LED display unit acquisition correction method

Abstract

The application relates to an LED display unit collection correction method, which excludes light spot bottom noise and cross interference, determines complete light spot brightness true value by using a steep region at the top of the light spot, realizes accurate collection and correction of LED display unit pixel brightness, and greatly improves collection efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of LED display optical acquisition and correction, and relates to a method for accurately acquiring pixel brightness of an LED display unit. Background Art

[0002] Conventional pixel acquisition requires accurate display, assuming adjacent light spots do not intersect, eliminating crosstalk. First, the light spots must be completely segmented. Then, the brightness integral of the complete spot is acquired, and the noise value is subtracted to obtain the true brightness value. Ensuring that adjacent light spots do not intersect requires acquisition in alternate rows and columns with sufficiently large intervals, which increases time costs and complexity. If correction coefficients can be calculated to account for the effects of adjacent light spot crosstalk during closely spaced acquisition, even in surface acquisition, significant acquisition time can be saved. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an LED display unit acquisition and correction method that can eliminate light spot bottom noise and cross interference.

[0004] In order to solve the above technical problems, the LED display unit acquisition and correction method of the present invention is as follows:

[0005] A camera is used to capture an image P2 of an LED display unit in the presence of cross-influence between the brightness of adjacent light spots. The camera pixel brightness values ​​at multiple discrete coordinate points in image P2 are fitted to obtain a continuous, smooth three-dimensional image Q2. Assuming the image plane is the xy plane, the three-dimensional image contains the coordinates of each point on the xy plane and its corresponding brightness value. For any light spot i in the three-dimensional image Q2, the brightness integral value of the brightness value above the inflection point brightness value is calculated and de-noised to obtain the brightness integral true value Mi. The complete spot brightness integral true value Fi of light spot i is calculated according to the following formula:

[0006]

[0007] in is the average value of the proportion above the predetermined inflection point, is the predetermined normalized proportion average;

[0008] The correction coefficient can be obtained according to the integral true value of the complete light spot brightness of each light spot, thereby correcting the LED display unit.

[0009] Furthermore, for any light spot i in the three-dimensional image Q2, the brightness values ​​of each coordinate point can be normalized according to the peak value; the brightness integral value of the normalized brightness value above the inflection point normalized brightness value is calculated and denoised to obtain the brightness integral true value Mi.

[0010] Furthermore, when all pixels of the LED display unit are fully lit, a camera is used to capture a picture P2 of the LED display unit.

[0011] Furthermore, the LED display unit image P2 may be captured by a camera when alternate rows and columns of pixels of the LED display unit are lit.

[0012] The average value of the proportion above the inflection point and the normalized mean value of the proportion Determined using the following method:

[0013] When there is no cross-influence on the brightness between adjacent light spots, a camera is used to capture an LED display unit image P1 when alternate rows and columns of pixels are lit; when there is cross-influence on the brightness between adjacent light spots, a camera is used to capture an LED display unit image P2;

[0014] Fitting the camera pixel brightness values ​​of multiple discrete coordinate points in images P1 and P2 to obtain continuous and smooth three-dimensional images Q1 and Q2 respectively;

[0015] For any light spot in the three-dimensional image Q1, calculate the brightness integral value of the brightness value above the inflection point brightness value and remove the noise to obtain the brightness integral true value M1; calculate the brightness integral value of the complete light spot and remove the noise to obtain the brightness integral true value F1; calculate the proportion of the brightness integral true value M1 in the brightness integral true value F1 to obtain the proportion above the inflection point r1;

[0016] r1=M1 / F1

[0017] For the corresponding light spot in the 3D image Q2, calculate the brightness integral value of the brightness value above the inflection point brightness value and remove the noise to obtain the brightness integral true value M2; normalize the brightness integral true value M2 to the brightness integral true value M1 to obtain the normalized proportion r2;

[0018]

[0019] Calculate the average value of the proportion r1 above the inflection point corresponding to all light spots in the three-dimensional image Q1 to obtain the average value of the proportion above the inflection point Calculate the average value of the normalized proportion r2 corresponding to all the spots in the three-dimensional image Q1 to obtain the normalized proportion average value

[0020] Furthermore, for any light spot in the three-dimensional image Q1, the brightness values ​​of each coordinate point can be normalized according to the peak value, and then the normalized brightness value at the inflection point A is calculated. g The above brightness integral value is de-noised to obtain the brightness integral true value M.

[0021] Furthermore, for the corresponding light spot in the three-dimensional image Q2, the brightness value of each coordinate point can be normalized according to the peak value, and then the normalized brightness value at the inflection point normalized brightness value A can be calculated. g The above brightness integral value is de-noised to obtain the brightness integral true value M2.

[0022] The present invention provides a method for extracting the brightness of a complete light spot from light spots that intersect and interfere with each other. Because the pixels are too small, there is mutual intersection at the bottom of the light spot, that is, the brightness of the light spot is distorted, while the top of the high-brightness light spot is minimally interfered with by the adjacent light spots, and the steep area at the top of the light spot already includes all the brightness information of the complete light spot. The present invention eliminates the noise and cross-interference at the bottom of the light spot, uses the steep area at the top of the light spot to determine the true value of the brightness of the complete light spot, and realizes the accurate collection and correction of the pixel brightness of the LED display unit. For LED display units with the same pixel spacing, only one picture is collected when all pixels are lit, and the integral true value of the brightness of the complete light spot of all pixels can be obtained according to the predetermined average value of the proportion above the inflection point and the normalized average value of the proportion; for LED display units with the same smaller spacing, multiple pictures containing all the light spots are collected by lighting pixels in alternate rows and columns, and the integral true value of the brightness of the complete light spot of all pixels is obtained according to the predetermined average value of the proportion above the inflection point and the normalized average value of the proportion, which greatly improves the collection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the spot brightness curve when there is no cross-influence between the bottom brightness of adjacent spots.

[0024] Figure 2 It is the spot brightness curve when there is cross-influence between the bottom brightness of adjacent spots.

[0025] Figure 3 It is the brightness curve of a single light spot under surface acquisition, acquisition at intervals of 2, acquisition at intervals of 4, and acquisition at intervals of 8. The horizontal direction is the x-coordinate and the vertical direction is the normalized brightness value.

[0026] Figure 4 It is the brightness curve of a single light spot collected at a surface interval of 4. The horizontal direction is the x-coordinate and the vertical direction is the normalized brightness value.

[0027] Figure 5 It is the brightness curve of a single light spot collected every 4 seconds. The horizontal direction is the x-coordinate and the vertical direction is the normalized brightness value.

[0028] Figure 6 It is the brightness curve of a single light spot collected every 8 seconds. The horizontal direction is the x-coordinate and the vertical direction is the normalized brightness value.

[0029] Figure 7 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0030] The application will be described in further detail below with reference to the drawings and embodiments, it should be understood that the specific embodiments described herein are merely intended for the purpose of interpretation of the application and are not intended to limit the application. In addition, it should be noted that only the parts related to the application are shown in the drawings for the purpose of description, rather than all the structures.

[0031] In the description of the application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0032] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include the direct contact of the first and second features, or can include the contact of the first and second features through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature to the second feature includes the vertical and oblique above of the first feature to the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature includes the vertical and oblique below of the first feature to the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0033] In the description of the present embodiment, the terms "upper", "lower", "left", "right" and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is only for the purpose of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0034] First, the feasibility of the LED display unit acquisition correction method of the present application is verified by the following method:

[0035] Step one, when the LED display unit pixels are lit every 4 rows and every 4 columns, use the camera to collect the LED display unit picture P1, a total of 16 pictures, as shown in Figure 1 In this case, there is no cross influence between the brightness of adjacent light spots; when all the pixels of the LED display unit are lit, use the camera to collect the LED display unit picture P2, as shown in Figure 2 In this case, there is cross influence between the brightness of adjacent light spots.

[0036] Step 2: Use the camera pixel brightness values ​​of multiple discrete coordinate points in the 16 images P1 and P2 to fit and obtain 16 continuous and smooth three-dimensional images Q1 and 1 three-dimensional image Q2 respectively; assume that the plane where the image is located is the xy plane, and the three-dimensional image contains the coordinates of each point on the xy plane and its corresponding brightness value.

[0037] Step 3. Select any light spot in the three-dimensional image Q1 and normalize the brightness values ​​of each of its coordinate points according to the peak value (that is, normalize according to the peak brightness value of 1, or do not perform normalization); draw a square A parallel to the xy plane with the peak point as the center and the period length 2D0 of the light spot as the side length; normalize the brightness values ​​of each of the coordinate points of the corresponding light spot in the three-dimensional image Q2 according to the peak value (or do not perform normalization); draw a square B parallel to the xy plane with the peak point as the center and the period length 2D0 of the light spot as the side length; that is, the number of coordinate points in the x-direction and y-direction in squares A and B is 2D0; calculate the correlation coefficient r of the corresponding light spots in the three-dimensional images Q1 and Q2 according to the following two-dimensional correlation coefficient formula, and compare the similarity of the two light spots.

[0038]

[0039] Among them, A (i，j) is the brightness value corresponding to any coordinate point (i, j) in square A, is the average value of the normalized brightness values ​​of all coordinate points in square A; B (i，j) is the brightness value corresponding to any coordinate point (i, j) in square B, is the average of the normalized brightness values ​​of all coordinate points in square B.

[0040] The method for obtaining the correlation coefficient r is not limited to the above method. You can also draw a circle parallel to the xy plane with the peak point as the center and the half-period length D0 of the light spot as the radius, and calculate the correlation coefficient of the two light spots based on the brightness values ​​of each coordinate point in the circular area where the light spots are located in the three-dimensional image Q1 and the three-dimensional image Q2.

[0041] The closer the correlation coefficient r is to ±1, the stronger the correlation between the two light spots is.

[0042] If the correlation coefficient between the two light spots is greater than 0.8, that is, the light spots with cross-influence at the bottom of the two light spots are strongly correlated with the complete light spots, it indicates that the cross-influenced light spots are likely to be restored to complete light spots, which is a prerequisite for the implementation of the present invention.

[0043] Step 4: Align the peak positions of the corresponding light spots in the three-dimensional images Q1 and Q2, and qualitatively observe that the inflection point of the light spot brightness value in the three-dimensional image Q2 appears near 0.6 times the peak value, as shown in the figure below. Figure 3 、 4as shown. Let the knee point normalized luminance value be A g =0.6, for any spot in the three-dimensional image Q1, the normalized luminance value at the knee point normalized luminance value A g The above luminance integral value is calculated and denoised to obtain the luminance integral true value M1 of the I1 region; the luminance integral value of the complete spot is calculated and denoised to obtain the luminance integral true value F1 of the I2 region; and the proportion r1 of the luminance integral true value M1 in the luminance integral true value F1 is calculated according to the following formula.

[0044] r1=M1 / F1

[0045] For the corresponding spot in the three-dimensional image Q2, the normalized luminance value at the knee point normalized luminance value A g The above luminance integral value is calculated and denoised to obtain the luminance integral true value M2 of the J region. The luminance integral true value M2 is normalized to the luminance integral true value M1 to obtain the normalized proportion r2;

[0046]

[0047] The complete spot luminance integral true value F2 of the spot is calculated according to the following formula.

[0048]

[0049] Similarly, the complete spot luminance integral true value F2 of all spots in the three-dimensional image Q2 is obtained.

[0050] Step five, the correction coefficient of each spot is calculated according to the complete spot luminance integral true value F2, to obtain the correction coefficient matrix of all pixels of the LED display unit, the correction coefficient matrix is uploaded to the control system, and the correction effect is observed. Experiments prove that the correction effect is good, which shows that the LED display unit pixel luminance can be accurately collected by using the present application.

[0051] As Figure 7 shown, taking the LED display unit with a large pixel pitch d1 as an example, the LED display unit collection and correction method of the present application is as follows:

[0052] Step 1, collect the picture P2 with the camera when all the pixels of the LED display unit are lit, and in this case, there is a cross-influence between the luminance of adjacent spots;

[0053] Step 2, fit the camera pixel luminance values of multiple discrete coordinate points in the picture P2 to obtain a continuous and smooth three-dimensional image Q2; let the plane of the picture be the xy plane, and the three-dimensional image contains the coordinates of each point on the xy plane and the corresponding luminance values;

[0054] Step 3: For any light spot i in the three-dimensional image Q2, calculate the brightness integral value of the area above the inflection point brightness value and remove noise to obtain the brightness integral true value Mi of area J; calculate the complete spot brightness integral true value Fi of light spot i according to the following formula;

[0055]

[0056] in is the average value of the proportion above the predetermined inflection point, is the predetermined normalized proportion average;

[0057] Similarly, the complete spot brightness integral true value of all spots can be obtained.

[0058] The correction coefficient can be obtained according to the integral true value of the complete light spot brightness of each light spot, thereby correcting the LED display unit.

[0059] In the step 3, for any light spot i in the three-dimensional image Q2, the brightness value of each coordinate point is normalized according to the peak value (ie, normalized according to the peak brightness value of 1); the normalized brightness value is calculated at the inflection point normalized brightness value A g The above brightness integral values ​​are denoised to obtain the brightness integral true value Mi of area J.

[0060] When calibrating an LED display unit with a smaller spacing d2, the camera can be used to capture 16 LED display unit images P2 containing the corresponding light spots of all pixels when the pixels on the LED display unit are lit every 4 rows and 4 columns. and the normalized mean value of the proportion Calculate the complete spot brightness integral true value of the spot corresponding to all pixels.

[0061] The average value of the proportion above the inflection point and the normalized mean value of the proportion Determined using the following method:

[0062] Step (1): When every four rows and every four columns of pixels on the LED display unit are lit, use the camera to capture one of the LED display unit images P1. In this case, there is no cross-influence on the brightness between adjacent light spots. When all pixels on the LED display unit are fully lit, use the camera to capture the LED display unit image P2. In this case, there is a cross-influence on the brightness between adjacent light spots.

[0063] Step (2) is to fit the camera pixel brightness values ​​of multiple discrete coordinate points in the images P1 and P2 to obtain continuous and smooth three-dimensional images Q1 and Q2 respectively; assuming that the plane where the images are located is the xy plane, the three-dimensional image contains the coordinates of each point on the xy plane and its corresponding brightness value.

[0064] Step (3): for any light spot in the three-dimensional image Q1, calculate the brightness integral value of the brightness value above the inflection point brightness value and remove the noise, to obtain the brightness integral true value M1 of the I1 area; calculate the brightness integral value of the complete light spot and remove the noise, to obtain the brightness integral true value F1 of the I2 area; calculate the proportion of the brightness integral true value M1 in the brightness integral true value F1 to obtain the proportion above the inflection point r1;

[0065] r1=M1 / F1

[0066] Step (4): For the corresponding light spot in the three-dimensional image Q2, calculate the brightness value at the inflection point normalized brightness value A g The above brightness integral value is denoised to obtain the brightness integral true value M2 of region J. The brightness integral true value M2 is normalized to the brightness integral true value M1 to obtain the normalized proportion r2,

[0067]

[0068] The average value of the proportion r1 above the inflection point corresponding to all light spots in the three-dimensional image Q1 is the average value of the proportion above the inflection point The average value of the normalized proportion r2 corresponding to all the spots in the three-dimensional image Q1 is the normalized proportion average value

[0069] In the step (3), for any light spot in the three-dimensional image Q1, the brightness value of each coordinate point can be normalized according to the peak value, and the normalized brightness value at the inflection point normalized brightness value A is calculated. g The above brightness integral value is de-noised to obtain the brightness integral true value M1 of the I1 region; in the step (4), for the corresponding light spot in the three-dimensional image Q2, the brightness value of each coordinate point is first normalized according to the peak value, and the normalized brightness value at the inflection point normalized brightness value A is calculated. g The brightness integral value under the above area is removed by noise to obtain the brightness integral true value M2 of area J.

[0070] For any LED display unit with a spacing of d1, it is only necessary to use the same camera to capture an LED display unit image P2 when all pixels on the LED display unit are fully lit, and then the average value of the proportion above the predetermined inflection point can be obtained. and the normalized mean value of the proportion The complete integral true value of the brightness of each light spot is calculated, and the acquisition efficiency is improved several times.

[0071] For LED display units with a smaller spacing d2, a camera can be used to capture an LED display unit image P1 when every 8 rows and 8 columns of pixels on the LED display unit are lit. In this case, there is no cross-influence on the brightness between adjacent light spots. A camera can be used to capture an LED display unit image P2 when every 4 rows and 4 columns of pixels on the LED display unit are lit. In this case, there is cross-influence on the brightness between adjacent light spots. This is used to determine the average proportion above the inflection point. and the normalized mean value of the proportion

[0072] The present invention is not limited to the above embodiment. For boxes with the same camera and the same spot spacing, the proportional relationship is fixed. The average value is determined by collecting data in every other row and column at a sufficiently large interval (at this time, there is no cross-influence on the brightness between adjacent spots). and average After that, in the subsequent correction process, only small-interval alternate row and column acquisition or surface acquisition is required. By using the above-mentioned invention method, the true value of the integral brightness of the light spot on the entire screen can be obtained, which can be used to calculate the correction coefficients of all pixels, which can effectively improve the acquisition efficiency.

Claims

1. A method for collecting and correcting LED display units, characterized in that The method is as follows: A camera is used to capture an image P2 of an LED display unit in the presence of cross-influence between the brightness of adjacent light spots. The camera pixel brightness values ​​at multiple discrete coordinate points in image P2 are fitted to obtain a continuous, smooth three-dimensional image Q2. Assuming that the plane on which image P2 resides is the xy plane, the three-dimensional image Q2 contains the coordinates of each point on the xy plane and its corresponding brightness value. For any light spot i in the three-dimensional image Q2, the brightness integral value of the brightness value above the inflection point brightness value is calculated and de-noised to obtain the brightness integral true value Mi. The complete spot brightness integral true value Fi of light spot i is calculated according to the following formula: in is the average value of the proportion above the predetermined inflection point, is the predetermined normalized proportion average; The correction coefficient can be obtained according to the integral true value of the complete light spot brightness of each light spot, thereby correcting the LED display unit; The average value of the proportion above the inflection point and the normalized mean value of the proportion Determined using the following method: When there is no cross-influence on the brightness between adjacent light spots, a camera is used to capture an LED display unit image P1 when alternate rows and columns of pixels are lit; when there is cross-influence on the brightness between adjacent light spots, a camera is used to capture an LED display unit image P2; Fitting the camera pixel brightness values ​​of multiple discrete coordinate points in images P1 and P2 to obtain continuous and smooth three-dimensional images Q1 and Q2 respectively; For any light spot in the three-dimensional image Q1, calculate the brightness integral value of the brightness value above the inflection point brightness value and remove the noise to obtain the brightness integral true value M1; Calculate the brightness integral value of the complete light spot and remove noise to obtain the true brightness integral value F1; Calculate the proportion of the brightness integral true value M1 in the brightness integral true value F1 to obtain the proportion above the inflection point r1; r1=M1 / F1 For the corresponding light spot in the 3D image Q2, calculate the brightness integral value of the brightness value above the inflection point brightness value and remove the noise to obtain the brightness integral true value M2; normalize the brightness integral true value M2 to the brightness integral true value M1 to obtain the normalized proportion r2; Calculate the average value of the proportion r1 above the inflection point corresponding to all light spots in the three-dimensional image Q1 to obtain the average value of the proportion above the inflection point Calculate the average value of the normalized proportion r2 corresponding to all the spots in the three-dimensional image Q1 to obtain the normalized proportion average value 2. The LED display unit acquisition and correction method according to claim 1, characterized in that: For any light spot i in the three-dimensional image Q2, the brightness values ​​of each coordinate point are first normalized according to the peak value; the brightness integral value of the normalized brightness value above the inflection point normalized brightness value is calculated and denoised to obtain the brightness integral true value Mi.

3. The LED display unit acquisition and correction method according to claim 1, characterized in that: When all pixels of the LED display unit are fully lit, a camera is used to capture an LED display unit image P2.

4. The LED display unit acquisition and correction method according to claim 1, characterized in that: When alternate rows and columns of pixels of the LED display unit are lit, a camera is used to capture an LED display unit image P2.

5. The LED display unit acquisition and correction method according to claim 1, characterized in that: For any light spot in the three-dimensional image Q1, the brightness value of each coordinate point is normalized according to the peak value, and then the normalized brightness value at the inflection point A is calculated. g The above brightness integral value is de-noised to obtain the brightness integral true value M1.

6. The LED display unit acquisition and correction method according to claim 1, characterized in that: For the corresponding light spot in the three-dimensional image Q2, the brightness value of each coordinate point is first normalized according to the peak value, and then the normalized brightness value at the inflection point is calculated. g The above brightness integral value is de-noised to obtain the brightness integral true value M2.

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