Exposure control method for exposure fusion

Abstract

The invention provides an exposure control method for exposure fusion, which comprises the following steps of: calculating a long exposure brightness mean value of pixels of (N-X) brightness from the lowest brightness in N brightness of a long exposure image, the total number of the pixels of the brightest X brightness in the N brightness being the total number of pixels of a long exposure bright area; when the long-exposure brightness mean value is not close to a long-exposure target mean value, adjusting the exposure amount for generating the long-exposure image, so that the two mean values are approximate or equal; k brightest pixels of a short-exposure image are determined, the long-exposure image and the short-exposure image are two images of the same scene, and K is equal to the total number of the pixels of the long-exposure bright area; calculating a short exposure brightness mean value of the K pixels; and when the short-exposure brightness mean value is not close to a short-exposure target mean value, adjusting the exposure amount for generating the short-exposure image, so that the two mean values are close to or equal to each other.

Description

Technical Field

[0001] The present invention relates to an exposure control method, and in particular to an exposure control method that can be used for exposure fusion. Background Art

[0002] Currently, most consumer-grade image sensors have a small dynamic range, while image sensors with a larger dynamic range are expensive. Therefore, in order to better capture high-contrast scenes, exposure fusion, which fuses multiple images with different exposures into a high dynamic range (HDR) image, has emerged. General exposure fusion processing can achieve a better result through multiple adjustments of exposure time and post-processing of image effects, but such processing is time-consuming, cumbersome and costly. For shooting in certain scenarios (for example, real-time video shooting), the current exposure fusion processing does not meet the requirements. Therefore, a simple and fast exposure control method is needed in the art. Summary of the invention

[0003] One of the purposes of the present invention is to provide an exposure control method that can be used for exposure fusion to avoid the problems existing in the prior art.

[0004] An embodiment of the exposure control method of the present invention includes a plurality of long exposure adjustment steps and a plurality of short exposure adjustment steps. The plurality of long exposure adjustment steps are mainly used to ensure that the details of the dark area and the non-overexposed area of ​​the long exposure image can be properly preserved. The plurality of short exposure adjustment steps are mainly used to ensure that the details of the bright area of ​​the short exposure image can be properly preserved.

[0005] In the above embodiment, the plurality of long exposure adjustment steps include: calculating a long exposure pixel quantity statistic value for each of N brightness levels (e.g., pure black, shadow brightness, normal brightness, highlight brightness, white, or overexposed brightness) of a long exposure image to obtain N long exposure pixel quantity statistic values, wherein N is a positive integer not less than 5; summing up X long exposure pixel quantity statistic values ​​of X brightest brightness levels among the N brightness levels of the long exposure image to obtain a long exposure bright area pixel total number, wherein the X long exposure pixel quantity statistic values ​​belong to the N long exposure pixel quantity statistic values. The invention provides a long exposure pixel quantity statistic value, wherein X is a positive integer less than N; calculating a long exposure brightness mean of pixels of (N x ) brightnesses starting from a lowest brightness among the N brightnesses of the long exposure image; and when a long exposure brightness mean difference between the long exposure brightness mean and a long exposure target mean is greater than a specific long exposure brightness mean difference, adjusting an exposure amount used to generate the long exposure image and making the adjusted exposure amount effective for the long exposure image, so that the long exposure brightness mean difference is not greater than the specific long exposure brightness mean difference.

[0006] In the aforementioned embodiment, the multiple short exposure adjustment steps include: calculating a short exposure pixel number statistic value for each of the multiple types of the N types of brightness of a short exposure image to obtain a plurality of short exposure pixel number statistic values, wherein the long exposure image and the short exposure image are two images of the same scene, the size of the long exposure image is equal to the size of the short exposure image, and the exposure used to generate the long exposure image is greater than the exposure used to generate the short exposure image; determining the brightest K pixels of the short exposure image, wherein K is a total number of short exposure bright area pixels, and a number difference between the total number of short exposure bright area pixels and the total number of long exposure bright area pixels is not greater than a specific number difference; calculating a short exposure brightness mean of the K pixels; and when a short exposure brightness mean difference between the short exposure brightness mean and a short exposure target mean is greater than a specific short exposure brightness mean difference, adjusting the exposure used to generate the short exposure image and making the adjusted exposure effective for the short exposure image, so that the short exposure brightness mean difference is not greater than the specific short exposure brightness mean difference.

[0007] Another embodiment of the exposure control method of the present invention includes a plurality of long exposure adjustment steps and a plurality of short exposure adjustment steps. The plurality of long exposure adjustment steps include: calculating a long exposure brightness mean value of pixels of (Nx) brightnesses from a lowest brightness among N brightnesses of a long exposure image, wherein the total number of pixels of the brightest X brightnesses among the N brightnesses is a total number of pixels in a long exposure bright area, and N is a positive integer not less than 5; and when a long exposure brightness mean difference between the long exposure brightness mean value and a long exposure target mean value is greater than a specific long exposure brightness mean difference, adjusting the exposure used to generate the long exposure image and making the adjusted exposure effective for the long exposure image, so that the long exposure brightness mean difference is not greater than the specific long exposure brightness mean difference. The multiple short exposure adjustment steps include: determining the brightest K pixels of a short exposure image, wherein the long exposure image and the short exposure image are two images of the same scene, the size of the long exposure image is equal to the size of the short exposure image, the exposure used to generate the long exposure image is greater than the exposure used to generate the short exposure image, K is a total number of short exposure bright area pixels, and a number difference between the total number of short exposure bright area pixels and the total number of long exposure bright area pixels is not greater than a specific number difference; calculating a short exposure brightness mean of the K pixels; and when a short exposure brightness mean difference between the short exposure brightness mean and a short exposure target brightness mean is greater than a specific short exposure brightness mean difference, adjusting the exposure used to generate the short exposure image and making the adjusted exposure effective for the short exposure image, so that the short exposure brightness mean difference is not greater than the specific short exposure brightness mean difference.

[0008] The features, embodiments and technical effects of the present invention are described in detail below with reference to the accompanying drawings for a preferred embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An embodiment of the exposure control method of the present invention is shown;

[0010] Figure 2 A histogram showing the statistical values ​​of the number of N long-exposure pixels;

[0011] Figure 3 A histogram showing the statistical values ​​of the number of N short-exposure pixels;

[0012] Figure 4 Another embodiment of the exposure control method of the present invention is shown;

[0013] Figure 5 Another embodiment of the exposure control method of the present invention is shown;

[0014] Figure 6 Another embodiment of the exposure control method of the present invention is shown; and

[0015] Figure 7 Another embodiment of the exposure control method of the present invention is shown.

[0016] Description of reference numerals:

[0017] S110~S140: Multiple long exposure adjustment steps

[0018] S150~S180: Multiple short exposure adjustment steps

[0019] S410~S420: Additional long exposure adjustment steps

[0020] S510~S530: Additional long exposure adjustment steps

[0021] S610: Additional long exposure adjustment step

[0022] S710~S720: Multiple long exposure adjustment steps

[0023] S730~S750: Multiple short exposure adjustment steps DETAILED DESCRIPTION

[0024] The present invention discloses an exposure control method that can be used for exposure fusion, which can simply and quickly control the exposure of a long exposure image and the exposure of a short exposure image. The long exposure image and the short exposure image are two images of the same scene, the size of the long exposure image (i.e., image width multiplied by image height) is equal to the size of the short exposure image, and the exposure used to generate the long exposure image is greater than the exposure used to generate the short exposure image.

[0025] Figure 1An embodiment of the exposure control method of the present invention is shown. Figure 1 The embodiment of the invention can be applied to an operation performed by a photographic device, the operation being used to control the exposure amount of the long and short exposures before adjusting the exposure fusion. The embodiment includes a plurality of long exposure adjustment steps and a plurality of short exposure adjustment steps. The plurality of long exposure adjustment steps are mainly used to ensure that the details of the dark area and the non-overexposed area of ​​a long exposure image can be properly preserved. The plurality of short exposure adjustment steps are mainly used to ensure that the details of the bright area of ​​a short exposure image can be properly preserved. These steps are further described below.

[0026] See also Figure 1 The multiple long exposure adjustment steps are used to adjust the exposure of a long exposure image, including:

[0027] S110: Calculate a long exposure pixel quantity statistic value of each of N brightness levels of the long exposure image to obtain N long exposure pixel quantity statistic values, wherein N is a positive integer not less than 5.

[0028] For example, the width and height of the long exposure image are 1920 pixels and 1080 pixels respectively, N is 256, the N brightness levels are from 0 to 255, and the histogram of the statistical values ​​of the N long exposure pixels is as follows: Figure 2 As shown, Figure 2 The horizontal axis is the brightness value, and the vertical axis is the statistical value of the number of long exposure pixels.

[0029] It is worth noting that the implementation of the present invention is not limited to the above examples. For example, the N brightness levels can be N brightness intervals (e.g., pure black, shadow brightness, normal brightness, highlight brightness, white, or overexposed brightness), each brightness interval includes a specific range of brightness values ​​(e.g., N is 5, and the N brightness levels are sequentially from dark to bright as the first brightness interval (intervals between a first preset brightness value range such as including Figure 2 The brightness value of 0 to 50), the second brightness range (the interval between a second preset brightness value range such as including Figure 2 The brightness value of 51 to 101), the third brightness range (the interval between a third preset brightness value range such as including Figure 2 The brightness value of 102 to 152), the fourth brightness range (the interval between a fourth preset brightness value range such as including Figure 2 The brightness value of 153 to 203) and the fifth brightness range (the interval between a fifth preset brightness value range such as including Figure 2 The brightness value of the pixel is in the range of 204 to 255), and the statistical value of the number of N long-exposure pixels can be derived from the above description.

[0030] S120: Sum up X long-exposure pixel quantity statistics of X brightest brightnesses among the N brightnesses of the long-exposure image to obtain a total number of long-exposure bright area pixels, wherein the X long-exposure pixel quantity statistics belong to the N long-exposure pixel quantity statistics, and X is a positive integer less than N.

[0031] For example: See Figure 2 , X is 4, the X brightnesses are 4 brightness values ​​from 252 to 255, the X long exposure pixel quantity statistics are 4 statistics corresponding to the 4 brightness values, 183, 179, 3 and 1, respectively, and the total number of long exposure bright area pixels is 183+179+3+1=366. It is worth noting that X can be determined according to implementation requirements.

[0032] It is also worth noting that the implementation of the present invention is not limited to the above examples. For example, the X types of brightness can be X types of brightness intervals, each brightness interval includes a specific range of brightness values ​​(for example: the fourth brightness interval and the fifth brightness interval mentioned above), and the X long-exposure pixel number statistics are the pixel number statistics corresponding to the X types of brightness intervals.

[0033] S130: Calculate a long exposure brightness average value of pixels of (N x ) brightnesses starting from a lowest brightness among the N brightnesses of the long exposure image.

[0034] For example: See Figure 2 , X is 4, the (NX) kinds of brightness are 252 kinds of brightness ranging from 0 to 251, the (NX) long exposure pixel quantity statistics are 252 statistical values ​​corresponding to the 252 kinds of brightness respectively, and the step of calculating the long exposure brightness average includes: multiplying the 252 kinds of brightness by the 252 long exposure pixel quantity statistics respectively to obtain a product; and then dividing the product by the sum of the 252 statistical values ​​to obtain the long exposure brightness average.

[0035] It is worth noting that the implementation of the present invention is not limited to the above examples. For example, the (NX) types of brightness can be (NX) types of brightness intervals, each brightness interval includes a specific range of brightness values ​​(for example: the first brightness interval to the third brightness interval mentioned above), the (NX) long exposure pixel number statistics are the (NX) pixel number statistics corresponding to the (NX) types of brightness intervals, and the step of calculating the long exposure brightness mean includes: multiplying a calculated value of each brightness interval (for example: the brightness average value) by the pixel number statistics corresponding to the brightness interval to obtain a product; and then dividing the product by the sum of the (NX) statistics to obtain the long exposure brightness mean.

[0036] S140: When a long exposure brightness mean difference between the long exposure brightness mean and a long exposure target brightness mean is greater than a specific long exposure brightness mean difference, adjusting the exposure used to generate the long exposure image and making the adjusted exposure effective for the long exposure image, so that the long exposure brightness mean difference is not greater than the specific long exposure brightness mean difference.

[0037] For example: See Figure 2 , the long exposure brightness mean is 130, the long exposure target mean is 100, the long exposure brightness mean difference is |130-100|=30, the specific long exposure brightness mean difference is 0, since 30>0 and 130>100, this indicates that the long exposure image is bright, so step S140 reduces the exposure of the long exposure image. For example: the long exposure brightness mean is 30, the long exposure target mean is 50, the long exposure brightness mean difference is |30-50|=20, the specific long exposure brightness mean difference is 0, since 20>0 and 30<50, this indicates that the long exposure image is dark, so step S140 increases the exposure of the long exposure image. It is worth noting that the long exposure target mean can be determined according to implementation requirements (for example, according to the current shooting scene); the specific long exposure brightness mean difference is preset or zero, and can be determined according to implementation requirements.

[0038] For example, the step of adjusting the exposure for generating the long exposure image includes adjusting at least one parameter (eg, at least one of sensitivity (ISO), aperture, shutter speed and exposure value (EV)) for generating the long exposure image.

[0039] See also Figure 1 The multiple short exposure adjustment steps are used to adjust the exposure of a short exposure image, including:

[0040] S150: Calculate a short-exposure pixel quantity statistic value of each of the multiple types of the N types of brightness of the short-exposure image to obtain a plurality of short-exposure pixel quantity statistic values.

[0041] For example, the width and height of the short exposure image are 1920 pixels and 1080 pixels respectively, N is 256, the N brightness levels are from 0 to 255, the multiple short exposure pixel number statistics are N short exposure pixel number statistics, and the histogram of the N short exposure pixel number statistics is as follows: Figure 3 As shown, Figure 3 The horizontal axis is the brightness value, and the vertical axis is the statistical value of the number of short exposure pixels.

[0042] S160: Determine the brightest K pixels of the short exposure image, wherein K is a total number of short exposure bright area pixels, and a difference between the total number of short exposure bright area pixels and the total number of long exposure bright area pixels is not greater than a specific difference.

[0043] For example: See Figure 3 , where K is equal to the total number of pixels in the long exposure bright area 366, and the K pixels correspond to the brightest M brightnesses among the N brightnesses of the short exposure image (for example: Figure 3 The 5 brightness values ​​range from 255 to 251), the brightest (M-1) brightness among the M brightness (for example: Figure 3 The four brightness values ​​255, 254, 253 and 252) correspond to the (M-1) short exposure pixel number statistics of the N short exposure pixel number statistics (for example: Figure 3 4 statistical values ​​0, 3, 115 and 118), the darkest brightness among the M brightnesses (for example: Figure 3 The brightness value 251) corresponds to a calculated statistical value, which is equal to K minus the sum of the statistical values ​​of the number of (M-1) short exposure pixels (for example: 366-(0+3+115+118)=130).

[0044] S170: Calculate a short-exposure brightness average of the K pixels.

[0045] For example, the step of calculating the short exposure brightness average includes: multiplying the (M-1) brightnesses by the (M-1) short exposure pixel quantity statistics to obtain a first product (for example: Figure 3 The brightness values ​​255, 254, 253 and 252 are multiplied by Figure 3 The statistical values ​​0, 3, 115 and 118 are multiplied to obtain 59593); the darkest brightness value is multiplied by the calculated statistical value to obtain a second product (for example: Figure 3 The brightness value 251 is multiplied by the calculated statistical value 130 to obtain 32630); and the sum of the first product and the second product is divided by K to obtain the short exposure brightness average (for example: ).

[0046] S180: When a short exposure brightness mean difference between the short exposure brightness mean and a short exposure target mean is greater than a specific short exposure brightness mean difference, adjust the exposure used to generate the short exposure image and make the adjusted exposure effective for the short exposure image, so that the short exposure brightness mean difference is not greater than the specific short exposure brightness mean difference.

[0047] For example: See Figure 3, the short exposure brightness mean is 252, the short exposure target mean is 200, the short exposure brightness mean difference is |252-200|=52, and the specific short exposure brightness mean difference is 0. Since 52>0 and 252>200, this indicates that the short exposure image is brighter, so step S180 reduces the exposure of the short exposure image. For example: the short exposure brightness mean is 20, the short exposure target mean is 50, the short exposure brightness mean difference is |20-50|=30, and the specific short exposure brightness mean difference is 0. Since 30>0 and 20<50, this indicates that the short exposure image is darker, so step S180 increases the exposure of the short exposure image. It is worth noting that the short exposure target mean can be determined according to implementation requirements (for example, according to the current shooting scene);

[0048] The specific short exposure brightness mean difference is preset or zero and may be determined according to implementation requirements.

[0049] For example, the step of adjusting the exposure for generating the short exposure image includes adjusting at least one of at least one parameter (eg, sensitivity (ISO), aperture, shutter speed, and exposure value) for generating the short exposure image.

[0050] It is worth noting that the adjustment of the short exposure image is not limited to the above examples. For example, the brightness range mentioned in the above example of the adjustment of the long exposure image can also be applied to the adjustment of the short exposure image.

[0051] Figure 4 Another embodiment of the exposure control method of the present invention is shown. Figure 1 An embodiment of Figure 4 In an embodiment of the present invention, the plurality of long exposure adjustment steps further include:

[0052] S410: Divide the total number of long-exposure bright area pixels by a total number of long-exposure pixels to obtain a bright area ratio, wherein the total number of long-exposure pixels is equal to the sum of the N long-exposure pixel quantity statistics.

[0053] For example: See Figure 2 , the total number of pixels in the long exposure bright area is 366, the total number of pixels in the long exposure is equal to the total pixels of the long exposure image 1920×1080=2073600, the bright area ratio is equal to

[0054] S420: When the bright area ratio is greater than a preset bright area ratio, reducing the exposure used to generate the long exposure image and making the adjusted exposure effective on the long exposure image.

[0055] For example: See Figure 2, the bright area ratio is 0.01765%, and the preset bright area ratio is 0.015%. Since 0.01765% is greater than 0.015%, it means that the long exposure image is bright, so step S420 reduces the exposure used to generate the long exposure image. It is worth noting that the preset bright area ratio is determined according to implementation requirements (for example, according to the current shooting scene).

[0056] It is worth noting that the multiple long exposure adjustment steps may further include: before calculating the long exposure brightness average, making the bright area ratio not greater than the preset bright area ratio (for example: making the bright area ratio equal to the preset bright area ratio).

[0057] Figure 5 Another embodiment of the exposure control method of the present invention is shown. Figure 1 An embodiment of Figure 5 In an embodiment of the present invention, the plurality of long exposure adjustment steps further include:

[0058] S510: Sum up Y long exposure pixel quantity statistics of Y brightness levels starting from a lowest brightness among the N brightness levels of the long exposure image to obtain a total number of long exposure dark area pixels, wherein the Y long exposure pixel quantity statistics belong to the N long exposure pixel quantity statistics, and Y is a positive integer less than N.

[0059] For example: See Figure 2 , Y is 9, the Y brightness is 9 brightness values ​​from 0 to 8, the Y long exposure pixel quantity statistics are 9 statistical values ​​corresponding to the 9 brightness values ​​50, 158, 264, 750, 1281, 1830, 2562, 3128 and 3477, and the total number of long exposure dark area pixels is 50+158+264+750+1281+

[0060] 1830+2562+3128+3477=13500.

[0061] S520: Divide the total number of long-exposure dark area pixels by the total number of long-exposure pixels to obtain a dark area ratio.

[0063] For example: See Figure 2 , the total number of pixels in the long exposure dark area is 13500, the total number of pixels in the long exposure is 2073600, and the dark area ratio is equal to

[0064] S530: When the dark area ratio is greater than a preset dark area ratio, increase the exposure amount for generating the long exposure image.

[0065] For example: See Figure 2, the dark area ratio is 0.65%, the preset dark area ratio is 0.5%, due to

[0066] 0.65% is greater than 0.5%, which means that the long exposure image is dark, so step S530 increases the exposure used to generate the long exposure image and makes the adjusted exposure effective for the short exposure image. It is worth noting that the preset dark area ratio is determined according to implementation requirements (for example, according to the current shooting scene).

[0067] It is worth noting that the multiple long exposure adjustment steps may further include: before calculating the long exposure brightness average, making the dark area ratio not greater than the preset dark area ratio.

[0068] Figure 6 Another embodiment of the exposure control method of the present invention is shown. Figure 1 An embodiment of Figure 6 In an embodiment of the present invention, the plurality of long exposure adjustment steps further include:

[0069] S610: When the exposure amount used to generate the long-exposure image is adjusted, adjusting the exposure amount used to generate the short-exposure image.

[0070] For example, the exposure adjustment amount used to generate the long exposure image is a long exposure adjustment amount, and the exposure adjustment amount used to generate the short exposure image is a short exposure adjustment amount. Step S610 satisfies the following conditions: a ratio of the long exposure adjustment amount to the short exposure adjustment amount meets a specific ratio; or an adjustment difference between the long exposure adjustment amount and the short exposure adjustment amount is less than a specific adjustment difference.

[0071] Figure 7 Another embodiment of the exposure control method of the present invention is shown. Figure 1 An embodiment of Figure 7 The embodiments do not include Figure 1 The implementation limitations of steps S110, S120 and S150 of the embodiment. Figure 7 The embodiment comprises the following steps:

[0072] S710: Calculate a long exposure brightness average of pixels of (N x) brightnesses starting from a lowest brightness among N brightnesses of a long exposure image, wherein the total number of pixels of X brightest brightnesses among the N brightnesses is a total number of pixels in a long exposure bright area, and N is a positive integer not less than 5.

[0073] S720: When a long exposure brightness mean difference between the long exposure brightness mean and a long exposure target brightness mean is greater than a specific long exposure brightness mean difference, adjust the exposure used to generate the long exposure image and make the adjusted exposure effective for the long exposure image, so that the long exposure brightness mean difference is not greater than the specific long exposure brightness mean difference.

[0074] S730: Determine K brightest pixels of a short exposure image, wherein the long exposure image and the short exposure image are two images of the same scene, a size of the long exposure image is equal to a size of the short exposure image, an exposure amount used to generate the long exposure image is greater than an exposure amount used to generate the short exposure image, K is a total number of pixels in a short exposure bright area, and a quantitative difference between the total number of pixels in the short exposure bright area and the total number of pixels in the long exposure bright area is not greater than a specific quantitative difference.

[0075] S740: Calculate a short-exposure brightness average of the K pixels.

[0076] S750: When a short exposure brightness mean difference between the short exposure brightness mean and a short exposure target mean is greater than a specific short exposure brightness mean difference, adjust the exposure used to generate the short exposure image and make the adjusted exposure effective for the short exposure image, so that the short exposure brightness mean difference is not greater than the specific short exposure brightness mean difference.

[0077] Since a person skilled in the art with ordinary knowledge can refer to Figures 1 to 6 The disclosure of the embodiments is to understand Figure 7 The details and variations of the embodiments of the present invention are described in detail, and repeated and redundant descriptions are omitted here.

[0078] It is worth noting that, under the premise of feasibility, a technician with ordinary knowledge in this technical field may selectively implement part or all of the technical features of any of the aforementioned embodiments, or selectively implement a combination of part or all of the technical features of the aforementioned multiple embodiments, so as to increase the implementation flexibility of the present invention.

[0079] In summary, the exposure control method of the present invention can simply and quickly control the exposure of a long-exposure image and the exposure of a short-exposure image, and is particularly suitable for real-time video shooting.

[0080] Although the embodiments of the present invention are described above, these embodiments are not intended to limit the present invention. A technician with ordinary knowledge in the technical field may change the technical features of the present invention according to the explicit or implicit contents of the present invention, and these changes all fall within the patent protection scope of the present invention. In other words, the patent protection scope of the present invention shall be defined in accordance with the protection scope of the claims of this specification.

Claims

1. A method for controlling exposure, comprising: Multiple long exposure adjustment steps, including: Calculating a long exposure pixel number statistic value of each of N brightnesses of a long exposure image to obtain N long exposure pixel number statistic values, wherein N is a positive integer not less than 5; summing up X long-exposure pixel quantity statistics of X brightest brightnesses among the N brightnesses of the long-exposure image to obtain a total number of long-exposure bright area pixels, wherein the X long-exposure pixel quantity statistics belong to the N long-exposure pixel quantity statistics, and X is a positive integer less than N; Calculating a long exposure brightness average value of pixels of (N x ) brightnesses starting from a lowest brightness among the N brightnesses of the long exposure image; and When a long exposure brightness mean difference between the long exposure brightness mean and a long exposure target brightness mean is greater than a specific long exposure brightness mean difference, adjusting the exposure used to generate the long exposure image and making the adjusted exposure effective for the long exposure image, so that the long exposure brightness mean difference is not greater than the specific long exposure brightness mean difference; Multiple short exposure adjustment steps, including: Calculating a short exposure pixel number statistic value for each of the multiple types of the N types of brightness of a short exposure image to obtain a plurality of short exposure pixel number statistic values, wherein the long exposure image and the short exposure image are two images of the same scene, a size of the long exposure image is equal to a size of the short exposure image, and an exposure amount used to generate the long exposure image is greater than an exposure amount used to generate the short exposure image; Determine the brightest K pixels of the short-exposure image, wherein K is a total number of short-exposure bright-area pixels, and a difference between the total number of short-exposure bright-area pixels and the total number of long-exposure bright-area pixels is not greater than a specific difference; Calculating a short exposure brightness average of the K pixels; and When a short exposure brightness mean difference between the short exposure brightness mean and a short exposure target mean is greater than a specific short exposure brightness mean difference, the exposure used to generate the short exposure image is adjusted and the adjusted exposure is effective on the short exposure image, so that the short exposure brightness mean difference is not greater than the specific short exposure brightness mean difference.

2. The method according to claim 1, characterized in that The total number of pixels in the short-exposure bright area is equal to the total number of pixels in the long-exposure bright area.

3. The method according to claim 1, characterized in that The sum of the N long exposure pixel quantity statistics is a total number of long exposure pixels, and the plurality of long exposure adjustment steps further include: Dividing the total number of long-exposure bright area pixels by the total number of long-exposure pixels to obtain a bright area ratio; and When the bright area ratio is greater than a preset bright area ratio, the exposure amount used to generate the long exposure image is reduced.

4. The method according to claim 1, characterized in that: The multiple long exposure adjustment steps further include: Sum up Y long-exposure pixel quantity statistics of Y brightnesses starting from a lowest brightness among the N brightnesses of the long-exposure image to obtain a total number of long-exposure dark area pixels, wherein the Y long-exposure pixel quantity statistics belong to the N long-exposure pixel quantity statistics, and Y is a positive integer less than N; Dividing the total number of long-exposure dark area pixels by the total number of long-exposure pixels to obtain a dark area ratio; and When the dark area ratio is greater than a preset dark area ratio, the exposure amount for generating the long exposure image is increased.

5. The method according to claim 1, characterized in that: The (NX) types of brightness respectively correspond to the (NX) long exposure pixel number statistical values ​​of the N long exposure pixel number statistical values, and the step of calculating the long exposure brightness average includes: multiplying the (NX) types of brightness by the (NX) long exposure pixel number statistical values ​​respectively to obtain a product; and then dividing the product by a sum of the (NX) long exposure pixel number statistical values ​​to obtain the long exposure brightness average.

6. The method according to claim 1, characterized in that The plurality of long exposure adjustment steps further include adjusting the exposure amount for generating the short exposure image when the exposure amount for generating the long exposure image is adjusted.

7. The method according to claim 6, characterized in that The multiple long exposure adjustment steps further include: an adjustment amount of the exposure amount used to generate the long exposure image is a long exposure adjustment amount, and an adjustment amount of the exposure amount used to generate the short exposure image is a short exposure adjustment amount; a ratio of the long exposure adjustment amount to the short exposure adjustment amount conforms to a specific ratio, or an adjustment amount difference between the long exposure adjustment amount and the short exposure adjustment amount is less than a specific adjustment amount difference.

8. The method according to claim 1, characterized in that The K pixels correspond to the brightest M brightnesses among the N brightnesses of the short exposure image, the brightest (M-1) brightnesses among the M brightnesses respectively correspond to the (M-1) short exposure pixel number statistical values ​​of the multiple short exposure pixel number statistical values, a darkest brightness among the M brightnesses corresponds to a calculated statistical value, the calculated statistical value is equal to the K minus a sum of the (M-1) short exposure pixel number statistical values, and the step of calculating the short exposure brightness average includes: multiplying the (M-1) brightnesses by the (M-1) short exposure pixel number statistical values ​​respectively to obtain a first product; multiplying the darkest brightness value by the calculated statistical value to obtain a second product; and dividing a sum of the first product and the second product by K to obtain the short exposure brightness average.

9. An exposure control method, comprising: Multiple long exposure adjustment steps, including: Calculating a long exposure brightness average of pixels of (N x ) brightnesses from a lowest brightness among N brightnesses of a long exposure image, wherein a total number of pixels of the brightest X brightnesses among the N brightnesses is a total number of long exposure bright area pixels, and N is a positive integer not less than 5; and When a long exposure brightness mean difference between the long exposure brightness mean and a long exposure target brightness mean is greater than a specific long exposure brightness mean difference, adjusting an exposure used to generate the long exposure image and making the adjusted exposure effective for the long exposure image, so that the long exposure brightness mean difference is not greater than the specific long exposure brightness mean difference; Multiple short exposure adjustment steps, including: Determine K brightest pixels of a short exposure image, wherein the long exposure image and the short exposure image are two images of the same scene, a size of the long exposure image is equal to a size of the short exposure image, the exposure used to generate the long exposure image is greater than the exposure used to generate the short exposure image, K is a total number of short exposure bright area pixels, and a number difference between the total number of short exposure bright area pixels and the total number of long exposure bright area pixels is not greater than a specific number difference; Calculating a short exposure brightness average of the K pixels; and When a short exposure brightness mean difference between the short exposure brightness mean and a short exposure target mean is greater than a specific short exposure brightness mean difference, the exposure used to generate the short exposure image is adjusted and the adjusted exposure is effective on the short exposure image, so that the short exposure brightness mean difference is not greater than the specific short exposure brightness mean difference.

10. The method according to claim 9, characterized in that The multiple long exposure adjustment steps further include: when the exposure amount for generating the long exposure image is adjusted, adjusting the exposure amount for generating the short exposure image, An adjustment amount of the exposure amount used to generate the long exposure image is a long exposure adjustment amount, and an adjustment amount of the exposure amount used to generate the short exposure image is a short exposure adjustment amount; a ratio of the long exposure adjustment amount to the short exposure adjustment amount conforms to a specific ratio, or an adjustment amount difference between the long exposure adjustment amount and the short exposure adjustment amount is less than a specific adjustment amount difference.

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