Automatic Exposure Control Method and Device

Abstract

The present application discloses an automatic exposure control method and apparatus. The method includes: dividing a first image into k sub-regions, where the first image is an image obtained after exposing the first image frame collected by a camera at the current moment, determining the brightness values of the respective sub-regions in the k sub-regions, determining a region of interest in the first image, where the region of interest is the region where the recognized target object is located, determining a first brightness value and a second brightness value of the first image according to the brightness values of the respective sub-regions and the region of interest, the first brightness value being the overall brightness value of the first image, and the second brightness value being the brightness value of the region of interest, determining a first target brightness value according to the second brightness value and a preset second target brightness value, determining a brightness ratio according to the first brightness value and the first target brightness value, and determining a target exposure parameter according to the brightness ratio and a first exposure parameter. According to the embodiments of the present application, it is possible to avoid the over-dark brightness of the target object in a high-brightness background environment.

Description

Technical Field

[0001] The present application belongs to the field of optoelectronic technology, and in particular relates to an automatic exposure control method and device. Background Art

[0002] Current machine vision camera exposure strategies primarily control camera exposure by controlling exposure duration and gain. The metering area used during exposure is typically the entire image or a fixed area in the center of the image. This exposure strategy is sufficient for image acquisition with standard cameras, but it has certain shortcomings for intelligent system applications, particularly in object tracking or recognition. Object tracking or recognition often requires a suitable exposure strategy to ensure the tracked / recognized object has the appropriate brightness. However, current global metering or fixed region of interest (ROI) metering methods struggle to ensure appropriate exposure for dynamic objects, easily resulting in the target object being too dim against a bright background. Summary of the Invention

[0003] The embodiments of the present application provide an automatic exposure control method and device, which can solve the problem of the target object being too dark in the existing high-brightness background environment.

[0004] In a first aspect, an embodiment of the present application provides an automatic exposure control method, the method comprising:

[0005] The first image is divided into k sub-areas, where k is a positive integer greater than 1, and the first image is an image obtained by exposing the first image frame captured by the camera at the current moment.

[0006] Determine the brightness value of each of the k sub-regions,

[0007] Determine a region of interest in the first image, where the region of interest is the region where the identified target object is located.

[0008] Determine a first brightness value and a second brightness value of the first image according to the brightness values of the sub-regions and the region of interest, wherein the first brightness value is the overall brightness value of the first image, and the second brightness value is the brightness value of the region of interest in the first image.

[0009] A first target brightness value is determined according to the second brightness value and a preset second target brightness value, wherein the second target brightness value is the target brightness value of the region of interest, and the first target brightness value is the overall target brightness value of the first image.

[0010] determining a brightness ratio according to the first brightness value and the first target brightness value,

[0011] Determine a target exposure parameter according to the luminance ratio and a first exposure parameter, where the first exposure parameter is the exposure parameter when the first image frame is exposed, and the exposure parameter includes an exposure duration and an exposure gain.

[0012] In some embodiments, determining a first target luminance value according to the second luminance value and a preset second target luminance value includes:

[0013] Determine a luminance difference with the second target luminance value as the minuend and the second luminance value as the subtrahend,

[0014] Determine the first target luminance value according to the luminance difference.

[0015] In some embodiments, the determining the first target luminance value according to the luminance difference includes:

[0016] When the second luminance value is greater than or equal to a first threshold, determine the first target luminance value according to the luminance difference.

[0017] In some embodiments, the determining the luminance ratio according to the first luminance value and the first target luminance value includes:

[0018] Determine a luminance ratio with the first target luminance value as the dividend and the first luminance value as the divisor.

[0019] In some embodiments, the determining the target exposure parameter according to the luminance ratio and the first exposure parameter includes:

[0020] When the luminance ratio is less than a second threshold, determine the target exposure parameter according to the luminance ratio and the first exposure parameter.

[0021] In some embodiments, the first exposure parameter includes a first exposure duration and a first exposure gain, and the determining the target exposure parameter according to the luminance ratio and the first exposure parameter includes:

[0022] Determine an exposure scheduling step corresponding to the luminance ratio,

[0023] Determine the product of the scheduling step, the first exposure duration, and the first exposure gain as a target exposure value,

[0024] Determine the exposure parameter interval where the target exposure value is located,

[0025] Determine the target exposure parameter according to the target exposure value and the exposure parameter interval.

[0026] In some embodiments, the exposure parameter range includes a maximum exposure duration, a minimum exposure duration, a maximum exposure gain, and a minimum exposure gain. It is characterized in that determining the target exposure parameter according to the target exposure value and the exposure parameter range includes:

[0027] Determine the suspected target exposure duration as the ratio of the target exposure value to the minimum exposure gain.

[0028] When the suspected target exposure duration is less than or equal to the maximum exposure duration, determine the suspected target exposure duration as the target exposure duration, and determine the minimum exposure gain as the target exposure gain.

[0029] In some embodiments, after determining the suspected target exposure duration with the target exposure value as the dividend and the minimum exposure gain as the divisor, the method further includes:

[0030] When the suspected target exposure duration is greater than the maximum exposure duration, determine the suspected target exposure gain as the ratio of the target exposure value to the maximum exposure duration, and determine the maximum exposure duration as the target exposure duration.

[0031] When the suspected target exposure gain is less than or equal to the maximum exposure gain, determine the suspected target exposure gain as the target exposure gain.

[0032] In some embodiments, the target exposure parameter includes a target exposure gain and a target exposure duration. After determining the target exposure parameter according to the brightness ratio and the first exposure parameter, the method further includes:

[0033] Map the target exposure gain to the exposure gain of the register, and map the target exposure duration to the exposure duration of the register.

[0034] Write the exposure gain and the exposure duration of the register into the memory of the camera.

[0035] In some embodiments, the method further includes:

[0036] When the camera acquires a second image frame, expose the second image frame with the target exposure gain and the target exposure duration to obtain a second image. The second image frame is an image acquired after the first image frame.

[0037] Update the second image to the first image.

[0038] Return to execute the step of dividing the first image into k sub-regions.

[0039] In a second aspect, an embodiment of the present application provides an automatic exposure control device, which includes:

[0040] An Image Signal Processing (ISP) module, configured to divide a first image into k sub-regions, where k is a positive integer greater than 1, and the first image is an image obtained after exposing the first image frame captured by the camera at the current moment.

[0041] The ISP module is further configured to determine the brightness value of each sub-region among the k sub-regions.

[0042] An Artificial Intelligence (AI) module, configured to determine a region of interest in the first image, where the region of interest is the region where the recognized target object is located.

[0043] A main control module, configured to determine a first brightness value and a second brightness value of the first image according to the brightness values of the sub-regions and the region of interest. The first brightness value is the overall brightness value of the first image, and the second brightness value is the brightness value of the region of interest in the first image.

[0044] The main control module is further configured to determine a first target brightness value according to the second brightness value and a pre-set second target brightness value. The second target brightness value is the target brightness value of the region of interest, and the first target brightness value is the overall target brightness value of the first image.

[0045] The main control module is further configured to determine a brightness ratio according to the first brightness value and the first target brightness value.

[0046] The main control module is further configured to determine a target exposure parameter according to the brightness ratio and a first exposure parameter, where the first exposure parameter is the exposure parameter when exposing the first image frame, and the exposure parameter includes exposure duration and exposure gain.

[0047] In a third aspect, an embodiment of the present application provides an automatic exposure control device, which includes: a processor and a memory storing computer program instructions.

[0048] When the processor executes the computer program instructions, the above-mentioned automatic exposure control method is implemented.

[0049] In a fourth aspect, an embodiment of the present application provides a computer storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the above-mentioned automatic exposure control method is implemented.

[0050] In a fifth aspect, an embodiment of the present application provides a computer program product, which includes computer program instructions. When the computer program instructions are executed by a processor, the above-mentioned automatic exposure control method is implemented.

[0051] In the present application, by determining the region of interest where the target object is located in each of the currently exposed first images, and determining the second brightness value of the region of interest and the first brightness value of the entire first image, then by comparing the second brightness value of the region of interest with a preset second target brightness value to determine a first target brightness value, and further based on the comparison result between the first brightness value and the first target brightness value, in combination with the first exposure parameter of the camera, the target exposure parameter of the camera is determined. This way of determining the target parameter ensures both the brightness of the entire image after exposure and the brightness of the region of interest. Compared with the prior art that only considers the brightness of the entire image, it can ensure that the brightness of the region of interest meets the user's requirements and avoid the problem that the target object is too dark in a high-brightness background environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] 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. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0053] Figure 1 is a schematic flowchart of an automatic exposure control method provided by an embodiment of the present application,

[0054] Figure 2 is a schematic flowchart of an automatic exposure control method provided by another embodiment of the present application,

[0055] Figure 3 is a schematic structural diagram of an automatic exposure control device provided by an embodiment of the present application,

[0056] Figure 4 is a schematic flowchart of an automatic exposure control method provided by still another embodiment of the present application,

[0057] Figure 5 is a schematic flowchart of an automatic exposure control method provided by yet another embodiment of the present application,

[0058] Figure 6 is a schematic hardware structure diagram of an automatic exposure control device provided by an embodiment of the present application,

[0059] Figure 7 is a schematic structural diagram of an automatic exposure control device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0060] The features and exemplary embodiments of various aspects of the present application will be described in detail below. To make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application and not to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0061] It should be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0062] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The embodiments will be described in detail below in conjunction with the accompanying drawings.

[0063] In the current exposure strategy of machine vision cameras, the exposure of the camera is mainly controlled by controlling the exposure duration and gain. The metering area used during exposure is usually the entire screen or a fixed area in the center of the screen. This exposure strategy is sufficient for image acquisition by ordinary cameras, but for the applications of intelligent systems, there are certain deficiencies in this exposure method, especially for the occasions of object tracking or recognition. In the occasions of object tracking or recognition, an appropriate exposure strategy is often required to make the object to be tracked / recognized have appropriate brightness. However, the current global metering or fixed region of interest (ROI) metering method is difficult to ensure appropriate exposure to make the object in motion have appropriate brightness, and it is easy to cause the problem that the target object is too dark under a high-brightness background environment.

[0064] Specifically, to solve the problems of the prior art, the embodiments of the present application provide an automatic exposure control method and device. First, the automatic exposure control method provided by the embodiments of the present application will be introduced below.

[0065] Figure 1 The flowchart of the automatic exposure control method provided by an embodiment of the present application is shown. The method includes the following steps:

[0066] S110, divide the first image into k sub-regions, where k is a positive integer greater than 1, and the first image is the image obtained after exposing the first image frame captured by the camera at the current moment.

[0067] S120, determine the brightness values of the respective sub-regions among the k sub-regions.

[0068] In this embodiment, the camera captures images by capturing image frames and exposing the captured image frames. Due to different ambient brightness levels and camera exposure parameters, the brightness values of different captured images are also different. To keep the brightness of the captured images within a suitable range, automatic exposure control can be performed on the camera. That is, for each captured first image, the exposure parameters of the camera are adjusted based on the brightness of the first image, so that the brightness of the subsequently captured images is close to or even meets the user's requirements.

[0069] Since there are differences in brightness at different positions in the first image, and the user's actual attention to different regions in the first image is different, in the user's view, the brightness of different regions in the first image has different effects on the overall brightness of the first image. Therefore, the first image can be divided into k sub-regions, and the brightness value of each sub-region can be determined separately. Then, the brightness value of the first image can be determined based on the brightness values of the respective sub-regions.

[0070] S130, determine the region of interest in the first image, where the region of interest is the region where the recognized target object is located.

[0071] S140, determine a first brightness value and a second brightness value of the first image based on the brightness values of the respective sub-regions and the region of interest, where the first brightness value is the overall brightness value of the first image, and the second brightness value is the brightness value of the region of interest in the first image.

[0072] In this embodiment, since there are differences in brightness at different positions in the image, and the user actually pays more attention to the target object in the image frame, the region where the target object is located can be designated as the region of interest for the user. And the overall brightness value of the first image, that is, the first brightness value, and the brightness value of the region of interest in the first image, that is, the second brightness value, are determined separately. And the target exposure parameters for exposing the next image frame are jointly determined based on the first brightness value and the second brightness value.

[0073] As an alternative embodiment, the weight coefficients of the respective sub-regions among the k sub-regions can be determined according to the region of interest, and the actual brightness value of the current image frame can be determined based on the brightness values of the respective sub-regions and the weight coefficients of the respective sub-regions.

[0074] In this embodiment, not all objects in the image frame are objects of interest to the user. Only the target object is the object of interest to the user. Therefore, image recognition can be performed on the image frame to obtain the area where the target object is located, and the area where the target object is located can be determined as the region of interest. Then, the weight coefficients of each sub-region are determined based on the region of interest. The weight coefficient of the brightness at the location of the target object in the actual brightness value of the image frame is relatively high, and the weight coefficient of the brightness at the location of the non-target object in the brightness value of the image frame is relatively low. Among them, the area where the target object is located can be determined as the region of interest.

[0075] For this reason, the current image frame can be divided into k sub-regions, and the weight coefficient of each sub-region is determined. Then, the actual brightness value of the current image frame is determined according to the brightness of each sub-region and the weight coefficient.

[0076] Exemplarily, the current image frame can be divided into a rectangular grid of a×b, and then the weight coefficient of each rectangular grid is determined. Then, the product of the brightness and the weight coefficient of each rectangular grid is used as the actual brightness value of the image frame. In this way, the actual brightness value of each image frame can be determined.

[0077] Exemplarily, the region of interest includes at least one sub-region. The weight coefficients of the sub-regions included in the region of interest are relatively high, and the weight coefficients of the sub-regions not included in the region of interest are relatively low. For example, if there are a total of 4 sub-regions in the image frame and the region of interest includes 2 sub-regions, then the weight coefficients of the two sub-regions included in the region of interest can be set to 0.8, and the weight coefficients of the two sub-regions not included in the region of interest can be set to 0.4.

[0078] S150. Determine a first target brightness value according to the second brightness value and a preset second target brightness value. The second target brightness value is the target brightness value of the region of interest, and the first target brightness value is the overall target brightness value of the first image.

[0079] In this embodiment, the first target brightness value is the brightness value that the user expects the next image as a whole to reach. The second target brightness value is preset by the user and is the brightness value that the user expects the region of interest in the next image to reach. The first target brightness value can be calculated according to the second brightness value of the region of interest and the second target brightness value. Then, the first target brightness value is compared with the first brightness value of the first image, and the target exposure parameter when the camera exposes the next image frame is determined according to the comparison result.

[0080] Exemplarily, when the second target brightness value is a definite value, the mapping relationship between the second brightness value and the first target brightness value can be set and stored in a mapping table. Whenever the second brightness value of an image is determined, the first target brightness value corresponding to the second brightness value can be determined by querying the mapping table.

[0081] S160. Determine a brightness ratio according to the first brightness value and the first target brightness value.

[0082] As an optional embodiment, the above S160 may include:

[0083] Determine a brightness ratio with the first target brightness value as the dividend and the first brightness value as the divisor.

[0084] S170. Determine a target exposure parameter according to the brightness ratio and a first exposure parameter, where the first exposure parameter is the exposure parameter when the first image frame is exposed, and the exposure parameter includes an exposure duration and an exposure gain.

[0085] In one embodiment, after the first target brightness value is determined, it is also necessary to determine the target exposure parameter of the camera according to the first target brightness value to implement the exposure control of the camera. The exposure parameter includes an exposure duration and an exposure gain.

[0086] Specifically, after the first brightness value of the whole first image is obtained, the first target brightness value can be used as the dividend and the first brightness value as the divisor to calculate the brightness ratio. Since the brightness ratio can be used to characterize the relationship between the first target brightness value and the first brightness value, it is possible to determine whether it is necessary to adjust the exposure parameter of the camera according to the brightness ratio, and the exposure control of the camera is achieved through the first exposure parameter.

[0087] Exemplarily, if the brightness ratio is greater than 0.9 and less than 1.1, it indicates that the first brightness value and the first target brightness value are relatively close, and there is no need to adjust the exposure parameter of the camera. If the brightness ratio is less than or equal to 0.9 or greater than or equal to 1.1, it is necessary to re-adjust the exposure parameter of the camera to perform the exposure control of the camera. In the above manner, it is possible to determine whether to adjust the exposure parameter of the camera based on the comparison result between the first target brightness value and the first brightness value.

[0088] In this application, by determining the region of interest (ROI) where the target object is located in each currently exposed first image, and determining the second brightness value of the ROI and the first brightness value of the entire first image, then by comparing the second brightness value of the ROI with a preset second target brightness value to determine the first target brightness value, and further based on the comparison result between the first brightness value and the first target brightness value, in combination with the first exposure parameter of the camera, the target exposure parameter of the camera is determined. This way of determining the target parameter ensures both the brightness of the entire image after exposure and the brightness of the ROI. Compared with the prior art that only considers the brightness of the entire image, it can ensure that the brightness of the ROI meets the user's requirements and avoid the problem of the target object being too dark in a high-brightness background environment.

[0089] As an alternative embodiment, the above S150 may include:

[0090] Determine the brightness difference with the second target brightness value as the minuend and the second brightness value as the subtrahend.

[0091] Determine the first target brightness value based on the brightness difference.

[0092] As an alternative embodiment, the step of determining the first target brightness value based on the brightness difference includes:

[0093] When the second brightness value is greater than or equal to the first threshold, determine the first target brightness value based on the brightness difference.

[0094] In this embodiment, the second target brightness value is preset by the user, representing the brightness value that the ROI is expected to reach. The brightness difference between the second brightness value and the second target brightness value can represent the gap between the actual brightness and the expected brightness of the ROI. Therefore, it is possible to determine whether the brightness of the ROI converges based on the brightness difference.

[0095] If the brightness difference is less than the first threshold, it indicates that the brightness of the ROI converges, and then the first target brightness value does not need to be set. If the brightness difference is greater than or equal to the first threshold, it indicates that the brightness of the ROI does not converge, and it is necessary to determine the first target brightness value for the next image frame based on the brightness difference and perform exposure control on the camera based on the first target brightness value.

[0096] Through the above method, it is possible to determine whether to determine the first target brightness value by comparing the actual brightness and the expected brightness of the ROI, and further adjust the target exposure parameter of the camera to perform exposure control on the camera.

[0097] As an alternative embodiment, the above S150 may include:

[0098] When the brightness ratio is less than the second threshold, the first exposure parameter is determined as the target exposure parameter;

[0099] When the brightness ratio is greater than or equal to the second threshold, the target exposure parameter is determined according to the brightness ratio and the first exposure parameter.

[0100] In this embodiment, the first exposure parameter is the exposure parameter when the camera captures the first image most recently. If the brightness ratio is less than the second threshold, it can be determined that the exposure control converges, that is, there is no need to adjust the exposure parameter. If the brightness ratio is greater than or equal to the second threshold, it can be determined that the exposure control does not converge. Therefore, it is necessary to further adjust the exposure parameter.

[0101] Specifically, the brightness ratio and the first exposure parameter can be combined for calculation to obtain a new target exposure parameter. The target exposure parameter includes the desired exposure duration and the desired exposure gain. In the above manner, the desired exposure duration and exposure gain can be determined.

[0102] As an alternative embodiment, the first exposure parameter includes a first exposure duration and a first exposure gain. The determining of the target exposure parameter according to the brightness ratio and the first exposure parameter includes:

[0103] Determine the exposure scheduling step corresponding to the brightness ratio,

[0104] Determine the product of the scheduling step, the first exposure duration, and the first exposure gain as the target exposure value,

[0105] Determine the exposure parameter interval where the target exposure value is located,

[0106] Determine the target exposure parameter according to the target exposure value and the exposure parameter interval.

[0107] In this embodiment, in order to avoid abnormal exposure gain calculated directly from the brightness ratio due to extremely large or small brightness ratio, the brightness ratio can be converted into an exposure scheduling step. The scheduling step can characterize the characteristics of the brightness ratio and there will be no numerical abnormality.

[0108] After obtaining the scheduling step, the product of the scheduling step, the first exposure duration, and the first exposure gain can be determined as the target exposure value, and then the exposure parameter interval where the target exposure value is located can be determined. In this way, the exposure parameter interval where the exposure parameter was located when capturing the previous image frame can be determined, and the value of the target exposure parameter can be determined according to the target exposure value and the exposure parameter interval.

[0109] In one embodiment, as Figure 2As shown in steps S210 - S212, the value of the target exposure parameter can be determined by the target parameter controller. Specifically, the brightness ratio and the exposure parameter of the previous frame can be used as the inputs of the target parameter controller. A piecewise function can be used to impose certain restrictions on the brightness ratio, thereby converting the brightness ratio into a scheduling step. The piecewise function is as follows:

[0110]

[0111] where adj_ratio represents the scheduling step, a and b are thresholds set in advance by the user, and ratio is the brightness ratio.

[0112] After determining the scheduling step, the product of the scheduling step and the first exposure duration and the first exposure gain can be determined as the target exposure value. The specific calculation formula is as follows:

[0113] EV = adj_ratio * ET prev * Gain prev

[0114] where adj_ratio represents the scheduling step, ET prev represents the first exposure duration, Gain prev represents the first exposure gain, EV represents the target exposure value. After obtaining the target exposure value, the target exposure value can be compared with the pre - set exposure value lookup table to determine the maximum exposure duration ET_max, the minimum exposure duration ET_min, the maximum exposure gain Gain_max, and the minimum exposure gain Gain_min corresponding to the target exposure value. Then, within the exposure parameter range, the target exposure duration ET for the next exposure is calculated. The specific calculation method is:

[0115] ET = EV / Gain_min

[0116] where EV represents the target exposure value, Gain_min is the minimum exposure gain, and ET is the suspected target exposure duration. If ET < ET_max, then ET can be directly determined as the target exposure duration, and Gain_min can be determined as the target exposure gain. If ET > ET_max, then ET is not available, and the exposure gain for the next exposure can be calculated through ET_max. The specific calculation method is:

[0117] Gain = EV / ET_max

[0118] where Gain is the suspected target exposure gain, EV represents the target exposure value, and ET_max represents the maximum exposure duration.

[0119] After obtaining the suspected target exposure gain, it is also necessary to judge the suspected target exposure gain. If the suspected target exposure gain is greater than the maximum exposure gain, then the maximum exposure gain can be determined as the target exposure gain, and the maximum exposure duration can be determined as the target exposure duration. If the suspected target exposure gain is less than or equal to the maximum exposure gain, then the suspected target exposure gain can be determined as the target exposure gain, and the maximum exposure duration can be determined as the target exposure duration.

[0120] Finally, the target exposure duration can be output as the exposure time for the next frame, and the target exposure gain can be output as the gain for the next frame.

[0121] Through the above method, the values of each exposure parameter can be directly obtained, and the exposure of the camera can be controlled based on these values.

[0122] As an optional embodiment, the exposure parameter range includes the maximum exposure duration, the minimum exposure duration, the maximum exposure gain, and the minimum exposure gain. It is characterized in that determining the target exposure parameter according to the target exposure value and the exposure parameter range includes:

[0123] Determine the ratio of the target exposure value to the minimum exposure gain as the suspected target exposure duration.

[0124] In the case where the suspected target exposure duration is less than or equal to the maximum exposure duration, determine the suspected target exposure duration as the target exposure duration, and determine the minimum exposure gain as the target exposure gain.

[0125] In this embodiment, after determining the exposure parameter range where the exposure parameter is located, that is, determining the maximum exposure duration, the minimum exposure duration, the maximum exposure gain, and the minimum exposure gain, then the ratio of the target exposure value to the minimum exposure gain can be determined as the suspected target exposure duration. If the suspected exposure duration is less than or equal to the maximum exposure duration, it can be considered that the suspected exposure duration is available, so the suspected exposure duration can be determined as the target exposure duration. Correspondingly, the minimum exposure gain can be determined as the target exposure gain.

[0126] Exemplarily, the maximum exposure duration is 30 milliseconds, the minimum exposure duration is 0.5 milliseconds, the maximum exposure gain is 10 times, and the minimum exposure gain is 2 times. Then when the target exposure value is 28, the suspected target exposure duration can be determined to be 14 milliseconds. Since 14 milliseconds is less than 30 milliseconds, 14 milliseconds can be determined as the target exposure duration, and 2 times can be determined as the target exposure gain.

[0127] As an optional embodiment, after determining the suspected target exposure duration with the target exposure value as the dividend and the minimum exposure gain as the divisor, the method further includes:

[0128] When the exposure duration of the suspected target is greater than the maximum exposure duration, the ratio of the target exposure value to the maximum exposure duration is determined as the suspected target exposure gain, and the maximum exposure duration is determined as the target exposure duration.

[0129] When the suspected target exposure gain is less than or equal to the maximum exposure gain, the suspected target exposure gain is determined as the target exposure gain.

[0130] In this embodiment, if the suspected exposure duration is greater than the maximum exposure duration, it can be considered that the suspected exposure duration is unavailable. Therefore, the suspected target exposure gain can be obtained by dividing the target exposure value by the maximum exposure duration. If the target exposure gain is greater than the maximum exposure gain, the maximum exposure gain is determined as the target exposure gain, and the maximum exposure duration is determined as the target exposure duration. If the suspected target exposure gain is less than or equal to the maximum exposure gain, the suspected target exposure gain can be determined as the target exposure gain, and the maximum exposure duration is determined as the target exposure duration.

[0131] Exemplarily, the maximum exposure duration is 30 milliseconds, the minimum exposure duration is 0.5 milliseconds, the maximum exposure gain is 10 times, and the minimum exposure gain is 2 times. Then, when the target exposure value is 90, the suspected target exposure duration can be determined to be 45 milliseconds. Since 45 milliseconds is greater than 30 milliseconds, the suspected target exposure gain can be determined to be 3 times. Since 3 times is less than 10 times, the target exposure gain can be determined to be 3 times, and the target exposure duration can be determined to be 30 milliseconds.

[0132] As an alternative embodiment, the target exposure parameters include a target exposure gain and a target exposure duration. After S170, the following may further be included:

[0133] Map the target exposure gain to the exposure gain of the register, and map the target exposure duration to the exposure duration of the register.

[0134] Write the exposure gain of the register and the exposure duration of the register into the memory of the camera.

[0135] In this embodiment, after each new target exposure duration and target exposure gain are determined, the target exposure duration and target exposure gain can be converted into write values in the camera register, and then the write values are written into the memory of the camera as the exposure duration and exposure gain for the next exposure.

[0136] As an alternative embodiment, the method further includes:

[0137] When the second image frame is acquired by the camera, the second image frame is exposed using the target exposure gain and the target exposure duration to obtain a second image, where the second image frame is an image acquired after the first image frame.

[0138] Update the second image to the first image.

[0139] Return to execute the step of dividing the first image into k sub-regions.

[0140] In this embodiment, every time an exposed image is obtained, the above process is executed once to update the exposure parameters in the camera in real time, so as to ensure that the brightness of the region of interest in each image always meets the user's requirements and avoid the problem that the target object is too dark in a high-brightness background environment.

[0141] In one embodiment, as Figure 3 shown, the above automatic exposure control method is applied to a camera device, which includes a controller 301 and a camera 305. The communication between the camera and the controller can include Mobile Industry Processor Interface / Low Voltage Differential Signaling / Gigabit Multimedia Serial Link and Inter-Integrated Circuit bus communication. The communication direction is to transmit the original image of the acquired image frame from the camera to the controller at high speed, and the controller transmits low-speed control signals to the camera.

[0142] Exemplarily, the controller further includes an Image Signal Processing (ISP) module 304, an Artificial Intelligence (AI) module 303, and a main control module 302. The ISP module is used to receive the original image transmitted by the camera, and perform image processing operations such as interpolation, white balance, and color correction on the original image, transform the original image into an image with correct color and high clarity, and transform the format of the original image into RGB format or YUV format, and then transmit the transformed image to the AI module. In addition, the ISP module is also used to count the H3A data in the original image. The H3A data includes the brightness values of each pixel point in the image and sends the H3A data to the main control module.

[0143] The AI module contains a trained neural network model, which can identify the target object in the image, determine the region where the target object is located, set this region as the region of interest, and then transmit the coordinates and relevant information of the region of interest to the main control module. The main control module contains functional modules such as calculation, storage, logical judgment, and communication, and is used to receive the H3A data transmitted by the ISP module and the coordinates and relevant information of the region of interest transmitted by the AI module. The main control module can implement exposure control of the camera based on the H3A data and the region of interest.

[0144] Exemplarily, the main control module includes a target brightness controller and an exposure parameter controller. Among them, the target brightness controller is used to calculate a first target brightness value based on the brightness difference between the second target brightness value of the region of interest and the actual second brightness value of the region of interest. This controller can be a single-input single-output controller, with the input of the controller being the brightness difference and the output being the first target brightness value. Specifically, the target brightness controller can apply control strategies such as PID control, neural network control, fuzzy control, LQR control, and adaptive control. The exposure parameter controller can be a multi-input multi-output controller, and the input parameters can include the brightness ratio and the exposure parameters when collecting the previous image frame, and the output parameters are the target exposure duration and the target exposure parameters.

[0145] In one embodiment, as Figure 4 shown in S410 - S490, first, the initial value is loaded at the camera end. After configuring the registers of the image sensor, the camera starts to work and exposes the image collected by the camera based on the exposure parameters in the current initial value to obtain the original image of an image frame. Moreover, the camera will send the original image to the ISP module.

[0146] The ISP module will perform statistics on the picture brightness of the original image, that is, H3A statistics. The H3A statistics function will divide the original image into a grid of a×b, and statistically calculate the average brightness information in each grid to obtain the H3A information, and then use the H3A information as the basic data for image brightness calculation and input it into the main control module. After H3A statistics, the ISP module will also process the original image. The specific processing includes steps such as black level correction, white balance adjustment, color interpolation, color correction, and gamma correction. Finally, the original image is processed into a color image, and the color image can be converted into RGB format or YUV format, and then the color image after format conversion is transmitted to the AI module.

[0147] After receiving the color image after format conversion, the AI module will identify the target object in the color image through the neural network set in the AI module. After identifying the position of the target object, the area where the position of the target object is located is set as the region of interest (ROI), and the RGB data / YUV data of the region of interest is transmitted to the main control module.

[0148] After receiving the RGB data / YUV data of the region of interest and the H3A information, the main control module can apply the target brightness controller to determine the target brightness of the entire screen through the target brightness controller based on the brightness difference between the actual brightness of the region of interest and the target brightness of the region of interest. It can also apply the exposure parameter controller to output the new target exposure duration and target exposure gain based on the brightness ratio between the target brightness of the entire screen and the actual brightness of the screen, as well as the exposure parameters of the previous frame.

[0149] Exemplarily, as Figure 5 shown in S510 - S550 in

[0150]

[0151] wherein, Y i and Y i+1 are respectively the current target brightness and the new target brightness, adj is the final adjustment value, error is the brightness difference, K p , K i , K d are respectively the adjustment coefficients of the proportional link, integral link, and differential link in the PID controller.

[0152] Through the above calculation method, the target object can be dynamically recognized by the neural network, and the area where the target object is located can be set as the region of interest. Further, through the closed-loop control of the target brightness controller and the exposure parameter controller, the brightness of the target object can be maintained within a suitable range under any lighting conditions. The above recognition of the target object and the closed-loop of the brightness statistics of the region of interest are independent of the closed-loop of automatic exposure in the related art, reducing the coupling degree between the setting of the region of interest and the automatic exposure algorithm, which is beneficial to the flexible arrangement of the algorithm on the hardware and the expansion of the algorithm function.

[0153] Based on the automatic exposure control method provided in the above embodiments, correspondingly, the present application also provides a specific implementation manner of the automatic exposure control device. Please refer to the following embodiments.

[0154] First, refer to Figure 6 , the automatic exposure control device 600 provided in the embodiments of the present application includes the following modules:

[0155] The Image Signal Processing (ISP) module 601 is used to divide the first image into k sub-regions, where k is a positive integer greater than 1. The first image is the image obtained after exposing the first image frame captured by the camera at the current moment.

[0156] The ISP module 601 is also used to determine the brightness value of each sub-region among the k sub-regions.

[0157] The Artificial Intelligence (AI) module 602 is used to determine the region of interest in the first image. The region of interest is the region where the recognized target object is located.

[0158] The main control module 603 is used to determine the first brightness value and the second brightness value of the first image according to the brightness values of the sub-regions and the region of interest. The first brightness value is the overall brightness value of the first image, and the second brightness value is the brightness value of the region of interest in the first image.

[0159] The main control module 603 is also used to determine the first target brightness value according to the second brightness value and the pre-set second target brightness value. The second target brightness value is the target brightness value of the region of interest, and the first target brightness value is the overall target brightness value of the first image.

[0160] The main control module 603 is also used to determine the brightness ratio according to the first brightness value and the first target brightness value.

[0161] The main control module 603 is also used to determine the target exposure parameter according to the brightness ratio and the first exposure parameter. Among them, the first exposure parameter is the exposure parameter when exposing the first image frame, and the exposure parameter includes exposure duration and exposure gain.

[0162] The device can ensure that the brightness of the region of interest meets the user's requirements and avoid the problem that the brightness of the target object is too dark in a high-brightness background environment by determining the region of interest where the target object is located in each captured image frame, determining the second brightness value of the region of interest, and then performing exposure control of the camera based on the second brightness value of the region of interest and the overall first brightness value.

[0163] As an implementation manner of the present application, the above main control module 603 may further include:

[0164] The first determination unit is used to determine the brightness difference with the second target brightness value as the minuend and the second brightness value as the subtrahend.

[0165] The second determination unit is used to determine the first target brightness value according to the brightness difference.

[0166] As an implementation manner of the present application, the above-mentioned second determination unit may include:

[0167] A difference calculation unit, configured to determine the first target brightness value according to the brightness difference when the second brightness value is greater than or equal to the first threshold.

[0168] As an implementation manner of the present application, the above-mentioned main control module 603 may include:

[0169] A ratio calculation unit, configured to determine a brightness ratio with the first target brightness value as the dividend and the first brightness value as the divisor.

[0170] As an implementation manner of the present application, the above-mentioned main control module 603 may further include:

[0171] A third determination unit, configured to determine the first exposure parameter as the target exposure parameter when the brightness ratio is less than the second threshold; and determine the target exposure parameter according to the brightness ratio and the first exposure parameter when the brightness ratio is greater than or equal to the second threshold.

[0172] As an implementation manner of the present application, the above-mentioned third determination unit is further configured to:

[0173] Determine the exposure scheduling step corresponding to the brightness ratio,

[0174] Determine the product of the scheduling step, the first exposure duration, and the first exposure gain as the target exposure value,

[0175] Determine the exposure parameter interval where the target exposure value is located,

[0176] Determine the target exposure parameter according to the target exposure value and the exposure parameter interval. As an implementation manner of the present application, the above-mentioned third determination unit is further configured to:

[0177] Determine the ratio of the target exposure value to the minimum exposure gain as the suspected target exposure duration,

[0178] When the suspected target exposure duration is less than or equal to the maximum exposure duration, determine the suspected target exposure duration as the target exposure duration and determine the minimum exposure gain as the target exposure gain.

[0179] As an implementation manner of the present application, the above-mentioned third determination unit is further configured to:

[0180] When the suspected target exposure duration is greater than the maximum exposure duration, determine the ratio of the target exposure value to the maximum exposure duration as the suspected target exposure gain and determine the maximum exposure duration as the target exposure duration.

[0181] When the suspected target exposure gain is less than or equal to the maximum exposure gain, determine the suspected target exposure gain as the target exposure gain.

[0182] As an implementation manner of this application, the above automatic exposure control device 600 is further configured to:

[0183] Map the target exposure gain to the exposure gain of the register, and map the target exposure duration to the exposure duration of the register,

[0184] Write the exposure gain of the register and the exposure duration of the register into the memory of the camera.

[0185] As an implementation manner of this application, the above automatic exposure control device 600 is further configured to:

[0186] When the camera acquires a second image frame, use the target exposure gain and the target exposure duration to expose the second image frame to obtain a second image, where the second image frame is an image acquired after the first image frame,

[0187] Update the second image to the first image,

[0188] Return to execute the step of dividing the first image into k sub-regions.

[0189] The automatic exposure control device provided by the embodiments of the present invention can implement each step in the above method embodiments. To avoid repetition, it will not be elaborated here.

[0190] Figure 7 FIG. shows a schematic hardware structure diagram of an automatic exposure control device provided by an embodiment of this application.

[0191] The automatic exposure control device may include a processor 701 and a memory 702 storing computer program instructions.

[0192] Specifically, the above processor 701 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0193] The memory 702 may include a mass storage for data or instructions. By way of example and not limitation, the memory 702 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disc, a magneto-optical disc, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 702 may include removable or non-removable (or fixed) media. Where appropriate, the memory 702 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, the memory 702 is a non-volatile solid-state memory.

[0194] The memory may include a read only memory (ROM), a random access memory (RAM), a magnetic disk storage media device, an optical storage media device, a flash memory device, an electrical, optical, or other physical / tangible memory storage device. Thus, in general, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described in reference to the method according to one aspect of the present disclosure.

[0195] The processor 701 reads and executes the computer program instructions stored in the memory 702 to implement any of the automatic exposure control methods in the above embodiments.

[0196] In one example, the automatic exposure control device may further include a communication interface 703 and a bus 710. Among them, as Figure 7 shown, the processor 701, the memory 702, and the communication interface 703 are connected through the bus 710 and complete communication with each other.

[0197] The communication interface 703 is mainly used to implement communication between the various modules, devices, units, and / or devices in the embodiments of the present application.

[0198] The bus 710 includes hardware, software, or both, and couples the components of the automatic exposure control device to each other. By way of example and not limitation, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a MicroChannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable bus or a combination of two or more of these. Where appropriate, the bus 710 may include one or more buses. Although the embodiments of the present application describe and illustrate specific buses, the present application contemplates any suitable bus or interconnect.

[0199] The automatic exposure control device may be based on the above embodiments, thereby implementing the automatic exposure control method and device described above.

[0200] In addition, in combination with the automatic exposure control method in the above embodiments, the embodiments of the present application may provide a computer storage medium to implement. Computer program instructions are stored on the computer storage medium, and when the computer program instructions are executed by a processor, any one of the automatic exposure control methods in the above embodiments is implemented, and the same technical effects can be achieved. To avoid repetition, it will not be described in detail here. Among them, the above computer-readable storage medium may include a non-transitory computer-readable storage medium, such as a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disc, etc., which is not limited here.

[0201] In addition, the embodiments of the present application also provide a computer program product, including computer program instructions, and when the computer program instructions are executed by a processor, the steps and corresponding contents of the foregoing method embodiments can be implemented.

[0202] It should be clear that the present application is not limited to the specific configurations and processes described above and illustrated in the figures. For the sake of brevity, the detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the method process of the present application is not limited to the specific steps described and illustrated, and those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present application.

[0203] The functional blocks shown in the above structural block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, and so on. When implemented in software, the elements of the present application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted via a data signal carried in a carrier wave on a transmission medium or a communication link. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical discs, hard disks, fiber optic media, radio frequency (RF) links, and so on. The code segment can be downloaded via a computer network such as the Internet, an intranet, and so on.

[0204] It should also be noted that in the exemplary embodiments mentioned in the present application, some methods or systems are described based on a series of steps or devices. However, the present application is not limited to the order of the above steps, that is, the steps can be executed in the order mentioned in the embodiments, can be different from the order in the embodiments, or several steps can be executed simultaneously.

[0205] As described above with reference to the flowcharts and / or block diagrams of methods, apparatuses, and computer program products according to embodiments of the present disclosure. It should be understood that each block in the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine such that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the functions / actions specified in one or more blocks of the flowcharts and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It should also be understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by dedicated hardware that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0206] The above is only the specific implementation manner of the present application. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, modules, and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein. It should be understood that the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present application.

Claims

1. An automatic exposure control method, characterized in that, The method includes: Dividing a first image into k sub-regions, where k is a positive integer greater than 1, and the first image is an image obtained by exposing the first image frame collected by a camera at the current moment; Determining the brightness value of each sub-region among the k sub-regions; Determining a region of interest in the first image, where the region of interest is the region where the recognized target object is located; Determining a first brightness value and a second brightness value of the first image according to the brightness values of the sub-regions and the region of interest, where the first brightness value is the overall brightness value of the first image, and the second brightness value is the brightness value of the region of interest in the first image; Determining a first target brightness value according to the second brightness value and a pre-set second target brightness value, where the second target brightness value is the target brightness value of the region of interest, and the first target brightness value is the overall target brightness value of the first image; Determining a brightness ratio according to the first brightness value and the first target brightness value; Determining a target exposure parameter according to the brightness ratio and a first exposure parameter, where the first exposure parameter is the exposure parameter when exposing the first image frame, and the exposure parameter includes exposure duration and exposure gain; The determining the target exposure parameter according to the brightness ratio and the first exposure parameter includes: When the brightness ratio is less than a second threshold, determining the first exposure parameter as the target exposure parameter; When the brightness ratio is greater than or equal to the second threshold, determining the target exposure parameter according to the brightness ratio and the first exposure parameter; The first exposure parameter includes a first exposure duration and a first exposure gain, and the determining the target exposure parameter according to the brightness ratio and the first exposure parameter includes: Determining an exposure scheduling step corresponding to the brightness ratio; Determining the product of the scheduling step, the first exposure duration, and the first exposure gain as the target exposure value; Determining the exposure parameter interval where the target exposure value is located; Determining the target exposure parameter according to the target exposure value and the exposure parameter interval.

2. The automatic exposure control method according to claim 1, wherein The determining the first target brightness value according to the second brightness value and the pre-set second target brightness value includes: Determining a brightness difference with the second target brightness value as the minuend and the second brightness value as the subtrahend; Determining the first target brightness value according to the brightness difference.

3. The automatic exposure control method according to claim 2, wherein The determining the first target brightness value according to the brightness difference includes: When the second brightness value is greater than or equal to a first threshold, determining the first target brightness value according to the brightness difference.

4. The automatic exposure control method according to claim 1, characterized in that The determining the brightness ratio according to the first brightness value and the first target brightness value includes: Determining a brightness ratio with the first target brightness value as the dividend and the first brightness value as the divisor.

5. The automatic exposure control method according to claim 1, wherein the exposure parameter range includes a maximum exposure duration, a minimum exposure duration, a maximum exposure gain, and a minimum exposure gain, characterized in that The determining the target exposure parameter according to the target exposure value and the exposure parameter interval includes: Determining the ratio of the target exposure value to the minimum exposure gain as a suspected target exposure duration. When the exposure duration of the suspected target is less than or equal to the maximum exposure duration, determine the exposure duration of the suspected target as the target exposure duration, and determine the minimum exposure gain as the target exposure gain.

6. The automatic exposure control method according to claim 5, wherein After determining the exposure duration of the suspected target with the target exposure value as the dividend and the minimum exposure gain as the divisor, the method further includes: When the exposure duration of the suspected target is greater than the maximum exposure duration, determine the ratio of the target exposure value to the maximum exposure duration as the suspected target exposure gain, and determine the maximum exposure duration as the target exposure duration. When the suspected target exposure gain is less than or equal to the maximum exposure gain, determine the suspected target exposure gain as the target exposure gain.

7. The automatic exposure control method according to claim 1, characterized in that The target exposure parameters include a target exposure gain and a target exposure duration. After determining the target exposure parameters according to the brightness ratio and the first exposure parameters, the method further includes: Map the target exposure gain to the exposure gain of the register, and map the target exposure duration to the exposure duration of the register. Write the exposure gain of the register and the exposure duration of the register into the memory of the camera.

8. The automatic exposure control method according to claim 7, wherein The method further includes: When the camera acquires a second image frame, expose the second image frame with the target exposure gain and the target exposure duration to obtain a second image, where the second image frame is an image acquired after the first image frame. Update the second image to the first image. Return to execute the step of dividing the first image into k sub-regions.

9. An automatic exposure control device, characterized in that, The device includes: An Image Signal Processing (ISP) module, configured to divide a first image into k sub-regions, where k is a positive integer greater than 1, and the first image is an image obtained by exposing a first image frame acquired by the camera at the current moment. The ISP module is further configured to determine the brightness values of each of the k sub-regions. An Artificial Intelligence (AI) module, configured to determine a region of interest in the first image, where the region of interest is the region where the identified target object is located. A main control module, configured to determine a first brightness value and a second brightness value of the first image according to the brightness values of the sub-regions and the region of interest, where the first brightness value is the overall brightness value of the first image, and the second brightness value is the brightness value of the region of interest in the first image. The main control module is further configured to determine a first target brightness value according to the second brightness value and a preset second target brightness value, where the second target brightness value is the target brightness value of the region of interest, and the first target brightness value is the overall target brightness value of the first image. The main control module is further configured to determine a brightness ratio according to the first brightness value and the first target brightness value. The main control module is further configured to determine target exposure parameters according to the brightness ratio and first exposure parameters, where the first exposure parameters are the exposure parameters when exposing the first image frame, and the exposure parameters include an exposure duration and an exposure gain. The main control module includes: A third determination unit, configured to determine the first exposure parameter as the target exposure parameter when the brightness ratio is less than a second threshold; and determine the target exposure parameter according to the brightness ratio and the first exposure parameter when the brightness ratio is greater than or equal to the second threshold. The third determination unit is further configured to determine an exposure scheduling step corresponding to the brightness ratio, determine a target exposure value by multiplying the scheduling step, the first exposure duration, and the first exposure gain, determine an exposure parameter interval where the target exposure value is located, and determine the target exposure parameter according to the target exposure value and the exposure parameter interval.

Images