Detection value calculation device, endoscope system, detection value calculation method, and detection value calculation program

Abstract

To favorably calculate a detection value for adjusting brightness of an observation image.SOLUTION: A detection value calculation device 41 comprises a processor 412 that processes an observation image obtained by imaging a subject image captured with an endoscope 2. The processor 412 calculates a representative luminance value of each of a plurality of luminance regions obtained by classifying a specific detection region in the observation image according to luminance values, specifies a specific treatment tool region in the observation image, counts detection pixels that exceed a specific luminance value among pixels in the detection region, executes adjustment processing to reduce the count number of detection pixels within the treatment tool region from the count number of detection pixels, calculates a weight for each of the plurality of luminance regions on the basis of the count number of detection pixels after the adjustment processing, and calculates the detection value for adjusting brightness of the observation image on the basis of the weights and the representative luminance value of each of the plurality of luminance regions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a detection value calculation device, an endoscope system, a detection value calculation method, and a detection value calculation program. [Background technology]

[0002] Conventionally, an endoscope system has been known that uses a light source device to irradiate illumination light onto a subject, such as the inside of a living body, and uses an endoscope to capture returned light (subject image) from the subject, thereby observing the subject (see, for example, Patent Document 1). In the endoscopic system described in Patent Document 1, a detection value (overall brightness value) for adjusting the brightness of an observation image captured using an endoscope is calculated from the brightness value of the observation image, and the amount of illumination light from the light source device to the subject is adjusted (dimming control) based on the detection value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4223778 Summary of the Invention [Problem to be solved by the invention]

[0004] When an endoscopic system is used in surgery or the like, a treatment tool such as forceps may be included in the observation image. In such a case, halation occurs in the portion of the treatment tool in the observation image due to the illumination light being reflected by the surface of the treatment tool, making it impossible to properly calculate the detection value. In other words, if light adjustment control is performed based on the detection value, the illumination light is reduced to suppress the halation, so the region of interest that a user such as a doctor wants to observe becomes dark, and the observation image is not suitable for observation.

[0005] Fig. 9 is a diagram illustrating the problem to be solved by the present invention. Specifically, Fig. 9 is a diagram showing the transition of the detection value and the average luminance value of the entire observation image when the light intensity of the illumination light is gradually increased. In Fig. 9, the horizontal axis represents time, and the vertical axis represents the detection value and the average luminance value. In Fig. 9, line L1 represents the detection value. Line L2 represents the average luminance value of the entire observation image. In the endoscope system described in Patent Document 1, when the luminance value of a region of a treatment tool that is predicted to appear in an observation image exceeds a boundary luminance value, a detection value is calculated from the luminance value of a region other than the treatment tool region in the observation image. As a result, a large change occurs in the detection value near the boundary luminance value, and as a result, the average luminance value of the entire observation image also changes discontinuously (see change T in Figure 9), resulting in an observation image that is not suitable for observation. Therefore, there is a demand for a technique that can accurately calculate detection values even when a treatment tool such as forceps is included in an observation image.

[0006] The present invention has been made in consideration of the above, and aims to provide a detection value calculation device, an endoscopic system, a detection value calculation method, and a detection value calculation program that can effectively calculate a detection value for adjusting the brightness of an observation image. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, a detection value calculation device according to the present invention includes a processor that processes an observation image obtained by capturing an image of a subject captured by an endoscope, and the processor calculates a representative luminance value for each of a plurality of luminance regions obtained by classifying specific detection regions in the observation image according to luminance values, identifies a specific treatment tool region in the observation image, counts detection pixels within the detection region that exceed a specific luminance value, performs adjustment processing to reduce the number of detection pixels within the treatment tool region from the count number of detection pixels, calculates a weight for each of the plurality of luminance regions based on the count number of detection pixels after the adjustment processing, and calculates a detection value for adjusting the brightness of the observation image based on the weight and the representative luminance value for each of the plurality of luminance regions.

[0008] An endoscopic system according to the present invention includes a light source device that supplies illumination light to illuminate a subject, an imaging device that generates an observation image by capturing an image of the subject captured by an endoscope, a detection value calculation device including a processor that calculates a detection value for adjusting the brightness of the observation image by processing the observation image, and a light source control device that adjusts the amount of light of the illumination light supplied from the light source device based on the detection value, wherein the processor calculates a representative luminance value for each of a plurality of luminance regions obtained by classifying specific detection regions in the observation image according to luminance values, identifies a specific treatment tool region in the observation image, counts detection pixels within the detection region that exceed a specific luminance value, and performs adjustment processing to reduce the number of detection pixels within the treatment tool region from the count number of detection pixels, calculates a weight for each of the plurality of luminance regions based on the count number of detection pixels after the adjustment processing, and calculates the detection value based on the weight and the representative luminance value for each of the plurality of luminance regions.

[0009] A detection value calculation method according to the present invention is a detection value calculation method executed by a processor of a detection value calculation device, which calculates a representative luminance value for each of a plurality of luminance regions classified according to luminance values for specific detection regions in an observation image obtained by capturing an image of a subject captured by an endoscope, identifies a specific treatment tool region in the observation image, counts detection pixels that exceed a specific luminance value among the pixels in the detection region, performs adjustment processing to reduce the count number of the detection pixels in the treatment tool region from the count number of the detection pixels, calculates a weight for each of the plurality of luminance regions based on the count number of the detection pixels after the adjustment processing, and calculates a detection value for adjusting the brightness of the observation image based on the weight and the representative luminance value for each of the plurality of luminance regions.

[0010] A detection value calculation program according to the present invention is a detection value calculation program to be executed by a processor of a detection value calculation device, and the detection value calculation program instructs the processor to execute the following: calculate a representative luminance value for each of a plurality of luminance regions classified according to luminance values of specific detection regions in an observation image obtained by capturing an image of a subject captured by an endoscope, identify a specific treatment tool region in the observation image, count detection pixels that exceed a specific luminance value among pixels in the detection region, perform adjustment processing to reduce the number of detection pixels counted in the treatment tool region from the number of detection pixels counted, calculate a weight for each of the plurality of luminance regions based on the number of detection pixels counted after the adjustment processing, and calculate a detection value for adjusting the brightness of the observation image based on the weight and the representative luminance value for each of the plurality of luminance regions. [Effects of the Invention]

[0011] According to the detection value calculation device, endoscope system, detection value calculation method, and detection value calculation program of the present invention, it is possible to satisfactorily calculate a detection value for adjusting the brightness of an observation image. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an endoscope system according to an embodiment. [Figure 2] FIG. 2 is a flowchart showing the operation of the processor. [Figure 3] FIG. 3 is a diagram illustrating the operation of the processor. [Figure 4] FIG. 4 is a diagram illustrating the operation of the processor. [Figure 5] FIG. 5 is a diagram illustrating a first modification of the embodiment. [Figure 6] FIG. 6 is a diagram illustrating a first modification of the embodiment. [Figure 7] FIG. 7 is a diagram illustrating a second modification of the embodiment. [Figure 8] FIG. 8 is a diagram illustrating a third modification of the embodiment. [Figure 9] FIG. 9 is a diagram illustrating the problem to be solved by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings. Note that the present invention is not limited to the embodiment described below. Furthermore, in the description of the drawings, the same parts are given the same reference numerals.

[0014] [Configuration of endoscope system] FIG. 1 is a diagram showing a configuration of an endoscope system 1 according to an embodiment. The endoscope system 1 is used in the medical field to observe the inside of a subject (inside a living body) using an endoscope. As shown in FIG. 1, the endoscope system 1 includes an endoscope 2, a display device 3, and a processing device 4.

[0015] In this embodiment, the endoscope 2 is a so-called flexible endoscope. The endoscope 2 is not limited to a flexible endoscope, and a so-called rigid endoscope may also be used. A portion of the endoscope 2 is inserted into a living body, captures images of the inside of the living body, and outputs image signals generated by the captured images. As shown in FIG. 1, the endoscope 2 includes an insertion section 21, an operation section 22, a universal cord 23, and a connector section 24.

[0016] The insertion section 21 has at least a portion that is flexible and is inserted into a living body. A light guide 25, an illumination lens 26, and an imaging device 27 are provided inside the insertion section 21.

[0017] The light guide 25 is routed from the insertion section 21 through the operation section 22 and the universal cord 23 to the connector section 24. One end of the light guide 25 is located at the distal end within the insertion section 21. When the endoscope 2 is connected to the processing device 4, the other end of the light guide 25 is located within the processing device 4. The light guide 25 transmits light supplied from a light source device 42 within the processing device 4 from the other end to one end.

[0018] The illumination lens 26 faces one end of the light guide 25 inside the insertion portion 21. The illumination lens 26 irradiates the light transmitted by the light guide 25 into the living body.

[0019] The imaging device 27 is provided at the tip portion inside the insertion section 21. The imaging device 27 captures images of the inside of a living body and outputs image signals generated by the image capture. Although not specifically shown in the drawings, the imaging device 27 includes an imaging optical system and an imaging unit. The imaging optical system irradiates the inside of the living body through the illumination lens 26, captures the returning light (subject image) from the inside of the living body, and forms an image on the imaging surface of the imaging element that constitutes the imaging unit. The imaging unit includes an imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), captures an image of a subject formed by an imaging optical system, and outputs an image signal generated by the image capture. For convenience of explanation, the image signal generated by the imaging device 27 will be referred to as an observed image below.

[0020] The operation section 22 is connected to the base end portion of the insertion section 21. The operation section 22 receives various operations on the endoscope 2. As shown in Fig. 1, the operation section 22 is provided with an insertion port 221. This insertion port 221 communicates with a treatment tool channel CH (pipe) extending from the tip of the insertion section 21, and is an insertion port for inserting a treatment tool (not shown) such as forceps into the treatment tool channel CH from the outside.

[0021] The universal cord 23 extends from the operating section 22 in a direction different from the direction in which the insertion section 21 extends, and is a cord on which signal lines and light guides 25, etc. are arranged to electrically connect the imaging device 27 and the control device 41 in the processing device 4 are electrically connected.

[0022] The connector 24 is provided at the end of the universal cord 23 and is detachably connected to the processing device 4. The connector 24 is provided with a memory 241. Treatment tool area information is recorded in the memory 241. This treatment tool area information is information specific to the endoscope 2, and is information indicating the area of the treatment tool that is predicted to appear in the observation image from the positions of the imaging optical system, the illumination lens 26, and the treatment tool channel at the tip of the insertion section 21 (coordinate values of pixels within the area of the treatment tool).

[0023] The display device 3 is an LCD (Liquid Crystal Display) or an EL (Electro Luminescence) display, etc., and displays the observed image after image processing by the processing device 4, etc.

[0024] 1, the processing device 4 includes a control device 41 and a light source device 42. In the present embodiment, the light source device 42 and the control device 41 are provided in a single housing as the processing device 4, but this is not limiting, and the light source device 42 and the control device 41 may be provided in separate housings.

[0025] The light source device 42 supplies illumination light, such as white light or excitation light that excites fluorescent substances contained in living organisms, to the other end of the light guide 25 under the control of the control device 41 .

[0026] The control device 41 corresponds to the detection value calculation device and the light source control device according to the present invention. This control device 41 comprehensively controls the operation of the entire endoscope system 1. As shown in FIG. 1 , the control device 41 includes an image processing unit 411, a processor 412, a memory 413, and an input unit 414.

[0027] The image processing unit 411 performs image processing on the observation image generated by the endoscope 2, generates a video signal for displaying the processed observation image on the display device 3, and outputs the video signal to the display device 3. Examples of image processing performed by the image processing unit 411 include optical black subtraction processing (clamping processing), white balance adjustment processing, demosaic processing, color correction matrix processing, gamma correction processing, YC processing for converting RGB signals into luminance color difference signals (Y, Cb / Cr signals), gain adjustment, noise removal, and filtering processing for structure enhancement.

[0028] The processor 412 is realized by a controller such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) executing various programs (including the detection value calculation program according to the present invention) recorded in the memory 413. The processor 412 controls the operations of the endoscope 2, the light source device 42, and the display device 3, and also controls the operation of the entire control device 41. The processor 412 is not limited to a CPU or an MPU, and may be configured by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The function of the processor 412 will be explained in the "Processor Operation" section below.

[0029] The memory 413 stores various programs executed by the processor 412 (including the detection value calculation program according to the present invention), information necessary for the processing of the processor 412, and the like. The input unit 414 is configured using a keyboard, a mouse, a switch, a touch panel, etc., and accepts user operations by a user such as an operator. Then, the input unit 414 outputs an operation signal to the processor 412 in accordance with the user operation.

[0030] [Processor Operation] Next, the operation of the above-mentioned processor 412 (including the detection value calculation method according to the present invention) will be described. Fig. 2 is a flowchart showing the operation of the processor 412. Figs. 3 and 4 are diagrams explaining the operation of the processor 412. Specifically, Fig. 3 is a diagram showing an observed image F. Fig. 4 is a diagram showing an example of relationship information showing the relationship between the count number of detected pixels and weight W. In Fig. 4, the horizontal axis represents the count number of detected pixels, and the vertical axis represents weight W. First, the processor 412 acquires the observed image F after image processing has been performed by the image processing unit 411 (step S1).

[0031] After step S1, the processor 412 divides a specific detection region in the observation image F acquired in step S1 into local regions Ar0 (step S2). For ease of explanation, in FIG. 3, only one local region Ar0 is shown by a dashed line. In this embodiment, the entire observation image F is used as the detection region. The detection region is not limited to the entire observation image F, and may be a partial region of the observation image F. In this embodiment, the local regions are regions obtained by dividing the observation image F (detection region) into 25 regions (5 × 5). The local regions may also be regions obtained by dividing the observation image F (detection region) into 9 regions (3 × 3), or another number of regions.

[0032] After step S2, the processor 412 calculates a representative luminance value for each local region Ar0 (step S3). Here, the representative luminance value of the local region Ar0 can be, for example, an average luminance value obtained by averaging the luminance values of all pixels in the local region Ar0. Note that the representative luminance value is not limited to the average luminance value, and the highest luminance value, the lowest luminance value, or an intermediate luminance value among all pixels in the local region Ar0 may be used.

[0033] After step S3, the processor 412 identifies a first area Ar1 and a second area Ar2 in the observed image F (detection area) (step S4). Specifically, the processor 412 classifies all local regions Ar0 whose representative luminance values are equal to or greater than a specific first luminance value as first regions Ar1 (FIG. 3). The processor 412 also classifies all local regions Ar0 whose representative luminance values are equal to or less than a second luminance value that is smaller than the first luminance value as third regions Ar3 (FIG. 3). The processor 412 also classifies all local regions Ar0 whose representative luminance values are smaller than the first luminance value and greater than the second luminance value as second regions Ar2 (FIG. 3). That is, in step S4, the processor 412 classifies the observed image F (detection region) into a plurality of luminance regions (first region Ar1, second region Ar2, and third region Ar3) according to the luminance values.

[0034] After step S4, the processor 412 calculates the representative luminance value of the first area Ar1 and the representative luminance value of the second area Ar2 (step S5). Here, the representative luminance value of the first region Ar1 can be, for example, an average luminance value obtained by averaging the representative luminance values of all local regions Ar0 included in the first region Ar1. Note that the representative luminance value is not limited to the average luminance value, and the highest representative luminance value, the lowest representative luminance value, or an intermediate representative luminance value among all local regions Ar0 included in the first region Ar1 may also be used. Note that the representative luminance value of the second region Ar2 is the same as the representative luminance value of the first region Ar1.

[0035] After step S5, the processor 412 counts the number of detected pixels whose luminance value is equal to or greater than a specific luminance value among all pixels in the observed image F (step S6).

[0036] After step S6, the processor 412 executes an adjustment process to adjust the number of detected pixels counted in step S6 (step S7). Specifically, the processor 412 acquires treatment tool region information from the memory 241 of the endoscope 2. The processor 412 identifies a treatment tool region Ar4 (FIG. 3) based on the treatment tool region information. The processor 412 then reads out reflection rate information indicating a reflection rate from the memory 413. The reflection rate is a value greater than or equal to 0 and less than 1. The processor 412 then multiplies the reflection rate by the number of detection pixels within the treatment tool region Ar4 among the counted numbers of detection pixels counted in step S6, and executes adjustment processing to reduce the count of detection pixels counted in step S6. For example, when the reflection rate is 0, the count of detection pixels within the treatment tool region Ar4 is 0, and therefore the count of detection pixels counted in step S6 becomes the count of detection pixels outside the treatment tool region Ar4.

[0037] After step S7, the processor 412 calculates the weight W based on the count number of the detected pixels after the adjustment process (step S8). Specifically, the processor 412 reads the relationship information from the memory 413. In this embodiment, the relationship information is information indicating a relationship in which the weight W increases linearly as the count number of detected pixels increases, as shown in Fig. 4. Then, the processor 412 calculates the weight W corresponding to the count number of detected pixels after the adjustment process based on the relationship information.

[0038] After step S8, the processor 412 calculates a detection value for adjusting the brightness of the observed image F based on the weight W and the representative brightness values of the first area Ar1 and the second area Ar2 using the following equation (1) (step S9).

[0039] [Number 1] Detection value = W × (representative luminance value of the first area Ar1) + (1 - W) × (representative luminance value of the second area Ar2) (1)

[0040] After step S9, the processor 412 executes dimming control of the light source device 42 (step S10). Specifically, the processor 412 executes dimming control to adjust the amount of illumination light supplied from the light source device 42 so that the detection value calculated in step S9 becomes the target luminance value.

[0041] According to the present embodiment described above, the following effects are achieved. In the control device 41 according to this embodiment, the processor 412 executes the processes of steps S1 to S9 described above. Therefore, when a treatment tool such as forceps is captured in the observation image F, the weight W can be reduced, and the weight of the first region Ar1 when calculating the detection value can be reduced. On the other hand, when a treatment tool such as forceps is not captured in the observation image F, the weight W is increased, and the weight of the first region Ar1 when calculating the detection value does not decrease. Therefore, the control device 41 according to the present embodiment can accurately calculate the detection value even when a treatment tool such as forceps is included in the observation image F. As a result, by controlling the light adjustment based on the detection value, the region of interest that a user such as a doctor wants to observe can be made appropriately bright, and the observation image F can be made suitable for observation.

[0042] (Other embodiments) Although the embodiments for carrying out the present invention have been described above, the present invention should not be limited to only the above-described embodiments. In this embodiment, the following modifications 1 to 5 may be adopted.

[0043] (Variation 1) In the above-described embodiment, when calculating the detection value, two luminance regions, a first region Ar1 and a second region Ar2, are used as the plurality of luminance regions according to the present invention, but this is not limiting and three or more luminance regions may be used. For example, when calculating the detection value, three luminance regions, a first region Ar1, a second region Ar2, and a third region Ar3, may be used. In this case, in step S9, processor 412 calculates the detection value using the following equation (2).

[0044] [Number 2] Detection value = W1 × (representative luminance value of the first area Ar1) + W2 × (representative luminance value of the second area Ar2) + (1 - W1 + W2) × (representative luminance value of the third area Ar3) (2)

[0045] In addition, in the formula (2), the representative luminance value of the third area Ar3 is calculated in the same way as the representative luminance values of the first area Ar1 and the second area Ar2.

[0046] 5 and 6 are diagrams illustrating a first modification of the embodiment. Specifically, Fig. 5 and Fig. 6 are diagrams illustrating an example of relationship information showing the relationship between the count number of detected pixels and the weight. In Fig. 5 and Fig. 6, the horizontal axis represents the count number of detected pixels, and the vertical axis represents the weight W. 5, the relationship information includes information indicating a relationship in which the weight W1 increases linearly as the count number of detection pixels increases, as shown by line L3, and information indicating a relationship in which the weight W2 decreases linearly as the count number of detection pixels increases, as shown by line L4. Then, based on the relationship information, the processor 412 calculates the weights W1 and W2 corresponding to the count numbers of detection pixels after the adjustment process, and calculates the detection value using equation (2).

[0047] 6, the relationship information includes information indicating a relationship in which the weight W1 increases linearly as the count number of detected pixels increases, as shown by line L5, and information indicating a relationship in which the weight W2 increases linearly as the count number of detected pixels increases, as shown by line L6. Then, based on the relationship information, the processor 412 calculates the weights W1 and W2 corresponding to the count numbers of detected pixels after the adjustment process, and calculates the detection value using equation (2).

[0048] Even when three or more luminance regions are used as the plurality of luminance regions according to the present invention as in the first modification described above, the same effects as those of the above-described embodiment are achieved.

[0049] (Variation 2) In the above-described embodiment, it may be configured to determine whether or not a treatment tool such as forceps is captured in the observation image F, and to execute step S7 only if it is determined that the treatment tool is captured (if it is determined that the treatment tool is not captured, step S6 is followed by step S8).

[0050] Here, as a method for determining whether or not a treatment tool such as forceps is captured in the observation image F, the following determination methods (1) to (3) can be adopted. In the determination method (1), the processor 412 determines whether or not a treatment tool such as forceps is captured in the observation image F by pattern matching, which is a known method.

[0051] 7 is a diagram illustrating a second modification of the embodiment, specifically, an observed image F. Incidentally, when a treatment tool such as forceps is reflected in the observational image F, the gradient of the luminance values (luminance distribution) on a line L7 extending from a corner of the observational image F toward the center position C of the observational image F in the treatment tool area Ar4 exhibits a specific gradient. In the determination method (2), the processor 412 determines that a treatment tool such as forceps is reflected in the observational image F when the gradient of the luminance values on the line L7 exhibits a specific gradient, and determines that the treatment tool is not reflected in the observational image F when the specific gradient is not exhibited.

[0052] In the determination method (3), the processor 412 determines that a treatment tool such as forceps is reflected in the observation image F when a specific switch provided on the operation unit 22 of the endoscope 2 is pressed, and determines that the treatment tool is not reflected in the observation image F when the specific switch is not pressed.

[0053] When the configuration of the present modified example 2 described above is adopted, step S7 can be executed only when a treatment tool such as forceps appears in the observation image F, and the detection value can be calculated more appropriately.

[0054] (Variation 3) In the above-described embodiment, the processor 412 divides the observation image F (detection region) into 100 regions of 10×10, and sets these regions as local regions Ar0, but the present invention is not limited to this. 8 is a diagram illustrating a third modification of the embodiment, specifically, an observed image F. For example, the processor 412 may divide the observation image F (detection region) into a plurality of radial local regions Ar0 centered on the central position C of the observation image F, as shown in FIG.

[0055] Even when the configuration of the third modified example described above is adopted, the same effects as those of the above-described embodiment are achieved.

[0056] (Variation 4) In the above-described embodiment, the reflection rate information is recorded in advance in the memory 413, but this is not limiting. The reflection rate information may be recorded in the memory 241 of the endoscope 2 as information specific to the endoscope 2, and the processor 412 may use the reflection rate information in step S7.

[0057] Even when the configuration of the fourth modification described above is adopted, the same effects as those of the above-described embodiment are achieved.

[0058] (Variation 5) In the above-described embodiment, step S7 may be executed (step S8 is executed after step S6 if it is determined that the object is not captured) only in the following cases.

[0059] Information indicating whether or not to execute step S7 is recorded in the memory 241 of the endoscope 2. Then, the processor 412 acquires the information, and if the information indicates that step S7 should be executed, executes step S7, and if the information indicates that step S7 should not be executed, does not execute step S7.

[0060] Even when the configuration of the fifth modified example described above is adopted, the same effects as those of the above-described embodiment are achieved. [Explanation of symbols]

[0061] 1. Endoscopy system 2 Endoscopy 3 Display device 4 Processing equipment 21 Insertion section 22 Control section 23 Universal Code 24 Connector part 25 Light Guide 26 Lighting Lens 27 Imaging device 41 Control device 42 Light source device 221 Insertion port 241 memory 411 Image Processing Unit 412 processors 413 memory 414 Input section Ar0 local region Ar1 First Area Ar2 Second Area Ar3 Third Region Ar4 Treatment equipment area C center position CH Treatment tool channel F Observation image L1~L7 line T transition

Claims

1. a processor for processing an observation image obtained by capturing an image of a subject captured by an endoscope; The processor: Calculating a representative luminance value for each of a plurality of luminance regions obtained by classifying specific detection regions in the observation image according to luminance values; Identifying a specific treatment tool region in the observation image; Counting detected pixels that exceed a specific luminance value among the pixels in the detection area; performing an adjustment process to reduce the count number of the detection pixels in the treatment tool region from the count number of the detection pixels; Calculating a weight for each of the plurality of luminance regions based on the count number of the detection pixel after the adjustment process; a detection value calculation device that calculates a detection value for adjusting the brightness of the observation image based on the weight and the representative luminance value for each of the plurality of luminance regions;

2. The processor:

2. The detection value calculation device according to claim 1, wherein the specific detection area is classified into a first area having the highest brightness value, a third area having the lowest brightness value, and a second area having a brightness value intermediate between the first area and the third area, as the plurality of brightness areas.

3. The processor:

2. The detection value calculation device according to claim 1, wherein the specific detection area is classified into an area having a high brightness value, an area having a low brightness value, and an area having an intermediate brightness value, as the plurality of brightness areas.

4. The processor: The detection value calculation device according to claim 2 , wherein only representative luminance values of the first region and the second region among the plurality of luminance regions are calculated.

5. The processor: The detection value calculation device according to claim 1 , wherein the detection region is divided into a plurality of rectangular local regions, and then the local regions are classified into the plurality of brightness regions.

6. The processor:

2. The detection value calculation device according to claim 1, wherein the detection region is divided into a plurality of local regions radially centered on a central position of the observation image, and then the local regions are classified into the plurality of brightness regions.

7. The processor: obtaining treatment tool area information indicating the treatment tool area from the endoscope; The detection value calculation device according to claim 1 , wherein the treatment tool region is identified based on the treatment tool region information.

8. The processor: performing image analysis on the observation image to determine whether or not a treatment tool is captured in the observation image; The detection value calculation device according to claim 1 , wherein the adjustment process is executed when it is determined that a treatment tool is captured in the observation image.

9. The processor:

9. The detection value calculation device according to claim 8, wherein whether or not a treatment tool is captured in the observation image is determined by pattern matching.

10. The processor:

9. The detection value calculation device according to claim 8, wherein whether or not a processing tool is captured in the observation image is determined based on a luminance distribution in a specific region in the observation image.

11. a light source device that supplies illumination light for illuminating an object; an imaging device that captures an image of a subject captured by an endoscope to generate an observation image; a detection value calculation device including a processor that calculates a detection value for adjusting the brightness of the observation image by processing the observation image; a light source control device that adjusts the amount of the illumination light supplied from the light source device based on the detection value, The processor: A specific detection region in the observation image is classified according to a luminance value, and a representative luminance value is calculated for each of a plurality of luminance regions; Identifying a specific treatment tool region in the observation image; Counting detected pixels that exceed a specific luminance value among the pixels in the detection area; performing an adjustment process to reduce the count number of the detection pixels in the treatment tool region from the count number of the detection pixels; Calculating a weight for each of the plurality of luminance regions based on the count number of the detection pixel after the adjustment process; An endoscope system that calculates the detection value based on the weight and a representative luminance value for each of the plurality of luminance regions.

12. A detection value calculation method executed by a processor of a detection value calculation device, comprising: A specific detection area in an observation image captured by an endoscope is classified according to brightness values, and a representative brightness value is calculated for each of the plurality of brightness areas; Identifying a specific treatment tool region in the observation image; Counting detected pixels that exceed a specific luminance value among the pixels in the detection area; performing an adjustment process to reduce the count number of the detection pixels in the treatment tool region from the count number of the detection pixels; Calculating a weight for each of the plurality of luminance regions based on the count number of the detection pixel after the adjustment process; A detection value calculation method for calculating a detection value for adjusting brightness of the observation image based on the weight and the representative luminance value for each of the plurality of luminance regions.

13. A detection value calculation program to be executed by a processor of a detection value calculation device, The detection value calculation program instructs the processor to execute the following: A specific detection area in an observation image captured by an endoscope is classified according to brightness values, and a representative brightness value is calculated for each of the plurality of brightness areas; Identifying a specific treatment tool region in the observation image; Counting detected pixels that exceed a specific luminance value among the pixels in the detection area; performing an adjustment process to reduce the count number of the detection pixels in the treatment tool region from the count number of the detection pixels; Calculating a weight for each of the plurality of luminance regions based on the count number of the detection pixel after the adjustment process; a detection value calculation program that calculates a detection value for adjusting the brightness of the observation image based on the weight and the representative luminance value for each of the plurality of luminance regions;

Images