related-art electronic endoscope apparatus. As shown in  FIG. 4 , for example, an E type scope  1 E has a CCD  2   e  mounted at its leading end portion, and its square-type electric connector  3   e  is connected to a square type connector receiver  5   e  of a processor unit  4 . Meanwhile, an F type scope  1 F has a CCD  2   f  mounted at its leading end portion, and its round-type electric connector  3   f  is connected to a round type connector receiver  5   f  of a processor unit  4 . These electric connectors  3   e  and  3   f  are for connecting to the processor unit  4  signal lines and the like for transmitting video signals obtained by the CCDs  2   e  and  2   f.  Although not shown, lightquides for supplying light source light into the scopes  1 E and  1 F as illumination light are connected to the processor unit  4  and the like by optical connectors. 
         [0006]    In addition, a patient circuit  10  including a timing generator  7 , an A/D converter  8 , a digital signal processor (DGP)  9 , and the like, as well as a secondary circuit  14  including a signal processing circuit  12 , a power supply circuit  13 , and the like, are provided in the processor unit  4 . An electrical isolator  15  constituted by a pulse transformer or a photocoupler is interposed between the patient circuit  10  and the secondary circuit  14 . 
         [0007]    According to such an electronic endoscope apparatus, by changing the shapes of the electric connectors  3   e  and  3   f  and the connector receivers  5   e  and  5   f  between the E type and the F type, it is possible to perform image processing and the like which are adapted to the respective types of scopes  1 E and  1 F while eliminating erroneous connection of the connectors. In addition, electrical safety of the client circuit  10  is ensured as the client circuit  10  is electrically separated by the isolator  15  from the secondary circuit  14  where the power supply circuit  13  which is directly connected to commercial supply is disposed. 
         [0008]    In the related-art electronic endoscope apparatus, it is practiced to dispose a timing generator  16  in the secondary circuit  14  shown in  FIG. 4 , for example (e.g., the aforementioned JP-A-11-289530). In this case, a CCD drive signal (such as a clock signal) outputted from the timing generator  16  is supplied to the CCDs  2   e  and  2   f  of the scopes  1 E and  1 F via the isolator  15  and the client circuit  10 . The other timing signals are also supplied to the client circuit  10  via the isolator  15 . However, in the case where the CCD drive signal is supplied to the CCDs  2   e  and  2   f  via the i9solator  15 , there is a problem in that a phase shift and the like can occur in the CCD drive signal and deteriorates the image quality. The higher the pixilation of the CCDs  2   e  and  2   f  is and the higher the speed of the CCD drive signal (clock signal) is, the greater the effect of this problem becomes. 
         [0009]    Accordingly, in the case of  FIG. 4 , the arrangement provided is such that the timing generator  7  is disposed in the client circuit  10 , and the CCDs  2   e  and  2   f  are driven by the CCD drive signal (such as clock signal) from this timing generator  7  to thereby make it possible to obtain an image of the object to be observed with excellent image quality. In addition, to cope with even higher pixilation in recent years, it is also practiced to mount a timing generator into the scope, as shown in the JP-A-2003-93341. 
         [0010]    In the related art, however, there are cases where the timing generator  7  for outputting the CCD drive signal is not mounted in the scope ( 1 E,  1 F, etc.) and cases where it is mounted therein, so that the processor unit ( 4 ) must be fabricated in conformity to the configuration of such scopes. Accordingly, in this case, there has been a problem in that different types of scopes cannot be connected to a single processor unit, entailing higher cost. 
       SUMMARY OF THE INVENTION  
       [0011]    The present invention has been devised in view of the above-described problems, and its object is to provide an electronic endoscope apparatus in which both the scope equipped with the timing generator and the scope not equipped therewith can be used by being connected to a single processor unit, and which makes it possible to form an excellent image by high-speed drive signals corresponding to highly pixilated imaging devices. 
         [0012]    To attain the above object, in accordance with a first aspect of the invention there is provided an electronic endoscope apparatus comprising a processor unit so as to allow an A type scope not having a timing generator and a B type scope having a timing generator to be connector-connected to the processor unit, the apparatus comprising: an in-client-circuit timing generator and a first image signal processing unit both corresponding the A type scope; and a second image signal processing unit corresponding to the B type scope, wherein control is provided such that when the A type scope is connected to the processor unit, the in-client-circuit timing generator and the first image signal processing unit are operated, whereas when the B type scope is connected to the processor unit, the second image signal processing unit is operated. 
         [0013]    In accordance with a second aspect of the invention, the processor unit further comprises: a D 1  type digital signal processor; and a D 2  type digital signal processor, each of the D 1  type digital signal processor and the D 2  type digital signal processor being connectable to both of the first image signal processing unit and the second image signal processing unit, and either one of the D 1  type digital signal processor and the D 2  type digital signal processor is selectively operated in correspondence with a difference in an image processing type of the scope. It should be noted that the aforementioned A, B, D 1 , and D 2  are for distinguishing the types. 
         [0014]    According to the configuration of the above-described first aspect of the invention, the type of scope is determined as the processor unit effects communication with the scopes connected thereto. When the A type scope is connected, the timing generator and the first image signal processing unit in the client circuit of the processor unit are turned on. As a CCD drive signal is supplied from this timing generator to the charge coupled device (CCD) of the A type scope, an imaging signal is outputted from the CCD. This imaging signal is supplied to the first image signal processing unit, where the imaging signal is subjected to predetermined signal processing, thereby forming an image of the object to the observed. 
         [0015]    Meanwhile, when the B type scope is connected, the second image signal processing unit in the processor unit is turned on. In this case, as a CCD is driven by a CCD drive signal from a timing generator within the scope, an imaging signal is outputted from the CCD. This imaging signal is supplied to the second image signal processing unit, where the imaging signal is subjected to predetermined signal processing, thereby forming an image of the object to the observed. 
         [0016]    According to the configuration of the above-described second aspect of the invention, either one of the D 1  type digital signal processor and the D 2  type digital signal processor is selected in correspondence with a difference in the image processing type of the connected scope irrespective of the A type and the B type. Even in cases where there is the difference in the image processing type of scopes of the same type, it is possible to perform excellent image processing. Namely, among the CCDs, there types such as a primary color system (R, G, B) CCD and a complementary color system (Y, Mg, Cy, G) CCD, and there are also differences in the pixel clock signal (or the number of pixels) and the like. The D 1  type digital signal processor or the D 2  type digital signal processor is selected in correspondence with the image processing type of each of such various CCDs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0017]      FIG. 1  is a circuit block diagram illustrating the configuration of a processor unit (main unit) of an electronic endoscope apparatus in accordance with an embodiment of the invention; 
           [0018]      FIGS. 2A and 2B  are circuit block diagrams illustrating configurations of an A type scope and a B type scope, respectively; 
           [0019]      FIG. 3  is a flowchart illustrating the operation of the electronic endoscope apparatus in accordance with the embodiment; and 
           [0020]      FIG. 4  is a diagram illustrating a configuration of the related-art electronic endoscope apparatus in which two types of scopes are connected. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    In addition, according to the second aspect of the invention, it is possible to use a digital signal processor corresponding to the difference in the image processing type of the scope irrespective of whether not the scope is a type equipped with a timing generator, and excellent image processing is made possible even if there is the difference between the primary color system the complementary color system, a difference in the number of pixels, and so forth in the imaging devices. 
         [0022]      FIGS. 1 ,  2 A, and  2 B show the configuration of an electronic endoscope apparatus in accordance with an embodiment of the invention.  FIG. 1  shows the configuration of a processor unit (main unit), and  FIGS. 2A and 2B  show configurations of A type and B type scopes (electronic endoscopes), respectively. First, as shown in  FIG. 2A , an A type scope  1 A is not equipped with a timing generator and has a CCD  2   a,  a correlated double sampling (CDS)/automatic gain control (AGC) circuit  18   a,  and a read-only memory (ROM) or a microcomputer or the like  20   a,  and a video signal is outputted as an analog signal. 
         [0023]    In addition, as shown in  FIG. 2B , a B type scope  1 B is equipped with a timing generator (TG)  21 , has a CCD  2   b,  a CDS/AGC circuit  18   b,  an A/D converter  22 , and a ROM  20   b,  and a video signal is outputted as a digital signal. It should be noted that the A type scope  1 A and the B type scope  1 B are connected to a processor unit  23  by means of connector portions (connector- and processor unit-side connector receivers)  24   a  and  24   b  of different shapes so as to discriminate the two scopes  1 A and  1 B and prevent erroneous connection. 
         [0024]    In  FIG. 1 , in the processor unit  23 , one client circuit board  26  is connected to a secondary circuit board  28  via an isolator (pulse transformer, photocoupler, or the like)  27 . A timing generator (TG)  30  corresponding to the aforementioned A type scope  1 A, a first (image) signal processing unit  31  having an A/D converter and the like and adapted to effect video processing of an output signal from the A type scope  1 A, and a second signal processing unit  32  having a buffer circuit and the like and adapted to effect video processing of an output signal from the B type scope  1 B are provided on the client circuit board  26 . In addition, a D 1  type digital signal processor (DSP)  33  and a D 2  type DSP  34  are respectively connected to the first signal processing unit  31  and the second signal processing unit  32 . 
         [0025]    In addition, the client circuit board  26  is provided with a front CPU (or a microcomputer)  36  and a DSP-use CPU  37 . This front CPU  36  effects communication with the ROMs (or microcomputers)  20   a  and  20   b  on the sides of the scopes  1 A and  1 B to determine the types (presence or absence of the TG, the type of DSP used, etc.) of the scopes  1 A and  1 B, and turns on and off the power supply of the timing generator  30 , the first signal processing unit  31 , and the second signal processing unit  32 . The DSP-use CPU  37 , upon receiving a DSP selection instruction signal from the front CPU  36 , turns on and off the first DSP  33  and the second DSP  34 . Namely, as for the scopes  1 A and  1 B, the type of DSP used is determined by the characteristics and type of an imaging device, i.e., by the type of image processing, irrespective of the presence or absence of the TG, and either corresponding DSP ( 33 ,  34 ) is selected. 
         [0026]    The embodiment has the above-described configuration. As shown in  FIG. 1 , the electronic endoscope apparatus in accordance with the invention is so configured as to be able to connect the plurality of scopes  1 A and  1   b  to the processor unit  23  by means of the connector portions  24   a  and  24   b  having different shapes. When either one of these scopes  1 A and  1 B is connected, the operation shown in  FIG. 3  is executed by the front CPU  36  and the DSP-use CPU  37 . 
         [0027]    In  FIG. 3 , first, the front CPU  36  effects communication with the ROMs  20   a  and  20   b  in the scopes  1 A and  1 B (Step  101 ). In an ensuing Step  102 , the type of the connected scope is discriminated, and if it is determined here that the scope is the A type scope  1 A, the operation proceeds to Step  103 . In Step  103 , the front CPU  36  turns on (the power supply of) the timing generator  30  and the first signal processing unit  31  and turns off (the power supply of) the second signal processing unit  32 . Then, in Step  104 , the type of the scope DSP is discriminated, and if it is determined here that the type of the scope DSP is the D 1  type, the operation proceeds to Step  105 . In Step  105 , an instruction signal is outputted to the DSP-use CPU  37  to turn on the D 1  type DSP  33  and turn off the D 2  type DSP  34 . As a result, the DSP-use CPU  37  turns on the D 1  type DSP  33  and turns off the D 2  type DSP  34  (Step  106 ). 
         [0028]    If it is determined in the aforementioned Step  104  that the type of the scope DSP is the D 2  type, the operation proceeds to Step  107 . In Step  107 , an instruction signal is outputted to the DSP-use CPU  37  to turn off the D 1  type DSP  33  and turn on the D 2  type DSP  34 . As a result, the DSP-use CPU  37  turns off the D 1  type DSP  33  and turns on the D 2  type DSP  34  (Step  108 ). 
         [0029]    Meanwhile, if it is determined in the aforementioned Step  102  that the connected scope is the B type scope  1 B, the operation proceeds to Step  110 , in which the front CPU  36  turns off the timing generator  30  and the first signal processing unit  31  and turns on the second signal processing unit  32 . Then, in Step  111 , the type of the scope DSP is discriminated, and if it is determined here that the type of the scope DSP is the D 1  type, the operation proceeds to Step  112 . In Step  112 , an instruction signal is outputted to the DSP-use CPU  37  to turn on the D 1  type DSP  33  and turn off the D 2  type DSP  34 . As a result, the DSP-use CPU  37  turns on the D 1  type DSP  33  and turns off the D 2  type DSP  34  (Step  113 ). 
         [0030]    If it is determined in the aforementioned Step  111  that the type of the scope DSP is the D 2  type, the operation proceeds to Step  114 . In Step  107 , an instruction signal is outputted to the DSP-use CPU  37  to turn off the D 1  type DSP  33  and turn on the D 2  type DSP  34 . As a result, the DSP-use CPU  37  turns off the D 1  type DSP  33  and turns on the D 2  type DSP  34  (Step  115 ). 
         [0031]    When the A type scope  1 A is thus connected, a CCD drive signal is supplied to the CCD  2   a  by using the timing generator (TG)  30  on the client circuit board  26 , whereby an image pickup signal is outputted from the CCD  2   a.  This image pickup signal is processed by the CDS/AGC circuit  18   a,  and an analog video signal is outputted from the scope  1 A to the processor unit  23 . Then, this analog video signal is converted to a digital video signal by the first signal processing unit  31 , and this digital video signal is processed by either the D 1  type DSP  33  or the D 2  type DSP  34 . An output of this DSP  33  or  34  is outputted to a monitor through signal processing in the secondary circuit board  28 , thereby displaying on the monitor an image (video image) of the object to be observed. 
         [0032]    Meanwhile, when the B type scope  1 B is connected, a CCD drive signal is supplied to the CCD  2   b  by using the timing generator (TG)  21  on the in the scope  1 B, whereby an image pickup signal is outputted from the CCD  2   b.  This image pickup signal is processed by the CDS/AGC circuit  18   b  and the A/D converter  22 , and a digital video signal is outputted from the scope  1 B to the processor unit  23 . Then, this digital video signal is subjected to buffer processing by the second signal processing unit  32 , and this digital video signal is processed by either the D 1  type DSP  33  or the D 2  type DSP  34 , thereby displaying on the monitor an image of the object to be observed through the processing by the secondary circuit board  28 . 
         [0033]    Although in the above-described embodiment both the front CPU  36  and the DSP-use CPU  37  were used, control of the turning on and off of the power supply of the DSPs  33  and  34  may be effected by using only the front CPU  36  without using this DSP-use CPU  37 . According to this arrangement, it is possible to attain a cost reduction. 
         [0034]    According to the electronic endoscope apparatus in accordance with the invention, advantages are obtained in that both the scope equipped with the timing generator and the scope not equipped therewith can be used by being connected to a single processor unit, that it is possible to form an excellent image by high-speed drive signals corresponding to highly pixilated imaging devices, and that cost reduction also becomes possible. 
         [0035]    The entire disclosure of each and every foreign patent application from which the benefit of foreign priority has been claimed in the present application is incorporated herein by reference, as if fully set forth.

Technology Category: 1