Light-supplementing photographing compensation method and system

Abstract

The invention relates to the technical field of image processing, and discloses a light supplement photographing compensation method and system, and the method specifically comprises the following steps: obtaining the current external environment brightness, and judging whether to trigger screen light supplement; when screen light supplement is triggered, a pre-calibrated compensation coefficient is called; and applying the compensation coefficient to an image processing process, and outputting a compensated image. The method can solve the problem that the brightness and color of the upper and lower areas of the image are not uniform when the front screen carries out light supplement photographing.

Description

Technical Field

[0001] The present invention relates to the technical field of image processing, and in particular to a fill-light photography compensation method and system. Background Art

[0002] With the popularity of smartphones, front-facing cameras are increasingly used in scenarios such as video calls and selfies. Users need to use front-facing cameras to take photos in various environments, especially in low-light environments.

[0003] Currently, when most smartphones use their front-facing cameras in low-light environments, the image brightness is also dim due to the low ambient brightness, affecting the user experience. While brightness can be improved by increasing exposure and gain on the back-end of the ISP (Image Signal Processor) platform, excessive digital gain introduces more difficult-to-eliminate noise, reducing image quality.

[0004] To address the issue of insufficient front-facing camera imaging in low-light conditions, the current mainstream solution is screen fill light technology. This involves adjusting the phone screen's brightness to maximum and displaying white when taking photos, providing additional light. Compared to adding a dedicated front-facing flash, screen fill light requires no additional hardware cost and has minimal impact on phone design.

[0005] However, screen fill light technology has a significant drawback: because the front camera is usually located at the top edge of the screen (such as in teardrop notches, notches, or punch-hole displays), the screen fill light captured by the camera is unevenly distributed. Specifically, the brightness of the upper half of the image is significantly lower than that of the lower half, and the brightness decreases as it approaches the top edge. This results in uneven brightness and color in the upper and lower areas of the captured photo.

[0006] Existing technology typically only performs standard color calibration for screen fill light photography, without addressing uneven light distribution. This results in suboptimal image quality when using screen fill light in low-light environments, impacting the user experience. Furthermore, the front camera placement varies across different phone models, leading to varying unevenness in the screen fill light distribution. Existing technology lacks the ability to customize solutions for different camera positions.

[0007] Due to the physical limitations of screen fill light technology itself and the shortcomings of existing calibration methods, the front camera of a mobile phone cannot obtain high-quality images with uniform brightness and color when taking pictures using screen fill light in low-light environments, making it difficult to meet users' photography needs in various lighting conditions. Summary of the Invention

[0008] The purpose of the present invention is to provide a fill light photography compensation method and system, which can solve the problem of uneven brightness and color in the upper and lower areas of the image when taking photos with fill light on the front screen.

[0009] To solve the above technical problems, the present invention provides a method for compensating for fill-light photography, which specifically includes the following steps:

[0010] Get the current external environment brightness to determine whether to trigger screen fill light;

[0011] When the screen fill light is triggered, the pre-calibrated compensation coefficient is called; and

[0012] The compensation coefficient is applied to the image processing process to output the compensated image.

[0013] Furthermore, the determination of whether to trigger screen fill light specifically includes: triggering screen fill light when the external environment brightness is lower than a preset threshold.

[0014] Furthermore, calling the pre-calibrated compensation coefficient specifically includes: determining a corresponding brightness gradient level according to the current ambient brightness, and calling the compensation coefficient corresponding to the level.

[0015] Furthermore, when the current environment brightness is between two brightness gradient levels, a neighboring interpolation method is used to calculate the corresponding compensation coefficient.

[0016] Furthermore, the compensation coefficient is obtained through a calibration process, and the calibration process specifically includes:

[0017] Establishing a calibration benchmark;

[0018] Obtaining the position information of the camera on the screen, and determining the screen light collection parameters based on the position information;

[0019] Based on the calibration reference and the screen light collection parameter, calibration is performed under multiple ambient brightness conditions to generate the compensation coefficient.

[0020] Furthermore, performing calibration under multiple ambient brightness conditions specifically includes:

[0021] Set multiple gradient brightness points from the brightness threshold that triggers screen fill light to the ambient brightness of complete darkness;

[0022] For each of the gradient brightness points, set the corresponding screen brightness and take photos with fill light;

[0023] Based on the photographic data of all the gradient brightness points and in combination with the screen light acquisition parameters, a compensation coefficient corresponding to each gradient brightness point is generated.

[0024] Furthermore, after setting the corresponding screen brightness and taking fill light photos, and before generating the compensation coefficients corresponding to each gradient brightness point, it also includes: judging whether the photos of all the gradient brightness points are completed; if not, continuing with the photos of the next gradient brightness point; if completed, entering data processing.

[0025] Furthermore, the photographing process includes photographing a symmetrical 24-color calibration chart, wherein the symmetrical 24-color chart has a vertically symmetrical color block arrangement; and performing vertical brightness and color analysis on the image obtained by photographing the calibration chart, while controlling the symmetry of the color blocks.

[0026] In addition, the present invention also provides a fill-light photography compensation system for implementing the fill-light photography compensation method described above, comprising:

[0027] Ambient brightness detection module, used to detect the current ambient brightness and determine whether to trigger screen fill light;

[0028] A parameter calling module, used to call a pre-calibrated compensation coefficient when triggering screen fill light; and

[0029] The image processing module is used to apply the compensation coefficient to the image processing process to output an image with uniform brightness and color.

[0030] Furthermore, it also includes a compensation coefficient calibration module, which is used to generate the compensation coefficient by shooting images under different ambient brightness.

[0031] Through the above technical solution, the present invention has the following beneficial effects:

[0032] By acquiring the current ambient brightness and determining whether to trigger screen fill light, calling a pre-calibrated compensation coefficient when the screen fill light is triggered, and applying the compensation coefficient to the image processing process, the uneven lighting problem captured by the front camera during screen fill light can be effectively solved, making the brightness and color of the upper and lower areas of the image more uniform, improving image quality and user experience. Furthermore, the method provided by the present invention does not require additional hardware costs and can achieve improved image quality through software algorithms alone.

[0033] Furthermore, by setting multiple brightness gradient levels and calculating the compensation coefficient using a neighboring interpolation method, combined with calibration using a specially designed symmetrical 24-color chart and color block symmetry control, customized compensation coefficients can be generated for varying ambient brightness levels and front camera positions, improving the adaptability and accuracy of the compensation effect in various usage scenarios. Furthermore, through strict control and verification of the calibration process, the reliability of the compensation coefficients has been improved, enabling end users to obtain more natural and uniform images when using the front camera in low-light environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is an overall flow chart of a fill light photography compensation method according to an embodiment of the present invention;

[0035] Figure 2 This is a flow chart of a fill light photography compensation method according to an embodiment of the present invention;

[0036] Figure 3 This is a specific flow chart of a fill light photography compensation method according to an embodiment of the present invention;

[0037] Figure 4 This is a specific flow chart of the compensation coefficient calibration process in the fill light photography compensation method according to one embodiment of the present invention;

[0038] Figure 5 A calibration curve diagram of brightness and color in a fill light photography compensation method according to an embodiment of the present invention;

[0039] Figure 6 A gray card image in a fill light photography compensation method according to an embodiment of the present invention;

[0040] Figure 7 A symmetrical 24-color chart is one of the images in the fill light photography compensation method according to one embodiment of the present invention;

[0041] Figure 8 This is another symmetrical 24-color chart used in the fill light photography compensation method in one embodiment of the present invention. DETAILED DESCRIPTION

[0042] Based on the teachings of this specification, those skilled in the art may form new technical solutions by cross-combining different implementation methods without generating technical contradictions. Such variations should be deemed to fall within the scope of protection of this patent.

[0043] The following describes a method and system for compensating for fill-light photography in more detail, with reference to the accompanying drawings. Preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art may modify the present invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as generally known to those skilled in the art and is not intended to limit the present invention.

[0044] The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are greatly simplified and not to exact scale, and are provided solely for the purpose of assisting in the description of the embodiments of the present invention.

[0045] like Figure 1-Figure 3As shown, the embodiment of the present invention proposes a convenient and practical fill light photography compensation method, which mainly solves the problem of uneven brightness and color in the upper and lower areas of the image when the front screen is filled with light to take pictures. With the development of science and technology, mobile phone front cameras are more and more widely used in daily life, and users have the need to take selfies in various environments. When using the front camera to take pictures in a dark environment, the image brightness will also be dark because the external environment is dark. Although the brightness can be improved by increasing exposure and gain through the back end of the ISP platform, excessive digital gain will introduce more noise that is difficult to eliminate. Specifically including the following steps:

[0046] S1. Get the current ambient brightness and determine whether to trigger screen fill light;

[0047] S2. When the screen fill light is triggered, the pre-calibrated compensation coefficient is called; and

[0048] S3. Apply the compensation coefficient to the image processing process and output the compensated image.

[0049] Through the above method, this embodiment can effectively solve the problem of uneven light captured by the front camera when the screen is filled with light, thereby improving imaging quality and user experience.

[0050] In step S1, the determination of whether to trigger screen fill light specifically includes: triggering screen fill light when the external environment brightness is lower than a preset threshold. Specifically, the preset threshold can be a specific lux value (an international unit of light intensity, used to measure the ambient brightness level), which is obtained by platform statistics. For example, when the ambient light brightness is lower than or equal to a lux, the system will automatically trigger the front screen fill light. It is known to those skilled in the art that the preset threshold can be set according to actual needs, and the expression of the preset threshold can also include an ISO (sensitivity standard established by the International Organization for Standardization) value or other light sensing parameters.

[0051] In step S2, calling the pre-calibrated compensation coefficient specifically includes determining a corresponding brightness gradient level based on the current ambient brightness and calling the compensation coefficient corresponding to that level. Specifically, multiple brightness gradient levels can be set, such as a lux, a1 lux, a2 lux, ..., and 0 lux, from the brightness threshold alux that triggers screen fill light to complete darkness (0 lux). Each level corresponds to a specific set of compensation coefficients used to correct for uneven screen fill light under that brightness condition.

[0052] Preferably, when the current ambient brightness falls between two brightness gradient levels, the corresponding compensation coefficient is calculated using a neighboring interpolation method. Specifically, in actual applications, the ambient brightness may not fall exactly on a preset gradient level. In this case, interpolation can be performed using the compensation coefficients of two adjacent levels to achieve a more accurate compensation effect. This interpolation method ensures a smooth transition between different brightness levels, avoiding sudden changes in the compensation effect.

[0053] In one embodiment, combining Figure 3 and Figure 4 As shown, the compensation coefficient is obtained through a calibration process, which specifically includes:

[0054] S21. Establish a calibration benchmark;

[0055] S22, obtaining the position information of the ornament on the screen by the camera, and determining the screen light collection parameters based on the ornament position information; and

[0056] S23. Based on the calibration reference and the screen light collection parameters, calibration is performed under multiple ambient brightness conditions to generate the compensation coefficient (wherein, calibration is performed under multiple ambient brightness conditions to generate a calibration coefficient, which is used as the compensation coefficient).

[0057] Among them, the calibration benchmark includes the Camera Golden module (a standard reference module with mid-range performance selected from a batch of modules produced) and the Screen Golden module. The Camera Golden module is a module with mid-range AE (auto exposure) photosensitivity data selected from a batch of Camera modules produced, and the AE photosensitivity data has been burned into a single Camera module. The Screen Golden module is a module with mid-range screen brightness data selected from a batch of screen modules produced. The camera placement position refers to the position of the Camera on the screen, which directly affects the screen fill light effect captured by the Camera. The design position of the front camera can include but is not limited to a water drop screen, a bangs screen, a hole-punch screen, etc.

[0058] In step S23, the calibration is performed under multiple ambient brightness conditions, specifically including:

[0059] S231, setting multiple gradient brightness points within the range from the brightness threshold for triggering screen fill light to the ambient brightness of complete darkness;

[0060] S232: For each gradient brightness point, set the corresponding screen brightness and perform fill light photography;

[0061] S233 : Based on the photographic data of all the gradient brightness points and in combination with the screen light acquisition parameters, generate a compensation coefficient corresponding to each gradient brightness point.

[0062] In one specific example, calibration is performed in a laboratory light box, where the light box's brightness is adjusted to simulate different ambient brightness conditions. At each gradient brightness point, a camera Golden module and a screen Golden module are used to perform photo tests. The captured data is then analyzed and processed to generate compensation coefficients for that brightness point.

[0063] Preferably, after setting the corresponding screen brightness and performing fill light photography, and before generating the compensation coefficients corresponding to each gradient brightness point, the process further includes: determining whether photography has been completed for all gradient brightness points; if not, proceeding to photography for the next gradient brightness point; if completed, entering data processing. Specifically, this is a cyclical verification process, ensuring that valid photography data is obtained for all set gradient brightness points, providing complete data support for subsequent compensation coefficient calculation.

[0064] In one embodiment, the photographing process includes photographing a calibration chart and performing upper and lower brightness and color analysis on the image obtained by photographing the calibration chart. Specifically, the calibration chart is a gray chart with 24 colors symmetrical in the center.

[0065] In one specific example, the photography process involves capturing a symmetrical 24-color calibration chart with vertically symmetrical color blocks. The resulting image is then analyzed for top-to-bottom brightness and color, while also monitoring the symmetry of the color blocks. This symmetrical 24-color chart is characterized by top-to-bottom symmetry, facilitating analysis of brightness and color differences between the upper and lower regions of the image. The camera center and the chart center must coincide during capture to improve the accuracy of the measured data. By analyzing the top-to-bottom brightness and color of the captured image, a detailed understanding of unevenness caused by screen fill light can be obtained, allowing for the generation of effective compensation coefficients.

[0066] In this embodiment, if Figure 5As shown, during calibration, the original image is aligned for brightness and color calibration at the top and bottom to generate a calibration curve. Specifically, analyzing a symmetrical 24-color chart image reveals brightness and color differences between the upper and lower regions of the image due to the relationship between the front camera's position and the screen's fill light. For example, with the camera widget positioned at the center of the top edge, a simplified compensation curve shows that the top of the image requires more compensation, while the bottom requires less. This is because the camera is positioned at the top edge of the screen, capturing weaker screen light in the top half and stronger in the bottom half. Therefore, the compensation curve should provide more gain in the top half and less gain in the bottom half to balance overall brightness and color performance. This compensation curve varies depending on the camera widget's position. For example, if the camera is positioned in the top left corner of the screen, the compensation curve will provide the most compensation in the top left and the least compensation in the bottom right. This customized compensation curve can accurately correct for unevenness caused by screen fill light.

[0067] In one embodiment, if Figure 6-Figure 8 As shown in the figure, the specific process of applying the compensation coefficient for detection is as follows: the generated calibration coefficient (i.e., compensation coefficient) is applied to the camera photo process, and the photos are taken under the same brightness conditions. Then, the generated photos are detected to determine whether the gray card and the symmetrical 24-color card meet the preset upper and lower brightness and color symmetry standards. Specifically, this detection process also includes filtering the gain noise in the upper and lower areas to retain the effective information of the symmetry. If the test result shows that the upper and lower areas of the image have achieved the expected symmetry, then proceed to the next step; if asymmetry still exists, it is necessary to re-shoot the gray card and the symmetrical 24-color card for calibration. Importantly, during the recalibration process, the difference value after the last application will be combined to provide the offset direction of the calibration coefficient for the current calibration, so that the compensation parameters can be adjusted more targetedly.

[0068] Preferably, after calibration of a particular luminance point is completed and verified, this embodiment outputs the calibration coefficient (i.e., compensation coefficient) for that luminance point, indicating that the calibration coefficient for that luminance point has passed verification. The calibration coefficient collection and verification process then continues for the next luminance gradient point until all set luminance gradient points are completed.

[0069] In this embodiment, once all configured gradient brightness points have been calibrated and verified, the system outputs a complete calibration coefficient table, specifically the calibration coefficient table corresponding to each brightness gradient point for the camera and screen fill light combination. This calibration coefficient table contains compensation parameters for all brightness gradient points, from the fill light trigger threshold to complete darkness, providing comprehensive data support for subsequent application in actual photography scenarios. This rigorous calibration-verification-adjustment process improves the accuracy and reliability of the generated compensation coefficients.

[0070] In addition, this embodiment also proposes a fill light photography compensation system for implementing the fill light photography compensation method described above, including: an ambient brightness detection module for detecting the current ambient brightness and determining whether to trigger screen fill light; a parameter calling module for calling a pre-calibrated compensation coefficient when triggering the screen fill light; and an image processing module for applying the compensation coefficient to the image processing process to output an image with uniform brightness and color.

[0071] In this embodiment, the ambient brightness detection module can obtain the current ambient brightness data through the light sensor of the mobile phone; the parameter calling module selects or calculates the appropriate compensation coefficient from the pre-stored compensation coefficient table according to the detected ambient brightness; the image processing module applies these compensation coefficients in the ISP (image signal processor) processing flow to correct the image.

[0072] Preferably, the fill-light photography compensation system also includes a compensation coefficient calibration module, which generates the compensation coefficients by capturing images under different ambient brightness levels. Specifically, this module is primarily used during the product development phase and is responsible for executing the aforementioned calibration process, generating a compensation coefficient table, and pre-setting it to the mobile phone system for use in actual photography.

[0073] In one embodiment, when the front camera is located at the center of the upper edge of the screen, the screen fill light causes the brightness of the upper half of the image to be significantly lower than that of the lower half. This is because the front camera is located at the upper edge of the screen, and the screen fill light can be considered a uniformly illuminated panel. The fill light captured by the camera is non-uniform, with the upper half of the image significantly lower than the lower half, and the brightness decreases as it approaches the upper edge. To address this situation, the compensation coefficient needs to significantly increase the brightness of the upper half of the image and make smaller adjustments to the lower half, thereby achieving a more uniform brightness distribution across the entire image.

[0074] In this embodiment, the symmetrical 24-color chart used during the calibration process is a special design of this embodiment. Unlike conventional 24-color charts, it emphasizes the symmetry of the color blocks. During calibration, not only the color blocks are monitored, but also the symmetry of the color blocks of the symmetrical 24-color chart (a color calibration chart containing 24 standard color blocks, used for color calibration in photography and image processing) is monitored to obtain more accurate screen fill light correction coefficients. This design enables the calibration process to more accurately capture unevenness caused by screen fill light, improving compensation effectiveness.

[0075] Preferably, the key to the fill light compensation technology of this embodiment lies in adding the application of screen fill light correction coefficients to the camera ISP processing flow in screen fill light scenarios, thereby improving the problem of uneven image brightness and color in screen fill light scenarios. This embodiment not only considers standard color calibration, but also pays special attention to the unevenness caused by screen fill light. Through a specialized calibration process and compensation algorithm, the front camera's photo quality in low-light environments is improved.

[0076] In this embodiment, when a user uses the front camera of a mobile phone to take a selfie in a low-light environment, the system first detects the current ambient brightness. When the ambient brightness falls below a preset threshold (e.g., 1 lux), the system automatically triggers the screen fill light function. At this time, the mobile phone screen displays white and lights up to maximum brightness for fill light.

[0077] Preferably, the front camera is typically physically located at the top edge of the screen (possibly a teardrop notch, notch, or punch-hole design). This results in uneven distribution of screen fill light captured by the camera. Specifically, the brightness of the top half of the image is significantly lower than that of the bottom half, and the brightness decreases as it approaches the top edge, affecting overall image quality and user experience. This embodiment primarily addresses this issue through the following two stages.

[0078] The calibration phase (product development phase) involves using the Camera Golden module and the Display Golden module as standard references; recording the position of the front camera attachment for a specific phone model; setting multiple gradient brightness points in a laboratory light box, from the triggering fill light threshold (a lux) to complete darkness (0 lux). At each gradient brightness point, the screen fill light is activated and a custom symmetrical 24-color chart is photographed. The brightness and color differences between the upper and lower areas of the captured image are analyzed; and compensation coefficients are generated for each gradient brightness point. These steps are repeated for all gradient brightness points, ultimately creating a complete compensation coefficient table, which is then pre-installed in the phone system.

[0079] The application phase (user use phase) includes: the user uses the front camera to take a photo in a dim environment; the system detects that the current ambient brightness is below a preset threshold, triggering the screen fill light; the system also selects the corresponding compensation coefficient from a preset compensation coefficient table based on the current ambient brightness (if the ambient brightness falls between two gradient levels, a more accurate compensation coefficient is obtained through interpolation). These compensation coefficients are applied in the ISP image processing flow; the compensated image is output, making the brightness and color of the upper and lower areas of the image more uniform.

[0080] In summary, the fill-light photography compensation method and system proposed in the present invention have the following advantages:

[0081] By acquiring the current ambient brightness and determining whether to trigger screen fill light, calling a pre-calibrated compensation coefficient when the screen fill light is triggered, and applying the compensation coefficient to the image processing process, the uneven lighting problem captured by the front camera during screen fill light can be effectively solved, making the brightness and color of the upper and lower areas of the image more uniform, improving image quality and user experience. Furthermore, the method provided by the present invention does not require additional hardware costs and can achieve improved image quality through software algorithms alone.

[0082] Furthermore, by setting multiple brightness gradient levels and calculating the compensation coefficient using a neighboring interpolation method, combined with calibration using a specially designed symmetrical 24-color chart and color block symmetry control, customized compensation coefficients can be generated for varying ambient brightness levels and front camera positions, improving the adaptability and accuracy of the compensation effect in various usage scenarios. Furthermore, through strict control and verification of the calibration process, the reliability of the compensation coefficients has been improved, enabling end users to obtain more natural and uniform images when using the front camera in low-light environments.

[0083] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for compensating for fill light photography, characterized in that: The details include: Get the current external environment brightness to determine whether to trigger screen fill light; When the screen fill light is triggered, the pre-calibrated compensation coefficient is called; and The compensation coefficient is applied to the image processing process to output the compensated image.

2. The fill light photography compensation method according to claim 1, wherein: The determining whether to trigger screen fill light specifically includes: triggering the screen fill light when the external environment brightness is lower than a preset threshold.

3. The fill light photography compensation method according to claim 1, wherein: The calling of the pre-calibrated compensation coefficient specifically includes: determining a corresponding brightness gradient gear according to the current ambient brightness, and calling the compensation coefficient corresponding to the gear.

4. The fill light photography compensation method according to claim 3, wherein: When the current ambient brightness is between two brightness gradient levels, the adjacent interpolation method is used to calculate the corresponding compensation coefficient.

5. The fill light photography compensation method according to claim 1, wherein: The compensation coefficient is obtained through a calibration process, which specifically includes: Establishing a calibration benchmark; Obtaining the position information of the camera on the screen, and determining the screen light collection parameters based on the position information; Based on the calibration reference and the screen light collection parameter, calibration is performed under multiple ambient brightness conditions to generate the compensation coefficient.

6. The fill-light photography compensation method according to claim 5, wherein: The performing of calibration under multiple ambient brightness conditions specifically includes: Set multiple gradient brightness points from the brightness threshold that triggers screen fill light to the ambient brightness of complete darkness; For each of the gradient brightness points, set the corresponding screen brightness and take photos with fill light; Based on the photographic data of all the gradient brightness points and in combination with the screen light acquisition parameters, a compensation coefficient corresponding to each gradient brightness point is generated.

7. The fill-light photography compensation method according to claim 6, wherein: After setting the corresponding screen brightness and taking fill light photos, and before generating the compensation coefficients corresponding to each gradient brightness point, it also includes: judging whether the photos of all the gradient brightness points are completed; if not, continuing with the photos of the next gradient brightness point; if completed, entering data processing.

8. The fill-light photography compensation method according to claim 6, wherein: The photographing process includes photographing a symmetrical 24-color calibration chart, where the symmetrical 24-color chart has a vertically symmetrical color block arrangement; and performing vertical brightness and color analysis on the image obtained by photographing the calibration chart, while controlling the symmetry of the color blocks.

9. A fill-light photography compensation system, used to implement the fill-light photography compensation method according to any one of claims 1 to 8, characterized in that: include: Ambient brightness detection module, used to detect the current ambient brightness and determine whether to trigger screen fill light; Parameter calling module, used to call the pre-calibrated compensation coefficient when triggering screen fill light; as well as The image processing module is used to apply the compensation coefficient to the image processing process to output an image with uniform brightness and color.

10. The fill-light photography compensation system according to claim 9, wherein: It also includes a compensation coefficient calibration module, which is used to generate the compensation coefficient by shooting images under different ambient brightness.

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