Patent Publication Number: US-2018028062-A1

Title: Endoscope processor

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Japanese Application No. 2016-146254 filed in Japan on Jul. 26, 2016, the contents of which are incorporated herein by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an endoscope processor, and in particular relates to an endoscope processor used in combination with a scanning type endoscope configured to optically scan an object. 
     2. Description of the Related Art 
     In an endoscope in a medical field, in order to reduce burdens on a subject, various technologies for narrowing a diameter of an insertion portion to be inserted into a body cavity of the subject have been proposed. Then, as one example of such technologies, a scanning type endoscope not including a solid-state image pickup device at a part corresponding to the insertion portion described above is known. 
     More specifically, a system including the scanning type endoscope is configured, for example, to transmit illumination light emitted from a light source by an optical fiber for illumination, two-dimensionally scan an object in a predetermined scanning route by driving an actuator for swinging a distal end portion of the optical fiber for illumination, receive return light from the object by an optical fiber for light reception, and generate an image of the object based on the return light received by the optical fiber for light reception. Then, for example, Japanese Patent No. 5490331 discloses an endoscope system similar to such a configuration. 
     More specifically, Japanese Patent No. 5490331 discloses an endoscope system including a scanning type endoscope, configured to use optical characteristic information of a predetermined objective optical system provided in the scanning type endoscope, and correct a magnification chromatic aberration generated due to the predetermined objective optical system. 
     SUMMARY OF THE INVENTION 
     An endoscope processor of one aspect of the present invention is an endoscope processor used in combination with a scanning type endoscope capable of scanning an object by displacing an irradiation position of illumination light to be radiated to the object, and includes: an image generation portion configured to respectively generate a plurality of color images according to return light of the illumination light radiated to the object; a correction processing portion configured to perform processing of acquiring a correction magnification for correcting a scanning width or a view angle of the scanning type endoscope in accordance with a reference value; and an image correction portion configured to perform magnification chromatic aberration correction processing for correcting a magnification chromatic aberration among the plurality of color images uniformly scaled according to the correction magnification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating a configuration of a main portion of an endoscope system including an endoscope processor relating to an embodiment; 
         FIG. 2  is a sectional view for describing a configuration of an actuator portion; 
         FIG. 3  is a diagram illustrating one example of a signal waveform of a drive signal supplied to the actuator portion; 
         FIG. 4  is a diagram illustrating one example of a spiral scanning route from a center point A to an outermost point B; 
         FIG. 5  is a diagram illustrating one example of a spiral scanning route from the outermost point B to the center point A; 
         FIG. 6  is a diagram for describing an outline of table data used in processing of the endoscope processor relating to the embodiment; 
         FIG. 7  is a diagram for describing a specific example of a calculation method of a scanning width of an endoscope; and 
         FIG. 8  is a diagram illustrating one example of a test chart available when acquiring the scanning width of the endoscope. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, the embodiment of the present invention will be described with reference to the drawings. 
       FIG. 1  to  FIG. 8  relate to the embodiment of the present invention. 
     An endoscope system  1  is configured, for example, as illustrated in  FIG. 1 , including a scanning type endoscope (abbreviated simply as an endoscope, hereinafter)  2  to be inserted into a body cavity of a subject, a main body device  3  to which the endoscope  2  can be attachably and detachably connected, a display device  4  connected to the main body device  3 , and an input device  5  capable of inputting information and giving an instruction to the main body device  3 .  FIG. 1  is a diagram illustrating a configuration of a main portion of the endoscope system including the endoscope processor relating to the embodiment. 
     The endoscope  2  is configured including an insertion portion  11  formed having an elongated shape insertable into a body cavity of a subject. 
     On a proximal end portion of the insertion portion  11 , a connector portion  61  for attachably and detachably connecting the endoscope  2  to a connector receiving portion  62  of the main body device  3  is provided. 
     Inside the connector portion  61  and the connector receiving portion  62 , though not shown in the figure, an electric connector device for electrically connecting the endoscope  2  and the main body device  3  is provided. In addition, inside the connector portion  61  and the connector receiving portion  62 , though not shown in the figure, an optical connector device for optically connecting the endoscope  2  and the main body device  3  is provided. 
     To a part from the proximal end portion to a distal end portion inside the insertion portion  11 , a fiber  12  for illumination which is an optical fiber configured to guide illumination light supplied from a light source unit  21  of the main body device  3  and emit the illumination light from an emission end portion, and a fiber  13  for light reception including one or more optical fibers for receiving return light from an object and guiding the return light to a detection unit  23  of the main body device  3  are inserted respectively. That is, the fiber  12  for illumination is configured having a function as a light guide portion. 
     An incident end portion including a light incident surface of the fiber  12  for illumination is arranged at a multiplexer  32  provided inside the main body device  3 . In addition, the emission end portion including a light emission surface of the fiber  12  for illumination is arranged near a light incident surface of a lens  14   a  provided on the distal end portion of the insertion portion  11 . 
     An incident end portion including a light incident surface of the fiber  13  for light reception is fixed and arranged around a light emission surface of a lens  14   b  on a distal end face of the distal end portion of the insertion portion  11 . In addition, an emission end portion including a light emission surface of the fiber  13  for light reception is arranged at a photodetector  37  provided inside the main body device  3 . 
     An illumination optical system  14  is configured including the lens  14   a  on which the illumination light through the light emission surface of the fiber  12  for illumination is made incident, and the lens  14   b  that emits the illumination light through the lens  14   a  to the object. 
     In a middle portion of the fiber  12  for illumination on a distal end portion side of the insertion portion  11 , an actuator portion  15  driven based on a drive signal supplied from a driver unit  22  of the main body device  3  is provided. 
     The fiber  12  for illumination and the actuator portion  15  are arranged respectively so as to have a position relation illustrated in  FIG. 2 , for example on a cross section vertical to a longitudinal axial direction of the insertion portion  11 .  FIG. 2  is a sectional view for describing a configuration of the actuator portion. 
     Between the fiber  12  for illumination and the actuator portion  15 , as illustrated in  FIG. 2 , a ferrule  41  as a bonding member is arranged. More specifically, the ferrule  41  is formed by zirconia (ceramic) or nickel, for example. 
     The ferrule  41  is, as illustrated in  FIG. 2 , formed as a square pole, and includes side faces  42   a  and  42   c  vertical to an X axis direction which is a first axial direction orthogonal to the longitudinal axial direction of the insertion portion  11 , and side faces  42   b  and  42   d  vertical to a Y axis direction which is a second axial direction orthogonal to the longitudinal axial direction of the insertion portion  11 . In addition, at a center of the ferrule  41 , the fiber  12  for illumination is fixed and arranged. 
     The actuator portion  15  includes, for example, as illustrated in  FIG. 2 , a piezoelectric element  15   a  arranged along the side face  42   a,  a piezoelectric element  15   b  arranged along the side face  42   b,  a piezoelectric element  15   c  arranged along the side face  42   c,  and a piezoelectric element  15   d  arranged along the side face  42   d.    
     The piezoelectric elements  15   a  to  15   d  have polarization directions individually set beforehand, and are configured to expand and contract respectively according to a drive voltage applied by the drive signal supplied from the main body device  3 . 
     That is, the piezoelectric elements  15   a  and  15   c  of the actuator portion  15  are configured as an actuator for an X axis capable of swinging the fiber  12  for illumination in the X axis direction by vibrating according to the drive signal supplied from the main body device  3 . Furthermore, the piezoelectric elements  15   b  and  15   d  of the actuator portion  15  are configured as an actuator for a Y axis capable of swinging the fiber  12  for illumination in the Y axis direction by vibrating according to the drive signal supplied from the main body device  3 . 
     Inside the insertion portion  11 , a nonvolatile memory  16  that stores information including a scanning width Wa used in processing to be described later, for example, as intrinsic endoscope information for each endoscope  2  is provided. Then, the endoscope information stored in the memory  16  is read by a controller  25  of the main body device  3  when the connector portion  61  of the endoscope  2  and the connector receiving portion  62  of the main body device  3  are connected and a power source of the main body device  3  is turned on. 
     The main body device  3  is configured having a function as the endoscope processor. More specifically, the main body device  3  is configured including the light source unit  21 , the driver unit  22 , the detection unit  23 , a memory  24 , and the controller  25 . 
     The light source unit  21  is configured including a light source  31   a,  a light source  31   b,  a light source  31   c,  and the multiplexer  32 . 
     The light source  31   a  includes a laser light source for example, and is configured to emit light of a red wavelength band (also called R light, hereinafter) to the multiplexer  32  when the light is emitted by control of the controller  25 . 
     The light source  31   b  includes a laser light source for example, and is configured to emit light of a green wavelength band (also called G light, hereinafter) to the multiplexer  32  when the light is emitted by the control of the controller  25 . 
     The light source  31   c  includes a laser light source for example, and is configured to emit light of a blue wavelength band (also called B light, hereinafter) to the multiplexer  32  when the light is emitted by the control of the controller  25 . 
     The multiplexer  32  is configured to multiplex the R light emitted from the light source  31   a,  the G light emitted from the light source  31   b,  and the B light emitted from the light source  31   c,  and supply the light to the light incident surface of the fiber  12  for illumination. 
     The driver unit  22  is configured to generate and supply a drive signal DA for driving the actuator for the X axis of the actuator portion  15  based on the control of the controller  25 . In addition, the driver unit  22  is configured to generate and supply a drive signal DB for driving the actuator for the Y axis of the actuator portion  15  based on the control of the controller  25 . Furthermore, the driver unit  22  is configured including a signal generator  33 , D/A converters  34   a  and  34   b,  and amplifiers  35   a  and  35   b.    
     The signal generator  33  is configured to generate a signal having a waveform indicated by an equation (1) below, for example, as a first drive control signal for swinging the emission end portion of the fiber  12  for illumination in the X axis direction and output the signal to the D/A converter  34   a,  based on the control of the controller  25 . Note that, in the equation (1) below, X(t) denotes a signal level at time t, Ax denotes an amplitude value independent of the time t, and G(t) denotes a predetermined function used in modulation of a sine wave sin(2πft). 
         X ( t )= Ax×G ( t )×sin(2 πft )   (1)
 
     In addition, the signal generator  33  is configured to generate a signal having a waveform indicated by an equation (2) below, for example, as a second drive control signal for swinging the emission end portion of the fiber  12  for illumination in the Y axis direction and output the signal to the D/A converter  34   b,  based on the control of the controller  25 . Note that, in the equation (2) below, Y(t) denotes the signal level at the time t, Ay denotes the amplitude value independent of the time t, G(t) denotes a predetermined function used in modulation of a sine wave sin(2πft+φ), and φ denotes a phase. 
         Y ( t )= Ay×G ( t )×sin(2π ft +φ)   (2)
 
     The D/A converter  34   a  is configured to convert the digital first drive control signal outputted from the signal generator  33  to an analog drive signal DA and output the drive signal DA to the amplifier  35   a.    
     The D/A converter  34   b  is configured to convert the digital second drive control signal outputted from the signal generator  33  to an analog drive signal DB and output the drive signal DB to the amplifier  35   b.    
     The amplifier  35   a  is configured to amplify the drive signal DA outputted from the D/A converter  34   a  and output the amplified drive signal DA to the piezoelectric elements  15   a  and  15   c  of the actuator portion  15 . 
     The amplifier  35   b  is configured to amplify the drive signal DB outputted from the D/A converter  34   b  and output the amplified drive signal DB to the piezoelectric elements  15   b  and  15   d  of the actuator portion  15 . 
     Here, for example, in the above-described equations (1) and (2), in a case that Ax=Ay and φ=π/2 are set, the drive voltage according to the drive signal DA having the signal waveform as illustrated by a broken line in  FIG. 3  is applied to the piezoelectric elements  15   a  and  15   c  of the actuator portion  15 , and the drive voltage according to the drive signal DB having the signal waveform as illustrated by a dashed line in  FIG. 3  is applied to the piezoelectric elements  15   b  and  15   d  of the actuator portion  15 .  FIG. 3  is a diagram illustrating one example of the signal waveform of the drive signal supplied to the actuator portion. 
     In addition, for example, in the case that the drive voltage according to the drive signal DA having the signal waveform as illustrated by the broken line in  FIG. 3  is applied to the piezoelectric elements  15   a  and  15   c  of the actuator portion  15  and the drive voltage according to the drive signal DB having the signal waveform as illustrated by the dashed line in  FIG. 3  is applied to the piezoelectric elements  15   b  and  15   d  of the actuator portion  15 , the emission end portion of the fiber  12  for illumination is spirally swung, and a surface of the object is scanned along a spiral scanning route as illustrated in  FIG. 4  and  FIG. 5  according to such swinging.  FIG. 4  is a diagram illustrating one example of the spiral scanning route from a center point A to an outermost point B.  FIG. 5  is a diagram illustrating one example of the spiral scanning route from the outermost point B to the center point A. 
     More specifically, first, at time T 1 , the illumination light is radiated to a position corresponding to the center point A of the irradiation position of the illumination light on the surface of the object. Thereafter, as the signal level of the drive signals DA and DB increases from the time T 1  to time T 2 , the irradiation position of the illumination light on the surface of the object is displaced to draw a first spiral scanning route to an outer side with the center point A as an origin, and further, when the time T 2  comes, the illumination light is radiated to the outermost point B of the irradiation position of the illumination light on the surface of the object. Then, as the signal level of the drive signals DA and DB decreases from the time T 2  to time T 3 , the irradiation position of the illumination light on the surface of the object is displaced to draw a second spiral scanning route to an inner side with the outermost point B as the origin, and further, when the time T 3  comes, the illumination light is radiated to the center point A on the surface of the object. 
     That is, the actuator portion  15  includes the configuration capable of displacing the irradiation position of the illumination light emitted through the emission end portion to the object along the spiral scanning route illustrated in  FIG. 4  and  FIG. 5  by swinging the emission end portion of the fiber  12  for illumination based on the drive signals DA and DB supplied from the driver unit  22 . In addition, the endoscope  2  includes the configuration capable of scanning the object by displacing the irradiation position of the illumination light to be radiated to the object. 
     The detection unit  23  has a function as a photodetection portion, and is configured to detect the return light received by the fiber  13  for light reception of the endoscope  2 , and generate and successively output a photodetection signal according to intensity of the detected return light. More specifically, the detection unit  23  is configured including the photodetector  37 , and an A/D converter  38 . 
     The photodetector  37  includes an avalanche photodiode for example, and is configured to detect the light (return light) emitted from the light emission surface of the fiber  13  for light reception, generate an analog photodetection signal according to the intensity of the detected light, and successively output the signal to the A/D converter  38 . 
     The A/D converter  38  is configured to convert the analog photodetection signal outputted from the photodetector  37  to a digital photodetection signal and successively output the signal to the controller  25 . 
     In the memory  24 , as control information used when controlling the main body device  3 , for example, information of a parameter for specifying the signal waveform in  FIG. 3 , and a mapping table which is a table indicating a correspondence relation between output timing of the photodetection signal successively outputted from the detection unit  23  and a pixel position to be an application destination of pixel information obtained by converting the photodetection signal is stored. 
     In the memory  24 , table data TD including a correction parameter for correcting the scanning width Wa of the endoscope  2  included in the endoscope information stored in the memory  16  is stored. 
     More specifically, the table data TD is, for example, as illustrated in  FIG. 6 , configured as data indicating the correspondence relation between the scanning width Wa of the endoscope  2  and a correction magnification Sa which is the correction parameter for correcting the scanning width Wa in accordance with a reference scanning width Wt.  FIG. 6  is a diagram for describing an outline of the table data TD used in the processing of the endoscope processor relating to the embodiment. 
     Correction magnifications Sa 1 , Sa 2 , . . . included in the table data TD in  FIG. 6  are calculated beforehand as values to be 1 in the case that the scanning width Wa is equal to the reference scanning width Wt, to be smaller than 1 in the case that the scanning width Wa is larger than the reference scanning width Wt, and to be larger than 1 in the case that the scanning width Wa is smaller than the reference scanning width Wt. In addition, the correction magnifications Sa 1 , Sa 2 , . . . included in the table data TD in  FIG. 6  are calculated as values capable of making the scanning width Wa coincide or roughly coincide with the reference scanning width Wt by being multiplied with the known amplitude values Ax and Ay. Furthermore, the reference scanning width Wt is preset as a reference value of the scanning width of the endoscope  2  in a state that production tolerance and/or time degradation of the actuator portion  15  has not occurred. 
     In the memory  24 , correction information to be used in magnification chromatic aberration correction processing for correcting a magnification chromatic aberration generated due to an optical characteristic of the illumination optical system  14  is stored. 
     More specifically, the above-described correction information includes a scaling rate SR for scaling an R image (to be described later) with a size of a G image (to be described later) as a reference and a scaling rate SB for scaling a B image (to be described later) with the size of the G image as the reference, for example. 
     The controller  25  includes an integrated circuit such as an FPGA (field programmable gate array), and is configured to perform an operation according to an operation of the input device  5 . In addition, the controller  25  is configured to detect whether or not the insertion portion  11  is electrically connected to the main body device  3  by detecting a connection state of the connector portion  61  in the connector receiving portion  62  through a signal line or the like not shown in the figure. Furthermore, the controller  25  is configured to read the control information stored in the memory  24  when the power source of the main body device  3  is turned on and perform the operation according to the read control information. In addition, the controller  25  is configured including a light source control portion  25   a,  a scanning control portion  25   b,  a correction processing portion  25   c,  and an image processing portion  25   d.    
     The light source control portion  25   a  is configured to perform the control for causing the R light, the G light and the B light to be repeatedly emitted in the order to the light source unit  21 , for example, based on the control information read from the memory  24 . 
     The scanning control portion  25   b  is configured to perform the control for causing the drive signals DA and DB having the signal waveform as illustrated in  FIG. 3  to be generated to the driver unit  22 , for example, based on the control information read from the memory  24 . In addition, the scanning control portion  25   b  is configured to perform the control for causing the amplitude value Ax of the drive signal DA and the amplitude value Ay of the drive signal DB to be changed to the driver unit  22 , based on the correction parameter obtained by the processing of the correction processing portion  25   c.    
     The correction processing portion  25   c  is configured to perform the processing of acquiring the correction parameter for correcting the scanning width Wa of the endoscope  2  included in the endoscope information, based on the endoscope information read from the memory  16  of the endoscope  2  connected to the main body device  3  and the table data TD read from the memory  24 . In addition, the correction processing portion  25   c  is configured to output the correction parameter obtained through the above-described processing to the scanning control portion  25   b.    
     The image processing portion  25   d  is configured including an image generation portion  25   m  and an image correction portion  25   n.    
     The image generation portion  25   m  is configured to generate the R image which is the image according to the return light of the R light radiated along the first spiral scanning route (the scanning route illustrated in  FIG. 4 ), the G image which is the image according to the return light of the G light radiated along the first spiral scanning route, and the B image which is the image according to the return light of the B light radiated along the first spiral scanning route respectively by converting the photodetection signal successively outputted from the detection unit  23  within a period from the time T 1  to T 2  to the pixel information and mapping the pixel information, for example, based on the mapping table included in the control information read from the memory  24 . 
     The image correction portion  25   n  is configured to perform the magnification chromatic aberration correction processing for correcting the magnification chromatic aberration among the R image, the G image and the B image generated by the image generation portion  25   m,  based on the correction information read from the memory  24 . In addition, the image correction portion  25   n  is configured to generate an observation image by combining the R image, the G image and the B image to which the above-described magnification chromatic aberration correction processing is executed, and successively output the generated observation image to the display device  4 . 
     More specifically, the image correction portion  25   n  is configured to perform the magnification chromatic aberration correction processing of scaling the R image generated by the image generation portion  25   m  at a magnification SR and scaling the B image generated by the image generation portion  25   m  at a magnification SB the scaling rates SR and SB included in the correction information read from the memory  24 , for example. 
     The display device  4  includes an LCD (liquid crystal display) for example, and is configured to display the observation image outputted from the main body device  3 . 
     The input device  5  is configured including one or more switches and/or buttons capable of instructing the controller  25  according to the operation by a user. Note that the input device  5  may be configured as a device separate from the main body device  3 , or may be configured as an interface integrated with the main body device  3 . 
     Next, the operation or the like of the endoscope system  1  including the configuration as described above will be described. 
     First, a specific example of a calculation method of the scanning width Wa stored in the memory  16  will be described while appropriately referring to  FIG. 7 .  FIG. 7  is a diagram for describing the specific example of the calculation method of the scanning width of the endoscope. 
     For example, upon manufacturing or a delivery inspection of the endoscope  2 , after connecting the respective portions of the endoscope system  1  and turning on the power source, as illustrated in  FIG. 7 , a factory operator arranges a distal end face FA of the endoscope  2  (insertion portion  11 ) and a light receiving surface FB of a position detection element (abbreviated as a PSD, hereinafter)  102  provided in an inspection jig  101  opposite to each other at a predetermined distance L, and wires a cable such that an output signal from the PSD  102  is inputted to a computer  111 . Note that, in  FIG. 7 , for convenience of illustration and description, the distal end face FA of the endoscope  2  (insertion portion  11 ) and the light emission surface of the lens  14   b  are flush. 
     Thereafter, the factory operator gives the instruction for starting scanning for an inspection to the controller  25  by operating an inspection switch (not shown in the figure) of the input device  5 , for example. 
     The light source control portion  25   a  performs the control for causing the G light to be intermittently generated to the light source unit  21 , when detecting that the inspection switch of the input device  5  is operated. In addition, the scanning control portion  25   b  performs the control for causing the drive signal DA having the amplitude value Ax and the drive signal DB having the amplitude value Ay to be generated to the driver unit  22 , when detecting that the inspection switch of the input device  5  is operated. 
     Then, according to the control of the light source control portion  25   a  and the scanning control portion  25   b  as described above, the light receiving surface FB of the PSD  102  is scanned by the pulsed G light emitted through the distal end face FA of the endoscope  2  (insertion portion  11 ), and position information indicating the irradiation position of the G light radiated to the light receiving surface FB along the spiral scanning route is outputted from the PSD  102  to the computer  111 . Note that it is assumed that the position information outputted from the PSD  102  to the computer  111  includes information capable of specifying the irradiation position of the G light radiated to the light receiving surface FB of the PSD  102  as a coordinate value of a rectangular coordinate system, for example. 
     The computer  111  acquires an irradiation position BGL (see  FIG. 7 ) of the G light corresponding to an outermost point of the spiral scanning route and an irradiation position CGL (see  FIG. 7 ) of the G light opposing the outermost point on an outermost periphery of the spiral scanning route respectively, based on the position information outputted from the PSD  102 . Then, the computer  111  calculates a distance between the irradiation position BGL and the irradiation position CGL as the scanning width Wa of the endoscope  2 . 
     That is, in the present embodiment, the scanning width Wa of the endoscope  2  calculated by the method illustrated above is stored in the memory  16 . In addition, according to the method illustrated above, the scanning width Wa of the endoscope  2  is stored in the memory  16  as a parameter indicating a scanning range of the spiral scanning route. Note that the computer  111  may be an arithmetic unit provided outside the main body device  3 , or may be an arithmetic unit built in the main body device  3 . 
     Next, a specific example of the operation performed in the controller  25  will be described. 
     After connecting the respective portions of the endoscope system  1  and turning on the power source, a user such as an operator gives the instruction for starting scanning for observation to the controller  25  by operating an observation start switch (not shown in the figure) of the input device  5 . 
     The correction processing portion  25   c  reads the endoscope information from the memory  16  of the endoscope  2  connected to the main body device  3  when the power source of the main body device  3  is turned on. Then, the correction processing portion  25   c  performs the processing of acquiring the correction parameter for correcting the scanning width Wa of the endoscope  2  included in the endoscope information based on the endoscope information read from the memory  16  of the endoscope  2  and the table data TD read from the memory  24 , and outputs the acquired correction parameter to the scanning control portion  25   b.    
     More specifically, the correction processing portion  25   c  performs the processing of acquiring the correction magnification Sa corresponding to the scanning width Wa of the endoscope  2  included in the endoscope information read from the memory  16  by referring to the table data TD as illustrated in  FIG. 6 , for example, and outputs the acquired correction magnification Sa to the scanning control portion  25   b.  That is, according to such processing of the correction processing portion  25   c,  for example, in the case that the scanning width included in the endoscope information read from the memory  16  is Wa 2 , the correction magnification Sa 2  is acquired as the correction parameter for correcting the scanning width Wa 2 , and the correction magnification Sa 2  is outputted to the scanning control portion  25   b.    
     The light source control portion  25   a  performs the control for causing the R light, the G light and the B light to be repeatedly emitted in the order to the light source unit  21 , when detecting that the observation start switch of the input device  5  is operated. 
     The scanning control portion  25   b  calculates a new amplitude value CAx by multiplying the amplitude value Ax by the correction magnification Sa obtained by the processing of the correction processing portion  25   c,  and calculates a new amplitude value CAy by multiplying the amplitude value Ay by the correction magnification Sa. Then, the scanning control portion  25   b  performs the control for causing the drive signal DA having the amplitude value CAx and the drive signal DB having the amplitude value CAy to be generated to the driver unit  22 , when detecting that the observation start switch of the input device  5  is operated. Note that the amplitude values CAx and CAy described above are held until the power source of the main body device  3  is turned off, for example. 
     That is, the scanning control portion  25   b  causes the R image, the G image and the B image generated by the image generation portion  25   m  to be uniformly scaled according to the correction magnification Sa, by increasing or decreasing the amplitude values Ax and Ay of the drive signal supplied to the endoscope  2  for displacing the irradiation position of the illumination light guided by the fiber  12  for illumination along the spiral scanning route according to the correction magnification Sa. 
     The image generation portion  25   m  generates the R image, the G image and the B image according to the photodetection signal successively outputted from the detection unit  23  respectively, based on the mapping table included in the control information read from the memory  24 . 
     The image correction portion  25   n  performs the magnification chromatic aberration correction processing of scaling the R image generated by the image generation portion  25   m  at the magnification SR and scaling the B image generated by the image generation portion  25   m  at the magnification SB using the scaling rates SR and SB included in the correction information read from the memory  24 . In addition, the image correction portion  25   n  generates the observation image by combining the R image, the G image and the B image to which the above-described magnification chromatic aberration correction processing is executed, and successively outputs the generated observation image to the display device  4 . 
     That is, the image correction portion  25   n  performs the magnification chromatic aberration correction processing for correcting the magnification chromatic aberration among the R image, the G image and the B image uniformly scaled according to the correction magnification Sa. In addition, the image correction portion  25   n  performs the processing of scaling the R image and the B image scaled according to the correction magnification Sa, with the size of the G image scaled according to the correction magnification Sa as the reference, as the magnification chromatic aberration correction processing. 
     According to the operation of the controller  25  as described above, the scanning width when scanning the object by radiating the light of three colors that are the R light, the G light and the B light along the spiral scanning route can be made to coincide or roughly coincide with the reference scanning width Wt. Therefore, according to the operation of the controller  25  as described above, the magnification chromatic aberration among the images of the three colors can be corrected in the state that dispersion of the size among the images of the three colors that are the R image, the G image and the B image generated due to the production tolerance and/or the time degradation or the like of the actuator portion  15 , that is, a generation factor of excessive correction and correction insufficiency of the magnification chromatic aberration, is eliminated. As a result, according to the present embodiment, the magnification chromatic aberration in the images acquired using the scanning type endoscope can be corrected appropriately (in proper quantities). 
     In addition, according to the present embodiment, the magnification chromatic aberration among the images of the three colors can be corrected appropriately (in proper quantities) without storing the plurality of scaling rates SR and the plurality of scaling rates SB for responding to the dispersion of the size among the images of the three colors that are the R image, the G image and the B image generated due to the production tolerance and/or the time degradation or the like of the actuator portion  15  in the memory  24 , for example. As a result, according to the present embodiment, a capacity of a storage medium such as the memory can be prevented from being oppressed due to many parameters to be used in the magnification chromatic aberration correction processing being stored in the storage medium. 
     Note that, according to the present embodiment, for example, in the case that the predetermined distance L is known, a view angle θa (see  FIG. 7 ) of the endoscope  2  calculated based on the predetermined distance L and the scanning width Wa of the endoscope  2  may be stored in the memory  16 , and the table data TE indicating the correspondence relation between the view angle θa and a correction magnification Sc which is a correction parameter for correcting the view angle θa in accordance with a reference view angle θt may be stored in the memory  24 . That is, in such a case, the view angle θa of the endoscope  2  is stored in the memory  16  as the parameter indicating the scanning range of the spiral scanning route. Note that the reference view angle θt is assumed to be preset as a reference value of the view angle of the endoscope  2  in the state that the production tolerance and/or the time degradation of the actuator portion  15  has not occurred. 
     In addition, according to the present embodiment, for example, in the case that the table data TD is stored in the computer  111  used upon the manufacturing or the delivery inspection of the endoscope  2 , the correction magnification Sa corresponding to the scanning width Wa of the endoscope  2  may be stored in the memory  16 . Furthermore, in such a case, for example, the scanning control portion  25   b  may read the endoscope information from the memory  16  and calculate the amplitude values CAx and CAy using the correction magnification Sa included in the read endoscope information. That is, in the case that the correction magnification Sa corresponding to the scanning width Wa of the endoscope  2  is stored in the memory  16 , at least some functions of the correction processing portion  25   c  may be incorporated in the scanning control portion  25   b.    
     In addition, according to the present embodiment, the correction magnification Sa acquired by the processing of the correction processing portion  25   c  may be outputted to the image correction portion  25   n,  for example, instead of being outputted to the scanning control portion  25   b.  Furthermore, in such a case, for example, the image correction portion  25   n  may perform the magnification chromatic aberration correction processing of uniformly scaling the R image, the G image and the B image at a magnification Sa and then further scaling the R image, which is scaled at the magnification Sa, at the magnification SR and scaling the B image, which is scaled at the magnification Sa, at the magnification SB. 
     Furthermore, according to the present embodiment, for example, in the case that a shift direction of a disposing position of the fiber  12  for illumination to the center of the actuator portion  15  is known, the image correction portion  25   n  may further perform pixel position correction processing of moving the pixel position of the R image scaled at the magnification SR in accordance with the pixel position of the G image and moving the pixel position of the B image scaled at the magnification SB in accordance with the pixel position of the G image. Note that, in the case of performing such pixel position correction processing, preferably, table data capable of respectively specifying a relative moving amount of the pixel position of the R image to the pixel position of the G image and a relative moving amount of the pixel position of the B image to the pixel position of the G image according to four to eight shift directions may be stored in the memory  24 . 
     On the other hand, according to the present embodiment, regardless of calculation of the scanning width Wa based on the position information obtained when the light receiving surface FB of the PSD  102  is scanned, for example, the scanning width Wa may be acquired based on the R image, the G image and the B image generated by the image generation portion  25   m  when a test chart  201  as illustrated in  FIG. 8  is scanned.  FIG. 8  is a diagram illustrating one example of a test chart available when acquiring the scanning width of the endoscope. 
     On a surface of the test chart  201 , as illustrated in  FIG. 8 , a plurality of circles CQ centering on a center point Q are concentrically drawn. In addition, on the surface of the test chart  201 , scanning width Wk 1 , Wk 2 , . . . corresponding to respective diameters of the plurality of circles CQ are written. 
     Here, a specific example of work using the test chart  201  will be described below. Note that, below, specific description relating to a part to which the already-described operation or the like is applicable is appropriately omitted. In addition, below, the case that five circles CQ centering on the center point Q are concentrically drawn on the surface of the test chart  201 , five scanning widths Wk 1  to Wk 5  corresponding to the respective diameters of the five circles CQ are written on the surface of the test chart  201 , and the five scanning widths Wk 1  to Wk 5  satisfy the relation of Wk 1 &lt;Wk 2 &lt;Wk 3 =Wt&lt;Wk 4 &lt;Wk 5  will be described as an example. 
     For example, in a facility of a destination of the endoscope  2 , a maintenance operator confirms that the respective portions of the endoscope system  1  are connected and the power source of the respective portions of the endoscope system  1  is supplied, and then arranges the distal end face FA of the endoscope  2  (insertion portion  11 ) and the surface of the test chart  201  opposite to each other at the predetermined distance L. In addition, when arranging the distal end face FA of the endoscope  2  (insertion portion  11 ) and the surface of the test chart  201  opposite to each other, the maintenance operator performs positioning for matching the center point A of the spiral scanning route with the center point Q of the plurality of circles CQ. 
     Thereafter, the maintenance operator gives the instruction for starting scanning for a simple inspection to the controller  25  by operating a simple inspection switch (not shown in the figure) of the input device  5 , for example. 
     When detecting that the simple inspection switch of the input device  5  is operated, the light source control portion  25   a  performs the control for causing the R light, the G light and the B light to be repeatedly emitted in the order to the light source unit  21 . In addition, when detecting that the simple inspection switch of the input device  5  is operated, the scanning control portion  25   b  performs the control for discarding the amplitude values CAx and CAy that are already held and causing the drive signal DA having the amplitude value Ax and the drive signal DB having the amplitude value Ay to be generated to the driver unit  22 . 
     Then, according to the control of the light source control portion  25   a  and the scanning control portion  25   b  as described above, the plurality of circles CQ drawn on the surface of the test chart  201  are scanned by the light of the three colors that are the R light, the G light and the B light emitted through the distal end face FA of the endoscope  2  (insertion portion  11 ), and the photodetection signal according to the return light of the light of the three colors is successively outputted from the detection unit  23 . 
     On the other hand, when detecting that the simple inspection switch of the input device  5  is operated, the image processing portion  25   d  performs the operation for generating an inspection image for the simple inspection by combining the R image, the G image and the B image generated in the image generation portion  25   m  and successively outputting the generated inspection image to the display device  4 . 
     Then, according to the operation of the image processing portion  25   d  as described above, the image before being scaled according to the correction magnification Sa, the scaling rate SR and the scaling rate SB is displayed at the display device  4  as the inspection image. In addition, according to the operation of the image processing portion  25   d  as described above, for example, in the case that the scanning width of the endoscope  2  connected to the main body device  3  is smaller than the reference scanning width Wt, the inspection image not including the three circles CQ corresponding to the scanning widths Wk 3  to Wk 5  is displayed at the display device  4 . Furthermore, according to the operation of the image processing portion  25   d  as described above, for example, in the case that the scanning width of the endoscope  2  connected to the main body device  3  is equal to or larger than the reference scanning width Wt, the inspection image including at least the three circles CQ corresponding to the scanning widths Wk 1  to Wk 3  is displayed at the display device  4 . 
     The maintenance operator specifies a scanning width Wkd (d=1, 2, 3, 4 or 5) corresponding to a circle CQD on the outermost side included in the inspection image by visually confirming the inspection image displayed at the display device  4 . In addition, the maintenance operator roughly calculates how far an outermost portion of the inspection image is separated from the circle CQD and acquires a rough estimate correction value Cd by visually confirming the inspection image displayed at the display device  4 . Thereafter, the maintenance operator calculates the (rough) scanning width Wa of the endoscope  2  by adding the rough estimate correction value Cd to the scanning width Wkd, and performs the operation for inputting the calculated scanning width Wa to the controller  25  in the input device  5 . 
     Then, according to work using the test chart  201  as described above, the processing for acquiring the correction magnification Sa corresponding to the scanning width Wa inputted according to the operation of the input device  5  is performed in the correction processing portion  25   c,  the processing for calculating the new amplitude values CAx and CAy according to the correction magnification Sa is performed in the scanning control portion  25   b,  and also the drive signal DA having the amplitude value CAx and the drive signal DB having the amplitude value CAy are outputted from the driver unit  22 . Thus, also in the case of acquiring the scanning width Wa through the work using the test chart  201 , effects almost similar to the effects in the case of acquiring the scanning width Wa through the work using the inspection jig  101  can be demonstrated. 
     On the other hand, by appropriately modifying the configuration of the main body device  3  of the present embodiment, the configuration may be adapted to the endoscope including the object optical system that obtains an optical image of the object and an image pickup device such as a CCD or a CMOS that picks up the optical image of the object. 
     More specifically, for example, the three images that are the R image, the G image and the B image according to the optical image of the object picked up by the image pickup device of the endoscope may be generated in the image generation portion  25   m,  the processing for scaling the three images and making the three images coincide with a predetermined reference size may be performed in the correction processing portion  25   c,  and the magnification chromatic aberration correction processing for correcting the magnification chromatic aberration among the three images scaled to the predetermined reference size may be performed in the image correction portion  25   n.    
     Note that it is needless to say that the present invention is not limited to each embodiment described above and various changes and applications are possible without deviating from the gist of the invention.