Electronic endoscope processor, electronic endoscope system

Abstract

To allow a part to be emphasized originally to be emphasized appropriately when contour emphasis processing is performed to a captured image while occurrence of a great undershoot is suppressed in a processor for electronic endoscope.SOLUTION: A processor for electronic endoscope acquires a captured image of living tissue and performs image processing. The processor for electronic endoscope has an emphasis operation part 27 for the captured image of the living tissue. The emphasis operation part 27 is provided with: an edge detection part 272 detecting an edge component for each pixel of the captured image of living tissue; an edge component correction part 273 which refers to threshold setting data where threshold of an edge component according to a luminance value is set and corrects an edge component of each pixel detected by the edge detection part 272; and an emphasis processing part 274 which performs contour emphasis processing to the captured image on the basis of the edge component corrected by the edge component correction part 273.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an endoscope processor and an endoscope system that acquire an imaging image of a biological tissue and perform image processing thereon.

Background Art

[0002] An endoscope device is used for observing and treating biological tissues inside the human body. Emphasis processing is performed on an imaging image obtained by imaging a biological tissue using an endoscope device to extract specific elements of the biological tissue and display the processed image on a display.

[0003] For example, Patent Document 1 describes a contour enhancement device that detects edge components of each pixel of an input luminance signal and adds weighting to the detected edge components. In this contour enhancement device, relatively large weighting is added to edge components related to pixels having a middle-level luminance value in the input luminance signal, and relatively small weighting is added to edge components related to pixels having a low-level or high-level luminance value in the input luminance signal, thereby preventing the occurrence of large undershoots (cat's eyes) generated around the contour and appropriately enhancing the contour of the subject.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Generally, since biological tissues to be observed are often covered with mucous membranes, specular reflection is likely to occur, and the imaging image may include whitened portions. In the edge enhancement method described in Patent Document 1, the weighting of high-luminance areas in the image is relatively low, so edge enhancement in high-luminance areas is suppressed. Therefore, although the occurrence of large undershoot in the whitened areas can be prevented, edge enhancement is suppressed even in high-luminance areas other than the whitened areas in the captured image, which leads to the problem of blurred images.

[0006] Therefore, the present invention aims to enable electronic endoscope processors to appropriately enhance areas that should be enhanced while suppressing the occurrence of large undershoots when performing contour enhancement processing on captured images. [Means for solving the problem]

[0007] One aspect of this disclosure is an electronic endoscope processor that acquires and processes images of biological tissue. This electronic endoscope processor is An edge detection unit that detects edge components for each pixel of an image of biological tissue, An edge component correction unit corrects the edge component of each pixel detected by the edge detection unit by referring to threshold setting data in which threshold values ​​for edge components are set according to the brightness value. The system includes an enhancement processing unit that performs contour enhancement processing on the captured image based on the edge components corrected by the edge component correction unit.

[0008] In the threshold setting data mentioned above, the threshold may be set such that the threshold for the edge component increases as the luminance value increases.

[0009] The edge component correction unit may, if the edge component detected by the edge detection unit exceeds the threshold, correct the edge component based on a parameter set to reduce the portion of the edge component that exceeds the threshold. In this case, the parameter is set such that the portion exceeding the threshold is reduced as the intensity of the contour enhancement process increases.

[0010] The electronic endoscope processor preferably includes an intensity changing unit that changes the intensity of the contour enhancement process according to user operation. The edge component correction unit adjusts the parameters based on the changed intensity when the intensity of the contour enhancement process is changed.

[0011] The enhancement processing unit may perform the contour enhancement processing according to a contour enhancement processing method selected from among a plurality of contour enhancement processing methods in response to user operation. In this case, each of the plurality of contour enhancement processing methods is associated with different threshold setting data. The edge component correction unit corrects the edge component by referring to the threshold setting data associated with the selected contour enhancement processing method.

[0012] The enhancement processing unit may perform the contour enhancement processing according to a contour enhancement processing method selected from among a plurality of contour enhancement processing methods in response to user operation. In this case, each of the plurality of contour enhancement processing methods is associated with different parameters. The edge component correction unit corrects the edge component by referring to the parameters associated with the selected contour enhancement processing method.

[0013] The electronic endoscope processor may further include a light source unit that generates either a first illumination light having a first wavelength band, or a second illumination light having a second wavelength band different from the first wavelength band, as illumination light for illuminating the biological tissue. In this case, the first illumination light and the second illumination light are each associated with different threshold setting data. The edge component correction unit corrects the edge component by referring to threshold setting data associated with the illumination light generated by the light source unit, among the first illumination and the second illumination light.

[0014] The processor for the electronic endoscope may further include a light source unit that generates, as illumination light for illuminating the biological tissue, either first illumination light in a first wavelength band or second illumination light in a second wavelength band different from the first wavelength band. In that case, the first illumination light and the second illumination light are each associated with different parameters. The edge component correction unit corrects the edge component by referring to the parameter associated with the illumination light generated by the light source unit among the first illumination and the second illumination light.

[0015] Another aspect of the present disclosure is an endoscope system including the processor for the endoscope and an endoscope connected to the processor for the endoscope and including an image pickup device that images the biological tissue.

Advantages of the Invention

[0016] According to the above-described processor for the electronic endoscope and the electronic endoscope system, when performing contour enhancement processing on the captured image in the processor for the electronic endoscope, it is possible to appropriately enhance the portions that should be originally enhanced while suppressing the occurrence of large undershoots.

Brief Description of the Drawings

[0017] [Figure 1] It is a block diagram showing an example of the configuration of an electronic endoscope system according to an embodiment. [Figure 2] It is a block diagram showing the configuration of an enhancement operation unit that performs edge enhancement of an image signal. [Figure 3] It is a diagram for explaining the processing content of an exemplary edge component correction unit. [Figure 4] It is a diagram showing an example of threshold setting data set in the enhancement operation unit. [Figure 5] It is a flowchart showing the details of the processing of the enhancement operation unit. [Figure 6] It is a diagram showing an image example comparing conventional edge enhancement and edge enhancement according to an embodiment.

Modes for Carrying Out the Invention

[0018] Hereinafter, the electronic endoscope system of the present embodiment will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an example of the configuration of the electronic endoscope system 1 of the present embodiment. As shown in FIG. 1, the electronic endoscope system 1 is a system specialized for medical use, and includes an electronic endoscope (endoscope) 10, a processor 20, and a monitor 30.

[0019] The processor 20 includes a system controller 21. The system controller 21 executes various programs and integrally controls the entire electronic endoscope system 1. Further, the system controller 21 is connected to an operation panel 26. The system controller 21 changes each operation of the electronic endoscope system 1 and parameters for each operation according to an instruction from an operator (observer) input to the operation panel 26. The system controller 21 outputs a clock pulse for adjusting the timing of the operation of each part to each circuit in the electronic endoscope system 1.

[0020] The processor 20 is equipped with a light source device 25 (an example of a light source unit). The light source device 25 emits illumination light L for illuminating subjects such as biological tissues within body cavities. The illumination light L includes white light, pseudo-white light, or special light. According to one embodiment, the light source device 25 preferably selects one of two modes: one in which it constantly emits white light or pseudo-white light as illumination light L, and another in which it alternately emits white light or pseudo-white light and special light as illumination light L, and emits white light, pseudo-white light, or special light based on the selected mode. White light is light having a flat spectral intensity distribution in the visible light band, while pseudo-white light is light whose spectral intensity distribution is not flat and is a mixture of light from multiple wavelength bands. Special light is light in a narrow wavelength band, such as blue or green, within the visible light band. Light in the blue or green wavelength band is used when highlighting and observing specific parts of biological tissue. The illumination light L emitted from the light source device 25 is focused by the focusing lens 29 onto the incident end face of the LCB (Light Carrying Bundle) 11 and then incident into the LCB 11. The light source of the light source device 25 is not limited, but may include, for example, an LED, a laser diode, or a high-brightness lamp (e.g., a xenon lamp, a metal halide lamp, a mercury lamp, or a halogen lamp).

[0021] Illumination light L, incident within the LCB11, propagates through the LCB11. The illumination light L that has propagated through the LCB11 is emitted from the exit end face of the LCB11 located at the tip of the electronic scope 10 and illuminates the subject via the light distribution lens 12. The reflected light from the subject illuminated by the illumination light L from the light distribution lens 12 forms an optical image on the light-receiving surface of the solid-state image sensor 14 via the objective lens 13.

[0022] The solid-state image sensor 14 is, for example, a single-chip color CCD (Charge Coupled Device) image sensor having a Bayer-type pixel arrangement. The solid-state image sensor 14 stores the optical image formed by each pixel on the light-receiving surface as an electric charge corresponding to the amount of light, and generates and outputs R (Red), G (Green), and B (Blue) image signals. Note that the solid-state image sensor 14 is not limited to a CCD image sensor and may be replaced with a CMOS (Complementary Metal Oxide Semiconductor) image sensor or other types of imaging devices. The solid-state image sensor 14 may also be equipped with a complementary color filter.

[0023] A driver signal processing circuit 15 is provided within the connection section of the electronic scope 10. The system controller 21 supplies a clock pulse to the driver signal processing circuit 15. The driver signal processing circuit 15 drives the solid-state image sensor 14 in accordance with the clock pulse supplied by the system controller 21, at a timing synchronized with the frame rate of the video processed on the processor 20 side. The driver signal processing circuit 15 receives an image signal of the subject from the solid-state image sensor 14 at a predetermined frame period. The frame period is, for example, 1 / 60 second or 1 / 30 second. The driver signal processing circuit 15 performs predetermined processing, including A / D conversion, on the image signal input from the solid-state image sensor 14 and outputs it to the image input processing unit 22 of the processor 20.

[0024] The image input processing unit 22 performs predetermined signal processing, such as noise reduction, demosaicing, and matrix calculations, on the image signal sent from the driver signal processing circuit 15. The image memory 23 is a memory that buffers image signals sent from the image input processing unit 22 on a frame-by-frame basis. The image of each frame stored in the image memory 23 is sequentially subjected to edge enhancement processing in the enhancement calculation unit 27 under the control of the system controller 21. Details of the enhancement calculation unit 27 will be described later. The image signal that has undergone edge enhancement processing is output to the image output processing unit 24 according to the timing control of the system controller 21.

[0025] The image output processing unit 24 processes the image signal, which has undergone edge enhancement by the enhancement calculation unit 27, on a frame-by-frame basis to generate screen data for monitor display, and converts the generated screen data for monitor display into a predetermined video format signal. The converted video format signal is output to the monitor 303. As a result, the image of the subject is displayed on the display screen of the monitor 30.

[0026] Next, the configuration of the enhancement calculation unit 27 will be described with reference to Figure 2. In Figure 2, the edge enhancement unit 27 performs edge enhancement processing on the input image I_in (image signal stored in the image memory 23) sent from the system controller 21, and generates an edge-enhanced output image I_out. As shown in Figure 2, the enhancement calculation unit 27 includes a YC separation unit 271, an edge detection unit 272, an edge component correction unit 273, an enhancement processing unit 274, an RGB conversion unit 275, and a memory 276. The input image I_in is an RGB signal. The YC separation unit 271 separates (converts) the RGB signal of the input image I_in into a luminance signal Y and chrominance signals Cb and Cr.

[0027] The edge detection unit 272 detects edge components on a pixel-by-pixel basis from the luminance signal Y obtained in the YC separation unit 271. For edge component detection, known spatial filters such as Laplacian filters or Sobel filters can be used. The edge component correction unit 273 corrects the edge component E detected by the edge detection unit 272. The purpose of correcting the edge component E is to suppress the occurrence of large undershoots while appropriately emphasizing the parts that should be emphasized. When correcting the edge component E, the edge component correction unit 273 accesses threshold setting data. The threshold setting data is stored in memory 276, which is a non-volatile memory. The threshold setting data sets the threshold for the edge component relative to the luminance value indicated by the luminance signal Y.

[0028] In one embodiment, the edge component correction unit 273 refers to threshold setting data and corrects the edge component E of each pixel detected by the edge detection unit 272. For example, the edge component E of each pixel is limited to be less than or equal to a threshold set according to the brightness value of each pixel. Generally, in subjects covered with mucous membranes such as the stomach and large intestine, high-luminosity white areas are generated due to specular reflection from the illumination light. Conventionally, when edge enhancement is applied to these white areas, unnatural enhancement (edge ​​undershoot) where the white areas are outlined in black tends to occur. In contrast, by limiting the edge component E to below a threshold set in advance according to the luminance value, this edge undershoot is less likely to occur.

[0029] The threshold setting data described above is preferably set in such a way that edge undershoot does not occur in the white areas, and that enhancement is not suppressed in areas other than the white areas that are normally observed in the image (e.g., blood vessels). If the edge component E is smaller than the threshold value corresponding to the brightness value, the edge component E is not reduced, and therefore the enhancement performance does not deteriorate. For this reason, it is preferable not to make the threshold too small so as not to deteriorate the enhancement performance of areas other than the white areas that are normally observed.

[0030] The enhancement processing unit 274 combines the luminance signal Y generated by the YC separation unit 271 and the edge component Ec, which is the component in which the edge component E has been corrected by the edge component correction unit 273, to generate a luminance signal Yh that has undergone contour enhancement processing (edge ​​enhancement). In this case, if the intensity of enhancement is to be changed according to the user's operation, the edge component Ec is multiplied by a coefficient that increases as the intensity increases, and then added to the luminance signal Y to generate the enhanced luminance signal Yh. The RGB conversion unit 275 converts the color difference signals Cb and Cr separated by the YC separation unit 271 and the luminance signal Yh obtained by the enhancement processing unit 274 into RGB signals to generate the output image I_out.

[0031] In one embodiment, if the edge component E detected by the edge detection unit 272 exceeds the threshold set by the threshold setting data, the edge component E is corrected by the edge component correction unit 273 based on parameters set to reduce the portion of the edge component E that exceeds the threshold. In other words, since the portion of the edge component E that exceeds the threshold may be a white area, the edge component E of this portion is reduced. Here, the parameters are set so that the greater the intensity of edge enhancement by the spatial filter for edge detection applied in the edge detection unit 272, the greater the portion that exceeds the threshold is reduced.

[0032] Figure 3 shows the processing details of an exemplary edge component correction unit 273 in one embodiment. Figure 3(a) shows an example of the distribution of brightness and edge components for multiple pixels contained in a portion of the input image, as detected by the edge detection unit 272. In Figure 3(a), area A is assumed to be the normal observation target area other than the white area, while areas B and C are assumed to be the white area. Furthermore, consider the case where the threshold shown in Figure 3(b) is set by threshold setting data, in contrast to the example in Figure 3(a). In this case, if the edge component detected for a pixel is below the threshold set according to the brightness value, the edge component is not substantially corrected. On the other hand, if the edge component detected for a pixel is greater than the threshold set according to the brightness value, the edge component is corrected based on parameters set to reduce the portion of the detected edge component that exceeds the threshold. Note that in Figure 3(b), the edge component after reduction is shown by a dotted line. In the example shown in Figure 3(a), area A is not corrected, but areas B and C are corrected so that the portion exceeding the threshold, which is set according to the luminance value, is reduced.

[0033] Here, if we let r be the rate of decrease for the portion exceeding the threshold (where 0 ≤ r < 1), the parameters are set to satisfy the following equation (1). Here, f is a function of the edge enhancement intensity S, and the parameters are set within the function f defined here. r = f(S) ... (1)

[0034] In one embodiment, a function f = α × S is defined. Here, the parameter α is set so that the reduction rate r is a specific value between 0 ≤ r < 1, depending on the edge enhancement intensity S. For example, if the edge enhancement intensity S is set to be variable between 6 levels from 1 to 6, the values ​​of the parameter α for the edge enhancement intensity S are set to 1 / 4, 1 / 8, 1 / 12, 1 / 16, 1 / 20, and 1 / 24, respectively, so that the reduction rate r is set to 0.25 regardless of the edge enhancement intensity S. Note that it is not necessary to keep the reduction rate r constant regardless of the edge enhancement intensity S; the function f may be defined so that the reduction rate r changes according to the edge enhancement intensity S, as long as the reduction rate r is in the range of 0 ≤ r < 1.

[0035] By correcting the edge component E based on parameters set to reduce the portion of the edge component E detected by the edge detection unit 272 that exceeds a threshold, it is possible to suppress edge undershoot in the white areas even when the edge enhancement intensity is increased (i.e., when strong enhancement is applied).

[0036] Furthermore, the function f in equation (1) is not limited to one that uses a parameter that changes linearly with respect to the magnitude of the edge enhancement intensity S, as defined by f = α × S; it may also use a parameter that changes nonlinearly with respect to the magnitude of the edge enhancement intensity S. In addition, the function f of the edge enhancement intensity S may differ depending on whether the edge component is positive or negative.

[0037] In one embodiment, the enhancement calculation unit 27 is configured to allow the edge enhancement intensity to be changed, so that the observer of the monitor 30 can set a desired intensity from among several intensities by operating the operation panel 26. In this case, as described above, the enhancement processing unit 274 adds the luminance signal Y generated by the YC separation unit 271 and an edge component obtained by multiplying the corrected edge component Ec by a coefficient that increases as the intensity increases, to generate the enhanced luminance signal Yh. In other words, the enhancement processing unit 274 functions as an intensity changing unit that changes the edge enhancement intensity according to the user's operation. When the enhancement intensity of the edge enhancement processing is changed, the edge component correction unit 273 adjusts the above parameters based on the changed intensity, thereby enabling edge enhancement to be performed after setting the optimal parameters according to the edge enhancement intensity selected by the user.

[0038] In one embodiment, it is preferable that the threshold setting data is configured such that the threshold for the edge component increases as the luminance value increases. This is because edge undershoot in the white area becomes more noticeable as the luminance value increases, and this configuration helps to suppress it. The example shown in Figure 3(b) illustrates a case where the threshold for the edge component increases linearly with respect to the luminance value, but this is not always the case. Figure 4 shows an example of different threshold setting data. As shown in Figures 4(a) to 4(c), the threshold for the edge component may be set non-linearly with respect to the luminance value, or there may be regions where the threshold with respect to the luminance value is constant. As shown in Figure 3(b), when linearly increasing the threshold for edge components with respect to luminance values, it is preferable to determine the slope based on how much edge component is needed in areas with high luminance values ​​for edge undershoot to be visible in the enhanced image. Note that while Figures 3(b) and 4(a)-(c) show the case where the absolute value of the threshold is equal regardless of whether the edge component is positive or negative, this is not the only case, and the absolute value of the threshold may be changed depending on whether the edge component is positive or negative.

[0039] Next, the operation of the processor 20 in this embodiment will be described with reference to Figure 5. The processor 20 continuously monitors whether the edge enhancement intensity has changed. If the edge enhancement intensity has changed (step S2: YES), it calculates the reduction rate r for reducing the portion of the edge components detected from the input image that exceeds a threshold, based on equation (1) above (step S4). The change in edge enhancement intensity is performed, as described above, for example, based on the operation input to the operation panel 26.

[0040] The processor 20 acquires the image signal (current frame) from the image input processing unit 22 on a frame-by-frame basis (step S6) and stores it in the image memory 23. The enhancement calculation unit 27 performs the processing in steps S8 to S22 on the current frame. The amplification unit 27 of the processor 20 takes each pixel of the current frame as a pixel of interest and performs the processing in steps S8 to S18 for all pixels (step S20: NO). Based on the brightness value of the pixel of interest, the amplification unit 27 calculates a threshold T by referring to threshold setting data (step S8). The amplification unit 27 calculates an edge component E from the brightness values ​​of the pixel of interest and its surrounding pixels (step S10). The amplification unit 27 calculates an edge component D (=ET) of the portion of the edge component E obtained in step S10 that exceeds the threshold T (step S12). Note that the edge component and threshold may be positive or negative as illustrated in Figure 3, but the threshold T and edge component E mentioned in this flowchart are absolute values.

[0041] If D > 0 (step S14: YES), then there is a portion of the edge component E obtained in step S10 that exceeds the threshold T, so the edge component E calculated in step S10 is corrected. Specifically, by calculating Ec = r × D + T using the reduction rate r obtained in step S4, the portion of the edge component E obtained in step S10 that exceeds the threshold T is reduced, and the corrected edge component Ec is calculated (step S16). Then, the enhancement calculation unit 27 adds the corrected edge component Ec to the brightness value of the pixel of interest and calculates the pixel value (RGB value) of the pixel of interest (step S18). This gives the enhanced pixel value of the pixel of interest.

[0042] If processing is completed for all pixels of the current frame (step S20: YES), the processor 20 converts the edge-enhanced image of the current frame into a video format signal and displays the image on the monitor 30 (step S22). If processing is not complete (step S24: NO), the processor 20 returns to step S2 to process the next frame.

[0043] As described above, according to the electronic endoscope system 1 of this embodiment, edge components are detected for each pixel of the image of biological tissue, and the edge components of each detected pixel are corrected by referring to threshold setting data in which a threshold for the edge component corresponding to the brightness value is set. Furthermore, edge enhancement processing is applied to each pixel based on the corrected edge components. Therefore, by limiting the edge component E to below a threshold set in advance according to the brightness value, unnatural enhancement (edge ​​undershoot) where white areas are bordered with black is less likely to occur in the image displayed on the monitor 30. Preferably, if the detected edge component exceeds the threshold indicated by the threshold setting data, the edge component is corrected based on a parameter set to reduce the portion of the edge component that exceeds the threshold. In this case, the parameter is set so that the greater the intensity of the edge enhancement process, the greater the reduction of the portion that exceeds the threshold. This suppresses the occurrence of large undershoots while appropriately enhancing the parts that should be emphasized.

[0044] Referring to Figure 6, the following are shown: an image of an exemplary biological tissue before enhancement (original image), an image obtained by applying edge enhancement to the original image using a conventional edge enhancement method (conventional method), and an image obtained by applying edge enhancement to the original image using the edge enhancement method of this embodiment (example). As shown in the original image, when imaging biological tissue, specular reflection from the illumination light on the mucous membrane covering the subject, such as the stomach or large intestine, generates not only the blood vessel portion (BV) but also a high-brightness white area (W). When edge enhancement is applied to this white area (W) using conventional methods, an unnatural enhancement (edge ​​undershoot) occurs where the white area is outlined in black, and the blood vessel portion (BV) is not sufficiently enhanced and becomes blurred. In contrast, in the example, the edge undershoot is suppressed to an unnoticeable degree, and the blood vessel portion (BV) is appropriately emphasized, making it easier to observe.

[0045] In one embodiment, the edge enhancement calculation unit 27 performs edge enhancement processing according to an edge enhancement processing method selected from among multiple edge enhancement processing methods in response to user operation. In this case, each of the multiple edge enhancement processing methods is associated with different threshold setting data. The edge component correction unit 273 corrects the edge component E by referring to the threshold setting data associated with the selected edge enhancement processing method. This allows the observer to switch edge enhancement processing methods such as spatial filters by inputting to the operation panel 26 according to their purpose and preference, enabling flexible operation tailored to the observer. For example, multiple spatial filters may be provided for edge enhancement. Some of these may be specialized for enhancing high-frequency parts of the captured image, while others may be specialized for enhancing low-frequency parts. In this case, when the applied spatial filter is switched, the corresponding threshold setting data and the parameters or function f (see Equation (1)) used to calculate the reduction rate r are changed. Such modification processes are performed at steps S2 to S4 in the flowchart of Figure 5.

[0046] In one embodiment, the light source device 25 generates either a first illumination light having a first wavelength band, or a second illumination light having a second wavelength band different from the first wavelength band. The first and second illumination lights are not limited to each other as long as they have different spectra, but as an example, the first illumination light is normal light (white light or pseudo-white light), and the second illumination light is special light (light with a narrower wavelength band than the wavelength band of normal light). Observation images obtained with special light can be different from observation images obtained with normal light, depending on the absorption characteristics of the biological tissue, so it is possible to highlight and observe certain characteristic parts of the biological tissue, making it easier to find lesions and other parts of the biological tissue. Since the images obtained with the first illumination light and the second illumination light are different, it is preferable that threshold setting data be associated with each illumination light. The edge component correction unit 273 corrects the edge component E by referring to the threshold setting data associated with the illumination light generated by the light source device 25, which is one of the first illumination or the second illumination light. This makes it possible to set an appropriate threshold according to the illumination light. In this case, it is preferable to change the parameter or function f (see equation (1)) used to calculate the reduction rate r according to the illumination light. In this case, the referenced threshold setting data, parameter or function f is changed according to the observer's input to the operation panel 26 for selecting either the first illumination light or the second illumination light. Such modification processing is performed at the points corresponding to steps S2 to S4 in the flowchart of Figure 5.

[0047] In one embodiment, multiple edge enhancement processing methods are provided in the enhancement calculation unit 27, and the light source device 25 is configured to emit multiple illumination lights of different spectra. Depending on the observer's operation, an edge enhancement processing method (spatial filter) and illumination light are selected. In this case, it is preferable that threshold setting data, parameters, or functions f to be applied are set for all combinations of spatial filter and illumination light.

[0048] Although the electronic endoscope processor and electronic endoscope system of the present invention have been described in detail above, the electronic endoscope processor and electronic endoscope system of the present invention are not limited to the above embodiments, and various improvements and modifications may be made without departing from the spirit of the present invention. [Explanation of Symbols]

[0049] 1… Electronic Endoscope System 10…Electronic scope 11…LCB 12…Light distribution lens 13…Objective lens 14… Solid-state image sensor 15…Driver signal processing circuit 20… Processor 21... System Controller 22…Image Input Processing Unit 23…Image memory 24…Image output processing unit 25...Light source device 26…Control Panel 27...emphasis calculation section 271...YC separation section 272... Edge detection unit 273... Edge component correction section 274…Emphasis processing unit 275...RGB conversion unit 276...memory 29… Focusing lens 30…Monitor

Claims

1. An electronic endoscope processor that acquires images of biological tissue and performs image processing, An edge detection unit that detects edge components for each pixel of an image of biological tissue, An edge component correction unit corrects the edge component of each pixel detected by the edge detection unit by referring to threshold setting data in which threshold values ​​for edge components are set according to the brightness value. The system includes an enhancement processing unit that performs contour enhancement processing on the captured image based on the edge components corrected by the edge component correction unit, The edge component correction unit corrects the edge component based on a parameter set to reduce the portion of the edge component that exceeds the threshold if the edge component detected by the edge detection unit exceeds the threshold. The parameters are set such that the greater the intensity of the contour enhancement process, the lower the portion exceeding the threshold. Processor for electronic endoscopes.

2. In the aforementioned threshold setting data, the threshold is set such that the threshold for the edge component increases as the brightness value increases. The electronic endoscope processor according to claim 1.

3. The system includes an intensity adjustment unit that changes the intensity of the contour enhancement process according to user operations, The edge component correction unit adjusts the parameters based on the changed intensity when the intensity of the contour enhancement process is changed. The electronic endoscope processor according to claim 1.

4. An electronic endoscope processor for acquiring and processing images of biological tissue, An edge detection unit that detects edge components for each pixel of an image of biological tissue, An edge component correction unit corrects the edge component of each pixel detected by the edge detection unit by referring to threshold setting data in which threshold values ​​for edge components are set according to the brightness value. The system includes an enhancement processing unit that performs contour enhancement processing on the captured image based on the edge components corrected by the edge component correction unit, The enhancement processing unit performs the contour enhancement processing according to the contour enhancement processing method selected from among a plurality of contour enhancement processing methods in response to user operation. Each of the aforementioned multiple contour enhancement processing methods is associated with different threshold setting data. The edge component correction unit corrects the edge component by referring to the threshold setting data associated with the selected contour enhancement processing method. Processor for electronic endoscopes.

5. The threshold setting data is set such that the threshold for the edge component increases as the brightness value increases. The electronic endoscope processor according to claim 4.

6. The enhancement processing unit performs the contour enhancement processing according to the contour enhancement processing method selected from among a plurality of contour enhancement processing methods in response to user operation. Each of the aforementioned multiple contour enhancement processing methods is associated with a different parameter. The edge component correction unit corrects the edge component by referring to the parameters associated with the selected contour enhancement processing method. The electronic endoscope processor according to claim 1.

7. An electronic endoscope processor for acquiring and processing images of biological tissue, An edge detection unit that detects edge components for each pixel of an image of biological tissue, An edge component correction unit corrects the edge component of each pixel detected by the edge detection unit by referring to threshold setting data in which threshold values ​​for edge components are set according to the brightness value. The system includes an enhancement processing unit that performs contour enhancement processing on the captured image based on the edge components corrected by the edge component correction unit, The system further includes a light source that generates either a first illumination light having a first wavelength band, or a second illumination light having a second wavelength band different from the first wavelength band, as illumination light for illuminating the biological tissue. The first illumination light and the second illumination light are each associated with different threshold setting data. The edge component correction unit corrects the edge component by referring to threshold setting data associated with the illumination light generated by the light source unit, among the first illumination light and the second illumination light. Processor for electronic endoscopes.

8. The system further includes a light source that generates either a first illumination light having a first wavelength band, or a second illumination light having a second wavelength band different from the first wavelength band, as illumination light for illuminating the biological tissue. The first illumination light and the second illumination light are associated with different parameters, The edge component correction unit corrects the edge component by referring to parameters associated with the illumination light generated by the light source unit, among the first illumination light and the second illumination light. The electronic endoscope processor according to claim 1.

9. An endoscope processor according to any one of claims 1 to 8, An endoscope system comprising: an endoscope connected to the endoscope processor and equipped with an image sensor for imaging biological tissue.

Images