Abstract:
An endoscope device having one or more processors configured to perform a control process including: processing an imaging signal to generate image data of a display image of a subject, wherein the image signal is generated by an image sensor, wherein the image sensor is arranged at a distal end of an insertion portion, and wherein a bending actuator is configured to bend the distal end; setting a first measurement point and a second measurement point on the display image; calculating a first subject distance from the first measurement point to a reference point of the image sensor, and a second subject distance from the second measurement point to the reference point; calculating a difference value between the first subject distance and the second subject distance; and controlling the bending actuator to bend the distal end of the insertion portion such that the difference value is decreased.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation application of PCT International Application No. PCT/JP2016/073314, filed in on Aug. 8, 2016, and claims benefit of Japanese Patent Application No. 2015-167097, filed in Japan on Aug. 26, 2015, the entire contents of which are incorporated herein by this reference. 
     
    
     BACKGROUND 
     1. Technical Field 
       [0002]    The present invention relates to an endoscope device, particularly, to an endoscope device that is capable of automatically controlling a relationship between a front end surface of an endoscope and a subject such that the relationship has a state in which the measurement is performed with appropriate accuracy. 
       2. Description of Related Art 
       [0003]    In the related art, an endoscope device has been widely used in the industrial field and the medical field. The endoscope device includes: an endoscope insertion portion that is inserted into an observation target, an imaging unit provided at a front end of the insertion portion that captures an image of the inside of the observation target, and a monitor on which the image is displayed, and thereby a user observes the image such that it is possible to examine the inside of the observation target. 
         [0004]    In addition, among the endoscope devices, there is an endoscope device having a measurement function such that it is possible to measure the size or the like of a scratch, a defect, or the like on a mechanical component. In such an endoscope device, when a user designates measurement points on an endoscopic image, measurement values related to the designated one point or two points, for example, a distance from the front end of the endoscope insertion portion to one point, a distance between two points, or the like is calculated and obtained. In such an endoscope device, in order to obtain accurate measurement results, a subject and a monitor surface (front end surface of the endoscope insertion portion) have to be set to have a state in which the measurement is performed with appropriate accuracy. More specifically, a bending manipulation is performed such that a surface of the subject which has a scratch, a defect, or the like and the front end surface of the endoscope insertion portion are parallel to each other, and thereby it is possible to measure the size of a scratch or a defect with accuracy. 
         [0005]    Therefore, JP-A-2009-14711 discloses an endoscope device that is capable of notifying a user of an inclination of a subject in a depth direction of an image in real time. The endoscope device uses the size of a mark of an arrow in a leftward-rightward direction that indicates the inclination of the subject in the depth direction of the image. For example, in a case where a mark on the left side of the arrow is displayed to be larger than a mark on the right side, the user can know that the mark side on the left side is the front side (close), and the mark side on the right side is the rear side (away). 
         [0006]    In this manner, the user can recognize the inclination of the subject in the depth direction of the image, and can perform a bending manipulation for setting the subject and the monitor surface to a state in which the measurement is performed with high accuracy. 
         [0007]    However, in the endoscope device of the related art, in order to actually set the subject and the monitor surface to a state in which the measurement is performed with appropriate accuracy, the user needs to manually operate the bending manipulation, and thus remarkable time and effort is required and it is highly difficult to perform the operation. 
         [0008]    An object of the present invention is to provide an endoscope device that is capable of automatically controlling a relationship between a subject and a front end surface of an endoscope insertion portion such that the relationship is in a state in which the measurement is performed with appropriate accuracy, based on a plurality of items of object distance information. 
       SUMMARY 
       [0009]    One aspect of the present invention provides an endoscope device comprising: an insertion portion comprising a distal end; an image sensor arranged at the distal end of the insertion portion, wherein the image sensor is configured to generate an imaging signal based on a subject image of a subject formed on the image sensor; a bending actuator configured to bend the distal end of the insertion portion so as to change an imaging visual field of the image sensor; and one or more processors comprising hardware, wherein the one or more processors are configured to perform a control process comprising: processing the imaging signal to generate image data of a display image of the subject to be displayed on a display; setting a first measurement point and a second measurement point on the display image of the subject; calculating a first subject distance from the first measurement point to a reference point of the image sensor, and a second subject distance from the second measurement point to the reference point of the image sensor; calculating a difference value between the first subject distance and the second subject distance; and controlling the bending actuator to bend the distal end of the insertion portion such that the difference value is decreased. 
         [0010]    Another aspect of the present invention provides a method comprising: performing a control process comprising: processing an imaging signal to generate image data of a display image of a subject to be displayed on a display, wherein the image signal is generated by an image sensor based on a subject image of the subject formed on the image sensor, wherein the image sensor is arranged at a distal end of an insertion portion, and wherein a bending actuator is configured to bend the distal end of the insertion portion so as to change an imaging visual field of the image sensor; setting a first measurement point and a second measurement point on the display image of the subject; calculating a first subject distance from the first measurement point to a reference point of the image sensor, and a second subject distance from the second measurement point to the reference point of the image sensor; calculating a difference value between the first subject distance and the second subject distance; and controlling the bending actuator to bend the distal end of the insertion portion such that the difference value is decreased. 
         [0011]    Another aspect of the present invention provides a computer-readable storage device storing instructions that cause one or more processors to: perform a control process comprising: processing an imaging signal to generate image data of a display image of a subject to be displayed on a display, wherein the image signal is generated by an image sensor based on a subject image of the subject formed on the image sensor, wherein the image sensor is arranged at a distal end of an insertion portion, and wherein a bending actuator is configured to bend the distal end of the insertion portion so as to change an imaging visual field of the image sensor; setting a first measurement point and a second measurement point on the display image of the subject; calculating a first subject distance from the first measurement point to a reference point of the image sensor, and a second subject distance from the second measurement point to the reference point of the image sensor; calculating a difference value between the first subject distance and the second subject distance; and controlling the bending actuator to bend the distal end of the insertion portion such that the difference value is decreased. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a view of the external appearance of an endoscope device according to an embodiment of the present invention. 
           [0013]      FIG. 2  is a block diagram illustrating an internal configuration of an endoscope device  1 . 
           [0014]      FIG. 3  is a sectional view illustrating an example of an internal configuration of an optical adapter  15  and a front end portion  11   a  of the embodiment. 
           [0015]      FIG. 4  is a diagram illustrating an example of a display screen displayed on a display unit when spot ranging starts. 
           [0016]      FIG. 5  is a diagram illustrating an example of a plurality of scalar circles having sizes different from each other. 
           [0017]      FIG. 6  is a flowchart illustrating an example of the flow of a process used during automatic bending control (automatic bending mode). 
           [0018]      FIG. 7  is a diagram illustrating an example of the display unit during execution of an automatic adjustment mode. 
           [0019]      FIG. 8  is a diagram illustrating another example of a display screen displayed on a display unit when spot ranging starts. 
           [0020]      FIG. 9  is a diagram illustrating still another example of a display screen displayed on a display unit when spot ranging starts. 
           [0021]      FIG. 10  is a diagram illustrating still another example of a display screen displayed on a display unit when spot ranging starts. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Hereinafter, an embodiment of the present invention will be described with reference to the figures. 
         [0023]      FIG. 1  is a view of the external appearance of an endoscope device according to an embodiment of the present invention. An endoscope device  1  is configured to include a manipulation unit  12  having an insertion portion  11 , and a main body portion  13 . A base end portion of the insertion portion  11  is connected to the manipulation unit  12 . The manipulation unit  12  and the main body portion  13  are connected to each other via a cable  14 . 
         [0024]    A front end portion  11   a  of the insertion portion  11  is provided with a bending portion, and a user bends the bending portion. In this manner, it is possible to adjust, to a desired direction, an imaging direction of an imaging device (for example, a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS)) provided on the front end side from the bending portion, and to easily observe an observation target. The front end portion  11   a  can be equipped with an optical adapter  15  as an adapter for an endoscope. Note that a user can select an optical adapter having a different visual field direction or viewing angle characteristics depending on an examination position, an examination state, or the like, and can install the optical adapter on the front end portion  11   a.    
         [0025]    The manipulation unit  12  is equipped with a display unit  12   a  and an operating device portion  12   b  including various types of buttons and a joystick, and the user can watch, at hand, an endoscopic image that is displayed on the display unit  12   a  while the user holds the manipulation unit  12  and operates the operating device portion  12   b . Further, the main body portion  13  is also equipped with a display unit  13   a . As will be described below, in a case where the manipulation unit  12  is used by being connected to the main body portion  13 , the user can also watch, on the main body portion  13 , the endoscopic image that is displayed on the display unit  13   a . Here, the display units  12   a  and  13   a  are, for example, liquid crystal displays (LCD). The display unit  12   a  is a display smaller than the display unit  13   a.    
         [0026]    Further, a cable  14  is provided with a connector  21  at a front end portion thereof. The connector  21  can be detachably connected to a connector  22  provided in the manipulation unit  12 . In other words, the manipulation unit  12  can be connected to the main body portion  13 . A signal line, a power line, and a light guide are connected to each of the connectors  21  and  22 . 
         [0027]    The user can use, as the endoscope device, a single device of the manipulation unit  12  to which the insertion portion  11  is connected, depending on a use environment of the endoscope device, or can use the manipulation unit  12  connected to the main body portion  13 . In other words, in the endoscope device  1 , the manipulation unit  12  equipped with the insertion portion  11  can be used not only as an endoscope device, but also as an endoscope device including the main body portion  13  and the manipulation unit  12  equipped with the insertion portion  11 . In a case where the manipulation unit  12  is used as a single device without being connected to the main body portion  13 , the user can use the manipulation unit  12  as a portable endoscope device. 
         [0028]      FIG. 2  is a block diagram illustrating an internal configuration of the endoscope device  1 .  FIG. 2  is a block diagram illustrating a configuration employed in a case where the front end portion  11   a  of the insertion portion  11  is equipped with the optical adapter  15 . 
         [0029]    As illustrated in  FIG. 2 , in a case where the manipulation unit  12  is used as the portable endoscope device, the user installs the optical adapter  15  on the front end portion  11   a  of the insertion portion  11 . In this case, a light source is, for example, a light emitting diode (hereinafter, referred to as an LED)  62  which is a light emitting device as a light source provided in the optical adapter  15 . In other words, the LED  62  is the light source provided in an adapter that can be installed on the front end portion  11   a  of the insertion portion  11 . Light from the LED  62  is illumination light that illuminates a subject. 
         [0030]    Note that the LED  62  may not be provided on the front end portion  11   a  of the insertion portion  11 , but may be provided inside the manipulation unit  12 , and light may be emitted from the front end portion  11   a  through a light guide  34  that is inserted into the insertion portion  11 , or another light guide separated from the light guide  34 . 
         [0031]    In addition, the front end portion  11   a  of the insertion portion  11  is equipped with a CCD  31  as an imaging device and a bending mechanism portion  32 . Optical lenses  33   a  and  33   b  are disposed on the front side of an imaging surface of the CCD  31 . 
         [0032]    Further, the light guide  34  is inserted into the insertion portion  11 . In a case where the manipulation unit  12  is used by being connected to the main body portion  13 , the light guide  34  guides illumination light from the main body portion  13  to the front end portion  11   a  of the insertion portion  11 . In other words, the light guide  34  that guides light from the light source of the main body portion  13  is inserted into the insertion portion  11 . 
         [0033]    A front end surface of the light guide  34  is fixed by being in close contact with a glass plate  35  provided on a front end surface of the front end portion  11   a  of the insertion portion  11 . A based end surface of the light guide  34  is fixed by being in close contact with a glass plate  36  provided on the connector  22  of the manipulation unit  12 . Hence, when the manipulation unit  12  is connected to the main body portion  13 , it is possible for the illumination light from the main body portion  13  to be incident on the base end surface of the light guide  34  and be emitted from the front end surface of the light guide  34  through the light guide  34 . 
         [0034]    The manipulation unit  12  includes an analog front end unit (hereinafter, referred to as an AFE)  41 , a CCD driving unit  42 , a bending driving unit  43 , an LED driving unit  44 , a buffer  45 , a camera control unit (hereinafter, referred to as a CCU)  46 , a CPU  47  as a control unit, an operating device portion  12   b , a display unit  12   a , a serial transmission unit  48 , a flash memory  49 , a signal/power line connecting portion  50 , a charge circuit  51 , and a battery  52 . 
         [0035]    The CCD  31  is connected to the CCD driving unit  42  of the manipulation unit  12  via a signal line L 1 , and is driven based on a drive pulse from the CCD driving unit  42 . The CCD driving unit  42  is connected to the CPU  47  and is controlled by the CPU  47 . The CCD  31  driven by the CCD driving unit  42  photoelectrically converts a subject image, generates an imaging signal, and outputs the signal to the AFE  41  via a signal line L 2 . The signal lines L 1  and L 2  are inserted into the insertion portion  11 . 
         [0036]    The imaging signal is converted into a digital signal in the AFE  41 , and the imaging signal output from the AFE  41  is supplied to the CCU  46  via the buffer  45 . The CCU  46  as a signal processing unit performs predetermined signal processing on the imaging signal so as to generate image data, and outputs the data to the CPU  47 . 
         [0037]    The CPU  47  as the control unit is a microcomputer, and includes a ROM, a RAM, or the like. The operating device portion  12   b  is connected to the CPU  47 . The operating device portion  12   b  includes a spot ranging start button, a spot ranging end button, switches for various types of functions such as an automatic adjustment mode switch, a freeze switch, a recording switch, or a joystick for the bending manipulation. The user operates a desired operating device, and thereby it is possible to instruct execution of a desired function. 
         [0038]    The CPU  47  executes a predetermined process based on an instruction signal from the operating device portion  12   b . The CPU  47  outputs image data of a live endoscopic image to the display unit  12   a  based on the image data from the CCU  46 ; however, when the freeze button is pressed down, the CPU  47  acquires a still image, outputs image data of the still image to the display unit  12   a , and displays the still image on the display unit  12   a . In addition, when the recording button is pressed down, the CPU  47  encodes a still image or a moving image and records encoded data to the flash memory  49  connected to the CPU  47  or a recording medium of the main body portion  13 . 
         [0039]    In addition, in a case where the manipulation unit  12  is connected to the main body portion  13 , the CPU  47  is connected to an electrical connecting portion  53  of the connector  22 , and can receive an instruction signal from the main body portion  13  via the electrical connecting portion  53 . In this case, the CPU  47  executes a process based on the instruction signal from the main body portion  13 . 
         [0040]    In addition, an output of the buffer  45  diverges, and the buffer  45  is also connected to the serial transmission unit  48 . The serial transmission unit  48  converts the image data input from the buffer  45  into a serial signal and outputs the serial signal to the signal/power line connecting portion  50 . 
         [0041]    The signal/power line connecting portion  50  is a circuit for connecting a signal line that transmits, to the main body portion  13 , the image data input from the serial transmission unit  48  and a power line that receives power from the main body portion  13 . In a case where the manipulation unit  12  is connected to the main body portion  13 , the signal/power line connecting portion  50  transmits the image data to the main body portion  13  via the electrical connecting portion  53  of the connector  22 . 
         [0042]    The charge circuit  51  is connected to the signal/power line connecting portion  50 , and it is possible to charge the battery  52  by the charge circuit  51 . When the manipulation unit  12  is connected to the main body portion  13 , and the CPU  47  detects the connection and the connection is performed, the CPU  47  receives power from the main body portion  13  via the electrical connecting portion  53  of the connector  22  and causes the charge circuit  51  to operate and charge the battery  52 . Conversely, in a case where connection is not performed, the CPU  47  stops the charge circuit  51  and drives the manipulation unit  12  with the battery  52 . 
         [0043]    In other words, the manipulation unit  12  has the battery  52 , and members of the manipulation unit  12  are driven and operate by power from the battery  52  installed inside the manipulation unit  12  when the operating unit is cut from the main body portion  13 . In addition, when the manipulation unit  12  is connected to the main body portion  13 , the operating unit receives power supply from the main body portion  13  and charge of the battery  52  is performed. 
         [0044]    The bending driving unit  43  is connected to the CPU  47 . The bending driving unit  43  includes a motor or the like and pulls or loosens a plurality of (here, four) wires  37  inserted into the insertion portion  11  in response to the drive control signal from the CPU  47 , and thereby a bending portion of the front end portion  11   a  is bent. The user operates a joystick of the operating device portion  12   b , thereby the bending mechanism portion  32  is actuated, and a visual field direction of the CCD  31  can be set to a desired direction. 
         [0045]    When the manipulation unit  12  is used as a single device, that is, as the portable endoscope device, the LED driving unit  44  is a circuit that drives the LED  62  of the optical adapter  15  installed on the front end portion  11   a . The LED driving unit  44  is controlled by the CPU  47 . Therefore, an LED driving signal line L 3  is inserted into the insertion portion  11 , and the front end portion  11   a  is provided with a contact point (not illustrated) on the signal line L 3 . When the optical adapter  15  is installed on the front end portion  11   a , the LED driving unit  44  and the LED  62  are connected to each other via the contact point on the signal line L 3 . 
         [0046]    In addition, the optical adapter  15  is an LED optical adapter, and includes optical lenses  61   a  and  61   b  and a discerning unit  63 . When the optical adapter  15  is installed on the front end portion  11   a  of the insertion portion  11 , the optical lenses  61   a  and  61   b  are optical members for collecting light from the subject on the imaging surface of the CCD  31  and forming a subject image. Hence, when the optical adapter  15  is installed on the front end portion  11   a  of the insertion portion  11 , the optical lenses  33   a  and  33   b  of the front end portion  11   a  and the optical lenses  61   a  and  61   b  of the optical adapter  15  configure an objective optical system of the CCD  31 . 
         [0047]    The LED  62  configures a light source for illumination when the manipulation unit  12  is used as the portable endoscope device. As described above, the CPU  47  controls the LED driving unit  44  such that the optimal drive current is supplied to the LED  62  via the signal line L 3  in order for the LED  62  to emit light having a predetermined light quantity. 
         [0048]    As described above, a plurality of adapters can be installed on the front end portion  11   a  of the insertion portion  11  connected to the manipulation unit  12 , and thus the insertion portion  11  can emit light from the LED  62  as the light source from the front end portion  11   a.    
         [0049]    The discerning unit  63  is a circuit for enabling the CPU  47  to discern the optical adapter  15 . For example, the discerning unit  63  is a resistor having a resistance value corresponding to the optical adapter  15 . The resistance value of the discerning unit  63  is read by the CPU  47 . Therefore, a signal line L 4  for the discerning unit  63  is inserted into the insertion portion  11 , and the front end portion  11   a  is provided with a contact point (not illustrated) on the signal line L 4 . When the optical adapter  15  is installed on the front end portion  11   a , the discerning unit  63  and the CPU  47  are connected to each other via the contact point on the signal line L 4 . 
         [0050]    As described above, the CPU  47  is capable of discriminating between types of optical adapters installed on the front end portion  11   a  by using a difference in resistance value of the discerning unit  63 . Note that the discerning unit  63  may not be a resistor, but may be a memory having discerning data. In this case, the CPU  47  discriminates between types of adapters based on discerning data read from the memory. 
         [0051]      FIG. 3  is a sectional view illustrating an example of an internal configuration of the optical adapter  15  and the front end portion  11   a  of the embodiment. As illustrated in  FIG. 3 , the optical adapter  15  is a direct-view-type optical adapter for the stereo measurement. The front end surface of the optical adapter  15  is provided with two optical lens systems  61   a  and  61   b . The optical adapter  15  is integrally fixed to the front end portion  11   a  with a female thread  65  of a fixed ring  64  screwed with a male thread  66  formed on the front end portion  11   a.    
         [0052]    The two optical lens systems  61   a  and  61   b  and the optical lenses  33   a  and  33   b  of the front end portion  11   a  enable two optical images to be formed on the imaging surface of the CCD  31  installed on the front end portion  11   a . As described above, the imaging signal photoelectrically converted by the CCD  31  is supplied to the CCU  46  via the signal line L 2 , the AFE  41 , and the buffer  45  so as to be converted into a video signal, and then is displayed on the LCD  12   a  via the CPU  47 . 
         [0053]    Next, spot ranging will be described.  FIG. 4  is a diagram illustrating an example of a display screen displayed on the display unit when spot ranging starts. 
         [0054]    When the user presses down the spot ranging start button provided on the manipulation unit  12 , the measurement points are set on the display unit  12   a . The measurement points are configured to include a measurement point  70   a  indicating the center of an imaging visual field, a measurement point  70   b  indicating an upward (U) direction, a measurement point  70   c  indicating a downward (D) direction, a measurement point  70   d  indicating a rightward (R) direction, and a measurement point  70   e  indicating a leftward (L) direction. The measurement points  70   b  and  70   c  are set on both upper and lower sides, respectively, with the measurement point  70   a  interposed therebetween, and the measurement points  70   d  and  70   e  are set on both right and left sides, respectively, with the measurement point  70   a  interposed therebetween. In addition, the measurement points  70   a  to  70   e  are set such that distances from the measurement point  70   a  to the measurement points  70   b  to  70   e  are equal to each other. Note that a position of the measurement point  70   a  is not limited to the center of the imaging visual field, and may be another position. 
         [0055]    In addition, the CPU  47  displays a scalar circle  71  as a circle connecting the measurement points  70   b  to  70   d  on the display unit  12   a . In other words, the measurement points  70   b  to  70   d  are provided on the circumference of the scalar circle  71 . Note that the scalar circle  71  is not limited to a circle, and may be, for example, a polygon such as a quadrangle or a pentagon. 
         [0056]    The CPU  47  as a distance measurement processing unit calculates a spatial coordinate (three-dimensional coordinate) of the measurement points  70   a  to  70   e  on the subject which are set as described above, and calculates, in accordance with the principle of triangulation, subject distance information from the measurement points  70   a  to  70   e  on the subject to the imaging surface of the CCD  31 . Note that the subject distance information is not limited to the distances from the measurement points  70   a  to  70   e  on the subject to the imaging surface of the CCD  31 , and, for example, may be distances from the measurement points  70   a  to  70   e  on the subject to the front end surface of the optical adapter  15 . 
         [0057]    The CPU  47  displays the calculated subject distance information at positions adjacent to the measurement points  70   a  to  70   e . In the example illustrated in  FIG. 4 , subject distance information C to the center measurement point  70   a  is 2.50 [cm], subject distance information U to the measurement point  70   b  in the U direction is 3.00 [cm], subject distance information D to the measurement point  70   c  in the D direction is 2.00 [cm] , subject distance information R to the measurement point  70   d  in the R direction is 3.00 [cm], and subject distance information U to the measurement point  70   e  in the L direction is 2.00 [cm]. Note that, in order to enhance recognizability of the user, for example, the measurement points  70   a  to  70   e  and the subject distance information may be displayed in a color that changes depending on the distance information. 
         [0058]    In addition, the CPU  47  as the control unit calculates a difference value Δd1 between the subject distance information U and the subject distance information D and a difference value Δd2 between the subject distance information R and the subject distance information L. The CPU  47  automatically performs bending control (electrically-actuated bending UD) in a UD direction such that the difference value Δd1 is decreased, and automatically performs bending control (electrically-actuated bending RL) in an RL direction such that the difference value Δd2 is decreased. At this time, in a case where the difference value Δd1 is not equal to or smaller than a predetermined threshold value, the CPU  47  performs the electrically-actuated bending UD until the difference value Δd1 is equal to or smaller than the predetermined threshold value. In a case where the difference value Δ2 is not equal to or smaller than a predetermined threshold value, the CPU  47  performs the electrically-actuated bending RL until the difference value Δd2 is equal to or smaller than the predetermined threshold value. 
         [0059]    In the example in  FIG. 4 , one scalar circle  71  is displayed on the display unit  12   a ; however, for example, a plurality of scalar circles having sizes different from each other may be provided, and the user may be able to select a scalar circle having any size. 
         [0060]      FIG. 5  is a diagram illustrating an example of a plurality of scalar circles having sizes different from each other. As illustrated in  FIG. 5 , in addition to the scalar circle  71 , a scalar circle  71   a  smaller than the scalar circle  71  and a scalar circle  71   b  larger than the scalar circle  71  are provided. 
         [0061]    The user can select a scalar circle having an appropriate size from the scalar circles  71 ,  71   a , and  72   b  depending on the size or the like of a scratch on the subject, that is, such that the scalar circle encloses the scratch. The CPU  47  changes the positions of the measurement points  70   b  to  70   e  which are displayed on the display unit  12   a  such that the positions are disposed on a selected scalar circle, depending on the scalar circles  71 ,  71   a  and  71   b  selected by the user. 
         [0062]    Next, automatic bending control of the endoscope device  1  having such a configuration will be described.  FIG. 6  is a flowchart illustrating an example of the flow of a process used during the automatic bending control (automatic bending mode). 
         [0063]    First, the CPU  47  performs a change process of the scalar circle in response to an instruction from the user (Step S 1 ). The user selects a scalar circle having an appropriate size from the plurality of scalar circles  71 ,  71   a , and  71   b  illustrated in  FIG. 5 , depending on the size or the like of a scratch which is measured. 
         [0064]    Next, when the user presses down the spot ranging start button (Step S 2 ), the CPU  47  determines whether or not the spot ranging end button is pressed down (Step S 3 ). The spot ranging start button and the spot ranging end button are provided on the operating device portion  12   b.    
         [0065]    In a case where the CPU  47  determines that the spot ranging end button is pressed down (Step S 3 : YES), the process is ended. Conversely, in a case where the CPU  47  determines that the spot ranging end button is not pressed down (Step S 3 : NO), the four measurement points  70   b  to  70   e  of UDRL are displayed on the display unit  12   a  (Step S 4 ). 
         [0066]    Next, the CPU  47  acquires the subject distance information UDRL at the four measurement points  70   b  to  70   e  of the UDRL (Step S 5 ), and the CPU  47  determines whether or not the automatic adjustment mode is ON (Step S 6 ). In a case where the CPU  47  determines that the automatic adjustment mode is not ON (Step S 6 : NO), the process returns to Step S 3 , and the same process is repeatedly performed. Conversely, in a case where the CPU  47  determines that the automatic adjustment mode is ON (Step S 6 : YES), the CPU  47  calculates the difference value Δd1 between the subject distance information UD and the difference value Δd2 between the subject distance information RL (Step S 7 ). 
         [0067]    Next, the CPU  47  determines whether or not the calculated difference values Δd1 and Δd2 are equal to or smaller than the predetermined threshold value (Step S 8 ). In a case where the CPU  47  determines that the calculated difference values Δd1 and Δd2 are not equal to or smaller than the predetermined threshold value (Step S 8 : NO), the CPU  47  controls the electrically-actuated bending UD and the electrically-actuated bending RL in a direction in which the difference values are decreased based on the information of the difference values Δd1 and Δd2 (Step S 9 ), the process returns to Step S 3 , and the same process is repeatedly performed. 
         [0068]    In a case where the CPU  47  determines that one of the difference values Δd1 and Δd2 is not equal to or smaller than the predetermined threshold value in Step S 8 , the CPU  47  controls the electrically-actuated bending UD or the electrically-actuated bending RL in a direction in which one difference value of the difference value Δd1 or Δd2, which is not equal to or smaller than the predetermined threshold value, is decreased, in Step S 9 . Conversely, in a case where the CPU  47  determines that the difference values Δd1 and Δd2 are equal to or smaller than the predetermined threshold value (Step S 8 : YES), the process is ended. 
         [0069]    As described above, the endoscope device  1  sets the plurality of measurement points  70   b  to  70   e  on the subject, and acquires the plurality of items of the subject distance information UDRL between the plurality of measurement points  70   b  to  70   e  and the imaging surface of the CCD  31  (or the front end surface of the optical adapter  15 ). The endoscope device  1  automatically performs the bending control in the UD direction and the bending control in the RL direction such that the difference value between the subject distance information UD or RL is decreased. As a result, when scalar measurement is performed, the endoscope device  1  is capable of performing the measurement in a state in which the subject surface and the front end surface of the optical adapter  15  are disposed such that the measurement is performed with appropriate accuracy. 
         [0070]    Hence, according to the endoscope device of the embodiment, it is possible to automatically control the relationship between the subject and the front end surface of an endoscope insertion portion such that the relationship is in a state in which the measurement is performed with appropriate accuracy, based on the plurality of items of object distance information. 
         [0071]    In addition, since the endoscope device  1  is capable of automatically controlling the relationship between the subject and the front end surface of the endoscope insertion portion such that the relationship is in a state in which the measurement is performed with appropriate accuracy, the user does not need to manually perform complicated and highly difficult bending manipulation. As a result, the endoscope device  1  is capable of executing the scalar measurement with higher accuracy, and thus it is possible to improve the examination efficiency. 
         [0072]    In the process in  FIG. 6 , the CPU  47  performs the bending control (automatic adjustment mode) while regularly calculating the difference values between the items of the subject distance information until the difference values between the items of the subject distance information are equal to or smaller than the predetermined threshold value; however, the process is not limited thereto. 
         [0073]    For example, the CPU  47  may always have the automatic adjustment mode performed during start-up of the endoscope device (that is, the automatic adjustment mode is not ended). In addition, the CPU  47  may execute the automatic adjustment mode for only a certain period of time with an input by the user such as the press-down of the spot ranging start button as a trigger, or the CPU  47  may perform the automatic adjustment mode for a certain period of time after the endoscope device  1  starts. 
         [0074]    Further, the CPU  47  may perform the bending control once based on the difference values between the items of subject distance information which have been calculated once. In addition, until the difference values between the items of subject distance information are 0, the CPU  47  may perform the bending control while regularly calculating the difference values between object distances. Furthermore, until the difference values between the items of subject distance information are 0 or are equal to or smaller than the predetermined threshold value, the CPU  47  may repeatedly execute that the bending control is performed only once based on the difference values between the items of subject distance information which have been calculated once. 
         [0075]    In addition, during execution of the automatic adjustment mode, that is, when the bending control is automatically performed, a bending manipulation with the joystick on the operating device portion  12   b  by the user is considered to result in an obstacle to the bending control. During the execution of the automatic adjustment mode, the CPU  47  may display, on the display unit  12   a , a character, an icon, or the like indicating that the automatic adjustment mode is executed. 
         [0076]      FIG. 7  is a diagram illustrating an example of the display unit during the execution of the automatic adjustment mode. As illustrated in  FIG. 7 , during a period of the execution of the automatic adjustment mode, the CPU  47  displays, on a predetermined region on the display unit  12   a , a character or an icon indicating that the automatic adjustment mode is executed. In the example in  FIG. 7 , the CPU displays, in an upper right region on the display unit  12   a , an icon  80  indicating that the automatic adjustment mode is executed. In a case where the subject distance information is equal to or smaller than the predetermined threshold value or the automatic adjustment mode is stopped by the input of the user, the CPU  47  deletes the display of the icon  80  from the display unit  12   a.    
         [0077]    In addition, also in a case where the user performs the bending manipulation with the joystick of the operating device portion  12   b  during the execution of the automatic adjustment mode, the CPU  47  may perform force-quit of the automatic adjustment mode such that there is no obstacle to the bending control when the user performs the bending manipulation by operating the joystick of the operating device portion  12   b  even during the execution of the automatic adjustment mode. Otherwise, in a case where the automatic adjustment mode is executed, the CPU  47  may set a limit such that the user does not perform the bending manipulation, for example, the joystick of the operating device portion  12   b  is locked, or a limit such that an operation signal from the joystick is canceled. 
       Modification Example 
       [0078]    In the embodiment described above, when the spot ranging start button is pressed down, the CPU  47  performs control of displaying the measurement points  70   a  to  70   e  and the scalar circle  71  on the display unit  12   a ; however, a display screen displayed on the display unit  12   a  is not limited thereto. 
         [0079]      FIGS. 8 to 10  are diagrams illustrating other examples of the display screen displayed on the display unit when spot ranging starts. In  FIGS. 8 to 10 , the same reference signs are assigned to the same configurations as those in  FIG. 4 , and the description thereof is omitted. 
         [0080]    As illustrated in  FIG. 8 , the CPU  47  may display only the measurement points  70   b  to  70   e  and the scalar circle  71  on the display unit  12   a  without displaying the center measurement point  70   a  in  FIG. 4 . 
         [0081]    In addition, as illustrated in  FIG. 9 , the CPU  47  may display only the measurement points  70   b  to  70   e  on the display unit  12   a without displaying the scalar circle  71  in  FIG. 8 . 
         [0082]    Further, as illustrated in  FIG. 10 , the CPU  47  may display, on the display unit  12   a , only two measurement points of the four measurement points  70   b  to  70   e  in  FIG. 9 . In this case, the CPU  47  displays, on the display unit  12   a , only the measurement points  70   b  and  70   c  of UD or the measurement points  70   d  and  70   e  of RL. In the example in  FIG. 10 , only the measurement points  70   b  and  70   c  of UD are displayed on the display unit  12   a.    
         [0083]    As illustrated in  FIG. 10 , the endoscope device  1  acquires the subject distance information of at least two measurement points of the measurement points  70   b  and  70   c  in the UD directions or the measurement points  70   d  and  70   e  in the RL directions, and it is possible to improve the accuracy of the scalar measurement through the automatic bending control such that the difference values between the items of subject distance information are decreased. 
         [0084]    Note that, as long as there are no contrary characteristics to characteristics of the process, the execution order of the steps in the flowchart in the specification may be changed, the plurality of steps may be simultaneously performed, or the steps may be executed in different orders for each time of execution. 
         [0085]    The present invention is not limited to the embodiment and the modification example described above, and it is possible to perform various modifications, alterations, or the like within a range in which the gist of the present invention is not changed.