Endoscope system and working method of endoscope system

Abstract

The present invention provides an endoscope system and an operating method of the endoscope system, wherein a plurality of still images are saved in a state suitable for comparison or superposition by a single command. During the period of emitting a first illumination light, a second illumination light is emitted by switching from the first illumination light during at least one frame. A first image (96) or a second image (95) obtained by photographing an observation object illuminated by the first illumination light or the second illumination light is acquired for each frame. From a plurality of first images (96) and second images (95) acquired during a predetermined period before the start of an image saving process, at least one first image (96) or second image (95) that satisfies a predetermined selection condition is selected and saved.

Description

Technical Field

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

[0002] In the medical field, diagnosis using an endoscope system comprising a light source device, an endoscope, and a processor device is widely performed. In diagnosis using an endoscope system, various information related to the surface structure of the observed object or the mucosal surface layer, etc., is sometimes obtained by using images obtained by imaging the observed object with the endoscope (hereinafter referred to as endoscopic images) through image-enhanced observation (IEE) using techniques such as illumination light.

[0003] In diagnosis using IEE, it is sometimes possible to make an appropriate diagnosis by acquiring multiple images obtained using various illumination sources, for example, and then comparing or overlaying these images in detail. As a technology for using multiple images consisting of normal images obtained using white light observation and images obtained using IEE, an endoscope system is disclosed that displays a dynamic image for oxygen saturation observation, a dynamic image for normal observation, and a dynamic image for vascular enhancement observation side by side on a display device. When a freeze button is pressed while the dynamic images are displayed, each dynamic image is saved as a still image after setting exposure conditions (Patent Document 1).

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-188364 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] Conventional technology selects and saves multiple still images with minimal blur, starting from the point in time when a freeze button is pressed during a moving image display to save a still image, for example, back to a certain period in the past. By comparing two images using multiple illumination lights—for example, an image using illumination light that emphasizes superficial blood vessels of the observation target and an image using illumination light that emphasizes mid- to deep-layer blood vessels of the same observation target—information about the depth of the observation target can be obtained, which is effective for diagnosing the extent of a lesion.

[0009] To save multiple still images corresponding to multiple illumination lights, for example, as in conventional techniques, the illumination lights are switched and a still image is saved for each illumination light. When observing and photographing an object while repeatedly switching between multiple illumination lights, it is desirable to extend the switching cycle of the illumination lights used for observation as much as possible due to issues such as photosensitivity. However, in this case, it is necessary to select an image that was not observed using the illumination light when the still image acquisition command was issued. The longer the illumination light switching cycle, the greater the time difference between the multiple images saved. The greater the time difference between the multiple images saved, the greater the possibility of significant positional deviations between the images due to, for example, movement of the object, resulting in the possibility of saving still images that are unsuitable for comparison or overlay.

[0010] On the other hand, to reduce the time difference between the multiple images stored, one approach is to shorten the switching cycle of the multiple illumination lights to shorten the illumination time of each illumination light. However, this approach may cause light flicker or photosensitivity, which becomes a trade-off with the time difference between images.

[0011] Furthermore, in Patent Document 1, in addition to the above, multiple illumination lights are automatically switched according to a predetermined sequence, and dynamic images corresponding to each illumination light are simultaneously displayed on a display. In this case, the frame rate is reduced to less than half compared to the case where the illumination light is not switched, making it difficult to diagnose an observation object that may be moving by comparing or superimposing multiple images, for example.

[0012] In view of the above-mentioned actual situation, an object of the present invention is to provide an endoscope system and an operating method of the endoscope system, wherein a plurality of still images are saved in a state suitable for comparison or superposition according to a single command.

[0013] Means for solving technical problems

[0014] The present invention relates to an endoscope system comprising multiple semiconductor light sources that emit light in mutually different wavelength bands, a light source processor, and an image processor. The light source processor controls the system so that, during a first period in which a first illumination light from among a plurality of illumination lights having different combinations of light intensity ratios is emitted by the multiple semiconductor light sources, the system switches from the first illumination light to emit a second illumination light having a combination different from the first illumination light for at least one frame. The image processor captures a first image or a second image obtained by photographing an observation object illuminated by the first illumination light or the second illumination light for each frame, and performs image storage processing to store the first image and the second image. When a processing start operation for starting the image storage processing is performed, at least one first image and one second image satisfying a preset selection condition are selected and stored from among the plurality of first images and the plurality of second images acquired during a preset period before the processing start operation.

[0015] It is preferable that the selection condition is the first image and the second image with the least blur among the plurality of first images and the plurality of second images acquired.

[0016] The selection condition is preferably set to be the first image and the second image with the smallest positional shift among the first image and the second image selected from the plurality of first images and the plurality of second images acquired.

[0017] The selection condition is preferably set to be the first image and the second image whose difference in acquisition time is the smallest among the first image and the second image selected from the plurality of acquired first images and the plurality of acquired second images.

[0018] Preferably, the light source processor alternately repeats the first period and the second period for emitting the second illumination light, and performs control to emit the first illumination light by switching with the second illumination light during at least one frame in the second period.

[0019] Preferably, the image processor controls display of the acquired first image and / or second image on the display, and displays at least the second image on the display during the second period.

[0020] Preferably, the image processor controls display of the acquired first image and / or second image on the display, and displays at least the first image on the display during the first period.

[0021] Preferably, the semiconductor light source includes a first semiconductor light source and a second semiconductor light source, wherein the first semiconductor light source emits a first narrow-band light with a central wavelength of 410±10nm and a wavelength range of 420~500nm, and the second semiconductor light source emits a second narrow-band light with a central wavelength of 450±10nm and a wavelength range of 380~420nm.

[0022] Preferably, the image processor stores the first image and the second image after adding information related to the illumination light used.

[0023] The present invention also provides an operating method for an endoscope system comprising multiple semiconductor light sources that emit light in different wavelength bands, a light source processor, and an image processor. The light source processor controls the system so that, during a first period in which a first illumination light from among a plurality of illumination lights having different combinations of light intensity ratios is emitted by the multiple semiconductor light sources, the system switches from the first illumination light to emit a second illumination light having a different combination from the first illumination light for at least one frame. The image processor captures a first image or a second image obtained by photographing an observation object illuminated by the first illumination light or the second illumination light for each frame, and performs image storage processing to store the first image and the second image. When a processing start operation is performed to start the image storage processing, at least one first image and one second image, respectively, that meet predetermined selection criteria is selected and stored from among the plurality of first images and the plurality of second images acquired during a predetermined period before the processing start operation.

[0024] Effects of the Invention

[0025] According to the present invention, a plurality of still images can be saved in a state suitable for comparison or superposition by a single command. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is an external view of the endoscope system.

[0027] Figure 2 This is an external view of the operating unit of an endoscope.

[0028] Figure 3 This is a block diagram showing the functions of an endoscope system.

[0029] Figure 4 This is an explanatory diagram for explaining four-color LEDs included in the light source unit.

[0030] Figure 5 Graph showing the spectrum of violet light V, blue light B, green light G, and red light R.

[0031] Figure 6 This is a graph showing the spectrum of the first illumination light.

[0032] Figure 7 It is a graph showing the spectrum of the second illumination light.

[0033] Figure 8 This is an explanatory diagram for explaining illumination light in the first special observation mode.

[0034] Figure 9 This is an explanatory diagram for explaining illumination light in the second special observation mode.

[0035] Figure 10 This is an explanatory diagram for explaining illumination light in the multi-observation mode.

[0036] Figure 11 This is an explanatory diagram showing the light-emission period setting menu.

[0037] Figure 12 This is an image diagram showing the first special observation image.

[0038] Figure 13 It is an explanatory diagram showing purple and blue light images and green and red light images obtained when the first illumination light is applied.

[0039] Figure 14 : is an image diagram showing the second special observation image.

[0040] Figure 15 It is an explanatory diagram showing purple and blue light images and green and red light images obtained when the second illumination light is applied.

[0041] Figure 16 This is an explanatory diagram for explaining an example of storage of a still image in the first special observation mode.

[0042] Figure 17 This is an explanatory diagram for explaining another example of storage of a still image in the first special observation mode.

[0043] Figure 18 This is an explanatory diagram for explaining an example of storing still images in the multi-observation mode.

[0044] Figure 19 This is an explanatory diagram for explaining an image displayed on the monitor in the first special observation mode.

[0045] Figure 20 This is an explanatory diagram for explaining images displayed on the monitor in the multi-view mode.

[0046] Figure 21 This is a flowchart showing a series of processes for saving still images in the first special observation mode. DETAILED DESCRIPTION

[0047] exist Figure 1 In the embodiment, 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 includes an insertion portion 12a to be inserted into the body of an observation object, an operating portion 12b provided at the base end of the insertion portion 12a, and a bending portion 12c and a front end portion 12d provided at the front end side of the insertion portion 12a. The bending portion 12c is adjusted by operating the angle button 12e (refer to FIG. Figure 2 The distal end portion 12d is directed toward a desired direction by the bending action of the bending portion 12c.

[0048] like Figure 2 As shown, the operation unit 12b includes, in addition to the angle button 12e, a mode switch 12g for switching observation modes, a zoom operation unit 12h for changing the imaging magnification, and a still image acquisition command unit 12f for issuing a still image acquisition command. Furthermore, the observation mode switching operation, zoom operation, or still image acquisition command can be performed using the keyboard 19 or a foot switch (not shown) in addition to the mode switch 12g or the viewer switch of the still image acquisition command unit 12f.

[0049] The endoscope system 10 has three modes: a normal observation mode, a special observation mode, and a multi-observation mode. The normal observation mode is a mode in which a normal observation image (hereinafter referred to as a normal image) is displayed on the display 18. The normal observation image is an image of natural color obtained by photographing the observation object using white light as illumination light. The special observation mode includes a first special observation mode and a second special observation mode. The first special observation mode is a mode in which a first special observation image (hereinafter referred to as a first image) emphasizing surface information such as surface blood vessels is displayed on the display 18. The second special observation mode is a mode in which a second special observation image (hereinafter referred to as a second image) emphasizing deep information such as deep blood vessels is displayed on the display 18. The multi-observation mode is a mode in which the first special observation mode and the second special observation mode are automatically switched.

[0050] The processor device 16 is electrically connected to a display 18 and a keyboard 19. The display 18 outputs and displays the normal image, the first image, the second image, and / or information accompanying these images. The keyboard 19 functions as a user interface for accepting input operations such as function settings. Furthermore, an external recording unit (not shown) for recording images or image information may be connected to the processor device 16.

[0051] exist Figure 3 In the figure, the light source device 14 is a device that emits illumination light to illuminate the observation object, and includes 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 a halogen light source. In addition, the light source unit 20 includes a filter for adjusting the wavelength of light emitted by the LED, etc. The light source processor 21 controls the amount of illumination light by turning on / off each LED, etc., and adjusting the drive current and drive voltage of each LED, etc. In addition, the light source processor 21 controls the wavelength of illumination light by changing the filter, etc.

[0052] like Figure 4As shown, in this embodiment, the light source unit 20 has four colors of LEDs: V-LED (Violet Light Emitting Diode: purple light emitting diode) 20a, B-LED (Blue Light Emitting Diode: blue light emitting diode) 20b, G-LED (Green Light Emitting Diode: green light emitting diode) 20c and R-LED (Red Light Emitting Diode: red light emitting diode) 20d.

[0053] like Figure 5 As shown, V-LED 20a generates violet light V with a central wavelength of 410±10 nm and a wavelength range of 380 to 420 nm. B-LED 20b generates blue light B with a central wavelength of 450±10 nm and a wavelength range of 420 to 500 nm. G-LED 20c generates green light G with a wavelength range of 480 to 600 nm. R-LED 20d generates red light R with a central wavelength of 620 to 630 nm and a wavelength range of 600 to 650 nm. In this specification, the symbol "to" indicates a range that includes both preceding and following numerical values. For example, "420 to 500 nm" means "between 420 nm and 500 nm."

[0054] The light source processor 21 controls the V-LED 20a, B-LED 20b, G-LED 20c, and R-LED 20d. In normal observation mode, the light source processor 21 controls each LED 20a to 20d so that the light intensity ratio of violet light V, blue light B, green light G, and red light R is Vc:Bc:Gc:Rc, which is the normal light intensity ratio.

[0055] In the first special observation mode, the light source processor 21 controls each LED 20a to 20d so that the first illumination light is emitted, wherein the light intensity ratio of the purple light V, blue light B, green light G, and red light R is Vs1:Bs1:Gs1:Rs1. The first illumination light preferably emphasizes the superficial blood vessels. Therefore, the first illumination light preferably makes the light intensity of the purple light V greater than the light intensity of the blue light B. For example, Figure 6 As shown, the ratio of the light intensity Vs1 of the purple light V to the light intensity Bs1 of the blue light B is set to "4:1".

[0056] In this specification, a combination of light intensity ratios includes situations where the ratio of at least one semiconductor light source is 0 (zero). Therefore, this includes situations where any one, or two or more, of the semiconductor light sources are not illuminated. For example, if the light intensity ratio combination of violet light V, blue light B, green light G, and red light R is 1:0:0:0, then illuminating only one of the semiconductor light sources while not illuminating the other three also provides a light intensity ratio, which is one of the combinations of light intensity ratios.

[0057] Furthermore, when in the second special observation mode, the light source processor 21 controls each LED 20a to 20d so that the second illumination light having a light intensity ratio of violet light V, blue light B, green light G, and red light R is Vs2:Bs2:Gs2:Rs2 is emitted. The second illumination light preferably emphasizes deep blood vessels. Therefore, the second illumination light preferably makes the light intensity of blue light B greater than that of violet light V. For example, Figure 7 As shown, the ratio of the light intensity Vs2 of the purple light V to the light intensity Bs2 of the blue light B is set to "1:3".

[0058] In the normal observation mode, the first special observation mode, or the second special observation mode, the combinations of light intensity ratios of violet light V, blue light B, green light G, and red light R, that is, the types of illumination light, are different from one another. The light source processor 21 controls the light source to emit a specific type of illumination light, such as the first illumination light, by switching from the first illumination light to the second illumination light for at least one frame. For example, the light source processor controls the light source to emit a different type of illumination light, such as the first illumination light, by switching from the second illumination light to the second illumination light for at least one frame. When the light source processor 21 switches to another type of illumination light during the period of emitting a specific type of illumination light, the switching to the other type of illumination light may be performed at any time during at least one frame, or the other type of illumination light may be controlled to be emitted periodically according to a preset cycle. Furthermore, since the period during which the specific type of illumination light is emitted is a period during which the specific type of illumination light is continuously emitted, it is possible to emit the specific type of illumination light again after switching to another type of illumination light and emitting the light during the period during which the specific type of illumination light is emitted.

[0059] In addition, "frame" refers to a frame for controlling the image sensor 45 (refer to Figure 3 ), for example, "one frame" refers to a period including at least an exposure period for exposing the imaging sensor 45 to light from the observation object and a reading period for reading an image signal. In this embodiment, the first period or the second period is defined corresponding to the "frame" as the unit of imaging.

[0060] In the special observation mode, the light emission control in the first period or the light emission control in the second period as described above by the light source processor 21 will be specifically described. Figure 8 As shown, during the first period of continuously emitting the first illumination light, the second illumination light is emitted by switching with the first illumination light in a cycle of one frame of the second illumination light emitting period 72 relative to five frames of the first illumination light emitting period 71, and the cycle is repeated. Or, as Figure 9 As shown, during the second period of continuous emission of the second illumination light, the first illumination light is emitted in a cycle of one frame of the first illumination light emission period 74 corresponding to five frames of the second illumination light emission period 73, switching with the second illumination light to emit the first illumination light, and repeating this cycle. In addition, in the figure, only some symbols are added to avoid complicating the figure.

[0061] When the multi-observation mode is set, the light source processor 21 alternately and repeatedly emits a specific type of illumination light, for example, a first period of first illumination light and a second period of continuous second illumination light. In the multi-observation mode, the light source processor 21 controls, for example, to emit the second illumination light during at least one frame of the first period, switching from the first illumination light to the second illumination light, and to emit the first illumination light during at least one frame of the second period.

[0062] The light emission control in the multi-observation mode based on the light source processor 21 is specifically described. Figure 10 As shown, during the first period 75 in which the first illumination light is continuously emitted, the second illumination light is emitted by switching with the first illumination light at a cycle of one second illumination light emission period 72 for five frames of the first illumination light emission period 71, and the second illumination light is emitted. This cycle is repeated during the first period 75. Then, during the second period 76 in which the second illumination light is continuously emitted, the first illumination light is emitted by switching with the second illumination light at a cycle of one first illumination light emission period 74 for five frames of the second illumination light emission period 73, and the first illumination light is emitted. This cycle is repeated during the second period 76. Then, the first illumination light is continuously emitted again during the first period 75, and the first and second periods 75 and 76 are repeated alternately. In this embodiment, the first period 75 and the second period 76 each last 20 frames.

[0063] The first period as the light emission period of the first illumination light and the second period as the light emission period of the second illumination light can be appropriately changed by the light emission period setting unit 22 connected to the light source processor 21. If the light emission period change operation is received by operating the keyboard 19, the light emission period setting unit 22 will change the light emission period as shown in FIG. Figure 11The light-emission period setting menu is displayed on the display 18. The first period can be changed between 2 and 60 frames, for example, and each light-emission period is assigned to the slider 81a. The second period can also be changed between 2 and 60 frames, for example, and each light-emission period is assigned to the slider 81b.

[0064] To change the first period, the first period is changed by aligning slider 82a with the position of the desired light-emitting period on slider 81a by operating keyboard 19. For the second period, the second period is also changed by aligning slider 82b with the position of the desired light-emitting period on slider 81b by operating keyboard 19. Furthermore, slider 81b is also assigned light-emitting periods ranging from 2 to 60 frames, for example. In this embodiment, in multi-observation mode, slider 81a assigns a light-emitting period of 20 frames to the first period, and slider 81b assigns a light-emitting period of 20 frames to the second period.

[0065] Light emitted by each of the LEDs 20a to 20d passes through an optical path coupling unit (not shown) composed of a reflector, lens, etc., and enters the light guide 41. The light guide 41 is built into the endoscope 12 and the universal cord (the cord that connects the endoscope 12 to the light source device 14 and the processor device 16). The light guide 41 transmits light from the optical path coupling unit to the distal end portion 12d of the endoscope 12.

[0066] The distal end portion 12d of the endoscope 12 is provided with an illumination optical system 30a and an imaging optical system 30b. The illumination optical system 30a includes an illumination lens 42, through which illumination light propagated by a light guide 41 is irradiated onto the observation object. The imaging optical system 30b includes 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 observation object, are incident on the imaging sensor 45 via the objective lens 43 and the zoom lens 44. As a result, an image of the observation object is formed on the imaging sensor 45. The zoom lens 44 is freely movable between the telephoto end and the wide-angle end by operating the zoom operation unit 12h, and the observation object imaged on the imaging sensor 45 is magnified or reduced.

[0067] The imaging sensor 45 is a color imaging sensor with one of the R (red), G (green), or B (blue) color filters provided for each pixel. It captures the object being observed and outputs image signals in each of the RGB colors. A CCD (Charge Coupled Device) imaging sensor or a CMOS (Complementary Metal-Oxide Semiconductor) imaging sensor can be used as the imaging sensor 45. Furthermore, instead of the imaging sensor 45 having primary color filters, a complementary color imaging sensor having complementary color filters for C (cyan), M (magenta), Y (yellow), and G (green) can be used. When using a complementary color imaging sensor, image signals in the four colors of CMYG are output. Therefore, through complementary color-primary color conversion, the four CMYG image signals are converted into three RGB image signals, resulting in the same RGB image signals as those of the imaging sensor 45. Alternatively, a monochrome sensor without color filters can be used in place of the imaging sensor 45.

[0068] The imaging sensor 45 is driven and controlled by an imaging processor (not shown). The control by the imaging processor varies depending on the mode. In the normal observation mode, the imaging processor controls the imaging sensor 45 to capture the observation object illuminated by normal light. Thus, a Bc image signal is output from the B pixel of the imaging sensor 45, a Gc image signal is output from the G pixel, and an Rc image signal is output from the R pixel. In the special observation mode or the multi-observation mode, the imaging processor controls the imaging sensor 45 to capture the observation object illuminated by special light. Thus, in the first special observation mode, a Bs1 image signal is output from the B pixel of the imaging sensor 45, a Gs1 image signal is output from the G pixel, and an Rs1 image signal is output from the R pixel. Similarly, in the second special observation mode, a Bs2 image signal is output from the B pixel of the imaging sensor 45, a Gs2 image signal is output from the G pixel, and an Rs2 image signal is output from the R pixel.

[0069] The CDS / AGC (Correlated Double Sampling / Automatic Gain Control) circuit 46 performs correlated double sampling (CDS) or automatic gain control (AGC) on the analog image signal obtained by the imaging sensor 45. The image signal passed through the CDS / AGC circuit 46 is converted into a digital image signal by an A / D (Analog / Digital) converter 47. The A / D-converted digital image signal is input to the processor device 16.

[0070] In the processor device 16, programs related to processes such as image storage are stored in a program memory (not shown). In the processor device 16, the central control unit 62, comprised of an image processor, executes the programs in the program memory, thereby realizing the functions of the image signal acquisition unit 51, the DSP (Digital Signal Processor) 52, the noise reduction unit 53, the memory 54, the signal processing unit 55, the image storage unit 56, the image storage control unit 61, the display control unit 57, and the video signal generation unit 58. Furthermore, the central control unit 62 receives information from the endoscope 12 and the light source device 14. Based on this information, the central control unit 62 controls not only the various components of the processor device 16 but also the endoscope 12 and the light source device 14. Furthermore, the central control unit 62 receives information such as commands from the keyboard 19.

[0071] The image signal acquisition unit 51 acquires the digital image signal of the endoscopic image input from the endoscope 12. The image signal acquisition unit 51 acquires the image signal obtained by shooting the observation object illuminated by each illumination light for each frame. The acquired image signal is sent to the DSP52. The DSP52 performs various signal processing such as offset processing, defect correction processing, demosaicing processing, linear matrix processing, gain correction processing, gamma conversion processing and YC conversion processing on the received image signal. In the offset processing, the dark current component is removed from the received image signal and an accurate zero level is set. In the defect correction processing, the signal of the defective pixel of the camera sensor 45 is corrected. De-mosaic processing (also called isotropic processing, synchronization processing) is performed on the image signal after the defect correction processing, and the signal of the missing color of each pixel is generated by interpolation. Through the demosaicing processing, all pixels have signals of each RGB color.

[0072] Linear matrix processing is performed on each color image signal after demosaicing to improve color reproducibility. Gain correction is performed by multiplying each color image signal after demosaicing by a specific gain to adjust the signal level of each image signal. Gamma conversion is then performed to adjust the brightness and chroma of each image signal. The DSP 52 performs YC conversion on each gamma-converted image signal and outputs the luminance signal Y and the color difference signals Cb and Cr to the noise reduction unit 53.

[0073] The noise reduction unit 53 performs noise reduction processing such as a moving average method or a median filter method on the image signal subjected to the gamma conversion processing by the DSP 52 . The image signal with reduced noise is stored in the memory 54 .

[0074] The signal processing unit 55 acquires the image signal after noise reduction from the memory 54. Furthermore, as needed, the acquired image signal is subjected to signal processing such as color conversion processing, color emphasis processing, and structure emphasis processing to generate a color endoscopic image of the observed object. Color conversion processing is a process that converts the color of the image signal through 3×3 matrix processing, grayscale conversion processing, and 3D LUT (lookup table) processing. Color emphasis processing is performed on the image signal after color conversion processing. Structural emphasis processing is a process that emphasizes specific tissues and structures contained in the observed object, such as blood vessels and pit patterns, and is performed on the image signal after color emphasis processing.

[0075] In normal observation mode, the signal processing unit 55 performs normal image processing on one frame of input noise-reduced image signals. This normal image processing includes color conversion processing such as 3×3 matrix processing, grayscale conversion processing, and 3D LUT processing, as well as color emphasis processing and structure emphasis processing such as spatial frequency emphasis. The image signal subjected to normal image processing is input to the image storage unit 56 as a normal image.

[0076] In the special observation modes, the signal processing unit 55 performs special image processing on the noise-reduced image signal of one frame input in the first special observation mode or the second special observation mode. This special image processing includes color conversion processing such as 3×3 matrix processing, grayscale conversion processing, and 3D LUT processing, as well as color emphasis processing and structure emphasis processing such as spatial frequency emphasis. The image signal subjected to special image processing is input to the image storage unit 56 as the first image or the second image.

[0077] The endoscopic images generated by the signal processing unit 55 are normal observation images when the observation mode is normal, and special observation images when the observation mode is special. Therefore, the content of color conversion processing, color emphasis processing, and structure emphasis processing differs depending on the observation mode. In normal observation mode, the signal processing unit 55 applies the aforementioned various signal processing steps to render the observed object in natural colors, generating a normal observation image. In special observation mode, the signal processing unit 55 applies the aforementioned various signal processing steps to, for example, emphasize the blood vessels of the observed object, generating a special observation image comprising a first image and a second image.

[0078] Because the semiconductor light source includes a first semiconductor light source that emits violet light V (first narrowband light) with a central wavelength of 410±10 nm and a wavelength range of 420 to 500 nm, and a second semiconductor light source that emits blue light B (second narrowband light) with a central wavelength of 450±10 nm and a wavelength range of 380 to 420 nm, in the special observation image generated by the signal processing unit 55, blood vessels (so-called superficial blood vessels) or blood located relatively shallow within the observation object relative to the surface of the mucosa appear in a magenta-based color (e.g., brown) in the first image, while blood vessels (so-called mid-deep blood vessels) located relatively deep within the observation object relative to the surface of the mucosa appear in a cyan-based color (e.g., green) in the second image. Consequently, the blood vessels or bleeding (blood) of the observation object are emphasized by the color difference compared to the mucosa, which appears in a pink-based color.

[0079] like Figure 12 As shown in FIG. 1 , the first image shows an image of the background mucosa BM and the superficial blood vessels VS1 in the observation object. The first image is obtained based on the first illumination light including purple light, blue light, green light and red light. Figure 13 As shown, when the first illumination light illuminates the observation object, the violet light V and blue light B in the first illumination light penetrate deeply into the surface layer where the superficial blood vessels VS1 are distributed. Therefore, the violet light image VP obtained based on the reflected light of the violet light V and blue light B includes an image of the superficial blood vessels VS1. In addition, here, the light intensity of the violet light V is stronger than the light intensity of the blue light B, so it is defined as the violet light image VP. Furthermore, the green light G and red light R in the first illumination light penetrate deeply into the background mucosa BM distributed deeper than the superficial blood vessels VS1 and the deep blood vessels VS2 (blood vessels located deeper than the superficial blood vessels VS1). Therefore, the green and red light image GRP obtained based on the reflected light of the green light G and red light R includes an image of the background mucosa BM. Based on the above, the first image is an image formed by combining the violet light image VP and the green and red light image GRP, and thus displays images of the background mucosa BM and the superficial blood vessels VS1.

[0080] like Figure 14 As shown in FIG. 1 , the second image shows an image of the background mucosa BM and deep blood vessels VS2 in the observation object. The second image is obtained based on the second illumination light including purple light, blue light, green light and red light. Figure 15As shown, when the second illumination light is irradiated onto the observation object, the violet light V and blue light B in the second illumination light penetrate deeply into the deep layer where the deep blood vessels VS2 are distributed. Therefore, the blue light image BP obtained based on the reflected light of the violet light V and blue light B includes an image of the deep blood vessels VS2. In addition, here, the light intensity of the blue light B is stronger than that of the violet light V, so the blue light image BP is used. Furthermore, the green light G and red light R in the second illumination light penetrate deeply into the background mucosa BM distributed deeper than the surface blood vessels VS1 and the deep blood vessels VS2 (blood vessels located deeper than the surface blood vessels VS1). Therefore, the green and red light image GRP obtained based on the reflected light of the green light G and red light R includes an image of the background mucosa BM. Based on the above, the second image is an image formed by combining the blue light image BP and the green and red light image GRP, and thus displays images of the background mucosa BM and the deep blood vessels VS2.

[0081] The image storage unit 56 performs image storage processing. Image storage processing is processing for storing images, for example, storing the first image and the second image. The image storage control unit 61 controls the image storage processing. Specifically, when a processing start operation for starting the image storage process is performed, the image storage control unit 61 performs control such that, from a plurality of images acquired during a predetermined period before the processing start operation, for example, a plurality of first images and a plurality of second images, at least one first image and one second image that meet predetermined selection conditions are selected and stored in the image storage unit 56.

[0082] The processing start operation is, for example, a still image acquisition command (freeze command or release command) operation based on the still image acquisition command unit 12f. When the still image acquisition command is input by operating the still image acquisition command unit 12f, the processing start operation is performed, and the image saving process is started. The image saving unit 56 saves the endoscopic images such as the first image and the second image selected by the pre-set selection conditions in the image saving unit 56 or the memory (not shown) under the control of the image saving control unit 61. The memory is an external storage device connected to the processor device 16 via a LAN (Local Area Network) or the like, for example, a file server or NAS (Network Attached Storage) of a system that archives endoscopic images such as a PACS (Picture Archiving and Communication System).

[0083] like Figure 16As shown, the image storage processing performed by the image storage control unit 61 is specifically performed as follows. In the first special observation mode, as the illumination light, during the first period of continuously emitting the first illumination light, the second illumination light is emitted in a cycle of a second illumination light emission period 72 of one frame relative to the first illumination light emission period 71 of five frames, switching with the first illumination light and emitting the second illumination light, and repeating this cycle. The imaging sensor 45 acquires an image signal by accumulating and reading out electric charge for each frame. In addition, in Figure 16 In FIG. 1 , the solid line indicates the acquisition of the first image signal by the imaging sensor 45, and the dashed line indicates the acquisition of the second image signal. The figure is schematic; for example, the storage and readout times are not necessarily the same. As described above, the image signal acquisition unit 51 acquires multiple first images of the observation object illuminated by the first illumination light during period 91, and acquires multiple second images of the observation object illuminated by the second illumination light during period 92.

[0084] When a still image acquisition command 93 is issued, the image storage control unit 61 controls the selection of at least one first image or second image that satisfies a selection condition from the plurality of first images and second images acquired during a predetermined period 94, and stores the selected image in the image storage unit 56. The selection condition can be set in advance, but is set to ensure that the first and second images are stored in a state suitable for comparison or superposition. For example, the image storage control unit 61 preferably sets the selection condition to the first image or second image that exhibits the least blur among the plurality of first images and the plurality of second images acquired.

[0085] As a method for selecting the first image or the second image with the least blur in the first image or the second image, a known method can be used. For example, the amount of blur in each image can be calculated, and the image with the least blur can be selected. As a method for calculating the amount of blur, there are mainly methods based on image analysis and methods based on the camera sensor 45. As a method based on image analysis, there is a method that estimates a point spread function (PSF (Point Spread Function)) for each of multiple areas in the image and estimates the direction and size of the blur with high precision from the point spread function (see Japanese Patent Gazette No. 5499050). In addition, there is a method that detects a motion vector from an image signal and detects the amount of image blur based on the motion vector (see Japanese Patent Laid-Open No. 3-16470). In addition, it is also preferable to use a method that calculates contrast and detects an image with a large contrast as an image with a small amount of blur.

[0086] exist Figure 16In the embodiment, the first image 96 and the second image 95 with the least blur are selected from the plurality of first images and the plurality of second images acquired in the predetermined period 94 in response to the still image acquisition command 93. The first image 96 and the second image 95 selected by the image storage control unit 61 are stored in the image storage unit 56 by the image storage control unit 61. In addition, the image storage unit 56 transmits the image signal sent from the signal processing unit 55 to the display control unit 57 for display in addition to processing the image storage.

[0087] Furthermore, while images acquired by the image signal acquisition unit 51 or stored by the image storage unit 56 include the time of acquisition as accompanying information, it is preferable that the image storage unit 56 store the first and second images while also including information related to the corresponding illumination light. In this case, information about the illumination light or observation mode is preferably also included as accompanying information. Furthermore, identifying information or an identifier such as a tag associated with the illumination light or observation mode may be appended to the image file name. This makes it easy to identify whether the acquired or stored image is the first or second image.

[0088] The display control unit 57 controls the display of images on the display 18, which serves as a display device. For example, in normal observation mode, the display 18 continuously displays normal images as moving images. In special observation mode, the display 18 continuously displays the first or second image as moving images. In multi-observation mode, the display 18 automatically switches between the first and second images and displays them as moving images. Furthermore, when a still image acquisition command 93 is issued, the display 18 displays endoscopic images, such as the first and second images, selected according to the selection conditions, as still images.

[0089] When displaying still images such as the first image and the second image, the display control unit 57 controls the display to adopt a display method set according to the purpose, in addition to displaying them side by side on the display 18, such as adjusting the transmittance of each image and displaying them overlappingly, or switching them in a short time of less than 1 second in the same area of ​​the display 18 to display them like an animation, etc.

[0090] The video signal generating unit 58 converts the normal image, special image, first image and second image stored in the image storage unit 56, and / or information accompanying these images, output from the display control unit 57, into a video signal that can be displayed in full color on the display 18. The converted video signal is input to the display 18. As a result, the normal image, special image, accompanying information, etc. are displayed on the display 18.

[0091] As described above, in the endoscope system 10, the illumination period of the illumination light used for observation is extended. During this illumination period, for example, images are acquired by switching to other illumination lights only for a single instant, such as a single frame. This allows for easy acquisition of multiple images corresponding to various illumination light types. Furthermore, since the illumination light is switched only for a single instant, such as a single frame, and the single illumination light type is continuously emitted, the user is unaware of the illumination switching, minimizing the risk of photosensitivity. Therefore, with this configuration, the endoscope system 10 can save multiple still images in a state suitable for comparison or overlay with a single still image acquisition command 93.

[0092] Furthermore, it is preferable that the image storage control unit 61 selects the first image and the second image with the smallest positional offset among the first image and the second image selected from the plurality of first images or the plurality of second images acquired. Since the positional offset between the selected first image and the second image is small, the first image and the second image can be stored in a state suitable for comparison or superposition.

[0093] As a method for selecting the first and second images with the smallest positional offset, a known method can be used. For example, among methods based on image analysis, there is a method of segmenting the first and second images and comparing the cumulative amount of the Gs1 image signal of the first image and the Gs2 image signal of the second image, which have similar signal characteristics in each region.

[0094] Furthermore, the image storage control unit 61 preferably sets the selection condition to the first image and the second image selected from the plurality of first images and the plurality of second images that have been acquired, wherein the difference in acquisition time is the smallest. The smaller the difference in acquisition time between the selected first image and the second image, the less likely the first image and the second image are to be positionally offset, thereby enabling the first image and the second image to be stored in a state suitable for comparison or superposition.

[0095] like Figure 17 As shown, through Figure 16 When a plurality of first images are acquired during period 91 and a plurality of second images are acquired during period 92 using the same illumination light, imaging sensor 45, and image signal acquisition unit 51, first image 96 and second image 95 acquired at a time close to the still image acquisition command 93 are selected from among the first and second images having the smallest difference in acquisition time. The first image 96 and second image 95 selected by the image storage control unit 61 are stored in the image storage unit 56 by the image storage control unit 61.

[0096] The above selection conditions may be used alone or in combination. For example, when there are multiple combinations of the first image and the second image with the smallest difference in acquisition time, the image with the least blur may be selected.

[0097] In the multi-observation mode, the image storage control unit 61 performs the image storage process as follows: Figure 18 The illumination light is the illumination light in the multi-observation mode. In the figure, the same symbols represent the same parts. Figure 18 In, with Figure 10 The same symbols represent the same parts. The imaging sensor 45 acquires image signals by accumulating and reading out electric charges for each frame. Figure 18 In FIG, the solid line indicates the first image signal acquisition by the imaging sensor 45, and the dotted line indicates the second image signal acquisition. Therefore, the image signal acquisition unit 51 acquires a plurality of first images obtained by capturing the observation object illuminated by the first illumination light during period 91, acquires a plurality of second images obtained by capturing the observation object illuminated by the second illumination light during period 92, acquires a plurality of second images obtained by capturing the observation object illuminated by the second illumination light during period 97, and acquires a plurality of first images obtained by capturing the observation object illuminated by the first illumination light during period 98.

[0098] When a still image acquisition command 93 is issued, the image storage control unit 61 performs control such that at least one first image and one second image satisfying a selection condition are selected from a plurality of first images and second images acquired during a predetermined period 94, and the images are stored in the image storage unit 56. The selection conditions and the like are the same as those in the special observation mode described above.

[0099] As described above, even in the multi-observation mode, the endoscope system 10 can save a plurality of types of still images in a state suitable for comparison or superposition by issuing a single still image acquisition command 93 .

[0100] Alternatively, the display control unit 57 may control the display 18 to continuously display the first image during the first period. During the first period, the second illumination light is emitted in a switching manner from the first illumination light for at least one frame, and the imaging sensor 45 acquires an image signal for each frame, but the first image is continuously displayed on the display 18.

[0101] like Figure 19 As shown, in the first special observation mode, the image signal acquisition unit 51 acquires multiple first images of the observation object illuminated by the first illumination light during period 91, and acquires multiple second images of the observation object illuminated by the second illumination light during period 92. In addition to controlling the display of the acquired first images on the display 18, the display control unit 57, in this embodiment, also controls the display 18 to not display the acquired second images. In this case, the first image before the acquisition of the second image can be displayed continuously while the second image is being acquired. Similarly, the second image is continuously displayed in the second special observation mode.

[0102] In multi-observation mode, such as Figure 20 As shown, the display control unit 57 continuously displays the first image on the display 18 during the first period 75 and continuously displays the second image on the display during the second period 76 .

[0103] As described above, the display control unit 57 controls the display 18 to continuously display the first image during the first period, thereby acquiring an image signal of a mode different from the mode currently being observed while displaying the endoscopic image on the display 18 without flickering. This allows the user to perform observation more stably.

[0104] Then, along Figure 21 The flowchart shown illustrates the series of steps for storing still images. In the first special observation mode, observation is performed in the first special observation mode (step ST110). During observation, the image signal acquisition unit 51 acquires the first image and the second image (step ST120). In this case, the endoscopic image displayed on the display 18 may continuously display the first image, or may switch between the first and second images as the images are acquired.

[0105] If a still image acquisition command is issued ("YES" in step ST130), the still image acquisition command initiates the image storage process. Therefore, during a predetermined period before the still image acquisition command is issued, one first image and one second image, each satisfying a predetermined selection condition, are selected from the plurality of first and second images acquired by the image signal acquisition unit 51 (step ST140). If no still image acquisition command is issued ("NO" in step ST130), observation and acquisition of the first and second images continue. The selected first and second images are stored by the image storage unit 56 (step ST150). The display control unit 57 displays the stored first and second images on the display 18 (step ST160). The display format is a predetermined format, for example, a superimposed display of the two images on the display 18. If observation is terminated ("YES" in step ST170), the series of processes ends. If observation is continued ("NO" in step ST170), observation returns to the first special observation mode.

[0106] In addition, in the above-mentioned embodiment, the present invention is applied to an endoscope system that processes endoscopic images when saving still images. However, the present invention can also be applied to a medical image processing system that processes medical images other than endoscopic images.

[0107] In the above-described embodiment, the hardware configuration of the processor device 16, including the central control unit 62, image signal acquisition unit 51, DSP 52, noise reduction unit 53, memory 54, signal processing unit 55, image storage unit 56, image storage control unit 61, display control unit 57, and video signal generation unit 58, which perform various processing functions, the light source processor 21, and the imaging processor, is composed of various processors as shown below. These various processors include general-purpose processors such as CPUs (Central Processing Units) that execute software (programs) and function as various processing units; processors such as FPGAs (Field Programmable Gate Arrays) whose circuit configuration can be modified after manufacturing, such as programmable logic devices (PLDs); and processors with circuit configurations specifically designed to perform various processing functions, such as dedicated circuits.

[0108] A processing unit may be composed of one of these various processors, or may be composed of a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs, CPUs and FPGAs). Furthermore, multiple processing units may be composed of one processor. As an example of a plurality of processing units being composed of one processor, first, there is a method in which a processor is composed of a combination of one or more CPUs and software, such as represented by a computer such as a client or a server, and the processor functions as multiple processing units. Second, there is a method in which a processor is used to implement the functions of the entire system including multiple processing units by one IC (Integrated Circuit) chip, such as represented by a System On Chip (SoC). In this way, various processing units are composed of one or more of the above-mentioned various processors as a hardware structure.

[0109] Furthermore, more specifically, the hardware structure of these various processors is an electric circuit (circuitry) in which circuit elements such as semiconductor elements are combined.

[0110] Explanation of symbols

[0111] 10-Endoscope system, 12-Endoscope, 12a-Insertion portion, 12b-Operation portion, 12c-Bending portion, 12d-Front end portion, 12e-Angle knob, 12f-Still image acquisition command portion, 12g-Mode switching switch, 12h-Zoom operation portion, 14-Light source device, 16-Processor device, 18-Display, 19-Keyboard, 20-Light source portion, 20a-V-LED, 20b-B-LED, 20c-G-LED, 20d-R-LED, 21-Light source processor, 22-Lighting period setting portion, 30a-Illumination optical system, 30b-Image pickup optical system, 41-Light guide, 42-Illumination lens, 43-Objective lens, 44-Zoom lens, 45-Image pickup sensor, 46-CDS / AGC circuit, 47- A / D converter, 51-image signal acquisition unit, 52-DSP, 53-noise reduction unit, 54-memory, 55-signal processing unit, 56-image storage unit, 57-display control unit, 58-video signal generation unit, 61-image storage control unit, 62-central control unit, 71, 74-first illumination light emission period, 72, 73-second illumination light emission period, 81a, 81b-slide bars, 82a, 82b-slide blocks, 91, 92, 97, 98-period, 93-still image acquisition command, 94-specified period, 95-second image, 96-first image, BM-background mucosa, VS1-superficial blood vessels, VS2-deep blood vessels, VP-purple light image, GRP-green and red light images, ST110~ST200-steps.

Claims

1. An endoscope system comprising: A plurality of semiconductor light sources emit light in different wavelength bands; A processor for a light source is configured to: emitting first illumination light during a first light emission period of the cycle, the first illumination light having a first combination of light intensity ratios among the plurality of semiconductor light sources; and emitting second illumination light during a second light emission period of the cycle, the second illumination light having a second combination of light intensity ratios among the plurality of semiconductor light sources, the second combination of light intensity ratios being different from the first combination of light intensity ratios; and Image processor, The light source processor is further configured to: emit the first illumination light and the second illumination light in each of the first period and the second period; The first period includes a plurality of consecutive cycles. In each of the cycles in the first period, the number of the first light-emitting periods exceeds the number of the second light-emitting periods, so that in the first period, the first illumination light is emitted for a longer duration than the second illumination light. Each cycle in the first period includes at least one first light-emitting period and at least one second light-emitting period. The second period includes a plurality of consecutive cycles, In each of the cycles in the second period, the number of the second light-emitting periods exceeds the number of the first light-emitting periods, so that in the second period, the second illumination light is emitted for a longer duration than the first illumination light. Each of the cycles in the second period includes at least one first light-emitting period and at least one second light-emitting period. The image processor is configured to: During the first period, a plurality of first images are acquired by capturing an observation object illuminated by the first illumination light. During the second period, a plurality of second images are acquired by capturing the observation object illuminated by the second illumination light. performing image storage processing for storing the plurality of first images and the plurality of second images, and At least one first image of the plurality of first images and at least one second image of the plurality of second images that satisfy a preset selection condition are selected and saved.

2. The endoscope system according to claim 1, wherein: The selection condition is set as the first image and the second image with the least blur among the plurality of the first images and the plurality of the second images.

3. The endoscope system according to claim 1 or 2, wherein: The selection condition is set as the first image and the second image having the smallest positional shift among the first image and the second image selected from the plurality of the first images and the plurality of the second images.

4. The endoscope system according to claim 1 or 2, wherein: The selection condition is set as the first image and the second image having the smallest difference in acquisition time among the first image and the second image selected from the plurality of first images and the plurality of second images.

5. The endoscope system according to claim 1, wherein: The image processor causes the at least one first image and / or the at least one second image to be displayed on a display, During the display period, at least the at least one second image is displayed on the display.

6. The endoscope system according to claim 1, wherein: The image processor causes the at least one first image and / or the at least one second image to be displayed on a display, During a display period, at least the at least one first image is displayed on the display.

7. The endoscope system according to claim 1 or 2, wherein: The semiconductor light source includes a first semiconductor light source and a second semiconductor light source, the first semiconductor light source emits a first narrow-band light with a central wavelength of 410±10nm and a wavelength range of 380~420nm, and the second semiconductor light source emits a second narrow-band light with a central wavelength of 450±10nm and a wavelength range of 420~500nm.

8. The endoscope system according to claim 1 or 2, wherein: The image processor stores the at least one first image and the at least one second image after adding information related to the illumination light used.

9. The endoscope system according to claim 1, wherein: The image processor is further configured to: controlling to display the at least one first image and / or the at least one second image on a display, and Control is performed so that only the at least one first image is displayed on the display during the first period.

10. A method for operating an endoscope system, the endoscope system comprising: A plurality of semiconductor light sources emit light in different wavelength bands; A processor for a light source is configured to: emitting first illumination light during a first light emission period of the cycle, the first illumination light having a first combination of light intensity ratios among the plurality of semiconductor light sources; and emitting second illumination light during a second light emission period of the cycle, the second illumination light having a second combination of light intensity ratios among the plurality of semiconductor light sources, the second combination of light intensity ratios being different from the first combination of light intensity ratios; and Image processor, The working method of the endoscope system includes: The light source processor causes the first illumination light and the second illumination light to be emitted in each of the first period and the second period. The first period includes a plurality of consecutive cycles. In each of the cycles in the first period, the number of the first light-emitting periods exceeds the number of the second light-emitting periods, so that in the first period, the first illumination light is emitted for a longer duration than the second illumination light. Each of the cycles in the first period includes at least one first light-emitting period and at least one second light-emitting period. The second period includes a plurality of consecutive cycles, In each of the cycles in the second period, the number of the second light-emitting periods exceeds the number of the first light-emitting periods, so that in the second period, the second illumination light is emitted for a longer duration than the first illumination light. Each of the cycles in the second period includes at least one first light-emitting period and at least one second light-emitting period. The image processor acquires a plurality of first images obtained by capturing an observation object illuminated by the first illumination light during the first period. The image processor acquires a plurality of second images obtained by capturing the observation object illuminated by the second illumination light during the second period. performing image storage processing of storing the plurality of first images and the plurality of second images by the image processor, and At least one first image of the plurality of first images and at least one second image of the plurality of second images that satisfy a preset selection condition are selected and stored by the image processor.

11. The operating method of the endoscope system according to claim 10, wherein: Controlling, by the image processor, to display the at least one first image and / or the at least one second image on a display, and The image processor controls to display only the at least one first image on the display during the first period.

Images