CN115334298A - A kind of testing method of visual navigation system imaging equipment - Google Patents

Abstract

The invention provides a method for testing imaging equipment of a visual navigation system, which includes blocking the field of view of the imaging device and calculating the non-uniformity of imaging; canceling the blocking of the field of view of the imaging device and calculating the non-uniformity of imaging again; Whether the uniformity is lower than the first threshold; judging whether the non-uniformity ratio of the normal working state and the occlusion state is lower than the second threshold; if the above judgments are all true, the imaging device works normally. The method is based on the non-uniformity technical index of the imaging equipment under the occlusion of the field of view and the normal working state, objectively judges the imaging performance, does not need to introduce external equipment, has high reliability, simple operation, and low cost.

Description

A kind of testing method of visual navigation system imaging equipment

technical field

The invention belongs to the technical field of visual navigation, and in particular relates to a testing method for imaging equipment of a visual navigation system.

Background technique

Computer vision, also known as machine vision, is a method that studies the use of computers to simulate human visual functions, extracts valuable information from images of objective things, processes and recognizes them, and finally uses them for actual detection, testing, navigation or control. It is a discipline involving image processing, computer science, physiological psychology and photogrammetry.

Visual navigation uses the visual image of the objective world acquired by the image sensor as the navigation information source, simulates the human visual function, recognizes and understands the image, and then obtains the navigation information of the carrier. It has the characteristics of strong autonomy, rich information, and high level of intelligence. , which can meet the requirements of high-precision relative navigation. As a developing new navigation system, the visual navigation system is getting more and more attention due to its intelligent and autonomous characteristics.

When the visual navigation system is applied in fields such as drones, the pre-flight imaging equipment test currently faces the following two problems:

(1) Generally, the subjective judgment method is used to connect the imaging device to the display device, observe the imaging effect through the display device, artificially judge the quality of the imaging effect, and determine whether the imaging device is working normally. This method is highly dependent on the display device, and some In some applications, the display device cannot be connected, and it is impossible to determine whether the imaging device is working normally through subjective judgment, and the reliability is poor;

(2) It is necessary to be equipped with special test equipment such as cooperation targets. The imaging equipment images the cooperation target. In order to ensure the imaging effect, the cooperation target pattern needs to be sharp and angular, with high resolution and high contrast. The overall production cost is high, and the cooperation target needs to be installed and debugged , the operation is complicated, which increases the operation complexity and economic cost.

Contents of the invention

Aiming at technical problems such as the existing testing method of imaging equipment of visual navigation system relying on testing equipment such as display equipment and cooperative targets, the testing method has poor reliability, complicated operation, and high cost, the present invention proposes a testing method of imaging equipment of visual navigation system, based on the imaging equipment in Block the field of view and non-uniformity technical indicators under normal working conditions, objectively judge the imaging performance, no need to introduce external equipment, high reliability, simple operation, low cost, and solve the problem of imaging function testing during the use of visual navigation systems.

The technical solution adopted by the present invention to solve the problems of the technologies described above is as follows:

A visual navigation system imaging device testing method, comprising the following steps

Block the field of view of imaging equipment and calculate imaging non-uniformity;

Cancel the occlusion of the field of view of the imaging device, and calculate the imaging non-uniformity again;

judging whether the non-uniformity when the field of view of the imaging device is blocked is lower than a first threshold;

Judging whether the non-uniformity ratio between the normal working state and the occlusion state is lower than the second threshold;

If the foregoing determinations are all established, the imaging device works normally.

Further, the blocking of the field of view of the imaging device is specifically to block the full field of view of the imaging device with an object of uniform material, and obtain the grayscale response of the entire target surface of the imaging device;

The canceling the shielding of the field of view of the imaging device specifically refers to removing the shielding of the field of view of the imaging device, and obtaining the grayscale response of the entire target surface of the imaging device in a normal working state of the imaging device.

Further, the non-uniformity calculation method is as follows

Among them, M and N are the number of rows and columns of pixels in the imaging device, V _ij is the gray value of the pixel corresponding to the i-th row and column j on the imaging device, and V _avg is the gray value of all pixels on the imaging device Grayscale response average.

Further, the first threshold calculation method is as follows

T _NU =1.2NU _max

Among them, NU _max is the maximum value of the non-uniformity of multiple sets of measured standard imaging equipment when the field of view is blocked.

Further, the non-uniformity ratio between the normal working state and the blocking state is

The second threshold calculation method is as follows

T _q =1.2Q _max

Among them, NU' is the non-uniformity of the normal working state of the imaging device; NU is the non-uniformity of the blocking state of the imaging device; Q _max is the maximum value of the non-uniformity ratio of multiple sets of standard imaging devices measured before and after blocking the field of view.

Further, the first threshold takes a value of 0.3, and the second threshold takes a value of 2.

The beneficial effect of the present invention compared with prior art:

The invention provides a method for testing imaging equipment of a visual navigation system. On the one hand, according to the non-uniformity when the field of view of the imaging equipment is blocked, the response difference of each pixel of the imaging device is investigated when the input is uniform; on the other hand, according to whether the blocking is Comparing the non-uniformity of the imaging equipment in the field of view, investigating the grayscale response of the imaging equipment in the conventional scene, and comprehensively determining whether the imaging equipment has passed the test.

Under the premise of ensuring the accuracy of the test, the method can obtain objective evaluation results without the subjective intervention of display equipment and test personnel, and can judge whether the imaging equipment of the visual navigation system is working normally, thereby improving the convenience of testing. The method realizes the test of the imaging device based on the non-uniformity technical index, does not depend on expensive test equipment, and has strong economy.

Detailed ways

Specific embodiments of the present invention will be described in detail below. In the following description, for purposes of explanation and not limitation, specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details.

Aiming at the problems existing in the prior art that the visual navigation system cannot be tested by connecting a display device in some application scenarios, the reliability of the tester’s subjective intervention test is poor, and high-cost testing equipment is required, the present invention provides a visual navigation system. A system imaging device testing method, comprising the following steps:

(1) Block the imaging field of view and calculate the imaging non-uniformity;

(2) Cancel the occlusion of the field of view, and calculate the imaging non-uniformity again;

(3) According to whether the non-uniformity when the field of view is blocked is lower than the first threshold, it is judged whether the imaging device is working normally;

(4) judging whether the imaging device works normally according to whether the non-uniformity ratio of the normal working state and the blocking state is lower than the second threshold;

(5) Based on the foregoing judgment results, determine whether the imaging device test is passed.

Further, the above-mentioned technical solution is realized through the following specific steps:

Step 1: Block the imaging field of view and calculate the imaging non-uniformity

Block the full field of view of the imaging device of the visual navigation system with an object of uniform material, obtain the grayscale response of the entire target surface of the imaging device, and calculate its non-uniformity NU

Among them, M and N are the number of rows and columns of pixels in the imaging device, V _ij is the gray value of the pixel corresponding to the i-th row and column j on the imaging device, and V _avg is the gray value of all pixels on the imaging device Grayscale response average.

Step 2: Cancel the occlusion of the field of view and calculate the imaging non-uniformity again

Remove the occlusion of the field of view of the imaging device, let the imaging device work normally, obtain the grayscale response of the entire target surface of the imaging device, and use formula (1) to calculate its non-uniformity NU'.

Step 3: Judging whether the imaging device is working normally according to the non-uniformity when the field of view is blocked

When the non-uniformity when the field of view is blocked meets the first threshold requirement, it is considered that the imaging device works normally.

NU≤T _NU (2)

Wherein, the first threshold T _NU is set according to the imaging characteristics and noise level of the imaging device, and the reference value is 0.3.

The setting of the first threshold T _NU may also be calculated by the following formula:

T _NU =1.2NU _max (3)

Among them, NU _max is the maximum value of the non-uniformity of multiple sets of measured standard imaging equipment when the field of view is blocked.

Step 4: Judging whether the imaging device is working normally according to the non-uniformity ratio

Calculate the non-uniformity ratio Q before and after blocking the field of view

If the value _Q is greater than the second threshold Tq, it is considered that the imaging device is working normally.

The second threshold T _q may take a reference value of 2.

The setting of the second threshold _Tq can also be calculated by the following formula:

T _q =1.2Q _max (5)

Among them, Q _max is the maximum value of the non-uniformity ratio of multiple sets of measured standard imaging equipment before and after blocking the field of view.

Step 5: Comprehensively judge whether the imaging equipment test is passed

When both steps 3 and 4 judge that the imaging device is working normally, it is considered that the visual navigation system test is passed; otherwise, it is considered that the test is not passed.

The invention provides a method for testing imaging equipment of a visual navigation system, which uses non-uniformity index evaluation when the field of view is blocked to ensure that the comprehensive performance of the imaging device is normal, including photodetector readout circuits, output video formats, etc.; before and after blocking The evaluation of the non-uniformity ratio index ensures that the optical system of the imaging device works normally. This test method, under the premise of ensuring the accuracy of the test, can obtain objective evaluation results without the subjective intervention of display equipment and test personnel, and can judge whether the imaging equipment of the visual navigation system is working normally, which improves the convenience of the test; at the same time, based on The non-uniformity technical index realizes the test of imaging equipment, does not depend on expensive test equipment, and has strong economy.

Features described and/or illustrated above for one embodiment may be used in the same or similar manner in one or more other embodiments, and/or be combined with or replace features in other embodiments Features in .

It should be emphasized that the term "comprising/comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps, components or combinations thereof .

The many features and advantages of these embodiments are apparent from this detailed description, and thus the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Moreover, since many modifications and changes will readily occur to those skilled in the art, it is not intended to limit the embodiments of the present invention to the precise structures and operations illustrated and described, but to cover all suitable modifications and equivalents falling within the scope thereof. thing.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Parts not described in detail in the present invention are well-known technologies for those skilled in the art.

Claims (6)

1. a visual navigation system imaging device testing method, is characterized in that, comprises the following steps Block the field of view of imaging equipment and calculate imaging non-uniformity; Cancel the occlusion of the field of view of the imaging device, and calculate the imaging non-uniformity again; judging whether the non-uniformity when the field of view of the imaging device is blocked is lower than a first threshold; Judging whether the non-uniformity ratio between the normal working state and the occlusion state is lower than the second threshold; If the foregoing determinations are all established, the imaging device works normally. 2. The visual navigation system imaging device testing method according to claim 1, wherein the blocking of the field of view of the imaging device is specifically the use of an object with a uniform material to block the full field of view of the imaging device to obtain the full target surface of the imaging device gray scale response; The canceling the shielding of the field of view of the imaging device specifically refers to removing the shielding of the field of view of the imaging device, and obtaining the grayscale response of the entire target surface of the imaging device in a normal working state of the imaging device. 3. visual navigation system imaging device test method according to claim 1, is characterized in that, described non-uniformity calculation method is as follows

Among them, M and N are the number of rows and columns of pixels in the imaging device, V _ij is the gray value of the pixel corresponding to the i-th row and column j on the imaging device, and V _avg is the gray value of all pixels on the imaging device Grayscale response average. 4. visual navigation system imaging device test method according to claim 1, is characterized in that, described first threshold calculation method is as follows T _NU =1.2NU _max Among them, NU _max is the maximum value of the non-uniformity of multiple sets of measured standard imaging equipment when the field of view is blocked. 5. visual navigation system imaging device test method according to claim 1, is characterized in that, the non-uniformity ratio of described normal working state and blocking state is

The second threshold calculation method is as follows T _q =1.2Q _max Among them, NU' is the non-uniformity of the normal working state of the imaging device; NU is the non-uniformity of the blocking state of the imaging device; Q _max is the maximum value of the non-uniformity ratio of multiple sets of standard imaging devices measured before and after blocking the field of view. 6. The visual navigation system imaging device testing method according to claim 1, wherein the first threshold value is 0.3, and the second threshold value is 2.