Endoscopic system, and method of operating the endoscopic system

Abstract

Provided are an endoscope system and an operation method for an endoscope system such that it is possible to easily acquire an optimal static image in accordance with changes in imaging conditions.　An endoscope system (10) comprises: an endoscope that images a subject and that comprises an instruction unit that carries out a selection condition switching instruction and a static image saving instruction; and a processor. The processor acquires an endoscope image per each frame, temporarily saves endoscope images selected on the basis of a first selection condition or a second selection condition in a temporary saving region (73), imparts an image evaluation value to each temporarily saved image by carrying out image evaluation, and saves an optimal static image selected via the image evaluation value on the basis of the static image saving instruction.

Description

Technical Field

[0001] The present invention relates to an endoscope system for storing still images and a method of operating the endoscope system.

Background Art

[0002] In the medical field, diagnosis using an endoscope system including an endoscope and a processor device is widely performed. By using the endoscope system, an image obtained by photographing an observation target as a subject with an endoscope (hereinafter referred to as an endoscope image) can be stored as a still image. The still image is used for display on a display or attachment to a medical report, etc., and is useful for diagnosis.

[0003] Due to the size limitation of the endoscope or the close distance to the subject, etc., in many cases, for example, a shake correction function provided in a general video camera or digital camera cannot be used. Therefore, as an endoscope system, there is known one that can display a still image with appropriate brightness and no blur by storing a captured image evaluated in terms of luminance and blur (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Endoscopes often lack autofocus functionality. In such cases, users had to manually adjust the distance to the subject to obtain a still image with optimal focus. However, as shown in Figure 20, since the subject of the endoscope is an organ, even after the user has appropriately adjusted the distance between the tip of the endoscope 12 and the subject 91 to a distance db, focused, and fixed the endoscope, the subject 91 may move, for example, by a distance dm due to pulsation or peristalsis. As a result, the distance between the endoscope 12 and the subject 91 becomes distance db+c, which is far from the focused distance db, and the resulting image is out of focus. Thus, there were times when it was difficult to obtain a still image with optimal focus because the shooting conditions, such as the distance to the subject, changed unexpectedly.

[0006] Alternatively, one could automatically acquire a large number of still images at multiple times and select the in-focus image from among them. However, this method would result in a large number of still images being stored at unintended times, making it difficult to select an image with proper focus, and could also increase the memory capacity required to store the still images.

[0007] The present invention aims to provide an endoscope system that can easily acquire optimal still images in response to changes in shooting conditions, and a method for operating the endoscope system. [Means for solving the problem]

[0008] The present invention relates to an endoscope system comprising an endoscope for photographing a subject and a processor, wherein the endoscope includes an instruction unit, the processor acquires endoscopic images obtained by photographing a subject with the endoscope frame by frame, temporarily stores the selected endoscopic images in a temporary storage area based on a first selection condition or a second selection condition, assigns an image evaluation value to each of the temporarily stored images in the temporary storage area by performing an image evaluation, switches between the first selection condition and the second selection condition based on a selection condition switching instruction, and saves the optimal still image selected from the temporarily stored images based on the image evaluation value based on a still image saving instruction, the instruction unit performs selection condition switching instructions and still image saving instructions.

[0009] When the processor begins acquiring endoscopic images, it is preferable to temporarily save the endoscopic images selected based on the first selection criterion.

[0010] The instruction unit performs a first action and a second action, and preferably issues a still image saving instruction during the second action.

[0011] Preferably, the indicator unit includes a momentary switch, the first action is pressing the momentary switch, and the second action is releasing the pressed momentary switch.

[0012] Preferably, the indicator unit includes an alternate switch, the first operation is the first pressing and releasing of the alternate switch, and the second operation is the second pressing and releasing of the alternate switch.

[0013] The processor measures the period from the first operation to the second operation, and the instruction unit, if the period is longer than or equal to a preset judgment period, preferably issues an instruction to switch the selection condition when the judgment period has elapsed since the first operation.

[0014] When a still image saving instruction is given, if the processor has temporarily saved the endoscopic image based on the second selection condition, it is preferable for the instruction unit to issue a selection condition switching instruction.

[0015] Preferably, the processor temporarily stores the selected endoscopic images in a temporary storage area as temporary storage images up to a preset maximum number, and the first selection condition includes, as the firstA selection condition, if the number of temporary storage images in the temporary storage area is less than the maximum number, the endoscopic images are temporarily stored in the temporary storage area as temporary storage images in order of the most recent acquisition time until the maximum number is reached, and as the firstB selection condition, if the maximum number of temporary storage images are temporarily stored in the temporary storage area, the temporary storage image with the oldest acquisition time among the temporary storage images stored in the temporary storage area is deleted from the temporary storage area, and then the endoscopic images are temporarily stored in the temporary storage area as temporary storage images in order of the most recent acquisition time.

[0016] Preferably, the processor temporarily saves the selected endoscopic images as temporary storage images in a temporary storage area up to a preset maximum number of images. The second selection condition is that, if the number of temporary storage images in the temporary storage area is less than the maximum number, the 2A selection condition is to temporarily save the endoscopic images in the temporary storage area as temporary storage images in order of the most recent acquisition time until the maximum number of images is reached. If the maximum number of temporary storage images is already saved in the temporary storage area, the 2B selection condition is to keep only the appropriate still images selected from the temporary storage images based on the image evaluation value in the temporary storage area as temporary storage images, delete the images other than the appropriate images from the temporary storage area, and then perform the 2A selection condition.

[0017] The processor temporarily saves the selected endoscopic images as temporary images in the temporary storage area up to a preset maximum number. The second selection condition is that if the number of temporary images saved in the temporary storage area is less than the maximum number, then as the second selection condition A, the endoscopic images are temporarily saved in the temporary storage area as temporary images in order of the most recent acquisition time until the maximum number is reached. If the maximum number of temporary images is saved in the temporary storage area, then as the second selection condition C, ,onePreferably, the process includes: keeping only appropriate still images selected from the saved images based on image evaluation values ​​as temporary saved images in the temporary storage area; deleting non-appropriate images from the temporary storage area; selecting the most recent endoscopic image and temporarily saving it as a temporary saved image in the temporary storage area; and then temporarily saving only appropriate still images selected from the temporarily saved images in the temporary storage area based on image evaluation values ​​as temporary saved images in the temporary storage area.

[0018] The system is equipped with a display that shows the optimal still image and / or the appropriate still image, and if the display was showing the optimal still image and / or the appropriate still image, it is preferable to update them to show the latest optimal still image and / or the appropriate still image, respectively.

[0019] The display comprises a main screen and a sub-screen, and it is preferable that the optimal still image is displayed on the main screen for a preset display period, and then displayed on the sub-screen after the display period.

[0020] It is preferable to include a notification unit that notifies the user about the update when the display updates and displays the optimal still image and / or appropriate still image.

[0021] The notification unit preferably notifies the user when the processor switches between the first and second selection conditions.

[0022] The notification unit prefers not to send another notification if the notification to the user is to be sent again within the predetermined minimum notification period.

[0023] The processor performs an image evaluation of the contrast and / or brightness of the temporarily stored image, and it is preferable that the image evaluation value is a value relating to the contrast and / or brightness of the temporarily stored image.

[0024] The processor performs an image evaluation regarding the confidence level and / or malignancy level of a specific lesion present in the subject of the temporarily stored image, and it is preferable that the image evaluation value is the confidence level and / or malignancy level.

[0025] When the processor sets a threshold for the image evaluation value and deems that there is a still image saving instruction when the image evaluation value above the threshold is given to the temporarily saved image, it is preferable to save the temporarily saved image with the image evaluation value above the threshold as the optimal still image.

[0026] The instruction unit preferably includes a freeze operation unit.

[0027] Moreover, the present invention is an operating method of an endoscope system including an endoscope equipped with an instruction unit for photographing a subject and a processor. The processor acquires an endoscope image obtained by photographing a subject with the endoscope for each frame, temporarily saves the endoscope image selected based on the first selection condition or the second selection condition in a temporary saving area as a temporarily saved image, assigns an image evaluation value to each of the temporarily saved images temporarily saved in the temporary saving area by performing image evaluation, switches between the first selection condition and the second selection condition based on a selection condition switching instruction, saves the optimal still image selected by the image evaluation value from the temporarily saved images based on a still image saving instruction, and the instruction unit gives a selection condition switching instruction and a still image saving instruction.

Advantages of the Invention

[0028] According to the present invention, an optimal still image can be easily acquired according to changes in the shooting situation.

Brief Description of the Drawings

[0029] [Figure 1] It is an external view of an endoscope system. [Figure 2] It is a block diagram showing the functions of an endoscope system. [Figure 3] It is an explanatory diagram explaining four-color LEDs included in a light source unit. [Figure 4] It is a graph showing the spectra of purple light V, blue light B, green light G, and red light R. [Figure 5] It is a block diagram showing the functions of an image storage unit. [Figure 6] It is a flowchart showing a series of processes for saving an optimal still image. [Figure 7] This is an explanatory diagram illustrating the selection criteria for 1A. [Figure 8] This is an explanatory diagram illustrating the selection criteria for 1B. [Figure 9] This is an explanatory diagram illustrating the first part of the selection criteria 2B and 2C. [Figure 10] This is an explanatory diagram illustrating the latter half of the selection criteria for Section 2B. [Figure 11] This is an explanatory diagram illustrating the latter part of the selection criteria for 2C. [Figure 12] This is an explanatory diagram illustrating the still image saving instruction performed under selection condition 2B. [Figure 13] This is an explanatory diagram illustrating the still image saving instruction performed under selection condition 2C. [Figure 14] This is an explanatory diagram illustrating how to obtain the optimal still image by pressing the freeze switch once. [Figure 15] This is an explanatory diagram illustrating how to obtain the optimal still image by pressing and holding the freeze switch. [Figure 16] This is an explanatory diagram about the temporary images that are acquired every other frame. [Figure 17] This is an explanatory diagram illustrating the use of threshold values ​​for image evaluation. [Figure 18] This is an explanatory diagram illustrating an example of displaying an optimal still image on a screen. [Figure 19] This is an explanatory diagram illustrating how to notify users of the update of the optimal still image by displaying it on a screen. [Figure 20] This is an explanatory diagram illustrating the case where the focus of an endoscopic image changes. [Modes for carrying out the invention]

[0030] In Figure 1, the endoscope system 10 includes an endoscope 12, a light source device 14, a processor device 16, a display 18, and a keyboard 19. The endoscope 12 is optically connected to the light source device 14 and electrically connected to the processor device 16. The endoscope 12 has an insertion section 12a that is inserted into the body of a subject who is the object of observation, 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.

[0031] The control unit 12b includes an angle knob 12e, a freeze control unit 12f for issuing selection condition switching instructions or still image saving instructions (explained later), and a zoom control unit 12g for changing the imaging magnification. Note that the still image saving instruction or zoom operation may be performed using the scope switch on the freeze control unit 12f or zoom control unit 12g, respectively, as well as switches on the processor unit 16, a keyboard 19, or a foot switch (not shown).

[0032] The processor unit 16 is electrically connected to the display 18 and the keyboard 19. The display 18 outputs and displays endoscopic images, whether moving or still, and / or information associated with these images. The keyboard 19 functions as a user interface that accepts input operations such as function settings. An external recording unit (not shown) for recording images and image information may also be connected to the processor unit 16.

[0033] In Figure 2, the light source device 14 emits illumination light to irradiate the object of observation and comprises a light source unit 20 and a light source processor 21 that controls the light source unit 20. The light source unit 20 is composed of, for example, a semiconductor light source such as a multi-color LED (Light Emitting Diode), a combination of a laser diode and a phosphor, or a xenon lamp or halogen light source. The light source unit 20 also includes an optical filter for adjusting the wavelength range of the light emitted by the LEDs, etc. The light source processor 21 controls the amount of illumination light by turning each LED on / off and adjusting the drive current and drive voltage of each LED, etc. The light source processor 21 also controls the wavelength range of the illumination light by changing the optical filter, etc.

[0034] As shown in Figure 3, in this embodiment, the light source unit 20 has four color LEDs: V-LED (Violet Light Emitting Diode) 20a, B-LED (Blue Light Emitting Diode) 20b, G-LED (Green Light Emitting Diode) 20c, and R-LED (Red Light Emitting Diode) 20d.

[0035] As shown in Figure 4, V-LED20a generates violet light V with a central wavelength of 410±10nm and a wavelength range of 380~420nm. B-LED20b generates blue light B with a central wavelength of 450±10nm and a wavelength range of 420~500nm. G-LED20c generates green light G with a wavelength range of 480~600nm. R-LED20d generates red light R with a central wavelength of 620~630nm and a wavelength range of 600~650nm.

[0036] The light source processor 21 controls V-LED20a, B-LED20b, G-LED20c, and R-LED20d. The light source processor 21 controls each LED 20a to 20d to emit illumination light with different combinations of light intensity ratios between purple light V, blue light B, green light G, and red light R, depending on multiple observation modes.

[0037] Each LED20a~20d The light emitted by the device is incident on the light guide 41 via an optical path coupling section (not shown) composed of mirrors, lenses, etc. The light guide 41 is built into the endoscope 12 and the universal cord (a cord connecting the endoscope 12, the light source device 14, and the processor device 16). The light guide 41 propagates the light from the optical path coupling section to the tip 12d of the endoscope 12.

[0038] The tip 12d of the endoscope 12 is provided with an illumination optical system 30a and an imaging optical system 30b. The illumination optical system 30a has an illumination lens 42, and illumination light propagated by the light guide 41 is irradiated onto the object of observation via the illumination lens 42. The imaging optical system 30b has an objective lens 43, a zoom lens 44, and an imaging sensor 45. Various types of light, such as reflected light, scattered light, and fluorescence from the object of observation, enter the imaging sensor 45 via the objective lens 43 and the zoom lens 44. As a result, an image of the object of observation is formed on the imaging sensor 45. The zoom lens 44 can be freely moved between the telephoto end and the wide-angle end by operating the zoom control unit 12g, thereby enlarging or reducing the image of the object of observation formed on the imaging sensor 45.

[0039] The image sensor 45 is a color image sensor equipped with either a red (R), green (G), or blue (B) color filter for each pixel, and it captures an object to be observed and outputs image signals of each RGB color. A CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor can be used as the image sensor 45. Alternatively, instead of the image sensor 45 equipped with primary color filters, a complementary color image sensor equipped with complementary color filters of cyan (C), magenta (M), yellow (Y), and green (G) may be used. When using a complementary color image sensor, a four-color image signal of CMYG is output. Therefore, by converting the four-color CMYG image signal to a three-color RGB image signal through complementary-to-primary color conversion, an RGB image signal similar to that of the image sensor 45 can be obtained. Alternatively, a monochrome sensor without color filters may be used instead of the image sensor 45.

[0040] The CDS / AGC (Correlated Double Sampling / Automatic Gain Control) circuit 46 performs correlated double sampling (CDS) and automatic gain control (AGC) on the analog image signal obtained from the imaging sensor 45. The image signal that has passed through the CDS / AGC circuit 46 is converted into a digital image signal by the A / D (Analog / Digital) converter 47. The digital image signal after A / D conversion is input to the processor device 16.

[0041] The processor unit 16 stores programs related to processing such as image saving in a program memory (not shown). In the processor unit 16, the central control unit 59, which is composed of the processor, operates the programs in the program memory, thereby realizing the functions of the image acquisition unit 51, noise reduction unit 53, signal processing unit 55, image saving unit 56, display control unit 57, video signal generation unit 58, and the central control unit 59. The central control unit 59 also receives information from the endoscope 12, such as the freeze operation unit 12f, and controls various parts of the processor unit 16, such as the image saving unit 56, as well as the endoscope 12 or the light source device 14, based on the received information. It also receives information such as instructions from the keyboard 19.

[0042] The image acquisition unit 51 acquires digital image signals of endoscopic images obtained by photographing the subject, which is the object of observation illuminated by the illumination light, with the endoscope 12, frame by frame. A "frame" is a unit for controlling the imaging sensor 45 (see Figure 2) that photographs the subject. For example, "1 frame" refers to a period that includes at least an exposure period in which the imaging sensor 45 is exposed to light from the object of observation illuminated by the illumination light, and a readout period in which the image signal is read out.

[0043] The acquired image signal is transmitted to the DSP52. The DSP52 performs digital signal processing, such as color correction, on the received image signal. The noise reduction unit 53 applies noise reduction processing, such as the moving average method or median filter method, to the image signal that has undergone color correction processing by the DSP52. The image signal with reduced noise is stored in the memory 54.

[0044] The signal processing unit 55 acquires the noise-reduced image signal from the memory 54. Then, it applies signal processing such as color conversion, color enhancement, and structure enhancement to the acquired image signal as needed to generate a color endoscopic image of the object being observed.

[0045] The image storage unit 56 performs image storage processing to save images. The display control unit 57 controls the display of images or information on the display 18, which is a display means. For example, it controls the display of endoscopic images on the display 18 in real time, or controls the display of saved still images in a set area such as a sub-screen of the display 18.

[0046] The video signal generation unit 58 converts various endoscopic images output from the display control unit 57 into video signals that can be displayed in full color on the display 18. The converted video signals are input to the display 18. As a result, the display 18 displays endoscopic images or various information as text or the like.

[0047] The image storage unit 56 comprises a temporary storage unit 61, an image evaluation unit 62, and an optimal still image storage unit 63. As shown in Figure 5, the temporary storage unit 61 comprises a selection condition switching instruction receiving unit 71, a selection condition switching unit 72, and a temporary storage area 73. The temporary storage unit 61 temporarily stores the endoscopic images selected based on the selection conditions as temporary storage images in the temporary storage area 73. The selection conditions are conditions for selecting the endoscopic images to be temporarily stored in the temporary storage area 73 from the endoscopic images acquired by the image acquisition unit 51 frame by frame. There are two types of selection conditions: first selection conditions and second selection conditions. The selection conditions are switched by the selection condition switching unit 72 based on the selection condition switching instruction received by the selection condition switching instruction receiving unit 71. The temporary storage area 73 has the function of a memory for temporarily storing endoscopic images and has a fixed capacity.

[0048] The selection condition switching instruction receiving unit 71 receives a selection condition switching instruction. This is an instruction to switch the selection criteria, from the first selection criterion to the second selection criterion, or from the second selection criterion to the first selection criterion. , within This is an instruction to switch the selection conditions when temporarily saving a selected image from the endoscopic image to the temporary storage area 73. When the selection condition switching instruction receiving unit 71 receives a selection condition switching instruction, the selection condition switching unit 72 switches the selection conditions. If there is no selection condition switching instruction, the selection conditions are not switched, and the previous selection conditions are continued. The selection condition switching instruction and the still image saving instruction described later are performed by the instruction unit. The selection condition switching instruction and still image saving instruction performed by the instruction unit will be described later.

[0049] The image evaluation unit 62 performs an image evaluation on each of the temporary images stored in the temporary storage area 73, and assigns an image evaluation value to each of the temporary images. The image evaluation unit 62 includes a contrast evaluation unit 74, a brightness evaluation unit 75, a confidence evaluation unit 76, and a malignancy evaluation unit 77. Temporary images to which image evaluation values ​​have been assigned are stored in the temporary storage area 73.

[0050] Image evaluation is performed based on temporarily stored images, and methods include calculating image evaluation values ​​through image analysis based on the features of the temporarily stored images, or assigning various values ​​to the temporarily stored images derived using a trained machine learning model as image evaluation values.

[0051] The image evaluation unit 62 evaluates the contrast and / or brightness of the temporarily stored image, and the image evaluation value is the contrast of the temporarily stored image. to The values ​​may be related to and / or brightness. Specifically, the contrast evaluation unit 74 performs an image evaluation for contrast for each of the temporarily stored images and assigns a contrast evaluation value to the corresponding temporarily stored image. The brightness evaluation unit 75 performs an image evaluation for brightness for each of the temporarily stored images and assigns a brightness evaluation value to the corresponding temporarily stored image.

[0052] Furthermore, the image evaluation unit 62 performs an image evaluation of the lesions present in the subject in the temporarily stored image, determining the degree of confidence and / or malignancy of a specific disease, and the image evaluation value can be the degree of confidence and / or malignancy of the disease, or a value related thereto. Specifically, the confidence evaluation unit 76 performs an image evaluation of each temporarily stored image, determining the degree of confidence regarding a specific disease, and assigns a confidence evaluation value to the corresponding temporarily stored image. In addition, the malignancy evaluation unit 77 performs an image evaluation of each temporarily stored image, determining the degree of malignancy regarding a specific disease, and assigns a malignancy evaluation value to the corresponding temporarily stored image.

[0053] The contrast evaluation unit 74, brightness evaluation unit 75, confidence evaluation unit 76, and malignancy evaluation unit 77 of the image evaluation unit 62 can each perform image evaluation using known methods. The contrast evaluation value assigned to a temporarily stored image by the contrast evaluation unit 74 indicates that a higher value means the image is in focus, and a lower value means the image is blurred or out of focus. Therefore, the contrast evaluation value allows for the selection of the endoscopic image with the best focus among the temporarily stored images. The same applies to the brightness evaluation unit 75, confidence evaluation unit 76, and malignancy evaluation unit 77; for example, a higher brightness evaluation value from the brightness evaluation unit 75 indicates a brighter endoscopic image, and a lower value indicates a darker endoscopic image. Therefore, when selecting the optimal still image from the temporarily stored images, it is possible to select a temporarily stored image whose brightness evaluation value falls within a certain range.

[0054] Similarly, the higher the confidence evaluation value from the confidence evaluation unit 76, the more confident it is that the characteristic portion of the subject is a specific disease, etc., in the endoscopic image. Furthermore, the higher the malignancy evaluation value from the malignancy evaluation unit 77, the more malignant the characteristic portion of the subject is considered to be a specific lesion, etc.

[0055] Image evaluation values ​​are not limited to these examples. Furthermore, especially when performing image evaluation using a pre-trained machine learning model, two or more of the following may be evaluated together, such as contrast, brightness, confidence level, and malignancy level, and it is not necessary to assign each image evaluation value as a separately calculated image evaluation value.

[0056] The optimal still image storage unit 63 comprises a still image storage instruction receiving unit 78 and an optimal still image storage area 79. Based on the still image storage instruction received by the still image storage instruction receiving unit 78, the optimal still image storage unit 63 selects the optimal still image from the temporarily stored images based on the image evaluation value and stores it in the optimal still image storage area 79.

[0057] An optimal still image is a still image that is suitable for saving, such as one with appropriate focus or brightness, or one that includes characteristic areas such as lesions. The optimal still image is selected from among the temporarily saved images temporarily saved by the temporary storage area 73 as a still image with optimal focus, etc., based on the image evaluation value.

[0058] The still image save instruction receiving unit 78 receives still image save instructions. The instruction unit issues the still image save instructions.

[0059] The instruction unit issues instructions for switching selection conditions and for saving still images. Therefore, it is preferable for the instruction unit to perform a first operation and a second operation. The first operation and the second operation are different operations performed by the instruction unit. Through the first and second operations, even if the instruction unit is, for example, a single switch, it can issue different instructions for switching selection conditions and saving still images.

[0060] The instruction unit is the control unit that performs instruction operations. The instructions given by the operation of the control unit are controlled by the control unit. Specifically, the control unit that performs instruction operations can be the freeze operation unit 12f provided on the operation unit 12b of the endoscope 12. The control unit that controls the instructions given by the operation can be the central control unit 59.

[0061] The freeze control unit 12f is a freeze switch among the various scope switches of the endoscope 12, also called the scope. By operating the freeze control unit 12f, the user can issue instructions for switching selection conditions and for saving still images. The instruction unit can be something other than the freeze control unit 12f, for example, a foot switch (not shown), a remote switch (not shown) connected to the processor device 16, or one of the various switches provided by the processor device 16.

[0062] The freeze operation unit 12f may perform the first and second operations by being a momentary switch or an alternate switch. If the freeze operation unit 12f is a momentary switch, the first operation can be pressing the momentary switch, and the second operation can be releasing the pressed momentary switch. Specifically, if the freeze operation unit 12f is a momentary freeze switch, a selection condition switching instruction is given when the user continues the first operation, which is pressing the freeze switch, and it is determined that it is a long press. Alternatively, the operation in which the user stops pressing the freeze switch and releases the switch can be designated as the second operation, and a still image save instruction can be given when the freeze switch is released.

[0063] When the freeze operation unit 12f is an alternate-type switch, the procedure is the same as when it is a momentary-type switch. The first operation is the first pressing and releasing of the alternate-type switch, and the second operation is the second pressing and releasing of the alternate-type switch. Specifically, when the freeze operation unit 12f is an alternate-type freeze switch, the first operation is when the user presses the freeze switch once to turn it on, and the on state is maintained and it is determined to be a long press. When the long press, which is the first operation, is performed, a selection condition switching instruction is given. The second operation is when the user presses the freeze switch a second time to turn it off. When the freeze switch is pressed a second time, a still image save instruction is given.

[0064] The determination of a long press can be as follows: The operation of the freeze operation unit 12f is transmitted to the central control unit 59 of the processor device 16. The central control unit 59 receives and determines the operation of the freeze operation unit 12f. The freeze operation unit 12f works in cooperation with the central control unit 59, and if the freeze operation unit 12f is a momentary type switch, it measures the period from the first operation to the second operation, and if the period is longer than or equal to a preset determination period, it issues a selection condition switching instruction to the selection condition switching instruction receiving unit 71 when the determination period has elapsed since the first operation. If the freeze operation unit 12f is an alternate type switch, it measures the time from the first operation, which is the first press and release, and if this time is longer than or equal to a preset determination period, it issues a selection condition switching instruction to the selection condition switching instruction receiving unit 71 when the determination period has elapsed since the first operation.

[0065] Even if the indicator unit is not the freeze operation unit 12f, by using a momentary switch or an alternate switch for the indicator unit, it is preferable to be able to give two types of instructions: an instruction to switch selection conditions and an instruction to save a still image.

[0066] Next, the operation of the endoscope system 10 will be explained in more detail. As shown in Figure 6, in observation using the endoscope system 10, the user takes a photograph of the observation target, which is the subject, with the endoscope 12 to obtain an endoscopic image. The image acquisition unit 51 acquires the endoscopic image frame by frame (step ST100). The image acquisition unit 51 acquires the endoscopic images in the order of the time of capture. Then, an image evaluation value is assigned to the temporarily saved image selected according to the first selection condition, and this is repeated (step ST110).

[0067] The temporary storage unit 61 preferably temporarily stores the endoscopic images selected based on the first selection condition when the image acquisition unit 51 begins acquiring endoscopic images. The first selection condition is to store the images in order of acquisition time using a first-in, first-out (FIFO) method. , withinEndoscopic images may be temporarily stored in the temporary storage area 73. It is preferable to temporarily store the selected endoscopic images in the temporary storage area 73 in a number that is no more than the maximum number of images pre-set.

[0068] The first selection condition may include a first-in, first-out (FIFO) selection condition and a first-in, first-out (FIFO) selection condition. If the number of temporarily stored images in the temporary storage area 73 is less than the maximum number, the first-in, first-out (FIFO) selection condition is used. Under the first-in, first-out (FIFO) selection condition, endoscopic images are temporarily stored in the temporary storage area 73 as temporary stored images in order of the most recent acquisition time until the maximum number is reached. If the maximum number of temporarily stored images is already stored in the temporary storage area 73, the first-in, first-out (FIFO) selection condition is used. Under the first-in, first-out (FIFO) selection condition, the oldest temporarily stored image among the temporarily stored images in the temporary storage area 73 is deleted from the temporary storage area, and then endoscopic images are temporarily stored in the temporary storage area 73 as temporary stored images in order of the most recent acquisition time, and this process is repeated. In this way, the first-in, first-out (FIFO) selection condition can be used to ensure that the number of temporarily stored images in the temporary storage area 73 does not exceed a preset maximum number.

[0069] As shown in Figure 7, for example, if the maximum number of images is set to 5, and there are fewer than 5 images temporarily stored in the temporary storage area 73, the 1A selection condition is used. Under the 1A selection condition, since there are fewer than 5 images temporarily stored in the temporary storage area 73, the endoscopic images are temporarily stored in the temporary storage area 73 in order of the most recent acquisition time until the maximum number of 5 images is reached. Therefore, if endoscopic image acquisition begins at time t1, at time t3, the temporary storage area 73 will contain the endoscopic images acquired from time t1 to time t3. Subsequently, the endoscopic images are temporarily stored in the temporary storage area 73 in the order they were acquired until the maximum number of 5 images is reached.

[0070] As shown in Figure 8, if the maximum number of temporary images (5) are temporarily stored in the temporary storage area 73, the 1B selection condition is used. Under the 1B selection condition, since the maximum number of temporary images are temporarily stored in the temporary storage area 73, a first-in, first-out (FIFO) method is used to ensure that the number of temporary images stored in the temporary storage area 73 never exceeds the maximum number. Therefore, if an endoscopic image is acquired at time t6, the endoscopic image taken at time t1 is deleted from the temporary storage area 73, and then the latest endoscopic image taken at time t6 is temporarily stored in the temporary storage area 73. In Figure 8, the images to be deleted are shown with shading. In this way, the number of temporary images stored in the temporary storage area 73 never exceeds the preset maximum number, thus preventing an increase in memory capacity.

[0071] Furthermore, the image evaluation unit 62 assigns an image evaluation value to each of the temporary images temporarily stored in the temporary storage area 73. In this embodiment, the contrast evaluation unit 74 performs a contrast evaluation on each of the temporary images and assigns a contrast evaluation value to the corresponding temporary image. A higher contrast evaluation value indicates a well-focused endoscopic image, while a lower contrast evaluation value indicates a blurred or shaky, out-of-focus endoscopic image.

[0072] Next, if there is an instruction to switch the selection condition (YES in step ST120), the selection condition is switched to the second selection condition (step ST140). The instruction to switch the selection condition is given by the instruction unit, as described above. In this embodiment, the instruction unit includes the freeze operation unit 12f of the endoscope 12, and the instruction to switch the selection condition is given when the freeze operation unit 12f is pressed and held. The case when there is no instruction to switch the selection condition (NO in step ST120) will be described later. After switching the selection condition to the second selection condition, an image evaluation value is assigned to the temporarily saved image selected by the second selection condition, and this is repeated (step ST150).

[0073] The second selection criterion may include a second selection criterion A and a second selection criterion B. The second selection criterion A is the same as the first selection criterion A. If the number of temporarily saved images is less than the maximum number and is temporarily saved in the temporary storage area 73, the second selection criterion A is used. In the second selection criterion A, endoscopic images are temporarily saved in the temporary storage area 73 as temporary saved images in order of the most recent acquisition time until the maximum number is reached. If the maximum number of temporarily saved images is temporarily saved in the temporary storage area 73, the second selection criterion B is used. In the second selection criterion B, only appropriate still images selected based on the contrast evaluation value are kept in the temporary storage area as temporary saved images, and all other images are deleted from the temporary storage area, after which the second selection criterion A is performed again. The appropriate still images are still images selected as candidates for selecting the optimal still image. In this way, the second selection condition B allows the number of temporary images temporarily stored in the temporary storage area 73 to not exceed a preset maximum number by repeatedly selecting the appropriate still image based on the contrast evaluation value from the maximum number of temporary storage images, deleting the other temporary storage images, adding temporary storage images again in order of shooting time, and when the number of temporary storage images reaches the maximum number, selecting the appropriate still image again based on the contrast evaluation value.

[0074] As shown in Figure 9, if the duration of pressing the freeze operation unit 12f exceeds the long-press judgment period at time tn and is determined to be a long press, a selection condition switching instruction is given at time tn, and the selection condition switching unit 72 switches the selection condition from the first selection condition to the second selection condition. In the second selection condition, if the maximum number of temporary saved images, 5 images, are temporarily saved in the temporary saving area 73, the second B selection condition is used. Whether to use the second A selection condition or the second B selection condition when a long press is determined is determined by how many temporary saved images are saved in the temporary saving area 73 when a long press is determined. In the second B selection condition, in the first half, if the endoscopic images taken from time tn to time tn+4 are used as temporary saved images, one endoscopic image Ptn+3, which is the temporary saved image with the highest contrast evaluation value, is selected as the appropriate still image from these temporary saved images. In Figure 9, the endoscopic image Ptn+3 selected from the temporary saved images that are the appropriate still image is shown in shaded form. Temporarily saved images other than appropriate still images will be deleted from the temporary storage area 73.

[0075] Next, as shown in Figure 10, in the latter half of the 2B selection condition, with the endoscopic image Ptn+3, which is a suitable still image taken at time tn+3, temporarily stored in the temporary storage area 73, endoscopic images taken from the next acquisition timing, time tn+5 to time tn+8, are temporarily stored in the temporary storage area 73 as temporary storage images. When the maximum number of 5 temporary storage images is temporarily stored in the temporary storage area 73, the 2B selection condition is performed. That is, a suitable still image is selected from the maximum number of 5 temporary storage images temporarily stored in the temporary storage area 73 based on the contrast evaluation value, and in the case of Figure 10, one endoscopic image Ptn+7, taken at time tn+7, is selected as the suitable still image. In Figure 10, the endoscopic image Ptn+3, which was the suitable still image, and the newly suitable endoscopic image Ptn+7 are shown with different shading. The updating of the suitable still image continues as long as the freeze operation unit 12f is pressed. In this way, appropriate still images are updated and temporarily stored, allowing for the acquisition of more suitable still images. Furthermore, since the number of temporarily stored images in the temporary storage area 73 will never exceed the pre-set maximum number, an increase in memory capacity can be prevented.

[0076] The second selection condition may include a second A selection condition and a second C selection condition. First, if the number of temporarily saved images is less than the maximum number and is temporarily saved in the temporary storage area 73, the second A selection condition is used. If the maximum number of temporarily saved images is temporarily saved in the temporary storage area 73, the second C selection condition is used. In the second C selection condition, if the maximum number of temporarily saved images is temporarily saved in the temporary storage area, only appropriate still images selected by contrast evaluation value from the temporarily saved images are temporarily saved in the temporary storage area as temporary saved images. Then, the endoscopic image with the most recent acquisition time is selected and temporarily saved in the temporary storage area as a temporary saved image. After that, only appropriate still images selected by contrast evaluation value from the temporarily saved images in the temporary storage area are temporarily saved in the temporary storage area as temporary saved images. Then, the second C selection condition is repeated. Thus, in the second C selection condition, from the maximum number of temporarily saved images, one appropriate still image is left in the temporary storage area based on the contrast evaluation value, and another temporary saved image is added in chronological order of shooting. Then, by comparing the contrast evaluation values ​​of these two temporary saved images, one appropriate still image is left, and another temporary saved image is added in chronological order of shooting. This process is repeated, ensuring that the number of temporary saved images temporarily stored in the temporary storage area 73 does not exceed the preset maximum number.

[0077] In the second selection condition, if the maximum number of temporary images (5) are temporarily stored in the temporary storage area 73, the second C selection condition may be used. In the second C selection condition, in the first half, as shown in Figure 9, if the maximum number of 5 endoscopic images taken between time tn and time tn+4 are used as temporary storage images, one temporary storage image with the best contrast evaluation value is selected from these temporary storage images as the appropriate still image. Of these temporary storage images, all temporary storage images other than the appropriate still image, endoscopic image Ptn+3, are deleted from the temporary storage area 73.

[0078] Next, as shown in Figure 11, in the latter half of the second C selection condition, after time tn+4, while the appropriate still image taken at time tn+3 is temporarily stored in the temporary storage area, the endoscopic image taken at the next acquisition timing, time tn+5, is temporarily stored as a temporary storage image in the temporary storage area 73. Two images are stored in the temporary storage area: the endoscopic image Ptn+3, which is the appropriate still image taken at time tn+3, and the endoscopic image Ptn+5, which was taken at time tn+5. After the temporary images are saved, the contrast evaluation values ​​of the two temporary images are compared, and the endoscopic image Ptn+5, taken at time tn+5 with the higher contrast evaluation value, is retained as the new appropriate still image. Figure 1 1 In this example, the endoscopic image Ptn+3, which was a suitable still image, and the newly suitable endoscopic image Ptn+5 are shown with different shades. With the suitable still image taken at time tn+5 temporarily stored in the temporary storage area, the endoscopic image taken at the next acquisition timing, time tn+6 (not shown), is temporarily stored as a temporary image in the temporary storage area 73. After the suitable still image taken at time tn+5 and the two temporary images taken at time tn+5 and time tn+6 are temporarily stored in the temporary storage area, the contrast evaluation values ​​of the two temporary images are compared, and this process is repeated. In this way, the suitable still image is updated and temporarily stored, so a more appropriate still image can be obtained. In addition, since the number of temporary images stored in the temporary storage area 73 does not exceed the preset maximum number, an increase in memory capacity can be prevented.

[0079] Next, if a still image saving instruction is given (YES in step ST160), the optimal still image is selected from the temporarily saved images based on the image evaluation value (step ST170). The optimal still image is the still image that is appropriate to save. The still image saving instruction is given by the instruction unit as described above. In this embodiment, since the instruction unit includes the freeze operation unit 12f of the endoscope 12, the still image saving instruction is given when the second operation, which is the release of the freeze operation unit 12f, occurs.

[0080] As described above, the instruction to save a still image is performed by the second operation of the freeze operation unit 12f. In this embodiment, the second operation is the user releasing the freeze switch, which is the freeze operation unit 12f, and the instruction to save a still image is given when the freeze switch is released.

[0081] As shown in Figure 12, if endoscopic images were temporarily saved according to the 2B selection condition, the freeze operation unit 12f is released when the still image save instruction is given. Since there were 5 temporarily saved images in the temporary save area 73 when the still image save instruction was given, one optimal still image is selected from the 5 temporarily saved images based on the contrast evaluation value. The 5 temporarily saved images include the endoscopic image Ptn+3 taken at time tn+3 and the endoscopic image Ptn+7 taken at time tn+7. The endoscopic image taken at time tn+3 is the past appropriate still image, which is the endoscopic image with the highest contrast evaluation value among the 5 endoscopic images taken from time tn to time tn+4. In Figure 12, the endoscopic image Ptn+3, which was an appropriate still image, and the endoscopic image Ptn+7, which has become an appropriate still image, are shown with different shading. By comparing endoscopic image Ptn+3 and endoscopic image Ptn+7 using contrast evaluation values, if endoscopic image Ptn+7 is selected, it will be determined that endoscopic image Ptn+7, which is the most focused endoscopic image among the 10 endoscopic images taken between time tn and time tn+9, is selected as the optimal still image.

[0082] Similarly, as shown in Figure 13, if endoscopic images were temporarily saved according to the second C selection condition, when the freeze operation unit 12f is released and a still image save instruction is issued, there are five temporarily saved images in the temporary saving area 73. Therefore, one optimal still image is selected from the five temporarily saved images based on the contrast evaluation value. The five temporarily saved images are endoscopic images taken from time tn to time tn+4, and include the endoscopic image Ptn+3 taken at time tn+3. The endoscopic image Ptn+3 is the past appropriate still image, which is the endoscopic image with the highest contrast evaluation value among the five endoscopic images taken from time tn to time tn+4. By comparing the endoscopic image Ptn+3 and the endoscopic image Ptn+5 acquired by the image acquisition unit 51 after the still image saving instruction using contrast evaluation values, if the endoscopic image Ptn+5 is selected, then the endoscopic image Ptn+5, which is the most focused endoscopic image among the six endoscopic images taken from time tn to time tn+5, is selected as the optimal still image. In Figure 13, the endoscopic image Ptn+3, which was the appropriate still image, and the endoscopic image Ptn+5, which was acquired after the still image saving instruction, are shown with different shades.

[0083] The optimal still image selected as described above is stored in the optimal still image storage area 79 (step ST180). The optimal still image stored in the optimal still image storage area 79 is a still image with excellent image evaluation value. In this embodiment, since contrast evaluation value was used as the image evaluation value, the optimal still image is an endoscopic image with excellent focus. Therefore, the optimal still image is suitable for display on the display 18 or for use in medical reports.

[0084] Next, the selection criteria are switched from the second selection criteria to the first selection criteria (step ST190). After saving the optimal still image, the central control unit 59, if the temporary storage unit had temporarily saved the endoscopic image based on the second selection criteria, sends a notification to the selection criteria switching instruction reception unit 71 to switch the selection criteria. alternate fingerThe process is as follows: If you want to stop acquiring endoscopic images (YES in step ST200), the endoscopic observation ends. If you do not want to stop acquiring endoscopic images (NO in step ST200), the process returns to step ST100 and repeats from the point where the endoscopic images are temporarily saved according to the first selection condition.

[0085] If there is no instruction to switch selection conditions in step ST120 (NO in step ST120), it means that the press by the freeze operation unit 12f is not determined to be a long press, and the duration for which the freeze operation unit 12f is pressed is less than the long press determination time, and it is determined to be a single press. In this case, since the press of the freeze operation unit 12f is released, a still image save instruction is given (step ST130), and the process proceeds to step ST170 to select the optimal still image. In step ST170 when the freeze operation unit 12f is pressed single, the optimal still image is selected from the temporarily saved images selected according to the first selection condition.

[0086] As described above, the endoscope system 10 allows the user to more reliably acquire optimal still images at the timing intended by the user through easy user operations, such as a single press or long press of the freeze switch. Even if there are changes in the shooting environment, such as fluctuations in the distance between the endoscope tip 12d and the observation target, and it is thought that the optimal still image cannot be obtained immediately after pressing the freeze switch, the optimal still image can be obtained through a simple operation: continuing to press and hold the freeze switch until the optimal still image is obtained, and then releasing the freeze switch when the optimal still image is deemed to have been obtained. Furthermore, by starting with the endoscope tip 12d closest to the observation target and gradually increasing the distance while pressing the freeze switch, for example, an optimal still image with focus can be obtained. Conversely, by starting from a point where the endoscope tip 12d is far from the observation target and gradually decreasing the distance while pressing the freeze switch, for example, an optimal still image with focus can be obtained. In addition, since a preset number of images are temporarily saved in this process, the increase in memory capacity due to the temporary storage of images can be suppressed.

[0087] As shown in Figures 14 and 15, the endoscope system 10 switches between the first and second selection conditions. Therefore, even if the best-focused endoscopic image is not obtained when the freeze control unit 12f is pressed, by continuing to press and hold the freeze control unit 12f until the point at which the best-focused endoscopic image is considered to have been obtained, the optimal still image with the best focus can be easily and reliably obtained. In the graphs shown at the top of Figures 14 and 15, the vertical axis represents the shooting distance, and the horizontal axis represents time t. The shooting distance is the distance between the tip 12d of the endoscope and the subject, and the graph uses distance db as the reference. Distance db is the distance at which the best-focused image can be obtained (see Figure 20). The subject is the object of observation for the endoscope 12 and is inside the lumen of the subject. Therefore, even if the position of the tip 12d of the endoscope 12 is fixed, the shooting distance may fluctuate regularly with time t due to pulsation or peristalsis, etc.

[0088] When a user attempts to acquire a still image, if the period from pressing the freeze operation unit 12f until releasing it is shorter than the long-press detection period, a temporary image is saved according to the first selection condition. In the case of Figure 14, a maximum of 5 images are temporarily saved in the temporary storage area 73. Because the first selection condition was a first-in, first-out method, 5 images are temporarily saved, going back from the time t6 when the freeze operation unit 12f was released, and the image acquired at time t2, which has the highest contrast evaluation value, is selected from among them. Endoscopic images Pt2 is acquired as the optimal still image. In Figure 14, the endoscopic image acquired at time t1 and the endoscopic image acquired at time t2 are shown with different shading, respectively, as the endoscopic image acquired at time t6 is deleted when it becomes a temporarily stored image.

[0089] In the case of Figure 14, a well-focused endoscopic image was obtained during the period in which the maximum number of images were acquired. However, depending on the timing of the single press of the freeze control unit 12f, it may not be possible to obtain a well-focused endoscopic image during the period in which the maximum number of images were acquired. That is, within a certain period of time preceding the single press of the freeze control unit 12f, there may not be a timing in which an endoscopic image with a shooting distance of distance db can be obtained. In the endoscopic system 10, as shown in Figure 15, for example, if it is thought that a well-focused endoscopic image cannot be obtained during the period in which the maximum number of images were acquired by a single press, the user can simply continue to press the freeze control unit 12f. If the period from pressing the freeze control unit 12f until releasing it is longer than the long-press judgment period, it is judged as a long press, the selection condition is changed from the first selection condition to the second selection condition, and a temporarily saved image is saved. In addition, the endoscopic system 10 allows confirmation of whether an appropriate still image was obtained by a single press of the freeze control unit 12f by displaying the optimal still image on the display 18. The display of the optimal still image will be described later.

[0090] In the case of Figure 15, a long press is detected at time tn+4, and after the long press detection, the endoscopic image is temporarily saved in the temporary storage area 73 according to the second selection condition. The second selection condition allows for the temporary saving of up to 5 images in the temporary storage area 73. Before the long press detection, only the endoscopic image Ptn, which was acquired at time tn with the highest contrast evaluation value according to the first selection condition, is temporarily saved in the temporary storage area 73. Then, the four endoscopic images from time tn+5 to time tn+8 are temporarily saved as temporary images. At time tn+8, when 5 temporary images are temporarily saved in the temporary storage area 73, a contrast evaluation is performed on the 5 temporary images saved in the temporary storage area 73 based on their contrast evaluation values, and the endoscopic image Ptn+6 with the highest contrast evaluation value is saved as the optimal still image. In Figure 15, the endoscopic image Ptn acquired at time tn, which was the appropriate still image, and the endoscopic image Ptn+6 acquired at time t6 are shown with different shading. In this way, the endoscopic image Ptn is updated, and the endoscopic image Ptn+6, which has better focus, can be saved as the optimal still image.

[0091] In this way, by having the user continue pressing the freeze control unit 12f until they believe, for example, that the optimal shooting distance is included, and then releasing the freeze control unit 12f when they believe the optimal shooting distance is included, it is possible to obtain a still image with the most appropriate shooting distance even if the subject is moving.

[0092] In this embodiment, the case where the maximum number of images temporarily stored in the temporary storage area 73 is 5 has been described. However, the maximum number can be arbitrarily set according to the purpose of shooting or the shooting environment. For example, if the frame rate is 60 frames per second, the maximum number can be set to 15. A maximum of 15 images corresponds to a shooting period of 0.25 seconds when the frame rate is 60 frames per second.

[0093] Furthermore, the maximum number of images that the temporary storage area 73 temporarily stores does not have to be consecutive frames of endoscopic images. The shooting period corresponding to the maximum number of images can be set arbitrarily, and non-consecutive frames of endoscopic images may be temporarily stored as temporary storage images. For example, if the number of frames is 60 frames / second, acquiring the maximum number of 15 images from consecutive frames results in a shooting period of 0.25 seconds, but acquiring the maximum number of 15 images every other frame results in a shooting period of 0.5 seconds. The shooting period corresponding to the maximum number of images can be called the blur reduction period, for example, if the image evaluation value is the contrast evaluation value. The blur reduction period is a period during which, even if the image evaluation value fluctuates, at least one optimal still image can be acquired in terms of the image evaluation value. Therefore, depending on the type of subject or the shooting environment, for example, the blur reduction period can be set to be shorter for fast-moving subjects and longer for slow-moving subjects, and so on, and can be adjusted arbitrarily.

[0094] Furthermore, the maximum number of images or the shooting period for which the temporary storage area 73 temporarily stores images may be adjusted by the first and second operations of the instruction unit. Specifically, if the long-press period of the freeze operation unit 12f is less than or equal to a preset judgment period, and the number of frames is 60 frames / second, the shooting period corresponding to the maximum number of images can be set to 0.25 seconds. If the long-press period is longer than the judgment period, the maximum number of images, 15, can be acquired every other frame, resulting in a shooting period of 0.5 seconds. The judgment period for determining the shooting period based on the long-press period may be set to three or more stages, not just the two stages described above.

[0095] As shown in Figure 16, in the detection period determination based on the long-press period, if the determination period has elapsed at time tn+3, the temporary storage unit 61 selects and temporarily saves every other frame of the endoscopic image, rather than saving each frame individually. This selection condition may also be included as a second selection condition. In Figure 16, the maximum number of images is set to 15. Therefore, when the number of temporarily saved images reaches 15, including the endoscopic image Ptn+3 taken at time tn+3, the optimal still image is selected and saved from the 15 temporarily saved images based on the contrast evaluation value. Consequently, if the long-press period is relatively long and the user is carefully observing the object of observation, the period for acquiring the maximum number of images can be set to be longer, and the timing of updating the optimal still image can also be extended. In this way, the period for acquiring the maximum number of images can be adjusted by the instruction unit.

[0096] Furthermore, the image evaluation unit 62 may set a threshold for the image evaluation value, and if it assigns an image evaluation value equal to or greater than the threshold to a temporarily saved image, the optimal still image saving unit 63 may consider that a still image saving instruction has been given and save the temporarily saved image with an image evaluation value equal to or greater than the threshold as the optimal still image. In other words, a threshold for the image evaluation value may be set in advance, and regardless of whether or not a still image saving instruction has been given, if a temporarily saved image with an image evaluation value equal to or greater than the threshold is acquired, this temporarily saved image may be saved as the optimal still image. As a result, if the optimal still image is set to be displayed on the display, the user can recognize that the optimal still image has been saved via the display 18 or the like while continuing to long-press, and then release the long-press.

[0097] As shown in Figure 17, the contrast evaluation threshold is set to 95. The contrast evaluation value can be a relative value with the contrast evaluation value of an image that is in focus with almost no blur set to 100. If a temporary image Ptn+6 with a contrast evaluation value of 98 is temporarily saved during long-press, the temporary storage unit 61 saves temporary image Ptn+6 as the optimal still image. If a temporary image with a contrast evaluation value of 98 is acquired after time Ptn+6, the new temporary image may be saved as the optimal still image, or it may not be saved. The user is notified by the notification unit that the optimal still image has been acquired. Specifically, for example, the user can be notified that the optimal still image has been acquired by the display 18 showing the optimal still image, or by the display 18 showing an alert, etc. The user can check on the display 18, etc., whether the desired still image has been acquired, and if so, can end the long-press. The notification unit will be described later.

[0098] The display 18 may display the saved optimal still image and / or appropriate still image. If the display 18 was displaying the optimal still image and / or appropriate still image, it can update them to display the latest optimal still image and / or appropriate still image, respectively. The display 18 may also have a main screen and a sub-screen. The optimal still image may be displayed on the main screen for a certain period of time, and then displayed on the sub-screen after that period. Alternatively, the optimal still image may be displayed on the main screen and the appropriate still image on the sub-screen, both updated to display the latest versions.

[0099] As shown in Figure 18, the main screen displays the endoscopic image Ptn-5, which is the most recently saved optimal still image. If a new optimal still image Ptn+6 is obtained, the endoscopic image Ptn-5, which was the optimal still image, may be updated and Ptn+6 displayed on the main screen. If the updated optimal still image Ptn+6 is displayed on the main screen, the endoscopic image Ptn-5, which was the optimal still image, is displayed on the sub-screen. Therefore, when endoscopic image Ptn-5 is displayed on the main screen, the sub-screen displays endoscopic image Ptn-7, which was the optimal still image obtained before endoscopic image Ptn-5 was obtained. Subsequently, if an endoscopic image with a better contrast evaluation value than endoscopic image Ptn+6 is obtained, the endoscopic image Ptn-5 on the sub-screen is updated and endoscopic image Ptn+6 is displayed on the sub-screen. Alternatively, the period for displaying the optimal still image on the main screen may be set to a predetermined display period, and after this period, it may be displayed on the sub-screen. During periods when the main screen does not display an optimal still image, it is preferable to display real-time endoscopic images as a video.

[0100] Alternatively, the display 18 may show only the main screen and update and display only the optimal still image, or it may have two or more sub-screens and display multiple past appropriate images. In this case, multiple past appropriate images selected from the most recent ones may be displayed in chronological order. By displaying the optimal still image and / or appropriate still image on the display 18, the user can understand from past appropriate still images how to manipulate the distance between the endoscope tip and the subject to obtain the desired still image. It is also preferable that the user can see at a glance whether or not the desired still image has already been obtained.

[0101] Furthermore, the endoscope system 10 may include a notification unit that notifies the user when the display 18 updates and displays the optimal still image and / or appropriate still image. The notification unit may be a display on the display 18 of the endoscope system 10, or it may be a sound or other means that the user can recognize as a notification. When notification is given by displaying on the display 18, it is preferable to notify the user in a way that allows them to recognize the display or update at a glance, by changing the color, thickness, or display format of the frame of each still image on the display 18 for a certain period of time after the optimal still image and / or appropriate still image has been updated.

[0102] As shown in Figure 19, for example, the display 18 includes a video display screen 81, a still image display main screen 82, and a still image display sub-screen 83. The video display screen 81 displays endoscopic images in real time. The still image display main screen 82 displays the optimal still image. When the optimal still image is updated, the optimal still image is displayed surrounded by a still image display notification frame 84, which is a thick colored line. The still image display notification frame 84 may also be made to blink. As described above, the still image display sub-screen 83 displays multiple past optimal still images in chronological order.

[0103] In this way, for example, when an appropriate still image is updated and displayed, the user is notified about the update, allowing the user to pay attention to the display 18. If the updated appropriate still image is the one the user desired, the user releases the freeze operation unit 12f at that point, allowing the updated appropriate still image displayed on the display 18 to be saved as the optimal still image in a timely manner.

[0104] Furthermore, the notification unit may notify the user of the change when the selection condition switching unit 72 switches between the first selection condition and the second selection condition. In this case as well, as described above, notification can be made, for example, by displaying the appropriate still image using the still image display notification frame 84 on the display 18.

[0105] Furthermore, it is preferable that the notification unit refrain from sending another notification if the notification to the user occurs again within the predetermined minimum notification period. By setting a minimum notification period, it is possible to avoid frequent and cumbersome notifications.

[0106] In the above embodiment, the present invention is applied to an endoscopic system that processes endoscopic images. However, the present invention can also be applied to medical image processing systems that process medical images other than endoscopic images when saving still images. Furthermore, the present invention can also be applied when saving still images, such as when the endoscopic image is an autofluorescence image obtained by capturing an autofluorescence image emitted from a subject by irradiation with excitation light.

[0107] In the above embodiment, the hardware structure of the processing unit that performs various processes, such as the central control unit 59, image acquisition unit 51, noise reduction unit 53, signal processing unit 55, image storage unit 56, display control unit 57, and video signal generation unit 58 included in the processor device 16, is a variety of processor 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), which is a processor whose circuit configuration can be changed after manufacturing, such as an FPGA (Field Programmable Gate Array); and a dedicated electrical circuit, which is a processor with a circuit configuration specifically designed to perform various processes.

[0108] 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 where 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 systems. 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.

[0109] Furthermore, the hardware structure of these various processors is, more specifically, an electrical circuit in the form of a combination of circuit elements such as semiconductor devices. [Explanation of Symbols]

[0110] 10 Endoscopy Systems 12 Endoscopes 12a Insertion section 12b Operation section 12c curved section 12d Tip 12e Angle Knob 12f Freeze Control Unit 12g zoom control section 14 Light source device 16 Processor Unit 18 displays 19-key keyboard 20 Light source section 20a V-LED 20b B-LED 20c G-LED 20d R-LED 21 Light source processor 30a illumination optical system 30b Imaging optical system 41 Light Guide 42 Illumination Lenses 43 Objective lens 44 zoom lens 45 Imaging Sensor 46 CDS / AGC circuit 47 A / D converters 51 Image acquisition unit 52 DSP 53 Noise Reduction Section 54 memory 55 Signal Processing Unit 56 Image storage section 57 Display Control Unit 58 Video signal generation unit 59 Central Control Unit 61 Temporary storage section 62 Image Evaluation Department 63 Optimal still image storage section 71 Selection Condition Switching Instruction Reception Unit 72 Selection Condition Switching Section 73 Temporary storage area 74 Contrast Evaluation Section 75 Brightness evaluation section 76 Confidence Evaluation Department 77. Malignancy Assessment Department 78 Still Image Save Instruction Reception Unit 79 Optimal still image storage area 81 Video display screen 82 Still Image Display Main Screen 83 Still Image Display Sub-screen 84 Still image display notification frame 91 Subject db, db+c, dm distance t, t1~t6, tn~tn+8 time Endoscopic images of Pt2, Ptn, Ptn-7 to Ptn+7 ST100~ST200 Step

Claims

1. Equipped with an endoscope and processor for photographing the subject, The endoscope is equipped with an indicator unit, The aforementioned processor, The endoscopic images obtained by photographing the subject with the endoscope are acquired frame by frame. The endoscopic image selected based on the first or second selection criterion is temporarily stored in the temporary storage area as a temporary storage image. For each of the temporary images temporarily stored in the temporary storage area, an image evaluation value is assigned by performing an image evaluation. Based on the selection condition switching instruction, the first selection condition and the second selection condition are switched. Based on the instruction to save a still image, the optimal still image selected from the temporarily saved images according to the image evaluation value is saved. The instruction unit performs the selection condition switching instruction and the still image saving instruction. The instruction unit performs a first operation and a second operation, and the second operation gives the instruction to save the still image. The processor measures the period from the first operation to the second operation, The instruction unit is an endoscope system that, if the period is longer than or equal to a predetermined judgment period, issues the selection condition switching instruction when the judgment period has elapsed since the first operation.

2. The endoscopic system according to claim 1, wherein the processor temporarily stores the endoscopic image selected based on the first selection condition when it starts acquiring the endoscopic image.

3. The indicator unit includes a momentary switch, The endoscope system according to claim 1, wherein the first action is pressing the momentary switch, and the second action is releasing the pressed momentary switch.

4. The indicator unit includes an alternate switch, The endoscope system according to claim 1, wherein the first operation is the first pressing and releasing of the alternate switch, and the second operation is the second pressing and releasing of the alternate switch.

5. The endoscope system according to any one of claims 1 to 4, wherein the instruction unit, when the still image saving instruction is given, gives the instruction to switch the selection condition if the processor has temporarily saved the endoscope image based on the second selection condition.

6. The processor temporarily stores the selected endoscopic images in the temporary storage area as temporary storage images, up to a maximum number set in advance. The endoscope system according to any one of claims 1 to 5, wherein the first selection condition includes, if the number of temporarily stored images in the temporary storage area is less than the maximum number, the first A selection condition is to temporarily store the endoscope images in the temporary storage area as temporary stored images in order of the most recent acquisition time until the maximum number is reached, and if the maximum number of temporary stored images is temporarily stored in the temporary storage area, the first B selection condition is to delete the temporary stored image with the oldest acquisition time from the temporary storage area, and then temporarily store the endoscope images in the temporary storage area as temporary stored images in order of the most recent acquisition time.

7. The processor temporarily stores the selected endoscopic images in the temporary storage area as temporary storage images, up to a maximum number set in advance. The endoscope system according to any one of claims 1 to 6, wherein the second selection condition is, if the number of temporarily stored images in the temporary storage area is less than the maximum number, the second A selection condition is to temporarily store the endoscope images in the temporary storage area as temporary stored images in order of the most recent acquisition time until the maximum number is reached, and if the maximum number of temporarily stored images is temporarily stored in the temporary storage area, the second B selection condition is to leave only the appropriate still images selected from the temporary stored images according to the image evaluation value as temporary stored images in the temporary storage area, and delete the images other than the appropriate still images from the temporary storage area, and then perform the second A selection condition.

8. The processor temporarily stores the selected endoscopic images in the temporary storage area as temporary storage images, up to a maximum number set in advance. The endoscope system according to any one of claims 1 to 6, wherein the second selection condition is, if the number of temporarily stored images in the temporary storage area is less than the maximum number, the second A selection condition is to temporarily store the endoscope images in the temporary storage area as temporary stored images in order of the most recent acquisition time until the maximum number is reached, and if the maximum number of temporary stored images is temporarily stored in the temporary storage area, the second C selection condition is to leave only the appropriate still images selected from the temporary stored images according to the image evaluation value as temporary stored images in the temporary storage area, delete the still images other than the appropriate images from the temporary storage area, select the endoscope image with the most recent acquisition time and temporarily store it in the temporary storage area as a temporary stored image, and then temporarily store only the appropriate still images selected from the temporary stored images in the temporary storage area according to the image evaluation value as temporary stored images.

9. The system includes a display that shows the optimal still image and / or the appropriate still image, The endoscope system according to claim 7 or 8, wherein if the display was displaying the optimal still image and / or the appropriate still image, it updates to display the latest optimal still image and / or the appropriate still image, respectively.

10. The aforementioned display comprises a main screen and a sub-screen, The endoscope system according to claim 9, wherein the optimal still image is displayed on the main screen for a preset display period, and after the display period, it is displayed on the sub-screen.

11. The endoscope system according to claim 9 or 10, further comprising a notification unit that notifies the user of the update when the display updates and displays the optimal still image and / or the appropriate still image.

12. The endoscope system according to claim 11, wherein the notification unit notifies the user of the switching when the processor switches between the first selection condition and the second selection condition.

13. The endoscope system according to claim 11 or 12, wherein the notification unit refrains from making the notification if the notification to the user is made again within a predetermined minimum notification period.

14. The endoscopic system according to any one of claims 1 to 13, wherein the processor performs the image evaluation on the contrast and / or brightness of the temporarily stored image, and the image evaluation value is a value relating to the contrast and / or brightness of the temporarily stored image.

15. The endoscopic system according to any one of claims 1 to 13, wherein the processor performs the image evaluation regarding the degree of confidence and / or malignancy of a specific lesion having in the subject captured in the temporarily stored image, and the image evaluation value is the degree of confidence and / or malignancy.

16. The endoscopic system according to any one of claims 1 to 15, wherein the processor sets a threshold for the image evaluation value, and when the image evaluation value equal to or greater than the threshold is assigned to the temporarily stored image, it is deemed that a still image saving instruction has been given, and the temporarily stored image to which the image evaluation value equal to or greater than the threshold is assigned is saved as the optimal still image.

17. The endoscope system according to any one of claims 1 to 16, wherein the instruction unit includes a freeze operation unit.

18. A method for operating an endoscope system comprising an endoscope equipped with a control unit for photographing a subject and a processor, The aforementioned processor, The endoscopic images obtained by photographing the subject with the endoscope are acquired frame by frame. The endoscopic image selected based on the first or second selection criterion is temporarily stored in the temporary storage area as a temporary storage image. For each of the temporary images temporarily stored in the temporary storage area, an image evaluation value is assigned by performing an image evaluation. Based on the selection condition switching instruction, the first selection condition and the second selection condition are switched. Based on the instruction to save a still image, the optimal still image selected from the temporarily saved images according to the image evaluation value is saved. The instruction unit performs the selection condition switching instruction and the still image saving instruction. The instruction unit performs a first operation and a second operation, and the second operation gives the instruction to save the still image. The processor measures the period from the first operation to the second operation, The instruction unit is an operating method for an endoscope system that, if the period is longer than or equal to a predetermined judgment period, issues the selection condition switching instruction when the judgment period has elapsed since the first operation.

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