Endoscopic system and its operating method

Abstract

Provided is an endoscope system and an operation method therefor for obtaining an image that is in focus while also reducing the size of an optical system.　A lens driving processor (44) drives a zoom lens (42) in accordance with the pressing of a freeze button (12h), and an image acquisition processor selects a post-pressing evaluation frame image (84, 224) whose evaluation value is highest as an optimal image from among post-pressing evaluation frame images (84, 85, 224, 225) which are, among examination images acquired in response to the movement of the zoom lens (42) during, within a given interval of time before and after the pressing of the freeze button (12h), an interval of time after said pressing, examination images for which evaluation values have been calculated, and the image acquisition processor displays the optimal image (100c).

Description

Technical Field

[0001] The present invention relates to an endoscope system that displays an evaluated image and an operating method thereof.

Background Art

[0002] In order to perform diagnosis and postoperative evaluation after an endoscopic examination, when a lesion or the like is detected, obtaining a still image is exclusively performed. Among the images taken during the examination, there may be an image that is out of focus on the observation site. One of the causes is that the distance between the endoscope and the observation site at the time of image capture is too close or too far, resulting in being out of the depth of field (out of focus). At this time, the focus can be adjusted by moving the endoscope back and forth. However, it is difficult for a user such as a doctor to manually focus, especially when the observation site is magnified in close proximity because the depth of field becomes shallow.

[0003] As a technology for automatically focusing on a subject, there is an autofocus mechanism for an endoscope as in Patent Document 1. The intraoral camera of Patent Document 2 realizes miniaturization and weight reduction by obtaining an image while automatically moving a focus lens when an imaging instruction is input without using an autofocus mechanism. Further, the endoscope of Patent Document 3 evaluates the brightness and amount of blur of the captured image and automatically selects an appropriate still image, thereby reducing the burden on the user to select an appropriate still image.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0005] Autofocus mechanisms present the problem of increasing the size and weight of the imaging optical system. Therefore, there is a need for technology that can miniaturize the optical system of an endoscope as much as possible without incorporating an autofocus mechanism, while maintaining a thin tip diameter, and acquiring and presenting focused images to the user.

[0006] The present invention aims to provide an endoscopic system and a method for operating the same that can obtain a focused image while miniaturizing the optical system. [Means for solving the problem]

[0007] The endoscope system of the present invention illuminates a subject and images the light from the subject. The endoscope system comprises an endoscope and a processor device. The endoscope images reflected light from the subject and has a zoom lens and a lens drive processor for driving the zoom lens. The processor device has an image acquisition processor. The lens drive processor drives the zoom lens in accordance with the pressing of the freeze button. Before the freeze button is pressed, the image acquisition processor acquires inspection images, which are sequentially continuous images. During the post-press evaluation time, which is the time after the freeze button is pressed, within the overall evaluation time, which is a certain period of time before and after the freeze button is pressed, the image acquisition processor acquires inspection images in conjunction with the movement of the zoom lens driven by the lens drive processor. From the inspection images acquired during the post-press evaluation time, the evaluation value of the inspection image selected as the post-press evaluation frame image is calculated. Among the post-press evaluation frame images for which an evaluation value has been calculated, the post-press evaluation frame image with the highest evaluation value is selected as the optimal image, and the optimal image is displayed. The image acquisition processor saves the inspection images for the evaluation-retaining frames from the inspection images acquired during the overall evaluation time as evaluation-retaining frame images, calculates the evaluation value of the saved evaluation-retaining frame images, the overall evaluation time is the sum of the post-press evaluation time and the pre-press evaluation time, which is the time before the freeze button is pressed, the evaluation-retaining frame images consist of post-press evaluation frame images and pre-press evaluation frame images that include inspection images acquired during the pre-press evaluation time, the image acquisition processor calculates the evaluation value of the post-press evaluation frame images and the pre-press evaluation frame images, and within the range of the evaluation-retaining frames, the image acquisition processor saves the inspection images excluding some frames as pre-press evaluation frame images during the pre-press evaluation time, and saves the inspection images of all frames as post-press evaluation frame images during the post-press evaluation time.

[0008] The image acquisition processor preferably saves the inspection images corresponding to the evaluation retention frames from the inspection images acquired during the overall evaluation time as evaluation retention frame images, and calculates the evaluation value of the saved evaluation retention frame images.

[0009] The total evaluation time is the sum of the post-press evaluation time and the pre-press evaluation time, which is the time before the freeze button is pressed. The evaluation retained frame image consists of a post-press evaluation frame image and a pre-press evaluation frame image that includes the inspection image acquired during the pre-press evaluation time. Preferably, the image acquisition processor calculates the evaluation values ​​of the post-press evaluation frame image and the pre-press evaluation frame image.

[0010] The image acquisition processor preferably saves the inspection images, excluding some frames, as pre-press evaluation frame images within the range of evaluation-holding frames, and saves all frames of the inspection images as post-press evaluation frame images during the pre-press evaluation time.

[0011] The image acquisition processor preferably saves the inspection images acquired during the overall evaluation time as evaluation-retaining frame images, excluding some frames, within the range of evaluation-retaining frames.

[0012] The overall evaluation time is preferably at least 0.5 seconds. The post-press evaluation time is preferably at least 0.3 seconds. The evaluation value is preferably the contrast value. The evaluation retention frame is preferably at least 15 frames.

[0013] Preferably, the image acquisition processor selects the image with the highest evaluation value from the pre-press evaluation frame images as the optimal pre-press image, selects the image with the highest evaluation value from the post-press evaluation frame images as the optimal post-press image, and then selects and displays the image with the higher evaluation value among the optimal pre-press image and the optimal post-press image as the optimal image.

[0014] When an image acquisition processor obtains an evaluation-retaining frame image in which the evaluation value is above the threshold, it is preferable to display the evaluation-retaining frame image in which the evaluation value is above the threshold as the optimal image.

[0015] The image acquisition processor preferably drives the zoom lens when the distance between the subject and the tip of the endoscope is between 2 mm and 6 mm after the freeze button is pressed.

[0016] The present invention provides an endoscope system that illuminates a subject, captures light from the subject, and includes an endoscope having a zoom lens and a lens drive processor for driving the zoom lens, and a processor device having an image acquisition processor. In the operation method of the endoscopic system The system includes the steps of: a lens drive processor driving a zoom lens in accordance with the pressing of the freeze button; an image acquisition processor acquiring inspection images, which are sequentially continuous images, before the freeze button is pressed; acquiring inspection images in conjunction with the movement of the zoom lens driven by the lens drive processor during the post-press evaluation time, which is the time after the freeze button is pressed, within the overall evaluation time, which is a certain period of time before and after the freeze button is pressed; calculating an evaluation value for the inspection image selected as the post-press evaluation frame image from the inspection images acquired during the post-press evaluation time; selecting the post-press evaluation frame image with the highest evaluation value from among the post-press evaluation frame images for which an evaluation value has been calculated as the optimal image; and displaying the optimal image. [Effects of the Invention]

[0017] The present invention provides an endoscope system and operating method that can obtain a focused image while miniaturizing the optical system. [Brief explanation of the drawing]

[0018] [Figure 1] This is a diagram illustrating the configuration of an endoscope system. [Figure 2] This is a graph showing the spectrum of white light. [Figure 3] This is a block diagram showing the functions of an endoscopy system. [Figure 4]It is an explanatory diagram showing the drive of the zoom lens. [Figure 5] It is an explanatory diagram showing the depth of the depth of field. [Figure 6] It is an explanatory diagram showing the relationship between the position of the zoom lens, the distance between the subject, and the depth of the depth of field. [Figure 7] It is an explanatory diagram showing the overall evaluation time, the pre-press evaluation time, the post-press evaluation time, the pre-press evaluation frame image, and the post-press evaluation frame image. [Figure 8] It is an image diagram of the setting screen. [Figure 9] It is an image diagram of the custom screen. [Figure 10] It is an explanatory diagram showing the evaluation unit and the selection unit when the threshold value is not set. [Figure 11] It is an explanatory diagram showing the evaluation unit and the selection unit when the threshold value is set to 350. [Figure 12] It is an explanatory diagram showing the evaluation unit and the selection unit when the threshold value is set to 300. [Figure 13] It is an image diagram of the display screen. [Figure 14] It is a flowchart showing the functions of the first embodiment. [Figure 15] It is a block diagram showing the functions of the evaluation unit of the second embodiment. [Figure 16] It is a block diagram showing the functions of the selection unit of the second embodiment. [Figure 17] It is an explanatory diagram showing the functions of the pre-press evaluation unit, the post-press evaluation unit, the pre-press selection unit, the post-press selection unit, and the overall selection unit. [Figure 18] It is a flowchart showing the functions of the second embodiment.

Modes for Carrying Out the Invention

[0019] [First Embodiment] In Figure 1, the endoscope system 10 includes an endoscope 12, a light source device 13, a processor device 14, a display 15, and a user interface 16. The endoscope 12 is optically connected to the light source device 13 and electrically connected to the processor device 14. The endoscope 12 has an insertion section 12a that is inserted into the body of the object to be observed, an operating section 12b provided at the base end of the insertion section 12a, and a bending section 12c and a tip section 12d provided at the tip end of the insertion section 12a. The bending section 12c bends by operating the angle knob 12e of the operating section 12b. The tip section 12d is directed in a desired direction by the bending movement of the bending section 12c.

[0020] In addition, the control unit 12b is equipped with an angle knob 12e, a freeze button 12h used to instruct the acquisition of a still image of the subject, and a zoom control unit 12i used to operate the zoom lens 42.

[0021] The endoscope 12 acquires examination images, which are a series of moving images that are sequentially continuous in time. In this specification, examination images include still images, evaluation hold frame images, pre-press evaluation frame images, and post-press evaluation frame images. If it is desired to acquire a still image, which is a single frame of the examination image, while the examination images are being acquired, pressing the freeze button 12h sends a command to the endoscope 12 and the processor device 14 to acquire a still image. The processor device 14 may be connected to a memory (not shown) for storing still images.

[0022] The processor unit 14 is electrically connected to the display 15 and the user interface 16. The display 15 outputs and displays inspection images and information associated with the inspection images. The user interface 16 has a keyboard, mouse, touchpad, microphone, etc., and has the function of accepting input operations such as function settings.

[0023] The light source unit 20 of the light source device 13 emits illumination light to illuminate the subject. The light source unit 20 includes, for example, a laser diode, an LED (Light Emitting Diode), a xenon lamp, or a halogen lamp, and emits illumination light (white light) with a spectrum as shown in Figure 2. White light includes so-called pseudo-white light, which is substantially equivalent to white light when imaging a subject using the endoscope 12, obtained by mixing violet light V, blue light B, green light G, or red light R as shown in Figure 2. The light source unit 20 also includes optical filters, etc., to adjust the wavelength band, spectrum, or light intensity of the illumination light as needed. The light source control unit 22 controls the on / off state and light intensity of each light source constituting the light source unit 20.

[0024] As shown in Figure 3, illumination light emitted from the light source 20 enters the endoscope 12 via the light guide 23. The tip 12d of the endoscope 12 is provided with an illumination optical system 30 and an imaging optical system 40. The illumination optical system 30 has an illumination lens 31, and the illumination light propagated by the light guide 23 is irradiated onto the object to be observed via the illumination lens 31. The imaging optical system 40 has an objective lens 41, a zoom lens 42, and an imaging sensor 43. Light from the object to be observed due to the illumination light enters the imaging sensor 43 via the objective lens 41 and the zoom lens 42. As a result, an image of the object to be observed is formed on the imaging sensor 43.

[0025] The zoom lens 42 is a group of lenses used to enlarge or reduce the object of observation (subject). Specifically, as shown in Figure 4, it consists of four lens groups, G1, G2, G3, and G4, arranged in order from the tip side of the tip portion 12d of the endoscope 12. When observing a subject at close range and magnifying it, such as when observing structures such as thin blood vessels or performing surgical procedures, i.e., when taking close-up shots, the zoom control unit 12i is operated to move the zoom lens groups G2 and G3 in the direction of a larger step number so that the focus is on the near view. On the other hand, when observing a subject over a wide area, such as when confirming the extent of invasion of a relatively large lesion, i.e., when taking distant shots, the zoom control unit 12i is operated to move the zoom lens groups G2 and G3 in the direction of a smaller step number so that the focus is on the distant view.

[0026] The lens drive processor 44 moves the zoom lens groups G2 and G3 between the furthest point (Step 1) and the nearest point (Step 5), as shown in Figure 4, in accordance with the operation of the zoom control unit 12i. In Figure 4, the dotted lines show the approximate positions of the zoom lens groups G2 and G3 from Step 1 to Step 5. The zoom lens groups G2 and G3 move from the position of Step 1 to the position of Step 5 either toward the front end of the front end 12d or toward the opposite side of the front end of the front end 12d. Meanwhile, the zoom lens groups G1 and G4 are fixed. As the zoom lens groups G2 and G3 move, the depth of field, which is the range in which the image appears to be in focus, changes. Note that the movement of the lens groups is not limited to this.

[0027] As shown in Figure 5, the depth of field changes depending on the position of the zoom lens groups G2 and G3. When the zoom lens groups G2 and G3 are in Step 1 (see Figure 4), the depth of field is deeper (the area in focus is wider). On the other hand, when the zoom lens groups G2 and G3 are in Steps 2 to 5 (see Figure 4), the depth of field is shallower than when the zoom lens groups G2 and G3 are in Step 1 (the area in focus is narrower). The shallower the depth of field, the more difficult it is to adjust the focus. In particular, as shown in Figure 6, in close-up photography where an inspection image is taken at high magnification close to the subject Ob, in addition to the shallow depth of field, the influence of movement on the subject, such as peristaltic movement, becomes greater, making it difficult to focus.

[0028] Figure 6 shows an example of the relationship between the position of the zoom lens group G2 and G3, the distance to the subject Ob, and the depth of field. In Example 1, the zoom lens group G2 and G3 are located at Step 2, which is suitable for long-distance photography where a wide area is observed, but the depth of field is in front of the subject Ob, so it is out of focus. In Example 2, the zoom lens group G2 and G3 are located at Step 3, which is suitable for close-up photography where smaller objects are magnified, but the depth of field is behind the subject Ob, so it is out of focus. On the other hand, Example 3 is also a close-up photography example, but the zoom lens group G2 and G3 are located between Step 2 and Step 3, and the depth of field is exactly on the surface of the subject Ob, so it is in focus. To obtain a still image in focus, it is necessary to move the zoom lens group G2 and G3 so that the depth of field is on the surface of the subject Ob, as in Example 3.

[0029] The lens drive processor 44 drives the zoom lens groups G2 and G3 not only when the zoom operation unit 12i is operated, but also when the freeze button 12h is pressed. When the freeze button 12h is pressed, the zoom lens groups G2 and G3 move at a constant speed toward the front end 12d or the opposite side, and the inspection image is acquired in conjunction with the movement of the zoom lens groups G2 and G3 driven by the lens drive processor 44.

[0030] It is preferable to drive the zoom lens groups G2 and G3 when the distance between the subject and the tip of the endoscope 12 is between 2 mm and 6 mm after pressing the freeze button 12h. This is because the distance between the subject and the tip of the endoscope 12 is between 2 mm and 6 mm when the zoom lens groups G2 and G3 are in the position between Step 2 and Step 3. This is also a position where the change in depth of field is large, making manual focus adjustment difficult, and therefore it is preferable to provide assistance with automatic shooting. Note that the range in which the zoom lens groups G2 and G3 move is not limited to between Step 2 and Step 3 (the distance between the subject and the tip of the endoscope 12 is between 2 mm and 6 mm). The movement range of the zoom lens 42 (zoom lens groups G1, G2, G3, G4) can be set arbitrarily.

[0031] When driving the zoom lens groups G2 and G3, they may be moved from their current position toward the tip or toward the opposite side, or they may be moved to the starting position (for example, the position of Step 2 or Step 3) and then moved toward the tip or the opposite side. With the above configuration, the lenses can be automatically zoomed when capturing still images, and images can be captured while changing the focus position. In addition, by not incorporating an autofocus mechanism and instead incorporating a single actuator for the zoom adjustment mechanism, the thin diameter of the endoscope can be maintained.

[0032] The image sensor 43, which forms an image of reflected light from the subject via the objective lens 41 and the zoom lens 42, is a CMOS (Complementary Metal Oxide Semiconductor) sensor, a CCD (Charge-Coupled Device) sensor, or the like.

[0033] The image sensor 43 may include a color image sensor equipped with a color filter (such as a Bayer filter) that converts the detected light into a color image signal, as well as a monochrome image sensor that is not equipped with a color filter that converts the detected light into a monochrome image signal. Furthermore, the color image sensor may convert the detected light into a CMY signal instead of an RGB signal.

[0034] When acquiring a color image, the image signal includes a B image signal output from the B pixels of the imaging sensor 43, a G image signal output from the G pixels of the imaging sensor 43, and a R image signal output from the R pixels of the imaging sensor 43. The image signal detected by the imaging sensor 43 is transmitted to the inspection image acquisition unit 51 of the processor device 14, where various signal processing and image processing such as noise reduction, color correction, and gradation correction are performed based on the image signal to generate an inspection image, which is either a monochrome or color image.

[0035] The processor unit 14 includes a central control unit 50, an inspection image acquisition unit 51, a setting unit 60, an evaluation unit 80, a selection unit 90, and a display control unit 100. The processor unit 14 is also equipped with a temporary storage memory 17. In the processor unit 14, the central control unit 50, which is composed of an image acquisition processor, operates the program in the program memory, thereby realizing the functions of the inspection image acquisition unit 51, the setting unit 60, the evaluation unit 80, the selection unit 90, and the display control unit 100.

[0036] In the setting unit 60, when the freeze button 12h is pressed and a still image, which is a single frame of inspection images, is acquired, the method for selecting and evaluating the optimal image candidate, which is the inspection image with the best focus among the inspection images (still images), can be set. During inspection, inspection images are transmitted from the inspection image acquisition unit 51 to the setting unit 60, and according to the settings in the setting unit 60, the inspection images are transmitted to the evaluation unit 80. The details of the setting unit 60 will be described below.

[0037] The user can set which examination images to evaluate before and after pressing the freeze button 12h, either before or during the examination. Specifically, as shown in Figure 7, in addition to the overall evaluation time, pre-press evaluation time, and post-press evaluation time, the user can set the evaluation frame and the threshold value for the evaluation value. The evaluation frame refers to the frame from which the examination image to be evaluated is acquired for which the evaluation value is calculated.

[0038] Referring to Figure 7, the method for selecting the inspection images to be evaluated will be explained. The total evaluation time is a certain period of time before and after pressing the freeze button 12h to acquire the inspection image SI to be transmitted to the evaluation unit 80. If the total evaluation time is too long, the number of inspection image SI to be evaluated will increase, putting a strain on the calculations of the processor device 14 and the capacity of the temporary storage memory 17. If it is too short, the number of inspection image SI that can serve as candidates for the optimal image will decrease. Therefore, the total evaluation time is preferably at least 0.5 seconds, and more preferably 1.0 second. Note that a total evaluation time of 1.0 second is appropriate when the frame rate of the imaging sensor 43 is 60 fps.

[0039] One frame refers to a period that includes at least the time from when the image sensor 43 receives an image signal until the signal readout is completed (the period during which one inspection image can be obtained). The overall evaluation time can be arbitrarily set on the settings screen 70, which will be described later.

[0040] Of the total evaluation time, the time before pressing the freeze button 12h is the pre-press evaluation time, and the time after pressing the freeze button 12h is the post-press evaluation time. During the post-press evaluation time, inspection images are acquired in conjunction with the movement of the zoom lens groups G2 and G3 driven by the lens drive processor 44. Preferably, the post-press evaluation time is the time required for the zoom lens groups G2 and G3 to move between each step. For example, if the time required for the zoom lens groups G2 and G3 to move from the position of Step 2 (see Figures 4 and 5) to the position of Step 3 (see Figures 4 and 5) is 0.33 seconds, then preferably the post-press evaluation time is at least 0.3 seconds.

[0041] The pre-press evaluation time is the total evaluation time minus the post-press evaluation time. For example, if the total evaluation time is 1.0 seconds and the post-press evaluation time is 0.3 seconds, the pre-press evaluation time is 0.7 seconds. The pre-press evaluation time and post-press evaluation time can be arbitrarily set in the settings screen 70 described later. It is also possible to set either the pre-press evaluation time or the post-press evaluation time to 0 seconds.

[0042] Of the inspection images acquired during the pre-press evaluation time, the images of the frames selected as the evaluation target according to the frame settings described later are designated as pre-press evaluation frame images. Similarly, of the inspection images acquired during the post-press evaluation time, the images of the frames selected as the evaluation target according to the frame settings are designated as post-press evaluation frame images. The pre-press evaluation frame images and post-press evaluation frame images are stored in the temporary storage memory 17 within the processor device 14 and transmitted to the evaluation unit 80.

[0043] The evaluation time, including the total evaluation time, pre-press evaluation time, and post-press evaluation time, is set via the user interface 16 from the settings screen 70 as shown in Figure 8. The total evaluation time, pre-press evaluation time, and post-press evaluation time can be entered from the input form 72. The input form 72 is not limited to this; tab input or voice input may also be used. With the above configuration, the evaluation time for the inspection images to be evaluated can be set so as not to strain the processor's calculations or the temporary storage memory 17.

[0044] On the settings screen 70, in addition to the evaluation time, the evaluation frame setting can be configured. The evaluation frame setting allows you to set the evaluation retention frame, which is the number of examination images (frames) to be saved in the temporary storage memory 17 within the total evaluation time. If the evaluation retention frame is too high, the number of examination images to be evaluated will increase, putting a strain on the calculations of the processor device 14 and the capacity of the temporary storage memory 17. If it is too low, there will be fewer examination images that can serve as candidates for the optimal image. Therefore, it is preferable that the evaluation retention frame is at least 15 frames or more. The evaluation retention frame can be entered from the input form 72 on the settings screen 70.

[0045] The number of evaluation frames before and after pressing the freeze button 12h can also be entered via input form 72 on the settings screen 70. Adding the number of evaluation frames before and after pressing the button gives the number of evaluation retention frames. If custom button 76 is selected, it can also be configured on custom screen 76a, as shown in Figure 9.

[0046] In the custom screen 76a shown in Figure 9, the evaluation frame pattern (hereinafter referred to as "pattern") of the examination image to be evaluated can be arbitrarily set. The evaluation time and evaluation frame settings entered in the input form 72 on the settings screen 70 may also be reflected.

[0047] In the specific examples shown in patterns 1 to 5 of Figure 9, the shaded frame 76b indicates the frame to be evaluated, and the white frame 76c indicates the frame not to be evaluated. In the custom screen 76a, frames can be selected using an alternate action: selecting a frame via the user interface 16 makes it an evaluation frame, and selecting it again deselects it. However, the method of selecting frames is not limited to this. Evaluation frame pattern templates, such as those shown in patterns 1 to 5, can also be selected using the radio button 76d. Note that Figure 9 shows the custom screen 76a when the frame rate of the endoscope 12 is 60fps.

[0048] Pattern 1 in Figure 9 is an example where the total evaluation time is 1.0 second, the post-press evaluation time is 0.3 seconds, and the evaluation retention frames are 30 frames. In this case, during the pre-press evaluation time, every other frame of the inspection image is saved as a pre-press evaluation frame image, and during the post-press evaluation time, all frames of the inspection image are saved as a post-press evaluation frame image. Pattern 1 is an evaluation frame pattern used when it is desired to acquire post-press evaluation frame images with priority over pre-press evaluation frame images within a limited total evaluation time and evaluation retention frames.

[0049] Pattern 2 in Figure 9 is an example where the total evaluation time is 1.0 second, the post-press evaluation time is 0.3 seconds, and the evaluation retention frames are 30 frames, and the inspection images acquired during the total evaluation time are saved as evaluation retention frame images every other frame. An evaluation retention frame image is an inspection image acquired in an evaluation retention frame. In other words, Pattern 2 is an evaluation frame pattern that saves inspection images every other frame in both the pre-press evaluation time and the post-press evaluation time. Pattern 2 is an evaluation frame pattern used when it is desired to acquire post-press evaluation frame images and pre-press evaluation frame images in a balanced manner within a limited total evaluation time and evaluation retention frames.

[0050] Pattern 3 in Figure 9 is an example where the total evaluation time is 1.0 second, the post-press evaluation time is 0.4 seconds, and the evaluation retention frames are 30 frames. In this case, during the pre-press evaluation time, every other frame of the inspection image is saved as a pre-press evaluation frame image, and during the post-press evaluation time, all frames of the inspection image are saved as a post-press evaluation frame image.

[0051] Pattern 4 in Figure 9 is an example where the total evaluation time is 1.0 second, the post-press evaluation time is 0.4 seconds, and the evaluation retention frames are 30 frames, and the inspection images acquired during the total evaluation time are saved as evaluation retention frame images every other frame.

[0052] Pattern 5 in Figure 9 is an example where the total evaluation time is 1.0 seconds, the post-press evaluation time is 0.4 seconds, and the evaluation retention frames are 30 frames. During the pre-press evaluation time, the inspection image is saved every other frame as a pre-press evaluation frame image. During the post-press evaluation time, the first four frames immediately after pressing the freeze button 12h are saved as a post-press evaluation frame image, skipping one frame. The next three frames are saved as a post-press evaluation frame image, skipping two frames. The next two frames are saved as a post-press evaluation frame image, skipping three frames. After that, post-press evaluation frame images are saved every three frames.

[0053] Pattern 5 is an evaluation frame pattern for when you want to have more post-press evaluation frame images in the early part of the post-press evaluation time, taking into account that the user presses the freeze button 12h when the image is in focus. Alternatively, you may acquire an inspection image at the moment the freeze button 12h is pressed and add it to either the pre-press evaluation frame image or the post-press evaluation frame image.

[0054] The evaluation frame patterns can be created arbitrarily. For example, in pattern 1, the examination images may be saved as pre-press evaluation frame images at intervals of 2 or 3 frames or more during the pre-press evaluation time. Alternatively, in pattern 2, the examination images acquired during the overall evaluation time may be saved as evaluation retention frame images at intervals of 2 or 3 frames or more.

[0055] According to the settings described above, the inspection images are saved in the temporary storage memory 17 within the processor device 14. When the freeze button 12h is pressed, first, the inspection images for the evaluation hold frames during the evaluation time before the button press are saved in the temporary storage memory 17. Next, during the evaluation time after the button press, inspection images are acquired in conjunction with the driving of the zoom lens groups G2 and G3, and if they are saved in the temporary storage memory 17, the pre-press evaluation frame images are sequentially deleted in chronological order. In this way, the post-press evaluation frame images are saved in the temporary storage memory 17 so as to fit within the evaluation hold frames, and the inspection images are saved without overwhelming the temporary storage memory 17.

[0056] If the evaluation-retaining frames do not fit within the overall evaluation time, either the overall evaluation time or the evaluation-retaining frames may take precedence. The choice of which to prioritize, overall evaluation time or evaluation-retaining frames, can be arbitrarily set. With the above configuration, the examination images to be evaluated can be set by selecting frames in a way that does not strain the processor or memory.

[0057] The settings screen 70 allows you to set a threshold for the evaluation value. The evaluation value is a value calculated by the evaluation unit 80, which evaluates the pixel values ​​of the evaluation-retaining frame image. If a threshold is set for the evaluation value, when an evaluation-retaining frame image is obtained in which the evaluation value is equal to or greater than the threshold, that evaluation-retaining frame image can be designated as the optimal image (see Figures 11 and 12 described later). The threshold for the evaluation value can be entered using the input form 72.

[0058] According to the settings in the setting unit 60, the pre-press evaluation frame image and the post-press evaluation frame image are transmitted to the evaluation unit 80. The evaluation unit 80 calculates an evaluation value from the evaluation-held frame image. The evaluation-held frame image is one or more images that combine the pre-press evaluation frame image and the post-press evaluation frame image, and is an inspection image stored in the temporary storage memory 17 within the range of the evaluation-held frame. The evaluation value is preferably a contrast value. However, the evaluation value may also be an edge amount, frequency, smoothing degree, brightness, etc.

[0059] The pre-press evaluation frame image and post-press evaluation frame image, for which evaluation values ​​have been calculated by the evaluation unit 80, are sequentially transmitted to the selection unit 90. As shown in Figure 10, the selection unit 90 selects the inspection image with the highest evaluation value from among the pre-press evaluation frame image and post-press evaluation frame image (evaluation-holding frame image) for which evaluation values ​​have been calculated as the optimal image. The evaluation-holding frame image selected as the optimal image is transmitted to the display control unit 100.

[0060] Figure 10 illustrates a specific example of the functions of the evaluation and selection units when no threshold is set. Pre-press evaluation frame images are those for which evaluation values ​​were calculated as follows: inspection image A81 is 10, inspection image B82 is 50, and inspection image C83 is 300. Inspection image D84 is 390 and inspection image E85 is 200. The inspection images are acquired in the order of inspection image A81, inspection image B82, inspection image C83, inspection image D84, and inspection image E85. Inspection image A81 (evaluation value 10), inspection image B82 (evaluation value 50), inspection image C83 (evaluation value 300), inspection image D84 (evaluation value 390), and inspection image E85 (evaluation value 200).

[0061] If a threshold for the evaluation value is set in the setting unit 60, the optimal image is selected as shown in the specific examples in Figures 11 and 12. Figure 11 shows a specific example where the threshold for the evaluation value is 350. In this case, the evaluation value of inspection image D84 is calculated to be 390, and when this is transmitted to the selection unit 90, the selection unit 90 selects inspection image D84 (evaluation value 390), which has an evaluation value equal to or greater than the threshold (350), as the optimal image. Unlike the example in Figure 10, when the optimal image is selected, a signal to that effect is transmitted to the lens drive processor 44, and the movement of the zoom lens groups G2 and G3 is stopped, even if it is in the middle of the evaluation time after pressing the button. That is, in the specific example in Figure 11, inspection images A81 (evaluation value 10), B82 (evaluation value 50), C83 (evaluation value 300), and D84 (evaluation value 390) are acquired, but inspection image E85 is not acquired.

[0062] Figure 12 shows a specific example where the evaluation threshold is 300. In this case, the evaluation value of inspection image C83, which is the pre-press evaluation frame image, is calculated to be 300, and when it is transmitted to the selection unit 90, the selection unit 90 selects inspection image C83 (evaluation value 300), which has been assigned an evaluation value equal to or greater than the threshold (300), as the optimal image. In this case, when the optimal image is selected, a signal to that effect is transmitted to the lens drive processor 44, and even if the freeze button 12h is pressed, the zoom lens groups G2 and G3 are not driven, and inspection image C83 is displayed as the optimal image. That is, in the specific example of Figure 12, unlike the example in Figure 10, inspection images A81 (evaluation value 10), B82 (evaluation value 50), and C83 (evaluation value 300) are acquired, but inspection images D84 and E85 are not acquired. With the above configuration, by not moving the zoom lens when a focused image is acquired, the time it takes to present the optimal image to the user can be shortened.

[0063] The display control unit 100 generates a display screen 100a as shown in Figure 13 and outputs it to the display 15. The display screen 100a shows the current inspection image 100b and the optimal image 100c. When the save button 100d on the display screen 100a is selected via the user interface 16, the optimal image 100c is saved to an external recording medium of the processor device 14, such as a report memory (not shown). When the cancel button 100e on the display screen 100a is selected, the display of the optimal image is canceled, and the display returns to the normal state where only the current inspection image 100b is displayed. With the above configuration, the optimal image can be confirmed and saved during inspection.

[0064] The sequence of events in this embodiment, from acquiring an inspection image to displaying the display screen 100a, will be explained in accordance with the flowchart shown in Figure 14. First, the inspection image acquisition unit 51 acquires an inspection image (step S101) and transmits it to the evaluation unit 80 according to the settings of the setting unit 60 (step S102). Next, an evaluation value is calculated (step S103). The selection unit 90 selects the optimal image (step S104), the display control unit 100 generates the display screen 100a, and it is displayed on the display 15 (step S105).

[0065] [Second Embodiment] In the second embodiment, as shown in Figure 15, the evaluation unit 80 is provided with a pre-press evaluation unit 201 and a post-press evaluation unit 202. Also, as shown in Figure 16, the selection unit 90 is provided with a pre-press selection unit 211, a post-press selection unit 212, and an overall selection unit 213. The other configurations are the same as in the first embodiment.

[0066] In this embodiment, the process from acquiring the inspection image to transmitting the inspection image to the evaluation unit 80 according to the settings of the setting unit 60, and further from the point where the selection unit 90 transmits the optimal image to the display control unit 100, is the same as in the first embodiment, so the explanation will be omitted.

[0067] In this embodiment, as illustrated in Figure 17, when an inspection image is transmitted to the evaluation unit 80, the pre-press evaluation frame image is transmitted to the pre-press evaluation unit 201, and the post-press evaluation frame image is transmitted to the post-press evaluation unit 202, and evaluation values ​​are calculated for each pre-press evaluation frame image and post-press evaluation frame image. The pre-press evaluation frame image for which an evaluation value has been calculated is transmitted to the pre-press selection unit 211, and the post-press evaluation frame image for which an evaluation value has been calculated is transmitted to the post-press selection unit 212.

[0068] The pre-press selection unit 211 selects the image with the highest evaluation value from the pre-press evaluation frame images as the optimal pre-press image and transmits it to the overall selection unit 213. Similarly, the post-press selection unit 212 selects the image with the highest evaluation value from the post-press evaluation frame images as the optimal post-press image and transmits it to the overall selection unit 213. The overall selection unit 213 selects the image with the higher evaluation value from the transmitted optimal pre-press image and optimal post-press image as the optimal image and transmits it to the display control unit 100.

[0069] Figure 17 provides a detailed explanation of a specific example. Inspection image F221 is a pre-press evaluation frame image for which evaluation values ​​of 10, inspection image G222 is 50, and inspection image H223 is 300 were calculated. The inspection images are acquired in the order of inspection image F221, inspection image G222, and inspection image H223. Inspection image F221 (evaluation value 10), inspection image G222 (evaluation value 50), and inspection image H223 (evaluation value 300) are transmitted to the pre-press selection unit 211. The pre-press selection unit 211 selects inspection image H223 (evaluation value 300), which has the highest evaluation value among inspection image F221 (evaluation value 10), inspection image G222 (evaluation value 50), and inspection image H223 (evaluation value 300), as the optimal pre-press image and transmits it to the overall selection unit 213.

[0070] Inspection image I224 is a post-press evaluation frame image for which an evaluation value of 390 was calculated, and inspection image J225 is an evaluation frame image for which an evaluation value of 200 was calculated. Note that the inspection images are acquired in the order of inspection image I224, then inspection image J225. Inspection image I224 (evaluation value 390) and inspection image J225 (evaluation value 200) are sent to the post-press selection unit 212. The post-press selection unit 212 selects inspection image I224 (evaluation value 390), which has the highest evaluation value from inspection image I224 (evaluation value 390) and inspection image J225 (evaluation value 200), as the optimal post-press image and sends it to the overall selection unit 213.

[0071] The overall selection unit 213 compares the evaluation values ​​of inspection image H223 (evaluation value 300), which is the optimal image before pressing, and inspection image I224 (evaluation value 390), which is the optimal image after pressing. Here, the evaluation value of inspection image H223 is 300 and the evaluation value of inspection image I224 is 390, so the overall selection unit 213 selects inspection image I224 (evaluation value 390), which has the higher evaluation value, as the optimal image and transmits it to the display control unit 100. The display screen 100a generated by the display control unit 100 is the same as in the first embodiment, so its description is omitted.

[0072] The setting for selecting the optimal image from the optimal image before pressing and the optimal image after pressing can be done in the setting unit 60. Furthermore, when selecting the optimal image using the method of this second embodiment, no threshold is set. With the above configuration, the optimal image can be selected from as many examination images as possible.

[0073] The sequence of events in this embodiment, from acquiring the inspection image to displaying the display screen 100a, will be explained in accordance with the flowchart shown in Figure 18. The pre-press evaluation frame image is transmitted to the pre-press evaluation unit 201, where an evaluation value is calculated (step S201). The post-press evaluation frame image is transmitted to the post-press evaluation unit 202, where an evaluation value is calculated (step S202). The pre-press selection unit 211 selects the image with the highest evaluation value from the pre-press evaluation frame images as the optimal pre-press image and transmits it to the overall selection unit 213 (step S203). The post-press selection unit 212 selects the image with the highest evaluation value from the post-press evaluation frame images as the optimal post-press image and transmits it to the overall selection unit 213 (step S204). The overall selection unit 213 selects the image with the highest evaluation value from the optimal pre-press image and the optimal post-press image as the optimal image and transmits it to the display control unit 100 (step S205).

[0074] In the first and second embodiments, the invention was described in an example in which the processor device 14 is provided in the endoscope system 10, but the present invention is not limited thereto, and other medical devices may be used. Furthermore, the endoscope 12 may be a rigid or flexible endoscope. In addition, some or all of the central control unit 50, the examination image acquisition unit 51, the setting unit 60, the evaluation unit 80, the selection unit 90, and the display control unit 100 of the endoscope system 10 may be provided in a medical image processing device that communicates with the processor device 14 and cooperates with the endoscope system 10. For example, it may be provided in a diagnostic support device that acquires images taken by the endoscope 12 directly from the endoscope system 10 or indirectly from a PACS (Picture Archiving and Communication Systems). Furthermore, a medical support device connected via a network to various inspection devices, including the endoscope system 10, such as the first inspection device, the second inspection device, ..., and the nth inspection device, may be equipped with some or all of the central control unit 50, the inspection image acquisition unit 51, the setting unit 60, the evaluation unit 80, the selection unit 90, and the display control unit 100 of the endoscope system 10.

[0075] In this embodiment, the hardware structure of the processing unit that executes various processes, such as the central control unit 50, inspection image acquisition unit 51, setting unit 60, evaluation unit 80, selection unit 90, and display control unit 100, is a variety of processors as shown below. These various processors include a CPU (Central Processing Unit), which is a general-purpose processor that executes software (programs) and functions as various processing units; a programmable logic device (PLD), such as an FPGA (Field Programmable Gate Array), whose circuit configuration can be changed after manufacturing; and a dedicated electrical circuit, which is a processor with a circuit configuration specifically designed to execute various processes.

[0076] A single processing unit may be composed of one of these various processors, or it may be composed of a combination of two or more processors of the same or different types (for example, multiple FPGAs, or a combination of a CPU and an FPGA). Alternatively, multiple processing units may be composed of a single processor. Examples of composing multiple processing units with a single processor include, firstly, a configuration in which one or more CPUs and software are combined to form a single processor, and this processor functions as multiple processing units, as is typical of computers such as client and server computers. Secondly, a configuration using a processor that realizes the functions of the entire system, including multiple processing units, on a single IC (Integrated Circuit) chip, as is typical of System-on-a-Chip (SoC) systems. Thus, various processing units are configured, in terms of hardware structure, using one or more of the above-mentioned various processors.

[0077] Furthermore, the hardware structure of these various processors is, more specifically, an electrical circuit formed by combining circuit elements such as semiconductor devices. The hardware structure of the memory unit is a storage device such as an HDD (hard disk drive) or SSD (solid state drive). [Explanation of symbols]

[0078] 10 Endoscopy Systems 12 Endoscopes 12a Insertion section 12b Operation section 12c curved section 12d Tip 12e Angle Knob 12h Freeze Button 12i Zoom Control Section 13 Light source device 14 Processor Unit 15 displays 16 User Interface 17 Temporary storage memory 20 Light source section 22 Light source control unit 23 Light Guide 30 Illumination optical system 31 Illumination Lens 40 Imaging Systems 41 Objective lens 42 Zoom Lens 43 Imaging Sensor 44 Lens drive processor 50 Central Control Unit 51. Inspection Image Acquisition Unit 60 Setting section 70 Settings screen 72 Input Forms 76 Custom Buttons 76a Custom screen 76b Diagonal frame 76c white frame 76d Radio button 80 Evaluation Department 81 Examination Image A 82 Examination Image B 83 Examination Image C 84 Examination Image D 85 Examination image E 90 Selection Section 100 Display Control Unit 100a display screen 100b Current examination image 100c Optimal Image 100d Save button 100e Cancel button 201 Pre-press evaluation section 202 Post-Press Evaluation Unit 211 Selection section before pressing 212 Selected section after pressing 213 General Selection Department 221 Examination Image F 222 Examination Image G 223 Examination Image H 224 Examination Image I 225 Examination Image J

Claims

1. In an endoscope system that illuminates a subject and images the light from the subject, An endoscope having a zoom lens and a lens drive processor for driving the zoom lens, A processor device having an image acquisition processor, The aforementioned lens drive processor is The zoom lens is driven in accordance with the press of the freeze button. The aforementioned image acquisition processor is: Before the freeze button is pressed, an inspection image, which is a series of moving images in chronological order, is acquired. During the overall evaluation time, which is a certain period of time before and after the freeze button is pressed, the inspection image is acquired in conjunction with the movement of the zoom lens driven by the lens drive processor during the post-press evaluation time, which is the time after the freeze button is pressed. From the inspection images acquired within the post-press evaluation time, the evaluation value of the inspection image selected as the post-press evaluation frame image is calculated. The aforementioned image acquisition processor is: From the inspection images acquired during the overall evaluation time, the inspection images for the evaluation retention frames are saved as evaluation retention frame images. The evaluation value of the saved evaluation-holding frame image is calculated, The aforementioned total evaluation time is the sum of the post-press evaluation time and the pre-press evaluation time, which is the time before the freeze button is pressed. The evaluation retention frame image consists of the post-press evaluation frame image and the pre-press evaluation frame image selected from the inspection image acquired during the pre-press evaluation time. The aforementioned image acquisition processor is: The evaluation values ​​of the post-press evaluation frame image and the pre-press evaluation frame image are calculated. The aforementioned image acquisition processor is: Within the scope of the aforementioned evaluation retention frame, During the pre-press evaluation time, the inspection images excluding some frames are saved as the pre-press evaluation frame images, and during the post-press evaluation time, all frames of the inspection images are saved as the post-press evaluation frame images. The image acquisition processor selects the post-press evaluation frame image or the pre-press evaluation frame image with the highest evaluation value from among the pre-press evaluation frame images for which the evaluation value has been calculated, in addition to the post-press evaluation frame image for which the evaluation value has been calculated, as the optimal image. An endoscope system that displays the aforementioned optimal image.

2. The endoscope system according to claim 1, wherein the overall evaluation time is at least 0.5 seconds.

3. The endoscope system according to claim 1 or 2, wherein the post-press evaluation time is at least 0.3 seconds.

4. The endoscope system according to any one of claims 1 to 3, wherein the evaluation value is a contrast value.

5. The endoscope system according to any one of claims 1 to 4, wherein the evaluation and holding frame comprises at least 15 frames.

6. The aforementioned image acquisition processor is: From the aforementioned pre-press evaluation frame images, the image with the highest evaluation value is selected as the optimal pre-press image. From the aforementioned post-press evaluation frame images, the image with the highest evaluation value is selected as the optimal post-press image. The endoscope system according to claim 1, wherein, from the optimal image before pressing and the optimal image after pressing, the one with the higher evaluation value is selected as the optimal image and displayed.

7. The aforementioned image acquisition processor is: The endoscope system according to any one of claims 1 to 6, wherein when an evaluation-retaining frame image is obtained in which the evaluation value is equal to or greater than a threshold, the evaluation-retaining frame image in which the evaluation value is equal to or greater than the threshold is displayed as the optimal image.

8. The aforementioned image acquisition processor is: The endoscope system according to any one of claims 1 to 7, wherein, after the freeze button is pressed, the zoom lens is driven when the distance between the subject and the tip of the endoscope is within the range of 2 mm to 6 mm.

9. The subject is illuminated, and the light from the subject is captured in an image. An endoscope having a zoom lens and a lens drive processor for driving the zoom lens, In a method for operating an endoscope system comprising a processor device having an image acquisition processor, The lens drive processor drives the zoom lens in response to the press of the freeze button, The image acquisition processor acquires inspection images, which are sequentially moving images, before the freeze button is pressed. The image acquisition processor acquires the inspection image in conjunction with the movement of the zoom lens driven by the lens drive processor during the post-press evaluation time, which is the time after the freeze button is pressed, within the overall evaluation time, which is a certain period of time before and after the freeze button is pressed. The image acquisition processor includes the step of calculating an evaluation value of the inspection image selected as a post-press evaluation frame image from the inspection images acquired within the post-press evaluation time, The image acquisition processor saves the inspection images for the evaluation-retaining frames from the inspection images acquired during the overall evaluation time as evaluation-retaining frame images, calculates the evaluation value of the saved evaluation-retaining frame images, the overall evaluation time is the sum of the post-press evaluation time and the pre-press evaluation time, which is the time before the freeze button is pressed, the evaluation-retaining frame images consist of post-press evaluation frame images and pre-press evaluation frame images selected from the inspection images acquired during the pre-press evaluation time, the image acquisition processor calculates the evaluation value of the post-press evaluation frame images and the pre-press evaluation frame images, the image acquisition processor saves the inspection images excluding some frames as pre-press evaluation frame images within the range of the evaluation-retaining frames during the pre-press evaluation time, and saves all frames of the inspection images as post-press evaluation frame images during the post-press evaluation time. The image acquisition processor selects the post-press evaluation frame image or the pre-press evaluation frame image with the highest evaluation value from among the pre-press evaluation frame images for which the evaluation value has been calculated, in addition to the post-press evaluation frame image for which the evaluation value has been calculated, as the optimal image. A method for operating an endoscope system that displays the aforementioned optimal image.

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