Image quality determination method and device, equipment and storage medium

Abstract

The invention relates to an image quality determination method and apparatus, a device and a storage medium. The method comprises the steps of obtaining a brightness center of a gray card image; respectively determining brightness values of a plurality of points in positive and negative directions of a direction axis taking the brightness center as an original point; respectively determining the brightness fading trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values of the plurality of points; and determining the image quality of the gray card image based on the symmetry of the brightness fading trends in the positive and negative directions. According to the method and the device, objective quantitative indexes can be provided for uniformity detection of the brightness fading trend, so that the image quality can be accurately determined based on the uniformity of the brightness fading trend, and the requirements on objectivity and accuracy of uniformity analysis in scenes such as flash lamp uniformity test and the like are met.

Description

Technical Field

[0001] The present disclosure relates to the field of image processing technology, and in particular to an image quality determination method, device, equipment and storage medium. Background Art

[0002] Image quality evaluation in related technologies includes analysis of image brightness uniformity, which usually requires measuring the brightness difference between each area in the picture and the adjacent area, and comparing it with a set threshold to determine whether the brightness difference of each area is abnormal, or measuring the brightness data of the entire picture and comparing it with the brightness center to determine the brightness uniformity of the picture, and then judge the image quality (the higher the brightness uniformity, the better the image quality). However, the above scheme not only has a large amount of calculation, but also cannot meet the requirements for objectivity and accuracy of uniformity analysis in scenes such as flash uniformity testing. Summary of the invention

[0003] In order to overcome the problems existing in the related art, the embodiments of the present disclosure provide an image quality determination method, apparatus, device and storage medium to solve the defects in the related art.

[0004] According to a first aspect of an embodiment of the present disclosure, a method for determining image quality is provided, the method comprising:

[0005] Acquire a brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes a center of a region with higher brightness in the gray card image;

[0006] Determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin;

[0007] Determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points;

[0008] Based on the symmetry of the brightness decay trends in the positive and negative directions, the image quality of the gray card image is determined.

[0009] In some embodiments, obtaining the brightness center of the gray card image includes:

[0010] Determining a histogram of the gray card image;

[0011] Acquire a target area in the histogram whose brightness value exceeds a set ratio of the gray card image;

[0012] The brightness center of the gray card image is determined based on the outer contour center of the target area.

[0013] In some embodiments, the gray card image is an image in RGB channel format;

[0014] Determining the histogram of the gray card image includes:

[0015] Convert the gray card image from RGB channels to YUV channels;

[0016] A histogram of the gray card image is determined based on a brightness channel Y in the YUV channels.

[0017] In some embodiments, determining the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin includes:

[0018] Taking the brightness center as the starting point, a plurality of points are respectively acquired in the positive and negative directions based on the respective target intervals in the positive and negative directions, wherein the respective target intervals in the positive and negative directions are determined based on the total number of pixels in the positive and negative directions and the set number of points;

[0019] The brightness value of each point is determined based on the pixel value in the interval area corresponding to each point in the multiple points to obtain the brightness values ​​of the multiple points, and the interval area is the area where each pixel in the target interval is located.

[0020] In some embodiments, the determining the brightness decay trend of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points respectively includes:

[0021] Normalizing the brightness value of the point based on the brightness value of the brightness center to obtain a normalized brightness value result of the point;

[0022] The brightness decay curves in the positive and negative directions are drawn based on the brightness value normalization result, and the brightness decay curves are used to characterize the brightness decay trends of the gray card image in corresponding directions.

[0023] In some embodiments, the method further comprises determining the symmetry based on:

[0024] Integrate the brightness fading curves in the positive and negative directions respectively over their respective value intervals to obtain the areas of the brightness fading curves in the positive and negative directions;

[0025] In response to the difference between the areas of the brightness decay curves in the positive and negative directions being less than or equal to a set threshold, it is determined that the brightness decay trends of the gray card image in the positive and negative directions are symmetrical.

[0026] In some embodiments, the direction axis includes a horizontal direction axis and / or a vertical direction axis.

[0027] According to a second aspect of an embodiment of the present disclosure, there is provided an image quality determination device, the device comprising:

[0028] A center acquisition module, used to acquire the brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes the center of a higher brightness area in the gray card image;

[0029] A brightness value determination module, used to determine the brightness values ​​of multiple points in the positive and negative directions of a direction axis with the brightness center as the origin;

[0030] A trend determination module, used to determine the brightness decay trends of the gray card image in the positive and negative directions respectively based on the brightness value of the brightness center and the brightness values ​​of the multiple points;

[0031] The quality determination module is used to determine the image quality of the gray card image based on the symmetry of the brightness decay trends in the positive and negative directions.

[0032] In some embodiments, the central acquisition module includes:

[0033] A histogram determination unit, used to determine a histogram of the gray card image;

[0034] An area acquisition unit, used for acquiring a target area in the histogram whose brightness value exceeds a set ratio of the gray card image;

[0035] A center determination unit is used to determine the brightness center of the gray card image based on the outer contour center of the target area.

[0036] In some embodiments, the gray card image is an image in RGB channel format;

[0037] The histogram determination unit is also used for:

[0038] Convert the gray card image from RGB channels to YUV channels;

[0039] Determine a histogram of the gray card image based on a brightness channel Y in the YUV channel;

[0040] In some embodiments, the brightness value determination module includes:

[0041] A multi-point acquisition unit, for acquiring a plurality of points in the positive and negative directions respectively based on respective target intervals in the positive and negative directions with the brightness center as the starting point, wherein the respective target intervals in the positive and negative directions are determined based on the total number of pixels in the positive and negative directions and a set number of acquisition points;

[0042] A brightness value determination unit is used to determine the brightness value of each point based on the pixel value in the interval area corresponding to each point in the multiple points to obtain the brightness values ​​of the multiple points, wherein the interval area is the area where each pixel in the target interval is located.

[0043] In some embodiments, the trend determination module includes:

[0044] A result acquisition unit, configured to normalize the brightness value of the point based on the brightness value of the brightness center to obtain a normalized result of the brightness value of the point;

[0045] The curve drawing unit is used to draw the brightness decay curves in the positive and negative directions respectively based on the brightness value normalization result, and the brightness decay curves are used to characterize the brightness decay trends of the gray card image in the corresponding directions respectively.

[0046] In some embodiments, the apparatus further comprises a symmetry determination module;

[0047] The symmetry determination module comprises:

[0048] An area acquisition unit, used to integrate the brightness fading curves in the positive and negative directions in their respective value intervals to obtain the areas of the brightness fading curves in the positive and negative directions;

[0049] The symmetry determination unit is used to determine that the brightness fading trends of the gray card image in the positive and negative directions are symmetrical in response to the difference between the areas of the brightness fading curves in the positive and negative directions being less than or equal to a set threshold.

[0050] In some embodiments, the direction axis includes a horizontal direction axis and / or a vertical direction axis.

[0051] According to a third aspect of an embodiment of the present disclosure, an electronic device is provided, the device comprising:

[0052] a processor and a memory for storing a computer program;

[0053] Wherein, the processor is configured to implement, when executing the computer program:

[0054] Acquire a brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes a center of a region with higher brightness in the gray card image;

[0055] Determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin;

[0056] Determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points;

[0057] Based on the symmetry of the brightness decay trends in the positive and negative directions, the image quality of the gray card image is determined.

[0058] According to a fourth aspect of an embodiment of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the following is implemented:

[0059] Acquire a brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes a center of a region with higher brightness in the gray card image;

[0060] Determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin;

[0061] Determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points;

[0062] Based on the symmetry of the brightness decay trends in the positive and negative directions, the image quality of the gray card image is determined.

[0063] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0064] The present disclosure obtains the brightness center of a gray card image, wherein the gray card image includes an image obtained by shooting a gray card with a flash light started, and the brightness center includes the center of a higher brightness area in the gray card image, and respectively determines the brightness values ​​of a plurality of points in the positive and negative directions of a direction axis with the brightness center as the origin, and then respectively determines the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the plurality of points, and then determines the image quality of the gray card image based on the symmetry of the brightness decay trends in the positive and negative directions, thereby providing an objective quantitative index for uniformity detection of the brightness decay trend, and then accurately determining the image quality based on the uniformity of the brightness decay trend, thereby meeting the requirements for objectivity and accuracy of uniformity analysis in scenes such as flash light uniformity testing.

[0065] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0067] Figure 1 is a flow chart of a method for determining image quality according to an exemplary embodiment of the present disclosure;

[0068] Figure 2 is a flow chart showing how to obtain the brightness center of a gray card image according to an exemplary embodiment of the present disclosure;

[0069] Figure 3 is a flowchart showing how to determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin according to an exemplary embodiment of the present disclosure;

[0070] Figure 4 is a flowchart showing how to determine the brightness decay trends of the gray card image in the positive and negative directions respectively based on the brightness value of the brightness center and the brightness values ​​of the multiple points according to an exemplary embodiment of the present disclosure;

[0071] Figure 5 is a flowchart showing how to determine that the brightness decay trend of the gray card image in the positive and negative directions is symmetrical according to an exemplary embodiment of the present disclosure;

[0072] Figure 6 is a flowchart of a method for determining image quality according to another exemplary embodiment of the present disclosure;

[0073] Figure 7 is a block diagram of an image quality determination device according to an exemplary embodiment of the present disclosure;

[0074] Figure 8 is a block diagram showing another apparatus for determining image quality according to an exemplary embodiment of the present disclosure;

[0075] Fig. 9 It is a block diagram of an electronic device according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0076] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0077] Figure 1is a flowchart of an image quality determination method according to an exemplary embodiment; the method of this embodiment can be executed by an image quality determination device, and the image quality determination device can be configured in an electronic device with data processing capabilities, such as a server, a workstation, a personal computer, a mobile terminal (such as a mobile phone, a tablet computer, etc.), a wearable device (such as glasses, a watch, etc.), etc. For example, Figure 1 As shown, the method includes the following steps S101-S104:

[0078] In step S101, the brightness center of the gray card image is obtained.

[0079] In this embodiment, after the gray card image is acquired, the brightness center of the gray card image can be acquired. The gray card image can include an image obtained by photographing the gray card with the flash turned on. As an example, the gray card can be a DxO_Grey card, etc., which is not limited in this embodiment. The brightness center includes the center of a higher brightness area in the gray card image. For example, the higher brightness area in the gray card image can be an area in the gray card image where the brightness value exceeds a set ratio of the gray card image. For example, the brightness center can usually be determined as the point with the highest brightness in the image.

[0080] For example, in scenarios such as flash uniformity testing, an image acquisition device (such as a camera or a smart phone) can be used to shoot a gray card with the flash turned on to obtain the gray card image (such as an RGB image), and then the quality of the gray card image is determined to reflect the flash uniformity (that is, the better the image quality, the higher the flash uniformity). It is understandable that the image captured by the image acquisition device with the flash turned on is usually brightest in the center and darker around the center. The flash uniformity test can be used to measure whether the image with the flash turned on will have obvious eccentric fading.

[0081] In some embodiments, the brightness center of the gray card image can be obtained by using an image processing algorithm in related technologies based on actual needs. This embodiment does not limit the specific acquisition method.

[0082] In other embodiments, it is also possible to Figure 2 The brightness center of the gray card image is obtained by the method in the embodiment, which will not be described in detail in this embodiment.

[0083] In step S102, the brightness values ​​of a plurality of points are determined in the positive and negative directions of a direction axis with the brightness center as the origin.

[0084] In this embodiment, after the brightness center of the gray card image is obtained, the brightness values ​​of multiple points can be determined in the positive and negative directions of the direction axis with the brightness center as the origin.

[0085] In some embodiments, the above-mentioned direction axis may include a horizontal direction axis and / or a vertical direction axis. For example, when the direction axis is a horizontal direction axis, the brightness values ​​of multiple points can be determined in the positive and negative directions (positive and negative directions of the x-axis) of the horizontal direction axis of the gray card image with the brightness center as the origin; when the direction axis is a vertical direction axis, the brightness values ​​of multiple points can be determined in the positive and negative directions (positive and negative directions of the y-axis) of the vertical direction axis of the gray card image with the brightness center as the origin; and when the above-mentioned direction axis includes both a horizontal direction axis and a vertical direction axis, the brightness values ​​of multiple points can be determined in the positive and negative directions of the x-axis and the positive and negative directions of the y-axis of the gray card image with the brightness center as the origin.

[0086] In some other embodiments, the above-mentioned method of determining the brightness values ​​of multiple points in the positive and negative directions respectively can refer to the following Figure 3 The embodiment will not be described in detail here.

[0087] In step S103, the brightness decay trends of the gray card image in the positive and negative directions are determined based on the brightness value of the brightness center and the brightness values ​​of the multiple points.

[0088] In this embodiment, after the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin are determined respectively, the brightness decay trends of the gray card image in the positive and negative directions can be determined respectively based on the brightness value of the brightness center and the brightness values ​​of the multiple points.

[0089] In some embodiments, after the brightness values ​​of the plurality of points are determined, a curve may be drawn based on the brightness values ​​of the plurality of points, so as to characterize the brightness decay trend of the gray card image in the positive and negative directions through the trend of the drawn curve.

[0090] In some other embodiments, the above method of determining the brightness decay trend of the gray card image in the positive and negative directions can be referred to as follows: Figure 4 The embodiment will not be described in detail here.

[0091] In step S104, the image quality of the gray card image is determined based on the symmetry of the brightness decay trends in the positive and negative directions.

[0092] In this embodiment, after the brightness decay trends of the gray card image in the positive and negative directions are determined based on the brightness value of the brightness center and the brightness values ​​of the multiple points, the image quality of the gray card image can be determined based on the symmetry of the brightness decay trends in the positive and negative directions. For example, if the symmetry of the brightness decay trends in the positive and negative directions is higher, it can be considered that the quality of the gray card image is better).

[0093] That is to say, this embodiment can determine the symmetry of the brightness fading trends of the gray card image in the positive and negative directions by comparing the similarity of the brightness fading trends of the gray card image in the positive and negative directions. That is, if the brightness fading trends in the positive and negative directions are more similar, it can be considered that the brightness fading trend of the gray card image in the set axis is more symmetrical, and the fading uniformity has a significant impact on the overall presentation and subjective feeling of the picture. The higher the brightness fading symmetry, the better the image performance (that is, the better the image quality). Therefore, analyzing the symmetry of the brightness fading trend is of substantial significance to the quantification of image quality.

[0094] In some other embodiments, the above method of determining that the brightness decay trend of the gray card image in the positive and negative directions is symmetrical can be referred to as follows: Figure 5 The embodiment will not be described in detail here.

[0095] As can be seen from the above description, the method of this embodiment obtains the brightness center of the gray card image, wherein the gray card image includes an image obtained by shooting the gray card with the flash on, and the brightness center includes the center of the area with higher brightness in the gray card image, and respectively determines the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin, and then determines the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points, and then determines the image quality of the gray card image based on the symmetry of the brightness decay trends in the positive and negative directions, so as to provide an objective quantitative indicator for uniformity detection of the brightness decay trend, and then accurately determine the image quality based on the uniformity of the brightness decay trend, thereby meeting the requirements for objectivity and accuracy of uniformity analysis in scenes such as flash uniformity testing.

[0096] Figure 2 This is a flowchart showing how to obtain the brightness center of a gray card image according to an exemplary embodiment of the present disclosure; based on the above embodiment, this embodiment uses how to obtain the brightness center of a gray card image as an example to exemplify.

[0097] like Figure 2 As shown, the acquisition of the brightness center of the gray card image in the above step S101 may include the following steps S201-S203:

[0098] In step S201, a histogram of the gray card image is determined.

[0099] In this embodiment, when acquiring the brightness center of the gray card image, the histogram of the gray card image may be determined first.

[0100] For example, the gray card image may be an image in RGB channel format. On this basis, in order to determine the histogram of the gray card image, the RGB channel of the gray card image may be first obtained, and then the gray card image may be converted from the RGB channel to the YUV channel, and then the histogram of the gray card image may be determined based on the brightness channel Y in the YUV channel.

[0101] It is understandable that YUV is a color space format, which is mainly used to optimize the transmission of color video signals. In the YUV color space, "Y" represents brightness (or grayscale value), which is responsible for describing the brightness of the image, which is the most sensitive part of the human eye; while "U" and "V" represent chrominance (or saturation), which are used to specify the color and saturation of the image. Compared with the RGB color space, the YUV color space can be more conveniently encoded and transmitted, reducing bandwidth occupancy and information errors. The visual characteristics of the human eye are more sensitive to brightness and relatively insensitive to position and color. Therefore, in this embodiment, the histogram of the gray card image can be determined based on the brightness channel Y in the YUV channel to show how many pixels there are at a certain brightness or a certain brightness range, so as to clearly reflect the distribution of pixel brightness in the image.

[0102] In step S202, a target area in the histogram whose brightness value exceeds a set ratio of the gray card image is obtained.

[0103] In this embodiment, after the histogram of the gray card image is determined based on the brightness channel Y in the YUV channel, a target area in the histogram whose brightness value exceeds a set ratio of the gray card image can be obtained.

[0104] It is worth noting that the above-mentioned set ratio can be set based on the needs of the actual scene, such as being set to 85%, etc., and this embodiment does not limit this. That is to say, after determining the histogram of the gray card image, the area in the histogram where the brightness value exceeds 95% of the entire image can be obtained as the above-mentioned target area.

[0105] In step S203, the brightness center of the gray card image is determined based on the center of the outer contour of the target area.

[0106] In this embodiment, after obtaining the target area in the histogram whose brightness value exceeds the set ratio of the gray card image, the brightness center of the gray card image can be determined based on the center of the outer contour of the target area. The outer contour center can be the geometric center of the outer contour of the target area.

[0107] On this basis, after the brightness center of the gray card image is determined, the brightness value of the brightness center can be obtained for subsequent use.

[0108] As can be seen from the above description, in this embodiment, by converting the gray card image from the RGB channel to the YUV channel, and determining the histogram of the gray card image based on the brightness channel Y in the YUV channel, and then obtaining the target area in the histogram whose brightness value exceeds the set ratio of the gray card image, and then determining the brightness center of the gray card image based on the outer contour center of the target area, the brightness center of the gray card image can be accurately obtained, and then the brightness values ​​of multiple points can be determined in the positive and negative directions of the set axis of the gray card image based on the brightness center, and the brightness decay trends of the gray card image in the positive and negative directions can be determined based on the brightness value of the brightness center and the brightness values ​​of the multiple points, and then the image quality of the gray card image can be determined based on the symmetry of the brightness decay trends in the positive and negative directions, so as to provide an objective quantitative index for the uniformity detection of the brightness decay trend, and then the image quality can be accurately determined based on the uniformity of the brightness decay trend, thereby meeting the objectivity and accuracy requirements for uniformity analysis in scenes such as flash uniformity testing.

[0109] Figure 3 It is a flowchart showing how to determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin according to an exemplary embodiment of the present disclosure; based on the above embodiment, this embodiment uses an example of how to determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin to illustrate.

[0110] like Figure 3 As shown, the above step S102, in which the brightness values ​​of multiple points are determined in the positive and negative directions of the direction axis with the brightness center as the origin, may include the following steps S301-S302:

[0111] In step S301, taking the brightness center as a starting point, a plurality of points are acquired in the positive and negative directions based on respective target intervals in the positive and negative directions.

[0112] In this embodiment, after the brightness center of the gray card image is obtained, a plurality of points may be obtained in the positive and negative directions based on the target intervals in the positive and negative directions, taking the brightness center as a starting point.

[0113] The target intervals in the positive and negative directions are determined based on the total number of pixels in the positive and negative directions and the set number of points.

[0114] Taking the horizontal axis as an example, its positive and negative directions can be right and left directions respectively. Furthermore, the target interval in the right direction can be determined based on the ratio of the total number of pixels from the center point to the right edge of the gray card image to the set number, and the target interval in the left direction can be determined based on the ratio of the total number of pixels from the center point to the left edge of the gray card image to the set number. For example, if the total number of pixels in the right direction is 500 and the set number is 100, the target interval in the right direction can be 5.

[0115] Similarly, if the vertical axis is taken as an example, its positive and negative directions can be the upper and lower directions respectively. Furthermore, the target interval in the upper direction can be determined based on the ratio of the total number of pixels from the center point to the upper boundary of the gray card image to the set number, and the target interval in the lower direction can be determined based on the ratio of the total number of pixels from the center point to the lower boundary of the gray card image to the set number.

[0116] It is worth noting that the above-mentioned set number can be set based on the actual number of points required. For example, if it is necessary to take 100 brightness values ​​of points in the positive and negative directions of the set axis, the set number can be 100.

[0117] In step S302, the brightness value of each point is determined based on the pixel value in the interval area corresponding to each point in the multiple points, so as to obtain the brightness values ​​of the multiple points.

[0118] In this embodiment, after taking the brightness center as the starting point and acquiring multiple points in the positive and negative directions based on the respective target intervals in the positive and negative directions, the brightness value of each point can be determined based on the pixel value in the interval area corresponding to each point in the multiple points to obtain the brightness values ​​of the multiple points.

[0119] The above-mentioned interval area may be an area where each pixel in the target interval is located. For example, if the target interval in the right direction may be 5, the corresponding interval area may be a 5*1 area where the 5 pixels are located.

[0120] For example, after obtaining multiple points in the positive and negative directions based on the target intervals in the positive and negative directions respectively, the average value of the pixel values ​​in the interval area corresponding to each point in the multiple points can be determined, and then the average value can be determined as the brightness value of each point to obtain the brightness values ​​of the multiple points.

[0121] Still taking the horizontal axis as an example, we can calculate the target interval of 100 points from the brightness center to the left and right edges respectively, and then obtain the brightness values ​​of 100 points from the center to the left and right edges based on the respective target intervals on the left and right sides, so as to obtain the average brightness value in the corresponding interval area as the brightness value of the point.

[0122] As can be seen from the above description, in this embodiment, by taking the brightness center as the starting point, a plurality of points are respectively acquired in the positive and negative directions based on the respective target intervals in the positive and negative directions, and the brightness value of each point is determined based on the pixel value in the interval area corresponding to each point in the plurality of points to obtain the brightness values ​​of the plurality of points. This can achieve accurate determination of the brightness values ​​of the plurality of points in the positive and negative directions of the set axis of the gray card image, and further, subsequent determination of the brightness decay trend of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the plurality of points, and determination of the image quality of the gray card image based on the symmetry of the brightness decay trend in the positive and negative directions can be achieved. This can provide an objective quantitative index for uniformity detection of the brightness decay trend, and further, can achieve accurate determination of the image quality based on the uniformity of the brightness decay trend, thereby meeting the requirements for objectivity and accuracy of uniformity analysis in scenes such as flash uniformity testing.

[0123] Figure 4 The present invention is a flowchart showing how to respectively determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points according to an exemplary embodiment of the present disclosure; based on the above embodiment, this embodiment uses an example of how to respectively determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points to exemplify.

[0124] like Figure 4 As shown, the determination of the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points in the above step S103 may include the following steps S401-S402:

[0125] In step S401, the brightness value of the point is normalized based on the brightness value of the brightness center to obtain a normalized brightness value result of the point.

[0126] In this embodiment, after the brightness values ​​of multiple points are determined in the positive and negative directions of the set axis of the gray card image, the brightness values ​​of the points can be normalized based on the brightness value of the brightness center to obtain the normalized brightness value results of the points.

[0127] For example, the brightness value of the brightness center can be taken as the normalized denominator to normalize the brightness value of the point, so as to obtain the normalized brightness value results of multiple points in the positive and negative directions. It can be understood that, usually, the brightness value of the brightness center is higher than the brightness values ​​of the multiple points, so by taking the brightness value of the brightness center as the normalized denominator to normalize the brightness value of the point, the brightness values ​​of the multiple points can be converted to the range of 0 to 1.

[0128] In step S402, the brightness decay curves in the positive and negative directions are respectively drawn based on the brightness value normalization result.

[0129] In this embodiment, after the brightness value of the point is normalized based on the brightness value of the brightness center to obtain the normalized brightness value result of the point, the brightness decay curves in the positive and negative directions can be drawn based on the normalized brightness value result. The brightness decay curves are used to characterize the brightness decay trends of the gray card image in the corresponding directions.

[0130] For example, after obtaining the normalized brightness values ​​of multiple points in the positive direction of the set axis (e.g., the positive direction of the x-axis), the normalized results can be connected in sequence to obtain a brightness decay curve in the positive direction. Similarly, the normalized results in the negative direction can be connected in sequence to obtain a brightness decay curve in the negative direction.

[0131] As can be seen from the above description, in this embodiment, the brightness value of the point is normalized based on the brightness value of the brightness center to obtain the normalized result of the brightness value of the point, and the brightness decay curves in the positive and negative directions are respectively drawn based on the normalized result of the brightness value, so that the brightness decay curves can be used to characterize the brightness decay trends of the gray card image in the corresponding directions respectively, and then the image quality of the gray card image can be determined based on the symmetry of the brightness decay trends in the positive and negative directions. It can provide an objective quantitative index for the uniformity detection of the brightness decay trend, and then the image quality can be accurately determined based on the uniformity of the brightness decay trend, thereby meeting the requirements for objectivity and accuracy of uniformity analysis in scenes such as flash uniformity testing.

[0132] Figure 5 This is a flowchart showing how to determine that the brightness fading trend of the gray card image in the positive and negative directions is symmetrical according to an exemplary embodiment of the present disclosure; based on the above embodiment, this embodiment uses how to determine that the brightness fading trend of the gray card image in the positive and negative directions is symmetrical as an example to exemplify.

[0133] like Figure 5As shown, the step S104 described above of determining that the brightness decay trend of the gray card image in the positive and negative directions is symmetrical may include the following steps S501-S502:

[0134] In step S501, the brightness fading curves in the positive and negative directions are respectively integrated over their respective value intervals to obtain the areas of the brightness fading curves in the positive and negative directions.

[0135] In this embodiment, when it is determined that the brightness fading trends of the gray card image in the positive and negative directions are symmetrical, the brightness fading curves in the positive and negative directions may be integrated over their respective value intervals to obtain the areas of the brightness fading curves in the positive and negative directions.

[0136] The value range of the two-point fading curve may be determined based on the positions of the points at both ends of the brightness fading curve.

[0137] In step S502, it is determined whether the difference between the areas of the brightness decay curves in the positive and negative directions is less than or equal to a set threshold: if so, step S503 is executed; if not, step S504 is executed.

[0138] In step S503, it is determined that the brightness decay trends of the gray card image in the positive and negative directions are symmetrical.

[0139] In step S504, it is determined that the brightness decay trends of the gray card image in the positive and negative directions are asymmetric.

[0140] In this embodiment, after obtaining the brightness decay curve areas in the positive and negative directions, the difference between the brightness decay curve areas in the positive and negative directions can be determined, and then the difference can be compared with a set threshold value. When the difference is less than or equal to the set threshold value, it can be determined that the brightness decay trends of the gray card image in the positive and negative directions are symmetrical, and when the difference is greater than the set threshold value, it can be determined that the brightness decay trends of the gray card image in the positive and negative directions are asymmetrical. It is worth noting that the above-mentioned set threshold value can be set based on the needs of the actual scene, and this embodiment does not limit this.

[0141] As can be seen from the above description, this embodiment integrates the brightness fading curves in the positive and negative directions in their respective value intervals to obtain the areas of the brightness fading curves in the positive and negative directions, and in response to the difference between the areas of the brightness fading curves in the positive and negative directions being less than or equal to a set threshold, determines that the brightness fading trends of the gray card image in the positive and negative directions are symmetrical, which can accurately determine the brightness fading trends of the gray card image in the positive and negative directions based on the brightness fading trends in the positive and negative directions, and provide an objective quantitative index for uniformity detection of the brightness fading trend, and then accurately determine the image quality based on the uniformity of the brightness fading trend, thereby meeting the requirements for objectivity and accuracy of uniformity analysis in scenes such as flash uniformity testing.

[0142] The present disclosure is described below with reference to an exemplary embodiment, but is not intended to limit the scope of the present disclosure.

[0143] Figure 6 FIG. 1 is a flowchart of a method for determining image quality according to another exemplary embodiment of the present disclosure; in this embodiment, the setting axis includes the horizontal axis and the vertical axis as an example for explanation. Figure 6 As shown, the image quality determination method of this embodiment includes the following steps S601-S607:

[0144] In step S601, the flash is turned on to shoot a gray card to obtain a gray card image (eg Figure 6 (as shown in the image on the right side of S601);

[0145] In step S602, the brightness center of the gray card image is found;

[0146] For example, the RGB channels of the gray card image can be obtained, and the gray card image can be converted from the RGB channels to the YUV channels (such as Figure 6 Then, the histogram of the gray card image is determined based on the brightness channel Y to locate the target area in the histogram whose brightness value exceeds 85% of the whole image, so that the outer contour of the target area can be located to find the geometric center of the contour, and then the geometric center can be used as the brightness center of the gray card image.

[0147] In step S603, starting from the brightness center, 100 points are acquired to the left and right on the horizontal axis respectively, and the brightness values ​​of the points are normalized to determine the brightness decay trend on the vertical axis.

[0148] Exemplarily, the interval values ​​of 100 points from the center to the left and right edges can be calculated respectively. For example, if there are 500 points from the center to the left edge, and a total of 100 points need to be taken, then the interval value in the left direction is 500 / 100=5; similarly, the corresponding interval value in the right direction can be calculated); based on the interval values ​​in the left and right directions, the brightness values ​​of 100 positions from the center to the left and right edges are obtained respectively. As an example, the brightness average of the interval area can be taken as the brightness value of the point; based on the brightness value of the brightness center, it is normalized to obtain the normalized result, so that a curve can be drawn based on the normalized result to obtain the brightness decay trend from the brightness center to the left and right edges as the brightness decay performance of the gray card image in the horizontal axis (such as Figure 6 As shown in the curve a below S603 in FIG.

[0149] In step S604, taking the brightness center as the starting point, 100 points are acquired upward and downward in the vertical axis respectively, and the brightness values ​​of the points are normalized to determine the brightness decay trend in the vertical axis.

[0150] Exemplarily, the interval value of 100 points from the center to the upper edges can be calculated respectively. For example, if there are 600 points from the center to the upper edge, and a total of 100 points need to be taken, then the interval value in the left direction is 600 / 100=6; similarly, the corresponding interval value in the lower direction can be calculated); based on the interval values ​​in the upper and lower directions, the brightness values ​​of 100 positions from the center to the upper and lower edges are obtained respectively. As an example, the brightness average of the interval area can be taken as the brightness value of the point; based on the brightness value of the brightness center, it is normalized to obtain the normalized result, so that a curve can be drawn based on the normalized result to obtain the brightness decay trend from the brightness center to the upper and lower edges as the brightness decay performance of the gray card image in the vertical axis (such as Figure 6 (as shown in the curve diagram b below S604).

[0151] In step S605, with respect to the fading trends in the left and right directions of the horizontal axis, the difference between the areas of the two fading curves is calculated as an objective quantitative value of the symmetry of the brightness fading trend in the horizontal axis.

[0152] Exemplarily, the two fading curves shown in graph a may be integrated on the abscissa axis (ie, the axis corresponding to the sequence number of the points) to obtain the areas of the two fading curves, and then the difference between the areas of the two fading curves may be calculated, such as 10.64.

[0153] In step S606, the difference between the areas of the two fading curves is calculated for the fading trends in the upper and lower directions of the vertical axis, which is used as an objective quantitative value of the symmetry of the brightness fading trend along the vertical axis.

[0154] Exemplarily, the two fading curves shown in graph b may be integrated on the horizontal axis (ie, the axis corresponding to the sequence number of the points) to obtain the areas of the two fading curves, and then the difference between the areas of the two fading curves may be calculated, such as 8.65.

[0155] In step S607, based on the set threshold, it is determined whether the brightness decay trends in the horizontal axis and the vertical axis are symmetrical.

[0156] Exemplarily, a threshold value K can be determined based on a large amount of experimental data, and then the obtained objective quantitative value of the brightness fading symmetry in the horizontal and vertical axes (i.e., the difference in the above-mentioned areas) is compared with the threshold value K: when the above-mentioned objective quantitative value is greater than the threshold value K, it can be determined that the fading trend of the gray card image in the axis is unevenly symmetrical; and when the above-mentioned objective quantitative value is less than or equal to the threshold value K, it can be determined that the fading trend of the gray card image in the axis is uniformly symmetrical.

[0157] From the above description, it can be seen that this embodiment can be used in scenarios such as flash uniformity testing to provide objective quantitative indicators for brightness attenuation uniformity evaluation, and to achieve objective analysis of the uniformity and symmetry of attenuation. The objective indicator quantification of brightness attenuation uniformity and symmetry has a complementary testing significance for the Luma Shading test.

[0158] Figure 7 is a block diagram of an image quality determination device according to an exemplary embodiment of the present disclosure; the device of this embodiment can be configured in an electronic device with data processing capabilities, such as a server, a workstation, a personal computer, a mobile terminal (such as a mobile phone, a tablet computer, etc.), a wearable device (such as glasses, watches, etc.), etc. For example, Figure 7 As shown, the device may include: a center acquisition module 110, a brightness value determination module 120, a trend determination module 130 and a quality determination module 140, wherein:

[0159] A center acquisition module 110 is used to acquire the brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes the center of a higher brightness area in the gray card image;

[0160] A brightness value determination module 120, configured to determine brightness values ​​of a plurality of points in the positive and negative directions of a direction axis with the brightness center as the origin;

[0161] A trend determination module 130, configured to determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the plurality of points;

[0162] The quality determination module 140 is used to determine the image quality of the gray card image based on the symmetry of the brightness decay trends in the positive and negative directions.

[0163] As can be seen from the above description, the device of this embodiment obtains the brightness center of the gray card image, wherein the gray card image includes an image obtained by shooting the gray card with the flash on, and the brightness center includes the center of the area with higher brightness in the gray card image, and respectively determines the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin, and then determines the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points, and then determines the image quality of the gray card image based on the symmetry of the brightness decay trends in the positive and negative directions, so as to provide an objective quantitative index for uniformity detection of the brightness decay trend, and then accurately determine the image quality based on the uniformity of the brightness decay trend, thereby meeting the requirements for objectivity and accuracy of uniformity analysis in scenes such as flash uniformity testing.

[0164] Figure 8 2 is a block diagram of another image quality determination device according to an exemplary embodiment of the present disclosure; the device of this embodiment can be configured in an electronic device with data processing capabilities, such as a server, a workstation, a personal computer, a mobile terminal (such as a mobile phone, a tablet computer, etc.), a wearable device (such as glasses, watches, etc.), etc. Among them, the center acquisition module 210, the brightness value determination module 220, the trend determination module 230 and the quality determination module 240 are similar to the aforementioned Figure 7 The functions of the center acquisition module 110 , the brightness value determination module 120 , the trend determination module 130 and the quality determination module 140 in the illustrated embodiment are the same and will not be described in detail herein.

[0165] like Figure 8 As shown, the central acquisition module 210 may include:

[0166] A histogram determination unit 211, used to determine the histogram of the gray card image;

[0167] The region acquisition unit 212 is used to acquire the target region in the histogram whose brightness value exceeds a set ratio of the gray card image;

[0168] The center determination unit 213 is used to determine the brightness center of the gray card image based on the outer contour center of the target area.

[0169] In some embodiments, the channel conversion unit 211 is further used to:

[0170] Convert the gray card image from RGB channels to YUV channels;

[0171] A histogram of the gray card image is determined based on a brightness channel Y in the YUV channels.

[0172] In some embodiments, the brightness value determination module 220 may include:

[0173] A multi-point acquisition unit 221 is used to take the brightness center as a starting point and acquire a plurality of points in the positive and negative directions based on respective target intervals in the positive and negative directions, wherein the respective target intervals in the positive and negative directions are determined based on the total number of pixels in the positive and negative directions and a set number of acquisition points;

[0174] The brightness value determination unit 222 is used to determine the brightness value of each point based on the pixel value in the interval area corresponding to each point in the multiple points to obtain the brightness values ​​of the multiple points. The interval area is the area where each pixel in the target interval is located.

[0175] In some embodiments, the trend determination module 230 may include:

[0176] A result acquisition unit 231 is used to normalize the brightness value of the point based on the brightness value of the brightness center to obtain a normalized brightness value result of the point;

[0177] The curve drawing unit 232 is used to draw the brightness decay curves in the positive and negative directions respectively based on the brightness value normalization result, and the brightness decay curves are used to represent the brightness decay trends of the gray card image in the corresponding directions respectively.

[0178] In some embodiments, the apparatus further comprises a symmetry determination module 250;

[0179] The symmetry determination module 250 may include:

[0180] An area acquisition unit 251 is used to integrate the brightness fading curves in the positive and negative directions in their respective value intervals to obtain the areas of the brightness fading curves in the positive and negative directions;

[0181] The symmetry determination unit 252 is used to determine that the brightness fading trends of the gray card image in the positive and negative directions are symmetrical in response to the difference between the brightness fading curve areas in the positive and negative directions being less than or equal to a set threshold.

[0182] In some embodiments, the above-mentioned set axis may include a horizontal axis and / or a vertical axis.

[0183] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0184] Fig. 9 900 is a block diagram of an electronic device according to an exemplary embodiment. For example, the device 900 may be a mobile phone, a computer, a digital broadcast terminal, a messaging device, a game console, a tablet device, a medical device, a fitness device, a personal digital assistant, etc.

[0185] Reference Fig. 9 , device 900 may include one or more of the following components: a processing component 902 , a memory 904 , a power component 906 , a multimedia component 908 , an audio component 910 , an input / output (I / O) interface 912 , a sensor component 914 , and a communication component 916 .

[0186] The processing component 902 generally controls the overall operation of the device 900, such as operations associated with display, phone calls, data communications, camera operations, and recording operations. The processing component 902 may include one or more processors 920 to execute instructions to complete all or part of the steps of the above-mentioned image quality determination method. In addition, the processing component 902 may include one or more modules to facilitate the interaction between the processing component 902 and other components. For example, the processing component 902 may include a multimedia module to facilitate the interaction between the multimedia component 908 and the processing component 902.

[0187] The memory 904 is configured to store various types of data to support operations on the device 900. Examples of such data include instructions for any application or method operating on the device 900, contact data, phone book data, messages, pictures, videos, etc. The memory 904 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0188] The power supply component 906 provides power to the various components of the device 900. The power supply component 906 can include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power for the device 900.

[0189] The multimedia component 908 includes a screen that provides an output interface between the device 900 and the user. In some embodiments, the screen may include a liquid crystal display panel and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from the user. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor may not only sense the boundaries of the touch or slide action, but also detect the duration and pressure associated with the touch or slide operation. In some embodiments, the multimedia component 908 includes a front camera and / or a rear camera. When the device 900 is in an operating mode, such as a shooting mode or a video mode, the front camera and / or the rear camera may receive external multimedia data. Each front camera and the rear camera may be a fixed optical lens system or have a focal length and optical zoom capability.

[0190] The audio component 910 is configured to output and / or input audio signals. For example, the audio component 910 includes a microphone (MIC), and when the device 900 is in an operating mode, such as a call mode, a recording mode, and a speech recognition mode, the microphone is configured to receive an external audio signal. The received audio signal can be further stored in the memory 904 or sent via the communication component 916. In some embodiments, the audio component 910 also includes a speaker for outputting audio signals.

[0191] I / O interface 912 provides an interface between processing component 902 and peripheral interface modules, such as keyboards, click wheels, buttons, etc. These buttons may include but are not limited to: home button, volume button, start button, and lock button.

[0192] The sensor assembly 914 includes one or more sensors for providing various aspects of status assessment for the device 900. For example, the sensor assembly 914 can detect the open / closed state of the device 900, the relative positioning of components, such as the display panel and keypad of the device 900, and the sensor assembly 914 can also detect the position change of the device 900 or a component of the device 900, the presence or absence of user contact with the device 900, the orientation or acceleration / deceleration of the device 900, and the temperature change of the device 900. The sensor assembly 914 can also include a proximity sensor configured to detect the presence of nearby objects without any physical contact. The sensor assembly 914 can also include a light sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly 914 can also include an acceleration sensor, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

[0193] The communication component 916 is configured to facilitate wired or wireless communication between the device 900 and other devices. The device 900 can access a wireless network based on a communication standard, such as WiFi, 2G or 3G, 4G or 5G or a combination thereof. In an exemplary embodiment, the communication component 916 receives a broadcast signal or broadcast-related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 916 also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module can be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology and other technologies.

[0194] In an exemplary embodiment, the device 900 may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the above-described image quality determination method.

[0195] In an exemplary embodiment, a non-transitory computer-readable storage medium including instructions is also provided, such as a memory 904 including instructions, and the instructions can be executed by the processor 920 of the device 900 to perform the above-mentioned image quality determination method. For example, the non-transitory computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0196] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0197] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for determining image quality, It is characterized in that The method comprises: Acquire a brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes a center of a region with higher brightness in the gray card image; Determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin; Determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points; Based on the symmetry of the brightness decay trends in the positive and negative directions, the image quality of the gray card image is determined.

2. The method according to claim 1, It is characterized in that The step of obtaining the brightness center of the gray card image includes: Determining a histogram of the gray card image; Acquire a target area in the histogram whose brightness value exceeds a set ratio of the gray card image; The brightness center of the gray card image is determined based on the outer contour center of the target area.

3. The method according to claim 2, It is characterized in that The gray card image is an image in RGB channel format; Determining the histogram of the gray card image includes: Convert the gray card image from RGB channels to YUV channels; A histogram of the gray card image is determined based on a brightness channel Y in the YUV channels.

4. The method according to claim 1, It is characterized in that The step of respectively determining the brightness values ​​of a plurality of points in the positive and negative directions of a direction axis with the brightness center as the origin includes: Taking the brightness center as the starting point, a plurality of points are respectively acquired in the positive and negative directions based on the respective target intervals in the positive and negative directions, wherein the respective target intervals in the positive and negative directions are determined based on the total number of pixels in the positive and negative directions and the set number of points; The brightness value of each point is determined based on the pixel value in the interval area corresponding to each point in the multiple points to obtain the brightness values ​​of the multiple points, and the interval area is the area where each pixel in the target interval is located.

5. The method according to claim 1, It is characterized in that The determining the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points respectively includes: Normalizing the brightness value of the point based on the brightness value of the brightness center to obtain a normalized brightness value result of the point; The brightness decay curves in the positive and negative directions are drawn based on the brightness value normalization result, and the brightness decay curves are used to characterize the brightness decay trends of the gray card image in corresponding directions.

6. The method according to claim 5, It is characterized in that The method further comprises determining the symmetry based on: Integrate the brightness fading curves in the positive and negative directions respectively over their respective value intervals to obtain the areas of the brightness fading curves in the positive and negative directions; In response to the difference between the areas of the brightness decay curves in the positive and negative directions being less than or equal to a set threshold, it is determined that the brightness decay trends of the gray card image in the positive and negative directions are symmetrical.

7. The method according to any one of claims 1 to 6, It is characterized in that The direction axis includes a horizontal direction axis and / or a vertical direction axis.

8. An image quality determination device, It is characterized in that The device comprises: A center acquisition module, used to acquire the brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes the center of a higher brightness area in the gray card image; A brightness value determination module, used to determine the brightness values ​​of multiple points in the positive and negative directions of a direction axis with the brightness center as the origin; A trend determination module, used to determine the brightness decay trends of the gray card image in the positive and negative directions respectively based on the brightness value of the brightness center and the brightness values ​​of the multiple points; The quality determination module is used to determine the image quality of the gray card image based on the symmetry of the brightness decay trends in the positive and negative directions.

9. An electronic device, It is characterized in that The device comprises: a processor and a memory for storing a computer program; Wherein, the processor is configured to implement, when executing the computer program: Acquire a brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes a center of a region with higher brightness in the gray card image; Determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin; Determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points; Based on the symmetry of the brightness decay trends in the positive and negative directions, the image quality of the gray card image is determined.

10. A computer-readable storage medium having a computer program stored thereon, It is characterized in that When the program is executed by the processor, it realizes: Acquire a brightness center of a gray card image, wherein the gray card image includes an image obtained by photographing a gray card with a flash light activated, and the brightness center includes a center of a region with higher brightness in the gray card image; Determine the brightness values ​​of multiple points in the positive and negative directions of the direction axis with the brightness center as the origin; Determine the brightness decay trends of the gray card image in the positive and negative directions based on the brightness value of the brightness center and the brightness values ​​of the multiple points; Based on the symmetry of the brightness decay trends in the positive and negative directions, the image quality of the gray card image is determined.

Images