Endoscope optical performance testing method based on machine vision improvement

Abstract

The invention relates to the technical field of endoscope optical performance testing, in particular to an improved endoscope optical performance testing method based on machine vision. The method converts the optical performance test of the endoscope from the traditional manual operation into automatic measurement, and specifically comprises the following steps of: measuring images of the endoscope under different test conditions by using a machine vision system so as to calculate various optical indexes of the endoscope; a mode of combining a Canny edge detection algorithm with a corresponding physical target is adopted, so that the calculation precision is improved; in the calculation process of indexes such as a field angle and an a value, a high-precision camera is used for analyzing imaging of a target, the calculation rate is improved by calculating geometric parameters and image features, and when sensitive indexes such as effective luminosity, unit relative distortion and a color rendering index are calculated, software is used for processing data obtained by a machine vision system, so that the calculation efficiency is improved. And personal errors are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of endoscope optical performance testing, in particular to an endoscope optical performance testing method based on machine vision improvement. Background Art

[0002] Traditional endoscope optical performance test methods often rely on manual operation, have certain errors, and have low test efficiency. With the continuous development of endoscope technology, the requirements for its optical performance are getting higher and higher. However, there is currently no operational test method in China for this test, so a more efficient and accurate test method is urgently needed. Summary of the invention

[0003] The present invention aims to provide an improved method for testing the optical performance of an endoscope based on machine vision, which improves the accuracy and efficiency of the test by automating the test of optical indicators.

[0004] An improved method for testing the optical performance of an endoscope based on machine vision, characterized in that it comprises the following steps:

[0005] Step 1, obtaining test target images of the endoscope under different test conditions;

[0006] Step 2: Use a machine vision system to measure the test target image obtained in step 1 to obtain the optical indicators of the endoscope, including: viewing angle, entrance pupil field angle, field angle, a value, angular resolution, effective depth of field, lighting effectiveness, comprehensive light efficiency, effective light rate, unit relative distortion, and color rendering index;

[0007] Step 3: Determine whether all the indicators obtained in step 2 are within the internationally specified indicator value range. If so, it means that the optical performance of the endoscope meets the requirements. If any of them is not within the internationally specified indicator value range, it indicates that there is an abnormality in the item, which needs to be recorded and processed.

[0008] Furthermore, the method for calculating the viewing angle and entrance pupil viewing angle indicators includes the following steps:

[0009] Draw standard concentric circles and crosshairs for aligning the test target in the camera window of the machine vision system, and align and coincide the center point of the crosshairs with the center point of the standard concentric circles to assist aiming;

[0010] Align the test target with the crosshairs, and measure the distance between the crosshairs and the target;

[0011] According to the distance between the crosshair and the target, the viewing angle and the entrance pupil field of view angle are calculated according to the following formula:

[0012]

[0013] Among them, W p Represents the viewing angle and the entrance pupil field of view angle, R2 is the maximum radius of the concentric circles drawn in the camera window, R1 is the minimum radius of the concentric circles drawn in the camera window, d1 is the distance of the test target before it moves relative to the endoscope lens, and d2 is the distance of the test target after it moves relative to the endoscope lens.

[0014] Furthermore, the method for measuring the field of view angle and a-value index is:

[0015] According to the differentiation ring diameter formula, concentric circles are drawn in the test target image with the center of the camera window of the machine vision system as the center of the circle, and then rays are drawn along the specified direction with the center of the circle as the starting point, and the rays are made to intersect with each scale ring of the concentric circle; the expression of the differentiation ring diameter formula is: Where β is the angular spacing between adjacent concentric circles, and d is the optical working distance;

[0016] The Canny edge detection algorithm is used to obtain the arc lines of each differentiation ring of the concentric circle, the number of intersections between the ray and each differentiation ring of the concentric circle is counted, and the number of intersections is multiplied by the preset concentric circle scale value to obtain the field of view angle;

[0017] The a value is calculated using the formula a=d2-2d1, where d1 is the distance of the test target before it moves relative to the endoscope lens, and d2 is the distance of the test target after it moves relative to the endoscope lens.

[0018] Furthermore, the measurement method of the angular resolution index and the effective depth of field index is:

[0019] Read the line pair readings on the test target image, obtain the corresponding line pair number according to the line pair readings, and use the table lookup method to find the corresponding angular resolution value in the angular resolution table specified in the national standard based on the line pair number, the actual size of the test target, and the imaging parameters of the camera;

[0020] Move the angular resolution test target back and forth relative to the endoscope lens, and record its moving range value; calculate the effective depth of field based on the angular resolution value and the moving range value;

[0021] The calculation formula for effective depth of field is as follows:

[0022]

[0023] Among them, d is the optical working distance, a is the a value in the index, r a (d) is the angular resolution value.

[0024] Furthermore, the testing method of the lighting effectiveness index is:

[0025] Use a flux meter to measure the luminous flux values ​​at multiple locations and calculate the edge uniformity U based on the luminous flux values. L And lighting mirror light effect IL eR ;

[0026] Edge uniformity U L The calculation formula is:

[0027]

[0028] Among them, E i Indicates the luminous flux value at position i, E j Represents the luminous flux value at position j;

[0029] Lighting mirror light effect IL eR The calculation formula is:

[0030]

[0031] Among them, is the average brightness of the field of view angle ω, and L0 is the brightness in the center direction of the field of view.

[0032] Furthermore, the comprehensive light efficiency index includes the comprehensive light efficiency SL of the endoscope. eR Integrated light effect with edge SL e-z , use a photometer to measure the photometric values ​​at multiple locations, and calculate the comprehensive mirror body light effect SL based on the obtained photometric values eR and edge integrated light effect SL e-z ;

[0033] Comprehensive mirror light effect SL eR The calculation formula is:

[0034] SL eR =IL eR ·OL eR

[0035]

[0036]

[0037] In the formula, IL eR For the lighting effect of the mirror, OL eR Imaging mirror light effect, is the field of view angle w p Average light transmittance of the full entrance pupil in the same direction, τ v-0 is the full pupil light transmittance in the center of the field of view, φ o and φ i is the light source luminosity value before and after the endoscope;

[0038] Edge integrated light effect SL e-z The calculation formula is:

[0039] SL e-z =SL sR LL e-z ·LL' e-z

[0040]

[0041] Where ω is the field of view, ω p is the entrance pupil field of view angle, z represents the spherical field of view shape of the endoscope imaging, and its value is When the vertical visual axis is a plane, z = ∞, take LL e-z =cos 4 ω,LL' e-z =cos 4 ω p .

[0042] Furthermore, the testing method of the effective luminosity rate index is:

[0043] The endoscope field of view image is obtained through a camera, and the endoscope exit pupil field of view angle and effective luminous rate are calculated based on the endoscope field of view image using a machine vision algorithm;

[0044] The calculation formula for the exit pupil field of view angle is:

[0045]

[0046] The calculation formula of effective luminosity is:

[0047]

[0048] Where L is the brightness of the cosine radiator, in cd / m2. 2 ),φ′ is the endoscope exit pupil luminous flux, unit lumen (lm).

[0049] Furthermore, the test method of the unit relative distortion index is:

[0050] Draw five standard circles in the camera window, one of which is recorded as the central circle, and the centers of the other four circles are distributed in the four directions of the upper and lower groups and the left and right directions with the central circle as the center, and the clustering from the centers of the upper and lower circles to the center of the central circle, and from the centers of the left and right circles to the center of the central circle are all equal;

[0051] The five standard circles drawn in the camera window are all regarded as ideal circles. Assuming that the distortion of the test target image at the center is the smallest, the distortion test image with the smallest distortion is aligned with the center circle of the camera window.

[0052] Then, machine vision technology is used to detect the difference between the remaining test target images and each ideal circle, and the unit relative distortion index can be calculated according to the following formula:

[0053] The calculation formula for unit relative distortion is:

[0054]

[0055] Wherein, the distortion δy'0 is defined as the difference between the actual image size y'0 of the side marker target and the ideal image size y' p ratio.

[0056] Furthermore, the testing method of the color rendering index is:

[0057] Use the spectrometer software to obtain the test data of the fiber end and the eyepiece end respectively. Use the test data of the fiber end and the eyepiece end to calculate the color rendering index Ra value under A standard light source, D65 standard light source, fiber output end, and eyepiece end respectively; special color rendering index R a The calculation formula is:

[0058]

[0059] In the formula, R i It is the color rendering index under 8 test color samples.

[0060] The method for testing the optical performance of an endoscope based on machine vision provided by the present invention is to transform the optical performance test of the endoscope from traditional manual operation to automated measurement. Specifically, the images of the endoscope under different test conditions are measured by using a machine vision system to calculate the optical indicators of the endoscope. The optical indicators of the endoscope include the viewing angle, entrance pupil field angle, field angle, angular resolution, effective depth of field, lighting effectiveness, comprehensive light efficiency, effective luminous rate, unit relative distortion and color rendering index of the endoscope. In the measurement process of the lighting effectiveness index, the calculation accuracy is improved by combining the Canny edge detection algorithm with the corresponding physical target; in the calculation process of indicators such as the field angle and a value, a high-precision camera is used to analyze the imaging of the target, and the calculation rate is improved by calculating the geometric parameters and image features. When sensitive indicators such as the effective luminous rate, unit relative distortion and color rendering index are used, the data obtained by the machine vision system are processed by software to avoid human errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 A schematic diagram of drawing standard concentric circles and a crosshair in a camera window in an embodiment;

[0062] Figure 2 This is a schematic diagram of aligning the test target and the crosshairs of the camera window in the embodiment;

[0063] Figure 3 A schematic diagram showing the intersection of rays and concentric circles drawn at the center of the camera window of the embodiment;

[0064] Figure 4 This is a schematic diagram of an embodiment using Canny edge detection to obtain concentric arcs;

[0065] Figure 5 This is a view display of the camera window after it is magnified 16 times during the target reading process of the embodiment;

[0066] Figure 6 A schematic diagram of endoscope field of view imaging and coordinates used in calculating the pupil field of view angle in an embodiment;

[0067] Figure 7 A schematic diagram of the arrangement of five standard circles drawn in the camera window of the embodiment;

[0068] Figure 8 is a schematic diagram of the alignment of the center circle of the target in the embodiment with the center circle of the standard;

[0069] Fig. 9 This is a schematic diagram of importing and outputting color rendering index data in an embodiment;

[0070] Fig.10 The flowchart of the method for testing the optical performance of an endoscope based on machine vision improvement according to an embodiment. DETAILED DESCRIPTION

[0071] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0072] like Fig.10 As shown, this embodiment provides an endoscope optical performance testing method based on machine vision improvement, comprising the following steps:

[0073] Step 1: Preparation before the test, including: adjusting the brightness of the light source according to the test requirements, removing background interference, adjusting the optical working distance between visual devices such as cameras and endoscopes in the visual measurement system, and calibrating the machine vision system to ensure the accuracy of the measurement.

[0074] Step 2: Use a CCD camera to obtain the test target images of the endoscope under different test conditions.

[0075] Step 3: Use a machine vision system to measure the test target image obtained in step 1 to obtain the optical indicators of the endoscope, including: viewing angle, entrance pupil field angle, field angle, a value, angular resolution, effective depth of field, lighting effectiveness, comprehensive light efficiency, effective luminous efficiency, unit relative distortion, and color rendering index.

[0076] Step 4: Determine whether all the indicators obtained in step 2 are within the internationally specified indicator value range. If so, it means that the optical performance of the endoscope meets the requirements. If any of them is not within the internationally specified indicator value range, it indicates that there is an abnormality in the item, which needs to be recorded and processed.

[0077] This embodiment introduces a machine vision system and combines the machine vision algorithm with a physical target to measure various optical indicators, effectively improving the accuracy and efficiency of endoscope performance measurement. The method for measuring the optical indicators of each phase in this embodiment is as follows:

[0078] The method for calculating the viewing angle and entrance pupil viewing angle indicators includes the following steps:

[0079] Draw standard concentric circles and crosshairs for aligning the test target in the camera window of the machine vision system, and align and coincide the center point of the crosshairs with the center point of the standard concentric circles. In this embodiment, draw the standard concentric circles and crosshairs in the camera window. Figure 1 , align the test target with the camera window crosshairs. Figure 2 , to assist aiming;

[0080] Align the test target with the crosshairs, and measure the distance between the crosshairs and the target;

[0081] According to the distance between the crosshair and the target, the viewing angle and the entrance pupil field of view angle are calculated according to the following formula:

[0082]

[0083] Among them, W p Represents the viewing angle and the entrance pupil field of view angle, R2 is the maximum radius of the concentric circles drawn in the camera window, R1 is the minimum radius of the concentric circles drawn in the camera window, d1 is the distance of the test target before it moves relative to the endoscope lens, and d2 is the distance of the test target after it moves relative to the endoscope lens.

[0084] The method for measuring the field of view angle and a value index is:

[0085] According to the differentiation ring diameter formula, concentric circles are drawn in the test target image with the center of the camera window of the machine vision system as the center of the circle, and then rays are drawn along the specified direction with the center of the circle as the starting point, and the rays are made to intersect with each scale ring of the concentric circle. The schematic diagram of the intersection of the ray and the concentric circle in this embodiment is shown in Figure 3 The expression of the differentiation ring diameter formula is: Where β is the angular spacing between adjacent concentric circles, and d is the optical working distance;

[0086] The Canny edge detection algorithm is used to obtain the arc lines of each differentiation ring of the concentric circle. In this embodiment, the concentric arc lines are obtained by using the Canny edge detection algorithm. Figure 4 As shown, the number of intersections between the counting ray and each differentiation ring of the concentric circle is multiplied by the number of intersections and the preset concentric circle scale value to obtain the field of view angle;

[0087] The a value is calculated using the formula a=d2-2d1, where d1 is the distance of the test target before it moves relative to the endoscope lens, and d2 is the distance of the test target after it moves relative to the endoscope lens.

[0088] The measurement method of the angular resolution index and the effective depth of field index is:

[0089] Enlarge the camera window by 16 times. The view after the camera window is enlarged by 16 times is shown in the figure. Read the line pair readings on the test target image, and obtain the corresponding line pair number according to the line pair readings. Based on the line pair number, the actual size of the test target, and the imaging parameters of the camera, use the table lookup method to find the corresponding angular resolution value in the angular resolution table specified in the national standard.

[0090] Table 1 shows the corresponding angular resolution values ​​found in the national standard line pair table based on the line pair number using the table lookup method in this embodiment:

[0091]

[0092] Move the angular resolution test target back and forth relative to the endoscope lens, and record its moving range value; calculate the effective depth of field based on the angular resolution value and the moving range value;

[0093] The calculation formula for effective depth of field is as follows:

[0094]

[0095] Among them, d is the optical working distance, a is the a value in the index, r a (d) is the angular resolution value.

[0096] The test method for the lighting effectiveness index is:

[0097] Use a flux meter to measure the luminous flux values ​​at multiple locations and calculate the edge uniformity U based on the luminous flux values. L And lighting mirror light effect IL eR ;

[0098] Edge uniformity U L The calculation formula is:

[0099]

[0100] Among them, E i Indicates the luminous flux value at position i, E j Represents the luminous flux value at position j;

[0101] Lighting mirror light effect IL eR The calculation formula is:

[0102]

[0103] Wherein, is the average brightness of the field of view angle ω, and L0 is the brightness in the center direction of the field of view. The brightness acquisition method of this embodiment is as follows: a light source is used to illuminate the integrating sphere, and when the light source passes through the cosine transmission material and enters the small hole of the integrating sphere, an illuminance meter is used to measure the illuminance value. At this time, there is a linear relationship between the illuminance value and the brightness value, and the contribution value of the optical microscope illumination light path to the edge light effect, that is, the brightness, can be obtained.

[0104] The comprehensive light efficiency index includes the comprehensive light efficiency SL of the endoscope eR Integrated light effect with edge SL e-z , use a photometer to measure the photometric values ​​at multiple locations, and calculate the comprehensive mirror body light effect SL based on the obtained photometric values eR and edge integrated light effect SL e-z ;

[0105] Comprehensive mirror light effect SL eR The calculation formula is:

[0106] SL eR =IL eR ·OL eR

[0107]

[0108] In the formula, IL eR For the lighting effect of the mirror, OL eR Imaging mirror light effect, is the field of view angle w p Average light transmittance of the full entrance pupil in the same direction, τ v-0 is the full pupil light transmittance in the center of the field of view, φ o and φ i is the light source luminosity value before and after the endoscope;

[0109] Edge integrated light effect SL e-z The calculation formula is:

[0110] SL e-z =SL sR LL e-z ·LL' e-z

[0111]

[0112] Where ω is the field of view, ω p is the entrance pupil field of view angle, z represents the spherical field of view shape of the endoscope imaging, and its value is When the vertical visual axis is a plane, z = ∞, take LL e-z =cos 4 ω,LL' e-z =cos 4 ω p .

[0113] The testing method of the effective luminosity rate index is:

[0114] The endoscope field of view image is obtained by a camera, and the endoscope exit pupil field of view angle and effective luminous rate are calculated based on the endoscope field of view image using a machine vision algorithm; the endoscope field of view imaging schematic diagram used in calculating the exit pupil field of view angle in this embodiment is as follows Figure 6 shown.

[0115] The calculation formula for the exit pupil field of view angle is:

[0116]

[0117] The calculation formula of effective luminosity is:

[0118]

[0119] Where L is the brightness of the cosine radiator, in cd / m2. 2 ),φ′ is the endoscope exit pupil luminous flux, unit lumen (lm).

[0120] The test method of the unit relative distortion index is:

[0121] Draw five standard circles in the camera window. One of the five standard circles is marked as the center circle. The centers of the other four circles are distributed in the four directions of the upper, lower, left and right groups with the center circle as the center. The distances from the centers of the upper and lower circles to the center of the center circle, and from the centers of the left and right circles to the center of the center circle are all equal. The final image can be seen in Figure 7 ;

[0122] The five standard circles drawn in the camera window are all regarded as ideal circles. Assuming that the distortion of the test target image at the center is the smallest, align the distortion test image with the smallest distortion with the center circle of the camera window. Figure 8 .

[0123] Then, machine vision technology is used to detect the difference between the remaining test target images and each ideal circle, and the unit relative distortion index can be calculated according to the following formula:

[0124] The calculation formula for unit relative distortion is:

[0125]

[0126] Wherein, the distortion δy'0 is defined as the difference between the actual image size y'0 of the side marker target and the ideal image size y' p ratio.

[0127] The testing method of the color rendering index is:

[0128] like Fig. 9 As shown, the spectrometer supporting software is used to obtain the test data of the fiber end and the eyepiece end respectively. The test data of the fiber end and the eyepiece end are used to calculate the color rendering index Ra value under A standard light source, D65 standard light source, fiber output end, and eyepiece end respectively; the special color rendering index R a The calculation formula is:

[0129]

[0130] In the formula, R i It is the color rendering index under 8 test color samples.

[0131] It should be noted that the improved endoscope optical performance testing method based on machine vision provided in this embodiment will use some auxiliary tools in the process of testing various optical indicators, such as target holder / various indicator test targets, endoscope holder, CCD camera connection structure, movable and rotatable light box light source structure, matching photometer, flux meter, integrating sphere, cosine projection material, spectrometer, illuminance meter industrial computer and other existing devices, and the operation of these devices can be carried out according to the existing operations.

[0132] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An improved method for testing the optical performance of an endoscope based on machine vision, characterized in that: The following steps are involved: Step 1, obtaining test target images of the endoscope under different test conditions; Step 2: Use a machine vision system to measure the test target image obtained in step 1 to obtain the optical indicators of the endoscope, including: viewing angle, entrance pupil field angle, field angle, a value, angular resolution, effective depth of field, lighting effectiveness, comprehensive light efficiency, effective light rate, unit relative distortion, and color rendering index; Step 3: Determine whether all the indicators obtained in step 2 are within the internationally specified indicator value range. If so, it means that the optical performance of the endoscope meets the requirements. If any of them is not within the internationally specified indicator value range, it indicates that there is an abnormality in the item, which needs to be recorded and processed.

2. The method for testing the optical performance of an endoscope based on machine vision improvement according to claim 1, characterized in that: The method for calculating the viewing angle and entrance pupil viewing angle indicators includes the following steps: Draw standard concentric circles and crosshairs for aligning the test target in the camera window of the machine vision system, and align and coincide the center point of the crosshairs with the center point of the standard concentric circles to assist aiming; Align the test target with the crosshairs, and measure the distance between the crosshairs and the target; According to the distance between the crosshair and the target, the viewing angle and the entrance pupil field of view angle are calculated according to the following formula: Among them, W p Represents the viewing angle and the entrance pupil field of view angle, R2 is the maximum radius of the concentric circles drawn in the camera window, R1 is the minimum radius of the concentric circles drawn in the camera window, d1 is the distance of the test target before it moves relative to the endoscope lens, and d2 is the distance of the test target after it moves relative to the endoscope lens.

3. The method for testing the optical performance of an endoscope based on machine vision improvement according to claim 1, characterized in that: The method for measuring the field of view angle and a value index is: According to the differentiation ring diameter formula, concentric circles are drawn in the test target image with the center of the camera window of the machine vision system as the center of the circle, and then rays are drawn along the specified direction with the center of the circle as the starting point, and the rays are made to intersect with each scale ring of the concentric circle; the expression of the differentiation ring diameter formula is: Where β is the angular spacing between adjacent concentric circles, and d is the optical working distance; The Canny edge detection algorithm is used to obtain the arc lines of each differentiation ring of the concentric circle, the number of intersections between the ray and each differentiation ring of the concentric circle is counted, and the number of intersections is multiplied by the preset concentric circle scale value to obtain the field of view angle; The a value is calculated using the formula a=d2-2d1, where d1 is the distance of the test target before it moves relative to the endoscope lens, and d2 is the distance of the test target after it moves relative to the endoscope lens.

4. The method for testing the optical performance of an endoscope based on machine vision improvement according to claim 1, characterized in that: The measurement method of the angular resolution index and the effective depth of field index is: Read the line pair readings on the test target image, obtain the corresponding line pair number according to the line pair readings, and use the table lookup method to find the corresponding angular resolution value in the angular resolution table specified in the national standard based on the line pair number, the actual size of the test target, and the imaging parameters of the camera; Move the angular resolution test target back and forth relative to the endoscope lens, and record its moving range value; calculate the effective depth of field based on the angular resolution value and the moving range value; The calculation formula for effective depth of field is as follows: Among them, d is the optical working distance, a is the a value in the index, r a (d) is the angular resolution value.

5. The method for testing the optical performance of an endoscope based on machine vision improvement according to claim 1, characterized in that: The test method for the lighting effectiveness index is: Use a flux meter to measure the luminous flux values ​​at multiple locations and calculate the edge uniformity U based on the luminous flux values. L And lighting mirror light effect IL eR ; Edge uniformity U L The calculation formula is: Among them, E i Indicates the luminous flux value at position i, E j Represents the luminous flux value at position j; Lighting mirror light effect IL eR The calculation formula is: Among them, is the average brightness of the field of view angle ω, and L0 is the brightness in the center direction of the field of view.

6. The method for testing the optical performance of an endoscope based on machine vision improvement according to claim 1, characterized in that: The comprehensive light efficiency index includes the comprehensive light efficiency SL of the endoscope eR Integrated light effect with edge SL e-z , use a photometer to measure the photometric values ​​at multiple locations, and calculate the comprehensive mirror body light effect SL based on the obtained photometric values eR and edge integrated light effect SL e-z ; Comprehensive mirror light effect SL eR The calculation formula is: SL eR =IL eR ·OL eR In the formula, IL eR For the lighting effect of the mirror, OL eR Imaging mirror light effect, is the field of view angle w p Average light transmittance of the full entrance pupil in the same direction, τ v-0 is the full pupil light transmittance in the center of the field of view, φ o and φ i is the light source luminosity value before and after the endoscope; Edge integrated light effect SL e-z The calculation formula is: SL e-z =SL sR ·LL e-z ·LL' e-z Where ω is the field of view, ω p is the entrance pupil field of view angle, z represents the spherical field of view shape of the endoscope imaging, and its value is When the vertical visual axis is a plane, z = ∞, take LL e-z =cos 4 ω,LL' e-z =cos 4 ω p .

7. The method for testing the optical performance of an endoscope based on machine vision improvement according to claim 1, characterized in that: The testing method of the effective luminosity rate index is: The endoscope field of view image is obtained through a camera, and the endoscope exit pupil field of view angle and effective luminous rate are calculated based on the endoscope field of view image using a machine vision algorithm; The calculation formula for the exit pupil field of view angle is: The calculation formula of effective luminosity is: Where L is the brightness of the cosine radiator, in cd / m2. 2 ),φ′ is the endoscope exit pupil luminous flux, unit lumen (lm).

8. The method for testing the optical performance of an endoscope based on machine vision improvement according to claim 1, characterized in that: The test method of the unit relative distortion index is: Draw five standard circles in the camera window, one of which is recorded as the central circle, and the centers of the other four circles are distributed in the four directions of the upper and lower groups and the left and right directions with the central circle as the center, and the clustering from the centers of the upper and lower circles to the center of the central circle, and from the centers of the left and right circles to the center of the central circle are all equal; The five standard circles drawn in the camera window are all regarded as ideal circles. Assuming that the distortion of the test target image at the center is the smallest, the distortion test image with the smallest distortion is aligned with the center circle of the camera window. Then, machine vision technology is used to detect the difference between the remaining test target images and each ideal circle, and the unit relative distortion index can be calculated according to the following formula: The calculation formula for unit relative distortion is: Wherein, the distortion δy'0 is defined as the difference between the actual image size y'0 of the side marker target and the ideal image size y' p ratio.

9. The method for testing the optical performance of an endoscope based on machine vision improvement according to claim 1, characterized in that: The testing method of the color rendering index is: Use the spectrometer software to obtain the test data of the fiber end and the eyepiece end respectively. Use the test data of the fiber end and the eyepiece end to calculate the color rendering index Ra value under A standard light source, D65 standard light source, fiber output end, and eyepiece end respectively; special color rendering index R a The calculation formula is: In the formula, R i It is the color rendering index under 8 test color samples.

Images