JPH08191440A - Method and device for correcting endoscope image - Google Patents

Abstract

PURPOSE: To display a sharp endoscope image resulting from correction and replacement into image data with uniform sensitivity and color tone when an image guide is inserted into a coronary artery of a human body to observe and diagnose a disease part and to attain reproduction and display of a transient phenomenon by mounting a recording and reproducing function for compressed digital image data. CONSTITUTION: An image processing section 200 is provided with a coordinate, sensitivity and color tone correction table reading data at a high speed and data to correct the transmission characteristic of an image guide of an endoscoping catheter are registered to the sensitivity and color tone correction table in advance. In the case of lumen endoscopy observation and diagnosis, data in the correction table are directly read synchronously with an output video signal from a video camera. Thus, a sharp endoscopic image in which uneven color tone and sensitivity for each picture element specific to the image guide is corrected is displayed, recorded and reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscopic image correction method and apparatus, for example, an endoscopic image correction method and apparatus for correcting brightness and color tone of each pixel and displaying a bright and clear lumen image with high resolution. It is about.

[0002]

2. Description of the Related Art Conventionally, in order to observe an intravascular affected area by inserting an image fiber catheter for endoscopic use into the affected area such as a blood vessel percutaneously or transtubally, as shown in FIG. The connector of the image guide 1 of the diameter image fiber catheter is connected to the eyepiece 2 attached to the small video camera (video camera) 4. Then, an image from the catheter is taken by the video camera 4 via the image guide 1 and the eyepiece 2. The output of the captured video signal (video signal) was connected to the monitor 6 capable of color display to observe and diagnose the enlarged image.

That is, a blood vessel lumen image on the eyepiece end surface of the image guide 1 is microscopically magnified by the eyepiece 2 and photographed by the video camera 4, and the photographed video signal output from the video camera 4 is input to the monitor 6. Then, the enlarged image is enlarged and displayed on the display screen of the monitor 6.

[0004]

However, as is well known, in the conventional optical fiber constituting the image guide, a portion called "core" for transmitting light and a portion called "clad" for not transmitting light are used. It is configured. (1) Therefore, a mesh pattern is generated in the conventional blood vessel lumen image on the connection end face of the image guide. However, the pixel arrangement of the mesh pattern and the arrangement of the image pickup elements of the video camera generally do not correspond to each other, and moire fringes are generated in the endoscopic image displayed on the monitor screen.

Therefore, when shooting with a video camera, the focus is shifted or the optical low-pass filter is provided to reduce moire fringes. (2) However, according to such a method, the resolution is impaired, and a clear photographed image cannot be obtained. For this reason, as shown in FIG. 13, as a countermeasure against the decrease in imaging sensitivity and resolution due to the reduction in diameter, a mesh pattern removal processing unit 26 that further processes an image captured by the video camera 24 is provided, and this mesh pattern is formed. The removal processing unit 26 is selectively connectable, and the video signal output of the high-resolution video camera 24 equipped with the high-magnification eyepiece 22 is sent to the mesh pattern removal processing unit 26, where the image of the endovascular catheter 18 is imaged. The brightest point of each pixel forming the guide, that is, the spire value is sampled, two-dimensional extension interpolation processing is performed between adjacent pixels, the processed video signal is output and input to the display monitor 30, and the photographing sensitivity and A system for performing real-time retinal pattern removal processing that displays a bright image without a mesh pattern without losing resolution has also been adopted.

In this image improvement processing method, when the image guide is photographed using an endoscopic catheter having a diameter extremely reduced, the brightness and uneven color tone due to the difference in transmission characteristics of the individual wires of the image guide are emphasized, Observation of the lesion site was a problem in diagnosis. An object of the present invention is to correct the brightness and color tone variations of each pixel in the image improvement processing method to display a bright and clear endoscopic image without a mesh pattern.

[0007]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and a correction is performed to make the variations in the brightness and color tone of each pixel in the above-mentioned image improvement processing method uniform, and a mesh pattern is obtained. It is an object of the present invention to provide a real-time endoscopic image correction process capable of displaying a bright and clear endoscopic image without any problem, and to provide a means for solving the above problem by being mounted on the angioscopic apparatus.

And, as one means for solving the above problems,
For example, the following configuration is provided. That is, each fiber of the image guide in the endoscopic image obtained by photographing the subject image transmitted through the image guide, which is transmitted through the image guide composed of a plurality of fusion-bonded fibers incorporated in the endoscope, An endoscopic image correction device that corrects and reduces differences in brightness and color tone for each pixel based on differences in transmission characteristics, and a white image holding unit that stores and holds an image obtained by photographing a white subject by the image guide. A coordinate data registration means for extracting the center coordinates of the core of each fiber forming the image guide from the image held by the white image holding means and registering it with the coordinate information for each fiber, and registering it in the coordinate data registration means The average value of the brightness of each color of the captured image data held by the white image holding means at the coordinate position is calculated, and the difference from the average value of each color calculated for each pixel is calculated. Calculating means, a correction data registering means for generating correction data for eliminating a difference between the average value calculated by the calculating means and registering the correction data for each color, and an input image to be processed photographed by the imaging means, A replacement unit that replaces the input image so as to eliminate the difference in color tone of each pixel at each coordinate position registered in the coordinate data registration unit according to the correction data registered by the correction data registration unit. It is characterized by being provided.

[0009]

With the above construction, the angioscopic apparatus which corrects the sensitivity and color tone accurately, corrects the brightness and the garbled color at the same time, and displays a clear lumen image with reduced moire fringes. Can be provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an overall view showing the configuration of an embodiment according to the present invention. In FIG. 1, reference numeral 1
Reference numeral 0 is an image guide, 11 is a light guide, and the image guide 10 and the light guide 11 constitute a catheter for an endoscopic blood vessel, a part of which is percutaneously inserted into a blood vessel of a patient. The blood vessel lumen image S10A transmitted through the inside 10 is connected to the eyepiece end surface. Reference numeral 12 is a light source that is an illumination light source that connects the light guide 11 to illuminate the inside of the blood vessel.

Reference numeral 13 is an eyepiece, and the eyepiece 13
Is attached to the high-resolution video camera 14, has an insertion coupling portion for connecting to the eyepiece surface of the image guide 10, has a focus adjusting function and a center axis fine movement adjusting function, and has a microscope at the center of the image sensor surface of the video camera 14. The endoscopic image S14A is formed in an appropriate size for enlargement and interpolation embedding processing (real-time mesh pattern removal processing) based on the peak value.

Reference numeral 14 designates a high resolution video camera which has an image pickup device therein and converts the above-mentioned internal image S14A into a video signal S1, 200 is an image processing section, 300 is a circulating image memory, 400 is an optical disk device, and 500 is remote. The controller 600 is a color monitor. Image processing unit 20
The detailed configuration of 0 is shown in FIG. As shown in FIG. 2, the video signal S1 from the high-resolution video camera 14 is input, and the sensitivity and color tone correcting means 220 corrects the variations in sensitivity and color tone due to the transmission characteristics of each pixel forming the image guide. The interpolation means 230 performs interpolation embedding processing between adjacent pixels, the smoothing means 240 removes edge components (quantization noise) generated by the interpolation processing, and outputs a smoothed video signal to the color monitor 600. The video signal is processed in real time so as to display a sharpened lumen image.

The control circuit 210 is a part which controls the image processing section 200 of the present embodiment and is constituted by, for example, a microprocessor, and performs processing such as preparation of a correction table for correcting the transmission characteristics of each pixel. The sensitivity / color tone correction unit 220 is composed of a non-volatile memory protected by an auxiliary power source (battery or the like) so that registered data is not lost due to a momentary power failure or the like.

The IF 250 stores the color-corrected data,
This is an interface for performing data communication with the circulating image memory 300 for reproduction and the optical disc device. FIG. 3 shows a detailed configuration example of the sensitivity / color tone correcting means 220 shown in FIG. 2 in the present embodiment. Sensitivity and color tone correction means 2 shown in FIG.
20a is characterized in that variations in transmission characteristics for each pixel forming the image guide 10 are processed by a digital correction table created by the control circuit 210a.

That is, in the endoscope apparatus for performing the image processing described above according to the present embodiment, first, the white object is photographed when the apparatus is activated, the photographed video signal is converted into a corresponding digital signal, and the signal is once converted. A process of storing in the frame memory 222, measuring the transmission characteristic of the image guide 10 by the control circuit 210a, generating correction data (replacement data) for correcting the measured transmission characteristic, and registering it in the sensitivity / color tone correction table 223b. I do. By performing the above-mentioned processing, the sensitivity and color tone can be easily corrected by simply referring to the above-mentioned table with respect to the imaged data from the subject thereafter, and the processing can be performed in real time. It should be noted that each of the above configurations can be configured by, for example, a microprocessor, and by configuring by the microprocessor, the hardware structure can be simplified, and even if the specification is changed, it can be easily dealt with.

In FIG. 3, S1r, S1g and S1b which are inputs to the A / D converter 221 are a red component, a green component and a blue component in the output video signal S1 of the video camera 14. 222 is a frame memory with a cumulative calculation function, 2
Reference numeral 23a is a sensitivity / color tone correction circuit, 224 is a core coordinate memory, and 210a is a control circuit. For example, a lumen image or the like transmitted by the image guide 10 and photographed by the high-resolution video camera 14 is caused by variations in transmission characteristics for each pixel.
As shown in FIG. 4A, the video signals S1r, S1g, and S1b having different amplitudes, which are sent to each pixel, are respectively A / D-converted.
221 is input. Then, the A / D 221 converts the input video signal into a parallel binary code which is a corresponding digital signal at high speed.

The video signal converted into a digital code by the A / D 221 is temporarily stored in the frame memory 222 with a cumulative calculation function. Then, the core coordinate memory 224
In accordance with the control signal output from the above, data corresponding to the center of the core of each fiber forming the image guide indicated by + in FIG. 4A is extracted, and the sensitivity / color tone correction circuit 223a has a built-in sensitivity / sensitivity correction circuit 223a. Color tone correction table 22
The data registered in 3b is selected, and the data in which the sensitivity and color tone are corrected for each pixel is output as shown in FIG. 4B.

The control circuit 210a is a video camera
The peaks corresponding to the centers of the pixels constituting the image guide photographed in Step 1 are detected, the detected peaks are numbered in the order of detection as shown in FIG. 5, and the coordinates on the frame are stored in the core coordinate memory 224a. to register. Further, the control circuit 210a performs the calculation processing of the average value of the brightness for all the pixels detected as described above, the calculation processing of the relative transmission rate of each pixel with respect to the calculated average value of the brightness, and the above-described processing. Sensitivity and color tone, a calculation process of sensitivity and color tone correction constants unique to each pixel corresponding to the number assigned to each pixel is executed, and the sensitivity / color tone correction table 223b in the sensitivity and color tone correction circuit 223a is executed based on the processing result. Register the data in.

The control circuit 210a of the present embodiment having the above-described configuration detects the center coordinates of pixels in the endoscopic image and registers it in the coordinate memory 224a, and the correction data registration process in the sensitivity / color tone correction table 223b. Explained. First, when the power of the apparatus is turned on or when a catheter is attached, a white subject (for example, sterilized gauze) is imaged through the image guide 10 and the eyepiece 13.
It is assumed that the image is taken in 4. Then, a white balance correction switch provided in a device (not shown) is operated and input. As a result, the following series of registration processes are transiently performed by using the sensitivity / color tone correcting means 220a provided in the image processing unit 200. In this process, in order to eliminate unevenness in sensitivity due to the shadow of the subject, images for a fixed time (for example, several seconds) are stored in the cumulative calculation frame memory 222 and are averaged by the camera shake effect.

That is, a white subject (eg, sterile gauze)
Is photographed by the video camera 14 for a certain period of time and is temporarily stored in the frame memory 222 in the sensitivity / color tone correcting means 220a. Then, the control circuit 210a (transmission characteristic measuring means) detects the brightest point of each pixel forming the image guide 10 and obtains the position coordinates and the image data value at the sampled brightest point. The obtained coordinate data is registered in the core coordinate memory 224a.

Then, the average of the green (G) values is obtained from the sampled image data of each pixel. And
The sensitivity ratio is calculated for each pixel with respect to the calculated average value (Gh) of the brightness of green (G), and the green correction output at each sampling point for each step from the minimum input level to the maximum input level. The data value is the average value (Gh (0 to 0
255)) is calculated and registered in the sensitivity / color tone correction memory (sensitivity / color tone correction table G) for each sampling point.

Also for red (R) and blue (B) components, the ratio of brightness to the average brightness (Gh) of green (G) is obtained for each pixel, and the minimum input level is calculated. As shown in FIG. 4B, for each step up to the maximum input level, a correction value that is equal to the green correction output data value at each sampling point is calculated, and the sensitivity / color tone correction memory for each sampling point is calculated. (Sensitivity / color tone correction tables R and B).

When attempting to correct a photographed image using the correction data registered in the sensitivity / color tone correction table 223b, the video camera 1 which has photographed the actual lumen image.
The video signal output of No. 4 is converted into a corresponding digital video signal by the A / D 221, and the digital video signal output is temporarily stored in the frame memory 222 and then read out.
Input to the sensitivity / color tone correction circuit 223a. Control circuit 21
By simultaneously inputting this input data value to the address from 0a, for example, the address storing the correction data corresponding to each input level at each sampling point is selected, and the correction data corrected corresponding to the input level is read. It is possible to output the corrected image data having the uniform brightness and accurate color tone for each pixel.

The data corrected so that the sensitivity and color tone are substantially uniform are two-dimensionally interpolated and embedded by the interpolating means 230 as will be described later, and the digital data having the mosaic pattern including the edge component by the interpolating processing. The video signal output is an analog video signal from which high-frequency components and flicker noise have been reduced and removed by the smoothing means 240 to correct the sensitivity and color tone, and the video signal smoothed by interpolating between pixels is input to the monitor. And a clear lumen image can be displayed.

Details of the interpolation means 230 of the image processing unit 200 shown in FIG. 2 will be described below with reference to FIGS. 6 and 7. As shown in FIG. 4 (B), the output of the sensitivity / color tone correcting means 220 is the data that matches the number of pixels in one screen obtained by sampling the brightest point corresponding to the center of each pixel forming the image guide 10. As a result, a bright lumen image cannot be displayed on the monitor screen as it is. Therefore, in the present embodiment, as shown in FIG. 7, the interpolation means 230 shown in FIG. 6 interpolates between two-dimensionally adjacent pixels to enhance brightness.

The interpolation means 230 shown in FIG.
1, H timer 232, AND gate 233, line memory 234, and timer 235. Hereinafter, a specific description will be given. The latch 231 is a sensitivity / color tone correction unit 2
It is a circuit that holds the output data of 20 for a certain period of time (approximately the scanning time for scanning between pixels) and interpolates in the horizontal direction. H
The timer 232 is a timer for inputting a control signal to the AND gate 233 and inputting image data (black level) to the line memory 234 so as to prevent tailing beyond the pixel interval in the horizontal direction. The line memory 234 is a memory that repeatedly reads out data in synchronization with the horizontal sync signal of the video camera 14 and outputs data interpolated in the vertical direction.

The V timer array 235 has an AND gate 23 to prevent tailing beyond the pixel interval in the vertical direction.
3 is a timer group for inputting a control signal to 3 and inputting image data (black level) to the line memory 234. The detailed structure of the smoothing means 240 shown in FIG. 2 is shown in FIG. Below, FIG.
The smoothing means 240 of this embodiment will be described with reference to FIG. The smoothing means 240 of this embodiment shown in FIG. 8 reduces and removes the mosaic pattern emphasized by the interpolation means 230 and the flicker noise generated by the peak extraction.

The interpolation means 230 shown in FIG.
241, adder circuit B242, field memory 243,
The D / A 245 and the control circuit 246 control the flicker noise reduction effect (low-pass filter) with respect to the time axis by the 241 addition circuit A, the addition circuit B, and the subtraction circuit 244. The field memory 243 is an image memory that delays data for one screen (field). D /
A 245 is a circuit that inputs the digital image data output from the field memory 243 and outputs a video signal converted into an analog video signal. The control circuit 246 is
The field memory 2 is a circuit for generating a control signal for effectively controlling the smoothing process by the smoothing means 240.
The two-dimensional smoothing process is controlled by repeating the writing and reading timings of the data to and from 43 with a fixed period with respect to the horizontal and vertical synchronizing signals, and
This is a circuit that controls the three-dimensional smoothing process by controlling the offset data added to the adder circuit 241 and the subtraction circuit 244.

The IF 250 shown in FIG.
0 is a connection circuit for controlling data communication with the optical disk device 400. In addition, the circulation image memory 300 stores the screen data obtained by sampling the brightest point located at the center of each pixel forming the image guide into the image processing unit 2.
The unit image data is read out through the IF 250 of 00, and the RGB data is recorded for each pixel number. Therefore, about 1/100 of the compression is applied to the general image storage method. Normally, data is recorded endlessly, and blood is injected into the intravascular observation site after injecting a clear liquid that eliminates blood that fills the blood vessel during observation and diagnosis of the blood vessel lumen. The IC memory device is capable of repeatedly observing the blood vessel lumen image for a certain period of time by switching control to the hold state immediately before refilling, and also capable of still display by selecting an appropriate time point.

Data storage and read operations to and from the circulating image memory 300 are instructed to the control circuit 210 via the remote controller 500. Circular image memory 30
0 is synchronously controlled with the video signal of the video camera 14,
The read data is input to the interpolation circuit 230 to form an image, and the reproduced image can be displayed on the color monitor 600. The optical disc device 400 is a device that stores compressed image data in a nonvolatile magneto-optical disc, similar to the circulating image memory 300. The data to be recorded in the device is not only image data but also at least the ID code and the pixel number and its coordinate data extracted from the video signal captured by the video camera 14 by enlarging the end face image of the image guide.

Optical disc device 400 and image processing unit 200
Data is exchanged with the interface via a dedicated interface.
-II Controls by installing a communication control circuit. The remote controller 500 is a communication control device having a keyboard with a display function capable of controlling the operation of the optical disc device 400. Wired / wireless is used as a transmission medium for transmitting control signals from the remote controller 500 to the optical disc device. Any medium may be used, for example, modulated infrared light is emitted and transmitted by being detected by a light receiving sensor provided in the endoscope apparatus main body, and a control signal from the remote controller 500 or the like. Based on the above, processing for controlling the optical disk device 400 is performed by the control circuit 210.

The color monitor 600 includes the image processing apparatus 20.
This is a device for displaying an endoscopic image by inputting an analog video signal that has been sharpened by image processing output from the D / A circuit 245 of 0. The flow of processing in the above configuration will be described below in order. The control circuit 210a is
First, the photographing data stored in the frame memory 222 is read out and the peak value for each pixel is calculated. Regarding the video signal output S1 of the video camera 14, the separated outputs for the red, green and blue components are S1r, S1g, S1b,
The peak value of each pixel extracted by the control circuit 210 is S1.
If px [number 0 to n] and its average value are Yp, the relative transmission rate yx of each pixel is separated into each color component of yg, yr, and yb, and the reference of the relative transmission rate of each pixel is obtained by the following calculation formula. The average value Yp of the sensitivities is obtained.

[0033]

## EQU1 ## Yp = S1pg.SIGMA. [Number 0 to n] / N However, the number of pixels N is calculated by n + 1. The relative transfer rates Yg, Yr, and Yb related to the sensitivity and color tone of each pixel [number 1 to n] are yg [number 1 to n] = S1pg [number 1 to n] / Yp yr [number 1 to n] = yg [Number 1-n], S1pr [Number 1-n]
/ S1pg [number 1 to n] yb [number 1 to n] = yg [number 1 to n] and S1pg [number 1 to n]
/ S1pg [number 1 to n]. When applying this relative transmission rate to the configuration of FIG.
A sensitivity / color tone correction table 223b that produces the following composition output is created. The formula for creating the table is shown below. Video signal S1p extracted from the brightest point of each pixel
Correction output Ycg, Y in which x is input to correct the sensitivity color tone
cr and Ycb are Ycg [number 1 to n] [0 to 255] = S1pg [number 1 to n] [number 0]
~ 255] / ypg [number 1 to n] Ycr [number 1 to n] [0 to 255] = S1pr [number 1 to n] [number 0]
~ 255] / ypr [number 1-n] Ycb [number 1-n] [0-255] = S1pb [number 1-n] [number 0]
~ 255] / ypb [Number 1-n] where the numbers 1-n in [] in the above calculation formula are pixel numbers assigned to each pixel, and 0-255 are all video analog input signals on the 255th floor. This is an example of the case where the tone is quantized and converted into an 8-bit digital code.

Therefore, the registration process in the control circuit 210a of the first embodiment is executed, for example, in the following procedure. Start → Mode setting (white balance) → Image storage (frame memory) → Peak detection (polar coordinate reading, numbering, coordinate memory writing) → Brightness average value calculation → Relative transmission rate calculation (pixel numbers 0 to N /
R, G, B) → Sensitivity, color tone correction constant calculation / correction table registration (pixel number 0 to N / R (0 to 255), G (0
~ 255), B (0-255),) → end of setting mode As described above, according to the present embodiment, an endoscope apparatus with a color tone correction processing function using an extra-fine diameter image guide, particularly a coronary lesion site, is used. In order to enhance patient safety and catheter operability when observing and treating the lumen by enlarging it on a color monitor, we used an endoscopic catheter composed of an image guide that was extremely thin. Then, the brightest point corresponding to the central portion of the strand of each fiber constituting the image guide is sampled to obtain the average value of all pixels, and the correction calculation is performed based on the sensitivity difference with respect to the average value for each pixel. In addition to the sensitivity, the tone correction also calculates the correction difference so that the sensitivity difference between the green color data, the red color data and the blue color data becomes equal and registers it in the correction memory. Yo When observing the lumen, by directly reading the correction data registered in the correction memory according to the video signal level, the image data in which the sensitivity and color tone of each pixel have been corrected is output, and the distance between each adjacent pixel is further increased. By inputting the video signal output subjected to the interpolation processing to the color monitor by the interpolation processing means for performing the two-dimensional interpolation processing, the brightness and the color tone are corrected for each pixel, and the video with a high resolution and a bright and clear lumen image is displayed. An endoscopic device can be provided.

[Second Embodiment] In the second embodiment, the structure of the sensitivity / color tone correcting means in the above-mentioned first embodiment is different, and instead of the structure of the first embodiment shown in FIG. 3, FIG. It has the configuration shown in. In the second embodiment, the analog multiplication circuit 226 is used as compared with the case where the variation in the transmission characteristics of each pixel forming the image guide of the first embodiment is processed by the sensitivity / color tone correction table 223b which is a digital correction table. It is characterized by processing by.

Also in the second embodiment, reference symbols S1r,
S1g and S1b are a red component, a green component, and a blue component of the output video signal S1 of the video camera 14, respectively. In the first embodiment, the sensitivity / color tone correction circuit 22
3a is provided with the sensitivity / color tone correction table 223b. However, in the second embodiment, this sensitivity / color tone correction circuit is omitted and the multiplication circuit 226 is provided instead, so that the sensitivity / color tone correction table of the first embodiment is provided. The correction table 223b is provided in the core coordinate memory 224b together with the core coordinate data. This sensitivity / color tone correction table 223b is
Basically, it is similar to that of the first embodiment, and the correction data is registered by the control circuit 210b in the same manner as in the first embodiment.

The processing of detecting the center coordinates of the pixels in the endoscopic image, registering them in the core coordinate memory 224b, and registering data in the sensitivity / color tone correction table 223b are performed when the power of the apparatus is turned on or when the catheter is attached. By photographing the subject and operating the white balance correction switch, a series of registration processes are performed transiently in the same manner as in the first embodiment described above.

The sensitivity / color tone correcting means 220b shown in FIG. 9 of the second embodiment will be described below with reference to FIGS. In FIG. 9, FIG. 3 of the first embodiment described above.
The same components as those shown in FIG. In FIG. 9, 226 is a high-speed analog multiplication circuit provided in a signal processing system for each color of green (G), blue (B), and red (R), and the multiplication circuit 226 is shown in FIG.
0 shooting information schematically shown on the upper left side (the state of the analog video signals S1r, S1g, S1b is shown on the lower side), and D
/ A225 output the sensitivity / color tone correction control analog signals S25r, S25g, S25b to the analog multiplication circuit of the red, green, and blue signal processing systems for each color, and the sensitivity / color shown in the right side of FIG. The analog video signal outputs S23r, S23g, and S23b whose color tones are corrected are output.

The core coordinate memory 224b of the second embodiment is
For the HV coordinates on the same frame as in the first embodiment described above, the core coordinate data of the brightest point of each pixel is stored and the sensitivity / color tone correction control supplied to the multiplication circuit 226 described below is stored. Analog signals S25r, S25g,
Digital correction data corresponding to S25b is also registered.

That is, along with the core coordinate data similar to that of the first embodiment, with respect to the HV coordinates, the number of each pixel is registered in the area occupied by each pixel, and the sensitivity and color tone correction constants unique to each pixel are registered. It is a coordinate table for reading out data in synchronization with the video camera 14 at the time of lumen imaging, and the read sensitivity / color tone correction data is input to the D / A 255, where it is converted into a corresponding analog signal to obtain sensitivity / color tone. Corrected analog control signals S25r, S25g, S25b
And is output to the multiplication circuit 226.

As shown on the right side of FIG. 10, the multiplication circuit 226 corrects the video signal output S2 so that the brightness and color tone of each pixel forming the image guide 10 are equalized.
3r, S23g, S23b are output. Further, the core coordinate memory outputs a gate signal for selectively extracting the read data of the frame memory 222 at the coordinates that coincide with the center point of the pixel shown in FIG. 10, and the interpolating means 230 takes in only the peak data.

As described above, according to the second embodiment,
As in the first embodiment, the sensitivity and color tone are accurately corrected, brightness and garbledness are corrected at the same time, and as a result, a blood vessel endoscopic device that displays a clear lumen image with reduced moire fringes is provided. it can.

[0043]

As described above, according to the present invention, the brightness and the color unevenness due to the variation of the transmission characteristics of each pixel peculiar to the image guide are the brightest points corresponding to the central portion of each pixel forming the image guide. Based on the average luminance of all the pixels sampled, the sensitivity and color tone are accurately corrected, the brightness and the garbledness are corrected at the same time, and a clear lumen image with reduced moire fringes is displayed. Can be provided. As a result, the image guide can be made as thin as possible without reducing the number of pixels, and it becomes possible to observe and diagnose the affected area of the blood vessel using a catheter for endovascular use that has increased flexibility, and damage such as damage to the intima of the blood vessel. Can be significantly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment according to the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of an image processing unit of the present embodiment illustrated in FIG.

FIG. 3 is one of the sensitivity / color tone correcting means of the present embodiment shown in FIG.
It is a figure explaining an example.

FIG. 4 is a diagram illustrating an example of sensitivity / color tone correction processing by a sensitivity / color tone correction table in the present embodiment.

FIG. 5 is a diagram illustrating an example of a core coordinate table in the present embodiment.

FIG. 6 is a diagram for explaining the interpolating means of the present embodiment shown in FIG.

FIG. 7 is a diagram illustrating an example of interpolation processing by the interpolation unit of the present embodiment.

FIG. 8 is a diagram for explaining the smoothing means of this embodiment shown in FIG.

FIG. 9 is a diagram for explaining an example (analog multiplication processing method) of the sensitivity / color tone correction means of the second embodiment according to the present invention.

FIG. 10 is a diagram illustrating an example of sensitivity / color tone correction processing according to the second embodiment.

FIG. 11 is a diagram illustrating an example of a sensitivity / color tone correction coordinate table in the second embodiment.

FIG. 12 is a diagram illustrating an example of a conventional technique.

FIG. 13 is a diagram illustrating an example of a conventional technique (real-time mesh pattern removal).

[Explanation of symbols]

10 Image Guide 11 Light Guide 12 Light Source 13 Eyepiece 14 High Resolution Video Camera 200 Image Processing Unit 210 Control Circuit (Transmission Characteristic Measuring Means) 220 Sensitivity and Color Tone Correction Means 221 A / D 222 Frame Memory 223a Sensitivity and Color Tone Correction Circuit (Sensitivity) , Color tone correction table) 224a core coordinate memory 224b core coordinate memory (analog multiplication processing) 225b D / A 226 multiplication circuit 230 interpolation means 231 latch 232 H timer 233 AND gate 234 line memory 235 V timer array 240 smoothing means 241 addition circuit A 242 Adder circuit B 243 Field memory 244 Subtraction circuit 245 D / A 246 Control circuit 250 IF 300 Circular image memory 400 Optical disc device 500 Remote controller 60 0 color monitor

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location G02B 23/24 BG06T 1/00 5/00 (72) Inventor Masami Uchibori 2-35, Hongo, Bunkyo-ku, Tokyo No. 8 Fukuda Electronics Co., Ltd. Hongo Business Office (72) Inventor Takanori Homura 2-35 Hongo, Bunkyo-ku, Tokyo No. 8 Fukuda Electronics Co., Ltd. Hongo Business Office (72) Inventor Isamu Suzuki 2-32 Hongo, Bunkyo-ku, Tokyo No. 8 Fukuda Electronics Co., Ltd. Hongo Business Office (72) Inventor Kiyoshi Takeuchi 2-35-8 Hongo, Bunkyo-ku, Tokyo Fukuda Electronics Co., Ltd. Hongo Business Office

Claims (14)

[Claims] 1. An endoscopic image obtained by photographing an object image transmitted through an image guide constituted by a plurality of fusion-bonding fibers incorporated in an endoscope by an image pickup means. An endoscopic image correction device that corrects and reduces the difference in brightness and color tone for each pixel based on the difference in transmission characteristics of each fiber, and a white image that stores and holds an image obtained by photographing a white subject by the image guide. Holding means, coordinate data registration means for extracting the center coordinates of the core of each fiber forming the image guide from the image held by the white image holding means, and registering it together with the coordinate information for each fiber, and the coordinate data registration The average value of the brightness for each color of the captured image data held in the white image holding means of the coordinate position registered in the means is calculated, and the difference from the average value for each color calculated for each pixel is calculated. A calculation unit that calculates a difference, a correction data registration unit that generates correction data that eliminates the difference between the average value calculated by the calculation unit, and registers the correction data for each color, and an input that is captured by the imaging unit and is to be processed. Replacement for replacing the input image so as to eliminate the difference in color tone of each pixel for each pixel at the coordinate position registered in the coordinate data registration means according to the correction data registered by the correction data registration means An endoscopic image correction device comprising: 2. The endoscopic image correction apparatus according to claim 1, wherein the correction data registration means generates and registers correction data for each level from the minimum level to the maximum level for each color. 3. The interpolating means for performing two-dimensional interpolation embedding processing between the corrected data of the center coordinates of the core of each fiber replaced by the replacing means. The endoscopic image correction device according to item 1. 4. The endoscopic image correction apparatus according to claim 3, further comprising a smoothing unit that smoothes the interpolation data interpolated by the interpolation unit. 5. The data for each color is data of red (R), green (G), and blue (B) of the data picked up by the image pickup means, according to any one of claims 1 to 4. The endoscopic image correction device according to claim 1. 6. The replacement unit converts the image data captured by the image capturing unit into a corresponding digital signal, and corrects the converted digital information based on the correction data registered by the correction data registering unit. The endoscopic image correction device according to claim 1. 7. The replacing unit converts the correction data registered by the correction data registering unit into a corresponding analog signal, and corrects the converted correction data by multiplying the analog image data to be processed captured by the image capturing unit. 2. Then, the endoscopic image correction apparatus according to claim 1, wherein the endoscopic image correction apparatus converts the corresponding digital signal. 8. The image guide in an endoscopic image obtained by photographing an object image transmitted through an image guide constituted by a plurality of fusion-bonding fibers incorporated in an endoscope by an image pickup means. An endoscopic image correction method in an endoscopic image correction device that corrects and reduces the difference in brightness and color tone for each pixel based on the difference in transmission characteristics of each fiber, wherein the white image obtained by photographing a white subject by the image guide is used. The image is stored and held, the center coordinates of the core of each fiber forming the image guide is extracted from the held white image and registered together with the coordinate information for each fiber, and then the held photographed white of the registered coordinate position. Obtain the average value of brightness for each color of the image data, calculate the difference from the average value for each color obtained for each pixel, and use correction data to eliminate the difference from the calculated average value. A correction data registration step of forming and registering for each color, and an input image to be processed photographed by the imaging means, for each pixel of each coordinate position registered according to the correction data registered in the registration step, for each pixel And a correction step of replacing the input image so as to eliminate the difference in color tone. 9. The correction data to be registered in the registration step is to generate and register correction data for each level from a minimum level to a maximum level for each color. Endoscopic image correction method. 10. The method according to claim 8, further comprising a two-dimensional interpolation embedding process between the corrected data of the center coordinates of the core of each fiber replaced in the correction step. Visual image correction method. 11. The endoscopic image correction method according to claim 10, further comprising smoothing processing for smoothing the interpolation data interpolated by the interpolation embedding processing. 12. The data for each color is data of red (R), green (G), and blue (B) of the data imaged by the imaging means, according to any one of claims 8 to 11. The endoscopic image correction method according to claim 1. 13. The replacement in the correction step is characterized in that the image pickup data picked up by the image pickup means is converted into a corresponding digital signal, and the converted digital information is corrected based on the correction data registered in the registration step. The endoscopic image correction method according to claim 8. 14. The replacement in the correction step is performed by converting the correction data registered in the registration step into a corresponding analog signal, and multiplying the converted correction data by the analog image data to be processed captured by the image capturing unit to perform correction. 9. The endoscopic image correction method according to claim 8, wherein the endoscopic image correction method is to convert the digital image into a corresponding digital signal.