JP2009240531A - Photographic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image focused in any area of it without inhibiting a size reduction of a scope part. <P>SOLUTION: An endoscope equipment to photograph an object illuminated with an illumination light at a predetermined focusing position of a plurality of focusing positions includes a control part 210, which determines whether the image is focused at almost all areas of the image based on a brightness of each pixel area of a first image photographed at a first focusing position. When the control part 210 determines that the image is not focused at almost all areas, the object is photographed at a second focusing position different from the first focusing position so that the focused areas in the first and second images can be composed to generate a composite image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an endoscope apparatus that acquires an image of a subject such as a body cavity.

  2. Description of the Related Art Conventionally, in the medical field, an endoscopic device for observing a tumor, a thrombus, etc. by inserting an elongated scope portion having a CCD attached at the tip into the body cavity of the subject and photographing the inside of the body cavity of the subject. Is widely used. According to such an endoscope apparatus, by directly photographing the inside of the body cavity of the subject, it is possible to grasp the color or shape of a lesion that is difficult to understand in a radiographic image without causing external damage to the subject. It is possible to easily obtain information necessary for determining a treatment policy. In such an endoscope apparatus, the inside of the body cavity of the subject is illuminated with illumination, and imaging is performed under the illumination.

  On the other hand, endoscopes often take images of elongated body cavities, and in such a case, an image from a short distance to a long distance is included in one image, and a part of the image, for example, the middle Only the part corresponding to the distance may be in focus, and the part corresponding to the short distance or the far distance may not be in focus.

In a normal camera, for a plurality of subjects in a single image, the shooting distance is measured for each of a plurality of subjects having different shooting distances, and shooting is repeated a plurality of times while shifting the focus position of the shooting optical system. A method has been proposed in which a portion in focus is selected from a plurality of photographing frames and a single image in which all the subjects are in focus is combined. However, such a camera requires distance measuring means, which increases the manufacturing cost. In addition, when this technology is applied to an endoscope apparatus, a space for installing a distance measuring means is required at the distal end of the scope part of the endoscope. Therefore, a doctor who wants to use a thin scope part as much as possible. It becomes impossible to respond to the request. Furthermore, when compositing images, it is necessary to specify a subject to be focused, which is troublesome. In an endoscopic device, since the inside of the stomach or the like is usually observed, unlike a landscape scene or a person scene captured by a camera, an image is an image composed of individual subjects. Because it is not clear, it is unclear which part of the image can be measured to obtain the shooting distance of multiple subjects.
In addition, it has a function to synthesize one image from a plurality of images photographed at different focal lengths, and divides each photographed image into a plurality of image regions corresponding to each other and has a large amount of high frequency components There has also been proposed an electronic still camera characterized by selecting and combining only focused image areas from corresponding image areas by preferentially selecting image areas. (Refer to Patent Document 2) This camera does not require distance measuring means, and it is not necessary to designate a subject to be focused at the time of synthesis.
Japanese Patent Laid-Open No. 10-10805 Japanese Patent Laid-Open No. 10-210341

  However, since an image normally observed with an endoscope is an image of a mucous membrane such as the stomach, in a local region, an image region in which the contrast of the image is small, and there is an influence of noise or the like, the high-frequency component amount is in focus. May not be extracted successfully. For this reason, when the technique described in Patent Document 2 is applied to an endoscope apparatus, the synthesized image may become unnatural.

  In view of the above circumstances, an object of the present invention is to provide an endoscope apparatus that can acquire an image that is in focus in the entire region of an image without preventing the diameter of the scope portion from being reduced. It is.

The endoscope apparatus according to the present invention includes a light source unit that emits illumination light, an imaging unit that captures an image of a subject irradiated with the illumination light at a predetermined focus position from a plurality of focus positions, and the image. In an endoscope apparatus having a control means for controlling the imaging operation of
The control means determines whether or not the entire area of the image is in focus based on the brightness of each pixel area of the first image captured at the first focus position;
If it is determined that the entire area of the image is not in focus, the imaging means causes the second image of the subject to be captured at a second focus position different from the first focus position. ,
A synthesized image is generated by synthesizing a focused area in the first image and a focused area in the second image.

  Here, the “brightness of the pixel region” may be the brightness of a single pixel or the brightness of a plurality of adjacent pixels. Specifically, the luminance value of one pixel or the average luminance value of a plurality of adjacent pixels can be used as the “brightness of the pixel region”. The “substantially the entire area of the image” means an area of 80% or more, preferably 90% or more, more preferably 95% or more of the image.

The control means includes a first area corresponding to the first focus position and a second area corresponding to the second focus position based on the brightness of each pixel area. Divided into
The first image may be generated by using the first image in the first region and the second image in the second region.

Further, reference brightness information that is the brightness of a pixel area of an image captured by placing a simulated subject having substantially the same light reflection characteristics as the subject at a predetermined subject distance and irradiating a predetermined amount of illumination light, and If it is provided with storage means for storing the depth of field for each of a plurality of focus positions,
The control means calculates a subject distance range of the subject based on the brightness of each pixel region of the first image and the reference brightness information, and sets the subject distance range and each of the plurality of focus positions. It may be determined from the depth of field whether or not the entire area of the image is in focus.

Further, the reference brightness information, which is the brightness of the pixel area of the image captured by illuminating a predetermined amount of illumination light with a simulated subject having light reflection characteristics substantially equal to that of the subject and illuminating with a predetermined amount of illumination light, If it has a storage means for storing the depth of field for each of a plurality of focus positions,
The control means calculates the subject distance of the subject for each pixel area based on the brightness of each pixel area of the first image and the reference brightness information, and calculates each calculated pixel area. A first area corresponding to the first focus position and the second focus based on a subject distance of the subject and a depth of field for each of the plurality of focus positions. You may divide | segment into the 2nd area | region corresponding to a position.

  The endoscope apparatus of the present invention determines whether or not the entire area of the image is in focus based on the brightness of each pixel area of the first image captured at the first focus position, If it is determined that the entire area of the image is not in focus, the imaging means causes the second image of the subject to be captured at a second focus position different from the first focus position. Ranging means conventionally required for synthesizing the in-focus area in the first image and the in-focus area in the second image to generate a composite image In order to determine whether or not the entire area of the image is in focus on the basis of the brightness of each pixel area. Even if the image contrast is low, the front with good accuracy Since it is possible to determine whether or not the entire area of the image is in focus, and only when the image is not in focus, images are acquired at a plurality of focus positions and a composite image is generated. Will improve.

The control means includes a first area corresponding to the first focus position and a second area corresponding to the second focus position based on the brightness of each pixel area. Divided into
A composite image can be easily generated as long as a composite image is generated by using the first image in the first region and the second image in the second region. .

  Further, reference brightness information that is the brightness of a pixel area of an image captured by placing a simulated subject having substantially the same light reflection characteristics as the subject at a predetermined subject distance and irradiating a predetermined amount of illumination light, and Storage means for storing depth of field for each of a plurality of focus positions, wherein the control means is configured to control the subject based on the brightness of each pixel area of the first image and the reference brightness information. When the subject distance range is calculated, and it is determined from the subject distance range and the depth of field for each of the plurality of focus positions whether or not the entire area of the image is in focus, it is better. With accuracy, it can be determined whether or not the entire area of the image is in focus.

  Further, the reference brightness information, which is the brightness of the pixel area of the image captured by illuminating a predetermined amount of illumination light with a simulated subject having light reflection characteristics substantially equal to that of the subject and illuminating with a predetermined amount of illumination light, Storage means for storing depth of field for each of a plurality of focus positions, and the control means is configured to control each pixel based on the brightness of each pixel area of the first image and the reference brightness information. For each region, calculate the subject distance of the subject, and based on the calculated subject distance of the subject for each pixel region and the depth of field for each of the plurality of focus positions, the first image, If the image is to be divided into a first area corresponding to the first focus position and a second area corresponding to the second focus position, the respective areas of the images having different focus positions may be combined. You can select the image that is in focus A more natural composite image can be generated.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an endoscope apparatus according to an embodiment of the present invention.

  The endoscope apparatus 10 shown in FIG. 1 operates in a moving image display mode for displaying an operation or a still image display mode for displaying a still image, and includes a light guide 110 made of an optical fiber that propagates illumination light. In addition, a CCD 120 is provided in the vicinity of the tip, and the scope unit 100 inserted into the body cavity of the subject, for example, the esophagus, etc. A processor unit 200 that generates image data for still images or image data for still images, a light source device 300 that supplies illumination light to the light guide 110, and a monitor 400 that displays image data generated in the processor unit 200. ing.

  The scope unit 100 is detachably attached to the processor unit 200 and the light source device 300, and an imaging optical system 180 for forming a subject image on the CCD 120 and a focus position changing unit 170 at the tip of the CCD 120. Is provided. The light guide 110 guides the illumination light emitted from the light source device 300 to the subject in the body cavity of the subject, and the CCD 120 receives the light reflected by the subject under the illumination light to thereby detect the subject. Analog image data representing an image is generated. Connected to the CCD 120 is a CDS / AGC circuit 130 for performing correlated double sampling (CDS) and performing automatic gain control (AGC) for appropriately amplifying analog data. A D conversion circuit 140 is connected. Analog image data generated by the CCD 120 passes through the CDS / AGC circuit 130 to the A / D conversion circuit 140 and is converted into digital image data. The digital image data is passed to the processor unit 200. A still image designation button 160 for switching the display mode from the moving image display mode to the still image display mode is provided at the base portion of the scope unit 100. The scope unit 100 also includes an EEPROM 150 that stores various types of information such as the model number of the scope unit 100.

  The processor unit 200 controls the entire endoscope apparatus 10 including the operation of each component of the scope 100, and generates a still image data when the still image display mode is instructed. When the moving image display mode is selected, the moving image data output from the scope unit 100 is output to the subsequent stage, and when the still image display mode is selected, it is output from the control unit 210. A switching unit 220 that outputs still image data to the subsequent stage, a signal processing circuit 230 that performs various image processing such as white balance correction, gamma correction, and saturation correction on the image data output from the switching unit 220; And a display control unit 240 that causes the monitor 400 to display display image data that has been subjected to image processing by the signal processing circuit 230. The control unit 210 is connected to a memory 250 that stores various control programs and various information necessary for control.

  The control unit 210 includes a histogram generation unit 211, an image region division unit 212, and an image composition unit 213. Details of the histogram generation unit 211, the image region division unit 212, and the image composition unit 213 will be described later.

The memory 250 stores focus position / depth of field information and reference luminance information described later. The focus position / depth of field information indicates the relationship between each focus position, the depth of field front end Dn, and the depth of field rear end Df, and is stored as a table. In the present embodiment, an example of matrix data stored in the memory 250 is as shown in Table 1 below.

  The light source device 300 includes a light source 310, a diaphragm 320 disposed between the light source 310 and the incident end of the light guide 110 of the scope unit 100, a light source control unit 330 that controls the operation of the entire light source unit device 300, A memory 340 on the light source device side that stores various control programs and various information necessary for control is provided. The light source controller 330 controls the amount of illumination light emitted from the light source device 300 by controlling the opening / closing amount of the diaphragm 320. In the present apparatus, when the moving image display mode is selected, the amount of illumination light emitted from the light source device 300 is set so that the illuminance of illumination light applied to the subject has an appropriate value. Adjusted automatically.

  Hereinafter, first, the photographing operation and the automatic adjustment operation of the illumination light irradiation amount when the moving image display mode is selected will be described.

    First, in the moving image display mode, image data output from the scope unit 100 is sent to both the switching unit 220 and the control unit 210. The switching unit 220 outputs the moving image image data output from the scope unit 100 to the signal processing circuit 230. The signal processing circuit 230 performs white balance correction, gamma correction, and saturation correction on the moving image data of each frame that is sequentially sent, and outputs the result to the display control unit 240. In the signal processing circuit 230, other known image processing such as sharpness processing and noise suppression processing may be appropriately performed.

  In parallel with the signal processing operation described above, the hiss and gram generation unit 211 in the control unit 210 of the processor unit 200 first obtains a luminance value for each pixel of the image data of each frame transmitted. The histogram generation means 211 of the control unit 210 creates a histogram as shown in FIG. 2 using this luminance value. The luminance value Y can be obtained as Y = (R + G + B) / 3 or Y = (R + 2B + B) / 4 if the pixel data is composed of RGB, for example. The vertical axis of this histogram is the frequency, and the horizontal axis is the luminance value. The control unit 210 calculates the following peak luminance value Yp, average luminance value Ya, and bottom luminance value Yb, which are histogram feature amounts, from this histogram.

Peak luminance value Yp: luminance value counted from the high luminance side of the histogram to obtain a predetermined relative cumulative frequency (preferably about 3% to 20%) Average luminance value Ya: luminance value serving as the average value of the histogram Bottom luminance value Yb : Luminance value counted from the low luminance side of the histogram to become a predetermined relative cumulative frequency (preferably about 3% to 20%) The peak luminance value Yp is a representative value on the high luminance side of the image data, and the bottom luminance value Yb is This is the low luminance side representative value of the image data. The luminance value of the image data can be regarded as being distributed in the range from the bottom luminance value Yb to the peak luminance value Yp.

  Next, the control unit 210 compares the average luminance value Ya with a preset reference average luminance value Yi, calculates an emission light amount I of illumination light when an image of the next frame is captured, and a light source control unit To 330. When the average luminance value Ya is smaller than the reference average luminance value Yi, the control unit 210 increases the amount of illumination light emitted when acquiring the next frame image, and the average luminance value Ya is larger than the reference average luminance value Yi. If the average luminance value Ya is equal to the reference average luminance value Yi, the amount of emitted light emitted from the illumination light is changed. I won't let you.

  In the light source control unit 330, based on the relationship between the illumination light emission amount stored in the memory 340 in advance and the opening / closing amount of the aperture, illumination light with a predetermined emission light amount I is emitted from the light source device 300. The opening / closing amount of the diaphragm 320 is controlled.

  In the present embodiment, the emission light amount of illumination light is controlled using the average luminance value Ya, but the present invention is not limited to this, and other luminance values, for example, counting from the high luminance side of the histogram are used. The emitted light quantity of the illumination light may be controlled so that the high-frequency luminance value Yc having a relative cumulative frequency of 20 is equal to a preset reference high-frequency luminance value Yi. Alternatively, the user may be able to select either the average luminance value Ya or the high frequency luminance value Yc.

Next, the operation when the still image display mode is selected will be described. The user presses the still image designation button 160 provided on the scope unit 100 at a desired timing while observing the moving image displayed on the monitor 400. When the still image designation button 160 is pressed, a still image display mode signal for switching the display mode to the still image display mode is transmitted from the still image designation button 160 into the control unit 210 of the processor 200. When the control unit 210 receives this still image display mode signal, the image data acquired at the timing when the still image display mode signal is received from the moving image image data output from the CCD 120 at the received timing. At the same time as generating a histogram of luminance values for each pixel area described above, this image data (hereinafter referred to as image data Ms) is taken into the memory 250. In addition,
In the still image display mode, the switching unit 220 outputs the image data output from the image composition unit 213 of the control unit 210 to the signal processing circuit 230.

  In the control unit 210, first, from the histogram of the image data Ms, the emission light amount Is of the illumination light when the image data Ms is acquired, and the reference luminance value information stored in the memory 250, the subject distance range Dsp to Dsb. Is calculated.

  The reference luminance value information includes a reference luminance value Yo, a reference subject distance Do, and a reference emitted light amount Io. The reference luminance value Yo is a luminance value of a predetermined pixel of an image captured by placing a mucous membrane having substantially the same reflectance as the subject at a reference subject distance Do and irradiating illumination light of a reference emission light amount Io, It is obtained in advance by actual measurement and stored in the memory 250.

In an endoscope, the luminance value Y of a pixel increases M times when the illuminance of the illumination light applied to the subject increases M times, and the illuminance of the illumination light applied to the subject when the subject distance D of the subject increases N times it can be considered that ^doubles 1 / N. The observed subject is the mucous membrane such as the stomach, and it can be considered that the reflectance is almost constant.

Therefore, the subject distance D of a predetermined pixel of the image data Ms can be calculated using the following formula (1).

  In Equation (1), Yo is a reference luminance value, Do is a reference subject distance, Io is a reference emission amount of illumination light, Y is a luminance value of a predetermined pixel of image data Ms, and I is image data Ms. This is the amount of emitted light of the illumination light.

As described above, since the luminance value of the image data Ms can be regarded as being distributed in the range of the bottom luminance value Yb to the peak luminance value Yp, if the subject distance range of the image data Ms is Dp to Db, Dp and Db can be obtained by the following equation (2).

  In the control unit 210, the depth of field range Dn when the image data Ms is imaged from the focus position when the image data Ms is imaged and the focus position / depth of field information stored in advance in the memory 250. ˜Df is obtained and compared with the subject distance range Dp˜Db.

  If the subject distance range Dp to Db is included in the depth of field range Dn to Df, it can be considered that the subject is in focus over the entire range of the subject distance. The control unit 210 reads the image data Ms captured in the memory 250 into the image composition unit 213 and outputs it to the switching unit 220. The switching unit 220 outputs the image data Ms output from the image composition unit 213 to the signal processing circuit 230. The signal processing circuit 230 performs white balance correction, gamma correction, and saturation correction on the image data Ms, and outputs the image data Ms to the display control unit 240. The display control unit 240 displays the image data Ms on the monitor 400 as a still image.

  On the other hand, when the subject distance range Dp to Db is not included in the depth of field range Dn to Df, the entire range of the subject range is not in focus. In this case, the control unit 210 refers to the depth of field information stored in the memory 250 and determines a focus position necessary for focusing on the entire subject distance range.

  First, at each focus position P1 to P5, the control unit 210 obtains the depth-of-field information rear end Df, the depth-of-field front end Dn, the reference luminance value Yo, the reference subject distance Do, the reference emitted light amount Io, and the image data Ms. A luminance value (rear end) Yf corresponding to the depth of field rear end Df and a luminance value (front end) Yn corresponding to the depth of field front end Dn are calculated using the emitted light amount Is of the illumination light at the time of imaging. .

The luminance value (rear end) Yf and the luminance value (front end) Yn for each focus position P1 to P5 are as shown in Table 2 below.

That is, if the luminance value Y of a predetermined pixel of the image data Ms is smaller than, for example, Yf3 and Yf4 <Y <Yn4, the image of the subject corresponding to this pixel can be focused by capturing at the focus position 4. Recognize. In addition, since the depth of field range for each focus position overlaps, the range of the brightness value to be focused at each focus position also overlaps. For this reason, the control unit 210 sets the boundary of the focused luminance value range of the object scene corresponding to each focus position to the middle of the overlapping range as shown in Table 3.

  The control unit 210 compares the focus luminance value range of the object scene corresponding to each focus position shown in Table 3 with the bottom luminance value Yb to the peak luminance value Yp of the image data Ms, and the bottom luminance value Yb to the peak. A focus position necessary to cover the range of the luminance value Yp is determined, an image is captured at a focus position where imaging is not performed at the focus position, and the image data is stored in the memory 250.

  For example, when the range of the bottom luminance value Yb to the peak luminance value Yp corresponds to the focus position P3, the focus position P4, and the focus position P5, and the image data Ms is an image captured at the focus position P3. The control unit 210 changes the focus and position by the focus position changing unit 170, takes images at the focus position P4 and the focus position P5, and stores the image data in the memory 250.

  The image area dividing unit 212 of the control unit 210 performs area division on the image data Ms based on the focused luminance range shown in Table 3 and the luminance value of each pixel of the image data Ms, thereby obtaining area data. And This indicates at which focus position the image taken is in focus for each local region of the image data among the plurality of taken images. FIG. 3A is an example of a screen displaying the image data Ms, and FIG. 3B is an example of area data obtained by dividing the image data Ms into areas. The area described as P3 is an area focused on the image taken at the focus position P3, and the areas described as P4 and P5 are areas focused at the focus positions P4 and P5, respectively. is there.

  In the image composition means 213, based on the area data shown in FIG. 3B, the area P3 uses the image data Ms imaged at the focus position P3, the area P4 uses the image data imaged at the focus position P4, and the area P5 Using the image data captured at the focus position P5, composite image data is generated and output to the switching unit 220.

  The switching unit 220 outputs the combined image data output from the image combining unit 213 to the signal processing circuit 230. The signal processing circuit 230 performs white balance correction, gamma correction, and saturation correction on the image data Ms, and outputs the result to the display control unit 240. The display control unit 240 displays the composite image data on the monitor 400 as a still image. On the monitor 400, a still image focused from a near view to a distant view is displayed. It should be noted that both the image data are set so that the combined result does not become unnatural near the boundary of the region, such as the boundary between the region using the image data Ms captured at the focus position P3 and the region using the image data captured at the focus position P4. Processing such as taking a weighted average of may be performed.

  When the user presses the still image designation button 160 provided on the scope unit 100 again, the display mode returns from the still image display mode to the moving image display mode. Alternatively, when a predetermined time has elapsed from the still image display mode, the mode may automatically return to the moving image display mode.

  As is clear from the above description, the endoscope apparatus does not need to include a distance measuring unit that has been necessary in the past, so that the entire image is focused without hindering the diameter reduction of the scope portion. Images can be acquired. Further, since it is determined based on the brightness of each pixel area whether or not the entire area of the image is in focus, even when the contrast of the image is low, the entire area of the image can be obtained with good accuracy. It can be determined whether or not the region is in focus. Furthermore, only when not in focus, images are acquired at a plurality of focus positions and a composite image is generated, so that the convenience of the apparatus is improved.

  The reference luminance information and depth-of-field information at each focus position vary depending on the sensitivity of the CCD 120 provided in the scope unit 100, the characteristics of the imaging optical system 180, and the like. In the case of being used by being connected to 200, it is necessary to set these pieces of information for each model of the scope unit 100. Therefore, for example, these pieces of information may be stored in the EEPROM 150 provided in the scope unit 100, and the processor unit 200 may read and use these pieces of information when the scope unit 100 and the processor unit 200 are connected.

  Further, if the memory 250 of the processor unit 200 stores reference luminance information corresponding to a plurality of scope units 100 and depth-of-field information at each focus position, the scope unit 100 and the processor unit 200, the model information of the scope unit 100 provided in the scope unit 100 and stored in the EEPROM 150 is read out, and the corresponding model is obtained from the reference luminance information and depth-of-field information stored for each model in the memory 250 of the processor 200. Those may be read out and used.

In the above embodiment, the reference luminance information is set to one value as “the luminance when the simulated subject is imaged at the reference subject distance with the reference emission amount”, and it is considered that the emission amount of the illumination light is adjusted. However, it does not consider changing the shutter speed setting or analog gain setting. When these change functions are installed, the reference luminance information in each setting combination is held and the reference luminance information of the corresponding setting is read and used, or the reference luminance information Yo is set to “reference shutter speed To, reference analog gain setting”. The luminance value when a simulated subject is photographed at the reference subject distance Do with the value Go and the reference emission light amount Io ”is stored, and the subject distance is calculated by applying the following formula instead of the formula (1). Can do.

  However, T is a shutter speed setting value and G is an analog gain setting value. Other equations can be similarly modified and used.

  In the still image display mode, as in the above-described embodiment, when it is determined that the image data is not in focus over almost the entire area, an image in focus from images taken at a plurality of focus positions is displayed. The case where the processing to be combined is made valid and the case where it is made invalid may be arbitrarily switched by a switch or the like.

  Further, when still image data is saved as an image file on a medium or the like, both the synthesized image data and the unsynthesized image data may be saved.

1 is a schematic configuration diagram of an endoscope apparatus according to an embodiment of the present invention. Figure showing a histogram Schematic diagram of the screen Schematic diagram of area data obtained by dividing image data into areas

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Endoscope apparatus 100 Scope part 110 Light guide 120 CCD
130 CDS / AGC circuit 140 A / D conversion circuit 150 EEPROM
160 Still image designation button 170 Focus position changing unit 180 Imaging optical system 200 Processor unit 210 Control unit 211 Histogram generating unit 212 Image region dividing unit 213 Image compositing unit 220 Switching unit 230 Signal processing circuit 240 Display control unit 250 Memory 300 Light source device 310 Light source 320 Aperture 330 Light source device side CPU
340 Light source device side memory 400 Monitor

Claims (4)

A light source unit that emits illumination light; an image capturing unit that captures an image of a subject irradiated with the illumination light at a predetermined focus position from a plurality of focus positions; and a control unit that controls an image capturing operation of the image. In an endoscope apparatus having
The control means determines whether or not the entire area of the image is in focus based on the brightness of each pixel area of the first image captured at the first focus position;
If it is determined that the entire area of the image is not in focus, the imaging means causes the second image of the subject to be captured at a second focus position different from the first focus position. ,
An endoscope apparatus, wherein a focused area in the first image and a focused area in the second image are synthesized to generate a synthesized image. The control means includes a first area corresponding to the first focus position and a second area corresponding to the second focus position based on the brightness of each pixel area. Divided into
The endoscope apparatus according to claim 1, wherein a composite image is generated by using the first image in the first region and using the second image in the second region. . Reference brightness information, which is the brightness of a pixel area of an image captured by illuminating a predetermined amount of illumination light and illuminating a predetermined amount of a simulated subject having substantially the same light reflection characteristics as the subject, Storage means for storing the depth of field for each focus position;
The control means calculates a subject distance range of the subject based on the brightness of each pixel area of the first image and the reference brightness information, and sets the subject distance range and each of the plurality of focus positions. 3. The endoscope apparatus according to claim 1, wherein it is determined whether or not the entire area of the image is in focus based on a depth of field. Reference brightness information, which is the brightness of a pixel area of an image captured by illuminating a predetermined amount of illumination light and illuminating a predetermined amount of a simulated subject having substantially the same light reflection characteristics as the subject, Storage means for storing the depth of field for each focus position;
The control means calculates the subject distance of the subject for each pixel area based on the brightness of each pixel area of the first image and the reference brightness information, and for each calculated pixel area A first area corresponding to the first focus position and the second focus based on a subject distance of the subject and a depth of field for each of the plurality of focus positions. The endoscope apparatus according to claim 2, wherein the endoscope apparatus is divided into a second region corresponding to the position.