Brightness balance correction method, device, image acquisition device and storage medium

Abstract

The present application provides a brightness balance correction method, device, image acquisition equipment and storage medium. The method includes: obtaining an image to be corrected; reading the photosensitivity of each pixel in the image to be corrected and the distance between each pixel and the optical axis pixel; determining the correction value of each pixel based on a preset brightness balance correction function, the photosensitivity of each pixel and the distance between each pixel and the optical axis pixel; wherein the brightness balance correction function is a linear function. In an embodiment of the present application, the preset brightness balance correction function is a linear function, that is, the current one-dimensional multi-time brightness correction curve is simplified to a straight line equation, thereby reducing the calculation amount and delay of the brightness balance correction, and this method can also reduce hardware resource overhead.

Description

Technical Field

[0001] The present application relates to the field of camera technology, and more specifically, to a brightness balance correction method and device, an image acquisition device and a storage medium. Background Art

[0002] The brightness of the image captured by the camera will gradually dim along the radial direction centered on the intersection of the lens optical axis and the image (i.e., the optical axis pixel point). Especially in fisheye cameras (a wide-angle camera), the brightness difference between the image optical axis pixel point and the image corners can reach 2 to 3.5 times. Therefore, for camera applications, especially wide-angle cameras, it is necessary to perform brightness balance correction on the captured images.

[0003] Currently, the most common brightness balance correction method is to use a uniform light intensity correction device, with the optical axis pixel point as the center, measure the brightness value along the radial direction of the center point, and use the brightness correction value of the center point as 1, calculate the brightness correction value along the radial direction of the center point, and then perform polynomial curve fitting. However, this method has high requirements on hardware resources and will cause high latency. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a brightness balance correction method, device, image acquisition equipment and storage medium, so as to provide a brightness balance correction method with low hardware resource requirements and low latency.

[0005] The present invention is achieved in that:

[0006] In a first aspect, an embodiment of the present application provides a brightness balance correction method, comprising: acquiring an image to be corrected; reading the photosensitivity value of each pixel in the image to be corrected and the distance between each pixel and the optical axis pixel; determining the correction value of each pixel based on a preset brightness balance correction function, the photosensitivity value of each pixel and the distance between each pixel and the optical axis pixel; wherein the preset brightness balance correction function includes a linear function.

[0007] In an embodiment of the present application, the preset brightness balance correction function includes a linear function, that is, the current one-dimensional multi-time brightness correction curve is simplified into a straight line equation, thereby reducing the calculation amount and delay of the brightness balance correction, and this method can also reduce hardware resource overhead.

[0008] In combination with the technical solution provided in the first aspect above, in some possible implementations, the function parameter of the preset brightness balance correction function includes the square of the distance between the pixel point and the optical axis pixel point.

[0009] In an embodiment of the present application, the function parameters of the preset brightness balance correction function include the square of the distance between the pixel point and the optical axis pixel point, that is, the square of the distance between the pixel point and the optical axis pixel point can be used as the independent variable, and the brightness correction curve can be simplified into a straight line equation. In this way, the calculation amount and delay of the brightness balance correction can be reduced while ensuring that the brightness balance correction has a better effect.

[0010] In combination with the technical solution provided in the first aspect above, in some possible implementations, the expression of the preset brightness balance correction function is: K(r 2 )=a0+a2r 2 ; Among them, K(r 2 ) represents the brightness correction coefficient; a0 represents the first brightness correction parameter, a2 represents the second brightness correction parameter; r 2 Represents the square of the distance between the pixel point and the optical axis pixel point.

[0011] In combination with the technical solution provided in the first aspect above, in some possible implementation methods, the correction value of each pixel is determined based on the preset brightness balance correction function, the photosensitivity of each pixel and the distance between each pixel and the optical axis pixel, including: performing integer operations based on the preset brightness balance correction function, the photosensitivity of each pixel and the distance between each pixel and the optical axis pixel to determine the correction value of each pixel; wherein the operation of the preset brightness balance correction function adopts binary shift integer operations.

[0012] In an embodiment of the present application, the operation of the preset brightness balance correction function adopts binary shift integer operation, that is, the current floating-point operation of the brightness balance correction is converted into integer operation. In this way, the calculation amount and delay of the brightness balance correction can be further reduced, and the hardware resource overhead can be further reduced.

[0013] In combination with the technical solution provided in the first aspect above, in some possible implementations, the expression of the preset brightness balance correction function is: n-m K(r 2 )=2 n-m +Int(2 n *a2)*Int(r 2 *2 -m ); wherein n represents the first preset parameter; m represents the second preset parameter; and Int() represents rounding down to an integer.

[0014] In combination with the technical solution provided in the first aspect above, in some possible implementations, the first preset parameter and the second preset parameter are determined by a preset formula: the preset formula is: Where L represents the number of bits of the multiplier, and the number of bits of the adder is 2L; R = Int (r 2 *2 -m ); k = 2 n-m *K(r 2 ); The setting conditions of the preset formula are: 2 The maximum value is less than 2 R ; K(r 2 ) is less than 2 k .

[0015] In the embodiment of the present application, by configuring the above preset formula, the integer operation bit length can be reduced, and the maximum accuracy of brightness balance correction can be achieved under the integer operation conditions supported by the hardware.

[0016] In combination with the technical solution provided in the first aspect above, in some possible implementations, the optical axis pixel point is the center point of the image to be corrected.

[0017] In an embodiment of the present application, the center point of the image to be corrected is directly used as the optical axis pixel point, so that there is no need to first verify the position of the optical axis pixel point during each brightness balance correction process. In this way, the efficiency of the brightness balance correction can be improved, and at the same time, it will not cause a significant impact on the correction result.

[0018] In a second aspect, an embodiment of the present application provides a brightness balance correction device, comprising: an acquisition module, used to acquire an image to be corrected; a reading module, used to read the photosensitivity value of each pixel point in the image to be corrected and the distance between each pixel point and the optical axis pixel point; a correction module, used to determine the correction value of each pixel point based on a preset brightness balance correction function, the photosensitivity value of each pixel point and the distance between each pixel point and the optical axis pixel point; wherein the preset brightness balance correction function includes a linear function.

[0019] In a third aspect, an embodiment of the present application provides an image acquisition device, comprising: a processor and a memory, wherein the processor and the memory are connected; the memory is used to store programs; the processor is used to call the programs stored in the memory to execute the method provided in the above-mentioned first aspect embodiment and / or in combination with some possible implementation methods of the above-mentioned first aspect embodiment.

[0020] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, executes a method provided in the embodiment of the first aspect above and / or in combination with some possible implementations of the embodiment of the first aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A module block diagram of an image acquisition device provided in an embodiment of the present application.

[0023] Figure 2 A flowchart of the steps of a brightness balance correction method provided in an embodiment of the present application.

[0024] Figure 3 A schematic diagram of a preset brightness balance correction function provided in an embodiment of the present application.

[0025] Figure 4 A module block diagram of a brightness balance correction device provided in an embodiment of the present application.

[0026] Icon: 100 - image acquisition device; 110 - processor; 120 - memory; 200 - brightness balance correction device; 210 - acquisition module; 220 - reading module; 230 - correction module. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0028] See also Figure 1 , a schematic structural block diagram of an image acquisition device 100 applying a brightness balance correction method and apparatus provided in an embodiment of the present application. In the embodiment of the present application, the image acquisition device 100 is a device including a camera, which can be but not limited to a video camera, a camera, a mobile phone, a tablet computer, etc. The above-mentioned camera can be but not limited to a fisheye camera or a panoramic camera. It should be noted that the above-mentioned devices and cameras are only used to facilitate the understanding of the embodiments of the present application, and should not be used as a limitation on the present embodiment.

[0029] Structurally, the image acquisition device 100 may include a processor 110 and a memory 120 .

[0030] The processor 110 is electrically connected to the memory 120 directly or indirectly to realize data transmission or interaction. For example, these elements can be electrically connected to each other through one or more communication buses or signal lines. The brightness balance correction device includes at least one software module that can be stored in the memory 120 in the form of software or firmware or solidified in the operating system (OS) of the image acquisition device 100. The processor 110 is used to execute the executable module stored in the memory 120, for example, the software function module and computer program included in the brightness balance correction device, so as to realize the brightness balance correction method. The processor 110 can execute the computer program after receiving the execution instruction.

[0031] The processor 110 may be an integrated circuit chip with signal processing capability. The processor 110 may also be a general-purpose processor, for example, a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. In addition, the general-purpose processor may be a microprocessor or any conventional processor, etc.

[0032] The memory 120 may be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), and an electric erasable programmable read-only memory (EEPROM). The memory 120 is used to store a program, and the processor 110 executes the program after receiving an execution instruction.

[0033] It should be noted that Figure 1 The structure shown is for illustration only. The image acquisition device 100 provided in the embodiment of the present application may also have Figure 1 Fewer or more components, or with Figure 1 In addition, Figure 1The components shown may be implemented by software, hardware or a combination thereof.

[0034] See also Figure 2 , Figure 2 A flowchart of the steps of the brightness balance correction method provided in the embodiment of the present application, which is applied to Figure 1 The image acquisition device 100 shown in FIG. 1 is a device for capturing images of a plurality of pixels. It should be noted that the brightness balance correction method provided in the embodiment of the present application is not based on Figure 2 The order shown below is limited, and the method includes: step S101-step S103.

[0035] Step S101: Acquire an image to be corrected.

[0036] The image to be corrected is an image taken by a camera of the image acquisition device 100 .

[0037] Step S102: reading the photosensitivity value of each pixel point in the image to be corrected and the distance between each pixel point and the optical axis pixel point.

[0038] The photosensitivity value V of each pixel point in the image to be corrected and the distance r between each pixel point and the optical axis pixel point are read in sequence.

[0039] Among them, the expression of the distance r between each pixel point and the optical axis pixel point is:

[0040]

[0041] In formula (1), x and y represent the horizontal coordinate and vertical coordinate of a pixel point in the image to be corrected; x0 and y0 represent the horizontal coordinate and vertical coordinate of the pixel point on the optical axis.

[0042] In one embodiment, the optical axis pixel point may be used as the center of the circle and circles may be constructed in sequence according to different radii. Accordingly, the distance between each pixel point and the optical axis pixel point is read to determine the radius r of the circle where each pixel point is located.

[0043] In one embodiment, the optical axis pixel point is the center point of the image to be corrected.

[0044] In an embodiment of the present application, the center point of the image to be corrected is directly used as the optical axis pixel point, so that there is no need to first verify the position of the optical axis pixel point during each brightness balance correction process. In this way, the efficiency of the brightness balance correction can be improved. At the same time, it will not cause a significant impact on the correction result. That is, it is difficult for the human eye to distinguish the difference between the results of brightness balance correction using the real optical axis pixel point and the results of brightness balance correction using the center point of the image to be corrected.

[0045] Step S103: determining the correction value of each pixel based on a preset brightness balance correction function, the photosensitivity of each pixel, and the distance between each pixel and the optical axis pixel; wherein the preset brightness balance correction function includes a linear function.

[0046] Finally, the correction value of each pixel is determined based on the preset brightness balance correction function, the photosensitivity of each pixel, and the distance between each pixel and the optical axis pixel. The correction value of each pixel is determined using the following formula:

[0047] V c =V*K(r) (2)

[0048] In formula (2), V c represents the correction value of the pixel, V represents the light sensitivity value of the pixel, and K(r) represents the brightness correction coefficient corresponding to the pixel. The brightness balance correction function corresponding to K(r) is the preset brightness balance correction function, and the corrected brightness balance correction function is a linear function. The preset brightness balance correction function provided in the embodiment of the present application can be referred to Figure 3 The hint, Figure 3 In the example, the brightness balance correction function is preset as a straight line equation.

[0049] That is, in the embodiment of the present application, the current one-dimensional multi-time brightness correction curve is simplified to a straight line equation, thereby reducing the amount of calculation and delay of brightness balance correction, and this method can also reduce hardware resource overhead.

[0050] In the embodiment of the present application, the function parameter of the preset brightness balance correction function includes the square of the distance between the pixel point and the optical axis pixel point.

[0051] Specifically, the horizontal coordinate of the preset brightness balance correction function may be the square of the distance between the pixel point and the optical axis pixel point.

[0052] That is, Figure 1 The horizontal axis r of the brightness correction curve shown in is replaced by r 2 , accordingly, Figure 1 The ordinate K(r) of the brightness correction curve shown in FIG. 1 is replaced by K(r 2 ).

[0053] Among them, the expression of the preset brightness balance correction function is:

[0054] K(r 2 )=a0+a2r 2 (3)

[0055] In formula (3), K(r 2 ) represents the brightness correction coefficient; a0 represents the first brightness correction parameter, a2 represents the second brightness correction parameter; r2 Represents the square of the distance between the pixel and the optical axis pixel.

[0056] It should be noted that, since the brightness usually gradually darkens in the radial direction with the optical axis pixel as the center, the brightness correction coefficient of the optical axis pixel is set to 1, that is, during the brightness balance correction process, the photosensitivity of the optical axis pixel remains unchanged. 2 )=1 is substituted into formula (3). Since the optical axis pixel is the center, r=0 at this time, and then a0=1 is calculated. The value of a2 can be calculated using a correction device.

[0057] The correction device includes a light source, a camera data control interface, and a data processing unit. The light source is any light source that can provide the camera with uniform brightness at all viewing angles. Specifically, the correction device can be an integrating sphere. Since the use of the correction device is well known in the art, no further explanation is given.

[0058] Since the value of a0 is 1, the above formula (3) can be changed to:

[0059] K(r 2 )=1+a2r 2 (4)

[0060] In this embodiment, the square of the distance between the pixel point and the optical axis pixel point is used as the independent variable, and the brightness correction curve is simplified to a straight line equation. Since the preset brightness balance correction function retains the quadratic term, the preset brightness balance correction function can reduce the calculation amount and delay of the brightness balance correction while ensuring that the brightness balance correction has a better effect.

[0061] In other embodiments, the brightness correction curve may be directly retained. The first-order term in is used to obtain the preset brightness balance correction function.

[0062] Among them, the preset brightness balance correction function is:

[0063] K(r)=a0+a1r (5)

[0064] In formula (5), K(r) represents the brightness correction coefficient; a0 and a1 represent the brightness correction parameters; r represents the distance between the pixel point and the optical axis pixel point. Among them, a0=1, and the value of a1 can be calculated using the correction device.

[0065] The following continues to explain the preset brightness balance correction function of formula (4). Since in formula (3), a2 is a floating point number less than 1, the brightness correction coefficient K(r 2) is also a floating point number. Therefore, in order to further reduce the amount of calculation and delay of brightness balance correction and further reduce hardware resource overhead, the current floating point operation of brightness balance correction is converted into integer operation.

[0066] That is, the above step S103 may specifically include: performing integer operations based on a preset brightness balance correction function, the photosensitivity of each pixel point, and the distance between each pixel point and the optical axis pixel point to determine the correction value of each pixel point; wherein the operation of the preset brightness balance correction function adopts binary shift integer operations.

[0067] In order to realize the above integer operation, the expression of the preset brightness balance correction function is:

[0068] 2 n-m K(r 2 )=2 n-m +Int(2 n *a2)*Int(r 2 *2 -m ) (6)

[0069] In formula (6), n represents the first preset parameter; m represents the second preset parameter; Int() represents rounding down to an integer. It should be noted that formula (6) can be understood as multiplying both sides of formula (3) by 2. n-m .

[0070] In one embodiment, specific values ​​of the first preset parameter n and the second preset parameter m can be obtained by a preset formula.

[0071] The expression of the preset formula is:

[0072]

[0073] In formula (7), L represents the number of bits of the multiplier, and the number of bits of the adder is 2L; R = Int(r 2 *2 -m ); k = 2 n-m *K(r 2 ); The setting conditions of the preset formula are: r 2 The maximum value is less than 2 R ; K(r 2 ) is less than 2 k .

[0074] The derivation process of formula (7) is explained below.

[0075] First, make a substitution in formula (6) and let k = 2 n-m *K(r 2 )、A2=Int(2 n *a2), R = Int(r2 *2 -m ) to get the transformed formula:

[0076] k=2 n-m +A2*R (8)

[0077] Assume the number of bits of the multiplier is L, the number of bits of the adder is 2L, and set r 2 The maximum value is less than 2 R ; K(r 2 ) is less than 2 k , we can get two equations:

[0078]

[0079] The expression of formula (7) can be derived through formula (9).

[0080] It should be noted that multiplying a binary integer by 2 to the power of n is equivalent to shifting the integer left by n bits, and dividing a binary integer by 2 to the power of n is equivalent to shifting the integer right by n bits, so all brightness balance correction operations can be completed by integer multiplication, integer addition, and shift operations. In addition, by configuring the above preset formula, the integer operation bit length can be reduced, and the maximum accuracy of brightness balance correction can be achieved under the integer operation conditions supported by the hardware.

[0081] Exemplarily, taking a 1080P (progressive) fisheye camera as an example, a preset brightness balance correction function of formula (6) is established, assuming that the multiplier bit length L=8 and the adder bit length 2L=16.

[0082] The relationship between the resolution of the 1080P image to be corrected and the distance between each pixel and the optical axis pixel (with the center point of the image to be corrected as the optical axis pixel) is: At this time, R = 21. Since the maximum uneven value of the brightness between the center and edge of the fisheye camera image will not exceed 4, that is, 2 k The maximum value of is 4, then k=2.

[0083] Substituting R=21 and k=2 into formula (7), we can obtain m=RL=21-8=13; n=2L+mk=16+13-2=27.

[0084] Of course, in other embodiments, the first preset parameter n and the second preset parameter m may also be fixed values. For example, the value of the first preset parameter n may be directly set to 27, and the value of the second preset parameter m may be directly set to 13. This application does not limit this.

[0085] The following is an explanation of the process of calculating the value of A2 through the correction device. It should be noted that the value of A2 can be either calculated by the image acquisition device and stored in the image acquisition device before leaving the factory, or it can be configured in the image acquisition device after A2 is calculated for the same type of camera.

[0086] The process specifically includes:

[0087] Step 1: Place the camera of the image acquisition device in the correction device, and adjust the camera exposure time from long to short until all pixel values ​​of the acquired image do not overflow.

[0088] Step 2: Create a three-column number table. The first column is the ordinal number N starting from zero, the second column is the accumulated value V of the pixel sensitivity value, and the third column is the accumulated number. The initial values ​​of columns V and N are zero.

[0089] Step 3: Read the photosensitivity value v of all pixels in the image one by one, and calculate the R value of this pixel (using a 1080P fisheye camera, m=13, n=27).

[0090] At this time, R = Int (r 2 / 2 13 )=Int(((x-960) 2 +(y-540) 2 ) / 2 13 ), add the v value to the data in column V and row R, and add 1 to the data in column N and row R.

[0091] Step 4: Divide the values ​​of all rows in column V by the data in the same row in column N to obtain the average value of the photosensitivity v.

[0092] Step 5: Use the first number in column V as the dividend and each number in column V as the divisor to perform division operation.

[0093] Step 6: N is the independent variable X, V is the dependent variable K, and a first-order linear fit is performed to obtain the specific values ​​of a0 and a2 in formula (3).

[0094] Step 7, based on the formula A2=Int(2 n *a2), A2 can be obtained and stored; it should be noted that the values ​​of m and n are also stored at the same time.

[0095] In addition, it should be noted that when the preset brightness balance correction function of formula (3) is used for calculation, the values ​​stored here are a0 and a2.

[0096] After the preset brightness balance correction function is calculated in the above manner, the preset brightness balance correction function can be applied to the brightness balance correction method provided in the embodiment of the present application.

[0097] In summary, in the embodiment of the present application, the preset brightness balance correction function is a linear function, that is, the current one-dimensional multiple brightness correction curve is simplified to a straight line equation, thereby reducing the amount of calculation and delay of the brightness balance correction, and this method can also reduce the hardware resource overhead. In addition, in the embodiment of the present application, the square of the distance between the pixel point and the optical axis pixel point is used as the independent variable, and the brightness correction curve is simplified to a straight line equation. In this way, while reducing the amount of calculation and delay of the brightness balance correction, it is possible to ensure that the brightness balance correction has a better effect. In addition, the calculation of the preset brightness balance correction function adopts binary shift integer operation, that is, the current floating-point operation of the brightness balance correction is converted into integer operation. In this way, the amount of calculation and delay of the brightness balance correction can be further reduced, and the hardware resource overhead can be further reduced.

[0098] In addition, it should be noted that in the R value calculation for the 1080P camera, the x and y values ​​will overflow in the 8-bit multiplier. The calculation of the R value needs to be modified. x and y are shifted left by 2 bits before the calculation, and the right shift obtained by the calculation is changed from 13 bits to 9 bits.

[0099] Specifically, R=(X 2 +Y 2 ) / 2 9 ), X and Y are the coordinates of the pixel after displacement. Then, calculate the equalization coefficient k = (2 n-m + A2*R). The sensitivity value V of the pixel point is multiplied by the equalization coefficient k and then shifted right by 6 bits to obtain the final correction value of the pixel point.

[0100] See also Figure 4 Based on the same inventive concept, the embodiment of the present application further provides a brightness balance correction device 200, which includes:

[0101] The acquisition module 210 is used to acquire the image to be corrected.

[0102] The reading module 220 is used to read the photosensitivity value of each pixel point in the image to be corrected and the distance between each pixel point and the optical axis pixel point.

[0103] The correction module 230 is used to determine the correction value of each pixel based on a preset brightness balance correction function, the photosensitivity value of each pixel and the distance between each pixel and the optical axis pixel; wherein the preset brightness balance correction function includes a linear function.

[0104] It should be noted that, since technicians in the relevant field can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0105] Based on the same inventive concept, an embodiment of the present application further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed, the method provided in the above embodiment is executed.

[0106] The storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that includes one or more available media. The available medium may be a magnetic medium (such as a floppy disk, a hard disk, a tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD)).

[0107] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0108] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0109] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0110] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0111] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A brightness balance correction method, characterized in that: include: Acquire the image to be corrected; Reading the photosensitivity value of each pixel point in the image to be corrected and the distance between each pixel point and the optical axis pixel point; Determine the correction value of each pixel based on a preset brightness balance correction function, the photosensitivity value of each pixel, and the distance between each pixel and the optical axis pixel; wherein the preset brightness balance correction function includes a linear function; The determining of the correction value of each pixel point based on a preset brightness balance correction function, the photosensitivity value of each pixel point, and the distance between each pixel point and the optical axis pixel point includes: Performing integer operations based on the preset brightness balance correction function, the photosensitivity value of each pixel point, and the distance between each pixel point and the optical axis pixel point to determine the correction value of each pixel point; wherein the operation of the preset brightness balance correction function adopts binary shift integer operations; The expression of the preset brightness balance correction function is: 2 n-m K(r 2 )=2 n-m +Int(2 n *a2)*Int(r 2 *2 -m ); Among them, K(r 2 ) represents the brightness correction coefficient; a2 represents the second brightness correction parameter; r 2 represents the square of the distance between the pixel point and the optical axis pixel point; n represents the first preset parameter; m represents the second preset parameter; Int() represents rounding down to an integer; The first preset parameter and the second preset parameter are determined by a preset formula: the preset formula is: Where L represents the number of bits of the multiplier, and the number of bits of the adder is 2L; R = Int (r 2 *2 -m ); k = 2 n-m *K(r 2 ); The setting conditions of the preset formula are: 2 The maximum value is less than 2 R ; K(r 2 ) is less than 2 k .

2. The method according to claim 1, characterized in that The optical axis pixel point is the center point of the image to be corrected.

3. A brightness balance correction device, characterized in that: include: An acquisition module, used for acquiring an image to be corrected; A reading module, used for reading the photosensitivity value of each pixel point in the image to be corrected and the distance between each pixel point and the optical axis pixel point; A correction module, used to determine the correction value of each pixel point based on a preset brightness balance correction function, the photosensitivity value of each pixel point and the distance between each pixel point and the optical axis pixel point; wherein the preset brightness balance correction function includes a linear function; The correction module is used to perform integer operations based on the preset brightness balance correction function, the photosensitivity value of each pixel point, and the distance between each pixel point and the optical axis pixel point to determine the correction value of each pixel point; wherein the operation of the preset brightness balance correction function adopts binary shift integer operations; The expression of the preset brightness balance correction function is: 2 n-m K(r 2 )=2 n-m +Int(2 n *a2)*Int(r 2 *2 -m ); Among them, K(r 2 ) represents the brightness correction coefficient; a2 represents the second brightness correction parameter; r 2 represents the square of the distance between the pixel point and the optical axis pixel point; n represents the first preset parameter; m represents the second preset parameter; Int() represents rounding down to an integer; The correction device determines the first preset parameter and the second preset parameter by a preset formula: the preset formula is: Where L represents the number of bits of the multiplier, and the number of bits of the adder is 2L; R = Int (r 2 *2 -m ); k = 2 n-m *K(r 2 ); The setting conditions of the preset formula are: 2 The maximum value is less than 2 R ; K(r 2 ) is less than 2 k .

4. An image acquisition device, characterized in that: include: A processor and a memory, the processor and the memory being connected; The memory is used to store programs; The processor is used to run the program stored in the memory to execute the method according to claim 1 or 2.

5. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a computer, the method according to claim 1 or 2 is executed.

Images