A method and system for judging image quality of photoelectric navigation equipment

Abstract

The application discloses a kind of applied to photoelectric navigation equipment image quality discrimination method and system, it is related to image adjustment field, method includes: the difference of the absolute value of the pixel value matrix of image in the adjacent two element values in preset direction, obtain absolute value matrix, preset direction is X axis and / or Y axis direction;Threshold value calculation is carried out to absolute value matrix, and multiplication coefficient matrix is obtained;Stretch based on multiplication coefficient matrix to absolute value matrix, obtain stretched absolute value matrix;Based on stretched absolute value matrix, determine the quality value of image.The application can be stretched to absolute value matrix by multiplication coefficient matrix, so that the image with relatively uniform pixel value or less feature points can still calculate the quality value of image, reduce the misjudgment rate of image quality calculation, improve the precision of layered image screening process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of image adjustment, in particular to a method and system for judging image quality of photoelectric navigation equipment. BACKGROUND

[0002] Photoelectric navigation equipment usually reads images in an image sensor, and calculates displacement of two frames of images by an algorithm; however, if the image quality in the image sensor is poor, there are few feature points in the image, and the image contrast is low, the matching degree of the image algorithm will be reduced, thus the photoelectric navigation equipment may calculate a wrong displacement. The image quality is used to judge whether the image in the photoelectric sensor meets the calculation requirements of the algorithm, if the image quality is poor, the image is not involved in the image matching operation, and the photoelectric navigation equipment will not calculate a wrong displacement, thus the correctness of the displacement of the equipment is ensured.

[0003] The prior art uses a histogram method to judge the image quality, and calculates the number of pixel points distributed in different regions, if the pixel points are uniformly distributed, the image quality is good, otherwise the image quality is poor. However, this method needs to distinguish different threshold values in detail, the threshold value range is difficult to set, the image distribution of different interfaces (black / white) of the photoelectric navigation equipment is quite different, and the calculated image quality result has a large error, thus the image quality is not accurate enough; another method is to divide the image into several blocks, calculate the absolute value of the average value difference of adjacent blocks, and sum to obtain the image quality, the image data is averaged by blocks, and in some images with uniform pixel points or obvious black and white layers, there is a misjudgment phenomenon, and this method also has low accuracy. SUMMARY

[0004] The present application aims to provide a method and system for judging image quality of photoelectric navigation equipment, by using different multiplication coefficients to stretch the difference of image pixel points, using a multiplication coefficient matrix to stretch the absolute value matrix, so that the image quality value can be calculated for an image with uniform pixel values or few feature points, the misjudgment rate of image quality calculation is reduced, and the accuracy of the layering image screening process is improved.

[0005] To achieve the above object, the present application provides the following scheme:

[0006] A method for judging image quality of photoelectric navigation equipment, the method comprising:

[0007] calculating the absolute value of the difference between two adjacent elements of a pixel value matrix of an image in a preset direction, to obtain an absolute value matrix, the preset direction being an X-axis and / or Y-axis direction;

[0008] performing threshold value calculation on the absolute value matrix to obtain a multiplication coefficient matrix;

[0009] stretch the absolute value matrix based on the multiplication coefficient matrix to obtain a stretched absolute value matrix;

[0010] determine the quality value of the image based on the stretched absolute value matrix.

[0011] Optionally, threshold calculation is performed on the absolute value matrix to obtain a multiplication coefficient matrix, and a formula of the multiplication coefficient matrix is as follows:

[0012] d i，j <D TH0 , m i，j =S1;

[0013] D TH0 d i，j <D TH1 , m i，j =S2;

[0014] d i，j D TH1 , m i，j =S3;

[0015] i=1, 2, 3…I;

[0016] j=1, 2, 3…J-1;

[0017] wherein d i，j is an element of the i-th row and the j-th column in the absolute value matrix, m i，j is an element of the i-th row and the j-th column in the multiplication coefficient matrix, D TH0 is a first threshold value, D TH1 is a second threshold value, S1 is a first multiplication coefficient value, S2 is a second multiplication coefficient value, S3 is a third multiplication coefficient value, I is a horizontal pixel number of the image, and J is a vertical pixel number of the image.

[0018] Optionally, the absolute value matrix is stretched based on the multiplication coefficient matrix to obtain a stretched absolute value matrix, and the stretching specifically includes:

[0019] calculating a product of the absolute value matrix and the multiplication coefficient matrix to obtain the stretched absolute value matrix.

[0020] Optionally, when the preset direction is an X or Y axis direction, the quality value of the image is determined based on the stretched absolute value matrix, and the determination specifically includes:

[0021] adding and averaging element values in the preset direction of the stretched absolute value matrix to obtain a quality factor array;

[0022] judging whether there are continuous T elements with a value less than a preset quality factor value in the quality factor array to obtain a first judgment result;

[0023] If the first determination result indicates yes, the quality value of the image is set to 0.

[0024] If the first determination result indicates no, the average of all elements in the quality factor array is calculated as the quality value of the image.

[0025] Optionally, when the preset direction is the X-axis and Y-axis directions, the quality value of the image is determined based on the stretched absolute value matrix, specifically including:

[0026] The average of the element values in the X-axis direction of the stretched absolute value matrix is calculated to obtain the quality factor array in the X-axis direction, and the average of the element values in the Y-axis direction of the stretched absolute value matrix is calculated to obtain the quality factor array in the Y-axis direction.

[0027] It is determined whether there are T continuous elements with values less than the preset quality factor value in the quality factor array in the X-axis direction and the quality factor array in the Y-axis direction, to obtain a second determination result.

[0028] If the second determination result indicates yes, the quality value of the image is set to 0.

[0029] If the second determination result indicates no, the average of all elements in the quality factor array in the X-axis direction is calculated as the quality value of the image in the X-axis direction, the average of all elements in the quality factor array in the Y-axis direction is calculated as the quality value of the image in the Y-axis direction, and the minimum quality value of the quality value of the image in the X-axis direction and the quality value of the image in the Y-axis direction is taken as the quality value of the image.

[0030] Optionally, the quality value of the image is determined based on the stretched absolute value matrix, and then further includes:

[0031] It is determined whether the quality value of the image is greater than a preset quality value, to obtain a third determination result.

[0032] If the third determination result indicates no, the image is discarded.

[0033] If the third determination result indicates yes, the image is retained.

[0034] A system for determining the quality of an image applied to a photoelectric navigation device, the system being applied to the method described above, and the system comprising:

[0035] An absolute value calculation module for calculating the absolute value of the difference between two adjacent elements in a pixel value matrix of an image in a preset direction, to obtain an absolute value matrix, the preset direction being the X-axis and / or Y-axis direction.

[0036] a threshold calculation module, configured to perform threshold calculation on the absolute value matrix to obtain a multiplication coefficient matrix;

[0037] a stretching module, configured to perform stretching on the absolute value matrix based on the multiplication coefficient matrix to obtain a stretched absolute value matrix;

[0038] a quality value calculation module, configured to determine the quality value of the image based on the stretched absolute value matrix.

[0039] An electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method as described above when executing the computer program.

[0040] A computer readable storage medium, wherein the storage medium stores a computer program, and the computer program is executed to implement the method as described above.

[0041] According to the embodiments of the present application, the following technical effects are provided.

[0042] The present application can calculate the quality value of an image with uniform pixel values or less feature points, reduce the misjudgment rate in the image quality calculation process, and improve the accuracy of the layered image screening process. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0044] Figure 1 The layered image in the image row direction provided for the embodiments of the present application;

[0045] Figure 2 The layered image in the image column direction provided for the embodiments of the present application;

[0046] Figure 3 The flowchart of the image quality determination method provided for the embodiments of the present application;

[0047] Figure 4 The coordinate diagram of the image pixel point arrangement provided for the embodiments of the present application;

[0048] Figure 5 The implementation process diagram of the image quality determination method provided for the embodiments of the present application. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0050] The present application aims to provide a method and system for judging image quality of photoelectric navigation equipment, which can calculate the quality value of an image with uniform pixel values or less feature points by stretching the absolute value matrix with a multiplication coefficient matrix, thereby reducing the misjudgment rate of image quality calculation and improving the accuracy of the layered image screening process.

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0052] As shown in Figure 1 and Figure 2 The layered image is characterized by similar pixel values in one or more regions of the image, but there is a big difference in pixel values between these regions. It is mainly divided into layered in the row direction and layered in the column direction. Such images will affect displacement calculation due to uniform pixel values or less feature points. Therefore, such images with poor image quality should be screened out to ensure accuracy.

[0053] Embodiment 1

[0054] As shown in Figure 3 The present application provides a method for judging image quality of photoelectric navigation equipment, which comprises the following steps:

[0055] Step 101: Calculate the absolute value of the difference between the values of two adjacent elements in the pixel value matrix of the image in a preset direction, to obtain an absolute value matrix, wherein the preset direction is the X-axis and / or Y-axis direction. The above method is not limited to the X direction, but can also be the Y direction, or a combination of the X and / or Y directions.

[0056] As shown in Figure 4 The following calculation is taken as an example with the preset direction being the Y direction:

[0057] First, read and store a frame of image data (pixel value matrix) P[I][J]; calculate the absolute value of the difference between two adjacent points in the Y direction of the image, to obtain a two-dimensional array (absolute value matrix) D[I][J-1].

[0058] Step 102: Perform threshold calculation on the absolute value matrix to obtain a multiplication coefficient matrix, and the formula is as follows:

[0059] di，j <D TH0, m i，j =S1.

[0060] D TH0 ≤d i，j <D TH1 m i，j =S2.

[0061] d i，j ≥D TH1 m i，j =S3.

[0062] i = 1, 2, 3... I.

[0063] j = 1, 2, 3... J-1.

[0064] Where, d i，j Let m be the element in the i-th row and j-th column of the absolute value matrix. i，j D is the element in the i-th row and j-th column of the multiplication coefficient matrix. TH0 As the first threshold, D TH1 S1 is the second threshold, S2 is the first multiplication coefficient value, S3 is the second multiplication coefficient value, I is the horizontal pixel count of the image, and J is the vertical pixel count of the image.

[0065] The following uses the d in the two-dimensional array (absolute value matrix) D[I][J-1] as an example. 1,1 Taking element D as an example for calculation, firstly, let's assume D is a given. TH0 D TH1 Two thresholds are used to define the threshold range: less than D. TH0 ;D TH0 and D TH1 Between; and greater than D TH1 Three ranges; preset three multiplication coefficient values ​​S1, S2, and S3 corresponding to three results that meet the threshold range, and then perform threshold calculations on the absolute value matrix D[I][J-1] one by one. For example: the first multiplication coefficient value S1 = 0; the second multiplication coefficient value S2 = 16; the third multiplication coefficient value S3 = 64.

[0066] Based on the two-dimensional array (absolute value matrix) D[I][J-1], d 1,1 The value of is used to calculate the multiplication coefficients (multiplication coefficient matrix) M[I][J-1) in a threshold manner.

[0067] If d 1,1 <D TH0 Then m 1,1 =0.

[0068] If D TH0 ≤d 1,1 <DTH1 then m 1,1 = 16.

[0069] if d 1,1 ≥ D TH1 then m 1,1 = 64.

[0070] Wherein, the multiplication coefficient (multiplication coefficient matrix) M[I][J-1] can be different values, or the same value.

[0071] As an embodiment of embodiment 1, when the preset direction is X or Y axis direction, the quality value of the image is determined based on the stretched absolute value matrix, specifically comprising:

[0072] Step 103: based on the multiplication coefficient matrix, stretching the absolute value matrix, calculating the product of the absolute value matrix and the multiplication coefficient matrix, obtaining the stretched absolute value matrix.

[0073] Step 104: determining the quality value of the image based on the stretched absolute value matrix.

[0074] Step 103 and step 104 calculation process as follows:

[0075] The number of elements in the preset direction of the stretched absolute value matrix is added to obtain the average value, and the quality factor array is obtained; it is judged whether there are continuous T elements with a value less than the quality factor preset value in the quality factor array, and the first judgment result is obtained; if the first judgment result is yes, the quality value of the image is set to 0; if the first judgment result is no, the average value of all elements in the quality factor array is calculated as the quality value of the image.

[0076] Finally, it is judged whether the quality value of the image is greater than the quality preset value, and the third judgment result is obtained; if the third judgment result is no, the image is discarded; if the third judgment result is yes, the image is retained.

[0077] As Figure 5 shown, the specific calculation process of step 103 and step 104 is: the elements in two-dimensional array (absolute value matrix) D[I][J-1] and multiplication coefficient (multiplication coefficient matrix) M[I][J-1] are multiplied two by two, and the values in Y axis direction are added to obtain one-dimensional array (quality factor array) Q[I]; one-dimensional array (quality factor array) Q[I] is compared one by one, if continuous T values are less than quality factor preset value Q TH1, the image is judged as a layered image, and the image cannot be used for displacement calculation, the image quality is poor, and the frame image is discarded; if the above conditions are not met, all elements in a one-dimensional array (quality factor array) Q[I] are added and averaged to obtain image quality (quality value of the image) Q; if the image quality Q> quality preset value Q TH2 , the image quality is good, and the frame image participates in operation; otherwise, the image quality is poor, and the frame image is discarded.

[0078] As another implementation in embodiment 1, when the preset direction is the X-axis and Y-axis directions, the quality value of the image is determined based on the stretched absolute value matrix, and specifically includes:

[0079] The element values in the X-axis direction of the stretched absolute value matrix are added and averaged to obtain the quality factor array in the X-axis direction, and the element values in the Y-axis direction of the stretched absolute value matrix are added and averaged to obtain the quality factor array in the Y-axis direction.

[0080] It is judged whether there are T consecutive elements with a value less than a quality factor preset value in the quality factor array in the X-axis direction and the quality factor array in the Y-axis direction, to obtain a second judgment result.

[0081] If the second judgment result indicates yes, the quality value of the image is set to 0.

[0082] If the second judgment result indicates no, the average of all elements in the quality factor array in the X-axis direction is calculated as the quality value of the image in the X-axis direction, the average of all elements in the quality factor array in the Y-axis direction is calculated as the quality value of the image in the Y-axis direction, and the minimum quality value of the quality value of the image in the X-axis direction and the quality value of the image in the Y-axis direction is taken as the quality value of the image; step 104 is performed.

[0083] Embodiment 2

[0084] The embodiment of the application also provides a system for judging image quality of a photoelectric navigation device, which is applied to the above method, and includes:

[0085] An absolute value calculation module is configured to calculate the absolute value of the difference between two adjacent element values of a pixel value matrix of an image in a preset direction, to obtain an absolute value matrix, and the preset direction is the X-axis and / or Y-axis direction.

[0086] A threshold calculation module is configured to perform threshold calculation on the absolute value matrix to obtain a multiplication coefficient matrix.

[0087] A stretching module is configured to stretch the absolute value matrix based on the multiplication coefficient matrix to obtain a stretched absolute value matrix.

[0088] a quality value calculation module configured to determine a quality value of the image based on the stretched absolute value matrix.

[0089] Embodiment 3

[0090] The embodiment of the present application also provides an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the method of the embodiment 1 when executing the computer program.

[0091] Embodiment 4

[0092] The embodiment of the present application also provides a computer readable storage medium, and the storage medium stores a computer program, and the computer program is executed to implement the method of the embodiment 1.

[0093] The advantage of the present application is that:

[0094] 1、The present application can be independently processed in each direction, can screen out layered images, and makes the image quality of the image with relatively uniform pixel value or less feature points still be calculated, uses different multiplication coefficient to stretch the difference of image pixel points, reduces the misjudgment rate of image quality calculation, improves the precision of the layered image screening process, improves the screening efficiency, and reduces the misjudgment rate of image quality calculation.

[0095] 2、The present application adopts the method of multiplying the absolute value matrix and the multiplication coefficient matrix, and the calculation is simple, fast and accurate, the quality value of the image with almost no feature points is very small, the quality value of the image with feature points is stretched, the quality value of the image with good quality and the image with poor quality is greatly different, and the threshold selection is simple and convenient.

[0096] The embodiments in the specification are described in a progressive manner, and each embodiment mainly describes the difference from other embodiments, and the same or similar parts of each embodiment can be referred to each other. For the system disclosed by the embodiment, since it corresponds to the method disclosed by the embodiment, the description is relatively simple, and the related parts can be referred to the method part.

[0097] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above embodiment description is only used to help understand the method of the present application and its core idea; meanwhile, for the general technical personnel in the art, according to the idea of the present application, the specific implementation manner and application range can be changed. In conclusion, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A method for judging image quality in optoelectronic navigation devices, characterized in that, The method includes: Calculate the absolute value of the difference between two adjacent element values ​​in the pixel value matrix of the image in a preset direction to obtain the absolute value matrix, wherein the preset direction is the X-axis and / or Y-axis direction; The absolute value matrix is ​​thresholded to obtain the multiplication coefficient matrix, and the formula is as follows: d i，j <D TH0 , m i，j =S1; D TH0 ≤d i，j <D TH1 , m i，j =S2; d i，j ≥D TH1 ,m i，j =S3; i = 1, 2, 3...I; j = 1, 2, 3...J-1; Where, d i，j Let m be the element in the i-th row and j-th column of the absolute value matrix. i，j D is the element in the i-th row and j-th column of the multiplication coefficient matrix. TH0 As the first threshold, D TH1 S1 is the second threshold, S2 is the first multiplication coefficient value, S3 is the second multiplication coefficient value, I is the horizontal pixel count of the image, and J is the vertical pixel count of the image. The absolute value matrix is ​​stretched based on the multiplication coefficient matrix to obtain the stretched absolute value matrix. Specifically, this includes: calculating the product of the absolute value matrix and the multiplication coefficient matrix to obtain the stretched absolute value matrix. The quality value of the image is determined based on the stretched absolute value matrix; Specifically, when the preset direction is the X-axis or Y-axis, the quality value of the image is determined based on the stretched absolute value matrix. This includes: summing the values ​​of the elements in the stretched absolute value matrix along the preset direction and averaging them to obtain a quality factor array; determining whether there are T consecutive elements in the quality factor array whose values ​​are less than a preset quality factor value to obtain a first determination result; if the first determination result indicates yes, then the quality value of the image is set to 0; if the first determination result indicates no, then the average value of all elements in the quality factor array is calculated as the quality value of the image. Specifically, the process involves determining whether there are T consecutive elements in the quality factor array whose values ​​are less than a preset quality factor value to obtain a first determination result. If the first determination result indicates yes, the quality value of the image is set to 0. If the first determination result indicates no, the average value of all elements in the quality factor array is calculated as the quality value of the image. This includes comparing the quality factor array one by one. If T consecutive values ​​are less than the preset quality factor value, the image is determined to be a layered image, which cannot be used for displacement calculation, and the image quality is poor. This frame of the image is then discarded. If the condition is not met, the average value of all elements in the quality factor array is calculated to obtain the quality value of the image. When the preset directions are the X-axis and Y-axis, the quality value of the image is determined based on the stretched absolute value matrix. Specifically, this includes: averaging the values ​​of the elements in the X-axis direction of the stretched absolute value matrix to obtain a quality factor array in the X-axis direction; averaging the values ​​of the elements in the Y-axis direction of the stretched absolute value matrix to obtain a quality factor array in the Y-axis direction; determining whether there are T consecutive elements in the quality factor arrays in the X-axis and Y-axis directions whose values ​​are less than a preset quality factor value, and obtaining a second determination result; if the second determination result indicates yes, then the quality value of the image is set to 0; if the second determination result indicates no, then the average value of all elements in the quality factor array in the X-axis direction is calculated as the quality value in the X-axis direction of the image, and the average value of all elements in the quality factor array in the Y-axis direction is calculated as the quality value in the Y-axis direction of the image, and the minimum quality value between the quality value in the X-axis and Y-axis directions of the image is taken as the quality value of the image.

2. The method for judging image quality in optoelectronic navigation equipment according to claim 1, characterized in that, The quality value of the image is determined based on the stretched absolute value matrix, and then the process further includes: Determine whether the image quality value is greater than the preset quality value to obtain the third judgment result; If the third judgment result is negative, then the image is discarded; If the third judgment result indicates yes, then the image is retained.

3. A system for judging image quality in optoelectronic navigation equipment, characterized in that, The system is applied to the method according to any one of claims 1-2, the system comprising: An absolute value calculation module is used to calculate the absolute value of the difference between two adjacent element values ​​in the pixel value matrix of an image in a preset direction, so as to obtain an absolute value matrix. The preset direction is the X-axis and / or Y-axis direction. The threshold calculation module is used to perform threshold calculation on the absolute value matrix to obtain the multiplication coefficient matrix; The stretching module is used to stretch the absolute value matrix based on the multiplication coefficient matrix to obtain the stretched absolute value matrix. The quality value calculation module is used to determine the quality value of the image based on the stretched absolute value matrix.

4. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method as described in any one of claims 1-2.

5. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed, implements the method as described in any one of claims 1-2.

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