TWI645373B - Auto exposure control method and electronic device using the same - Google Patents

Abstract

The electronic device of the present invention performs photography in accordance with a dynamically varying weight array generated by an automatic exposure control method. The automatic exposure control method includes: step a: obtaining a cut preview picture into a plurality of blocks; step b: sorting the blocks according to brightness, and calculating a preview image according to the order of the blocks and the preset weight array; Weighting the average brightness for automatic exposure to obtain an automatic exposure picture; Step c: determining whether the over-exposure ratio or the over-dark ratio in the luminance histogram of the automatic exposure picture falls within a desired interval to determine whether to generate a correction weight array; : calculating the weighted average brightness of the preview picture according to the preset weight array or the correction weight array and the order of the blocks, to perform automatic exposure to obtain a target automatic exposure screen; and step e: determining the target automatic exposure screen Whether the overall brightness falls within the desired brightness interval determines whether the control electronics is to take a picture, or continues to fine tune the preset weight array or correct the weight array.

Description

Automatic exposure control method and electronic device using same

The present invention relates to an automatic exposure control method and an electronic device using the same, and more particularly to an automatic exposure control method capable of dynamically adjusting a brightness weight value and an electronic device using the same.

In the current common automatic exposure control method, when calculating the brightness of a picture block, a common practice of setting the brightness weight is to make the weights of each picture block equal, and to maximize the weight of the picture in the middle position block. The blocks are sorted according to the brightness and then assigned different weights. However, in these practices, the weight values are all fixed values.

In the case where all the blocks are given a weight and the weight value is a fixed preset value, when an over-bright or too dark object appears on the screen and the proportion of the image is not large, it is impossible to converge the brightness or increase the exposure in time. Improve object visibility. In the case that different blocks are given different weights according to different brightness thresholds and the weight values are fixed preset values, the weight values corresponding to different brightness threshold intervals are limited in setting. The limitation is that the difference between the weight values corresponding to different brightness threshold intervals may not be too large, or the screen may flicker due to the adjustment of the brightness.

In order to be able to converge the brightness in time or increase the exposure to improve the visibility of the object, and to avoid flickering due to the adjustment of the brightness of the picture, the present invention provides an automatic exposure control method capable of dynamically adjusting the brightness of the preview picture.

The automatic exposure control method provided by the present invention is applicable to an electronic device. The electronic device includes a photography module and a controller, wherein the controller performs the automatic exposure control method to control the photography module to perform photography according to one of the dynamic arrays of weights. The automatic exposure control method includes: step a: obtaining a preview image of the photography module, and cutting the preview image into a plurality of blocks; and step b: sorting the blocks according to the brightness, and according to the blocks Sorting and preset weight arrays to calculate the weighted average brightness of the preview image for automatic exposure to obtain an automatic exposure screen; Step c: determining whether the overexposure ratio in the luminance histogram of the automatic exposure screen falls within a desired overexposure interval or Whether the over dark ratio falls within the desired dark interval to determine whether to correct the preset weight array of the photographic module to obtain the correction weight array; Step d: calculate according to the preset weight array or the correction weight array and the order of the blocks Pre-viewing the weighted average brightness of the picture for automatic exposure to obtain the target automatic exposure picture; and step e: determining whether the overall brightness of the target automatic exposure picture of the photography module falls within the desired brightness interval, to determine the control photography module according to the pre- Set the weight array or correction weight array for photography, or further fine tune the preset weight array or correct the weight array.

In addition, the present invention also provides an electronic device including a photographic module, a memory and a controller. The memory is set to store an automatic exposure control program. The controller is coupled to the camera module and the memory, and is configured to execute the automatic exposure control program to control the camera module to perform photography according to one of the dynamic arrays of weights. In this electronic device, the controller runs an automatic exposure control program to perform the aforementioned automatic exposure control method.

1‧‧‧Electronic device

10‧‧‧Photography module

20‧‧‧ memory

20a‧‧‧Auto Exposure Program

30‧‧‧ Controller

a~e‧‧‧step

C1, c2, c3‧‧‧ steps

Steps c3-1, c3-2, c3-3, c3-4, c3-5, c3-6‧‧

E1, e2, e3‧‧‧ steps

IM‧‧‧ preview screen

T0, T1~T24‧‧‧ blocks

D1, D2‧‧‧ too dark ratio

N1‧‧‧Preset Exposure Adjustment Index

N2, N3‧‧‧corrected exposure adjustment index

B1, B2, B3‧‧‧ overexposure ratio

BT‧‧‧ target overexposure ratio

FIG. 1A is a flow chart of an automatic exposure control method according to an exemplary embodiment of the invention.

FIG. 1B is a flow chart of step c in the automatic exposure control method according to an exemplary embodiment of the invention.

1C is a flow chart of step c3 in the automatic exposure control method according to an exemplary embodiment of the invention.

FIG. 1D is a flow chart of step e in the automatic exposure control method according to an exemplary embodiment of the invention.

2 is a schematic diagram of performing steps a and b in an automatic exposure control method according to an exemplary embodiment of the invention.

FIG. 3 is a schematic diagram of performing step c in an automatic exposure control method according to an exemplary embodiment of the invention.

4A and 4B are schematic diagrams showing a luminance histogram in an automatic exposure control method according to an exemplary embodiment of the invention.

5A, 5B, and 5C are schematic diagrams of a low light priority re-array, an average weighted array, and a high-light priority re-array, respectively, in an automatic exposure control method according to an exemplary embodiment of the present invention.

FIG. 6 is a flow chart of an electronic device according to an exemplary embodiment of the invention.

Various illustrative embodiments are described more fully hereinafter with reference to the accompanying drawings. However, the inventive concept may be embodied in many different forms and should not be construed as being limited to the illustrative embodiments set forth herein. Rather, these exemplary embodiments are provided so that this invention will be in the In the figures, like numerals are used to indicate like elements.

[An embodiment of an automatic exposure control method]

The automatic exposure control method provided in this embodiment is applicable to an electronic device having a photographing function, such as a mobile phone, a tablet computer, a monitoring device, and the like. In general, Lee With the automatic exposure control method provided in this embodiment, it is possible to dynamically provide a weight array for adjusting the brightness of the captured picture of the electronic device.

Please refer to FIG. 1A. FIG. 1A is a flowchart of an automatic exposure control method according to an exemplary embodiment of the present invention.

As shown in FIG. 1A, the automatic exposure control method provided in this embodiment generally includes the following steps: Step a: Obtain a preview image of the camera module, and cut the preview image into a plurality of blocks; Step b: According to the brightness Sorting the blocks, and calculating a weighted average brightness of the preview image according to a preset weight array for automatic exposure to obtain an automatic exposure screen; Step c: determining whether the overexposure ratio in the luminance histogram of the automatic exposure screen is Whether the desired overexposure interval or the over dark ratio falls within the desired over dark interval to determine whether to correct the preset weight array of the photographic module to obtain the correction weight array; step d: the preset weight array or correction determined according to step c The weight array and the ordering of the blocks, calculating the weighted average brightness of the preview picture for automatic exposure to obtain the target automatic exposure picture; and step e: determining whether the overall brightness of the target automatic exposure picture falls within the desired brightness interval to determine The control photography module performs photography according to the preset weight array or the correction weight array determined in step c, or further Correcting the preset weight or the weight array weight array.

Next, the details of the respective steps in the automatic exposure control method provided by the present embodiment will be further explained.

Referring first to FIG. 2, FIG. 2 is a schematic diagram of performing steps a and b in an automatic exposure control method according to an exemplary embodiment of the invention.

As shown in FIG. 2, in step a, the preview screen IM of the electronic device is first acquired, and the preview screen IM is cut into a plurality of blocks. For convenience of explanation, in the present embodiment, the preview screen IM is set to be cut into 25 blocks T0 to T24. Next, in step b, the 25 blocks T0 to T24 of the preview screen IM are sorted according to the brightness. For convenience of explanation, in the present embodiment, the luminance of the block T0 is the lowest and the luminance of the block T24 is the highest. Then, the weighted average brightness of the preview image is calculated according to a preset weight array, and For automatic exposure to get an automatic exposure screen. It should be noted that the preset weight array corresponds to a preset exposure adjustment index N.

Please refer to FIG. 5A to FIG. 5C for details of the weight array. FIG. 5A, FIG. 5B and FIG. 5C are respectively a low light priority re-array and an average weight array in the automatic exposure control method according to an exemplary embodiment of the present invention. Schematic diagram of a heavy array with high light priority. The low-light priority re-array, the average weighted array, and the high-light priority re-array in FIGS. 5A, 5B, and 5C are three weighting arrays for calculating the weighted average luminance of the preview picture but having different weight distributions. In the low-light priority re-array, the low-luminance block is assigned a larger weight, and the calculated weighted average brightness is lower, so that the underestimated weighted average brightness is automatically exposed, and a larger exposure effect is obtained. In this embodiment, the exposure adjustment index N corresponding to the low-light priority re-array is set to 100; conversely, in the high-light priority re-array, the high-luminance block is assigned a larger weight, and after automatic exposure, A smaller exposure effect is obtained, and the corresponding exposure adjustment index N is set to zero. In addition, in the average weight array, the block in which the brightness is centered is assigned a larger weight, and the block in which the brightness is higher or lower is assigned a smaller weight, and the corresponding exposure adjustment index N is set to 50. In this embodiment, the weight array corresponding to the other exposure adjustment index N can be obtained by interpolating the low-light priority re-array, the average weight array, and the two arrays of the high-light priority re-array.

Next, the details of the step c in the automatic exposure control method provided by the present embodiment will be explained.

First, please refer to FIG. 1B. FIG. 1B is a flowchart of step c in the automatic exposure control method according to an exemplary embodiment of the present invention.

As shown in FIG. 1B, step c in the automatic exposure control method provided in this embodiment is implemented by determining whether the overexposure ratio in the luminance histogram of the automatic exposure screen falls within a desired overexposure interval or is too dark. Whether the ratio falls within the expected over dark interval (step c1); if the overexposure ratio in the luminance histogram of the auto exposure screen falls within the desired overexposure interval or the over dark ratio falls within the desired over dark interval, the preset is not corrected Weight array (step c2); and if the overexposure ratio in the luminance histogram of the auto exposure screen does not fall If it is desired that the overexposure interval or the over dark ratio does not fall within the desired over dark interval, the preset weight array is corrected to obtain a correction weight array (step c3).

Referring to FIG. 3, FIG. 4A and FIG. 4B, FIG. 3 is a schematic diagram of performing step c in the automatic exposure control method according to an exemplary embodiment of the invention. In addition, FIG. 4A and FIG. 4B are schematic diagrams showing a luminance histogram in an automatic exposure control method according to an exemplary embodiment of the invention.

In this embodiment, the execution details of step c may be slightly different depending on the current mode of operation of the electronic device. In general, when the ambient light is strong, the module with the photographic function in the electronic device can choose to work in the day mode, and when the ambient light is weak, the module with the photographic function in the electronic device can choose to work in the night mode. .

In the daytime mode, since the ambient light is sufficient, if the automatic exposure is performed based on the unweighted average brightness of the preview image, it is easy to mislead to make the exposure compensation insufficient, causing some scenes to be too dark, so the automatic provided by the embodiment is executed. In the exposure control method, the weighted average brightness of the preview picture is calculated with an appropriate weight array for automatic exposure, and the main purpose is to adjust the over-dark ratio of the picture in the day mode to an appropriate value. In the night mode, the situation of the automatic exposure control method provided by the embodiment is mainly to adjust the overexposure ratio of the screen in the night mode to the situation that the partial scene is overexposed due to the lack of ambient light and the misleading compensation. Appropriate value.

It should be noted that those having ordinary knowledge in the technical field of the invention should understand the brightness histogram of the picture, the overexposure ratio and the over dark ratio in the luminance histogram, and therefore, the terms are not described herein.

The details of the execution of step c in the night mode will be exemplified below.

In the night mode, in step c1, it is determined whether the overexposure ratio in the luminance histogram of the auto exposure screen falls within the desired overexposure interval. It should be noted that, in step c, the most ideal way is to adjust the overexposure ratio in the luminance histogram of the auto exposure screen to the target overexposure ratio BT as shown in FIG. However, considering the brightness histogram of the auto exposure screen may cause slight fluctuations due to noise, so as long as the automatic exposure The overexposure ratio in the luminance histogram of the light picture IM can fall within a desired overexposure interval, and can be regarded as reaching the target overexposure ratio BT. That is to say, this expected overexposure interval can be regarded as a tolerance interval centered on the target overexposure ratio BT.

Assume that the target overexposure ratio BT is 30% in the night mode, and assume that the expected overexposure interval is the target overexposure ratio BT ± 3%, that is, the expected overexposure interval is 27% to 33%. At this time, if the overexposure ratio in the luminance histogram of the automatic exposure screen is 31%, the process proceeds to step c2, and the preset weight array is not corrected. At this time, if the overexposure ratio in the luminance histogram of the auto exposure screen is 60%, the process proceeds to step c3, and the preset weight array is corrected to obtain a correction weight array.

In the following description, the details of correcting the preset weight array to obtain the correction weight array (ie, the details of step c3) will be explained with reference to FIG. 1C and FIG. 3 simultaneously; however, it should be explained that, since this example is used The details of the step c3 in the night mode are explained, and in the embodiment, the night mode is set for the target overexposure ratio, so in each step below the step c3, only the overexposure ratio is calculated, and It is not necessary to calculate for a dark ratio.

1C is a flow chart of step c3 in the automatic exposure control method according to an exemplary embodiment of the invention. As shown in FIG. 1C, step c3 includes: calculating a difference between the overexposure ratio and the target overexposure ratio (step c3-1); according to the difference between the overexposure ratio and the target overexposure ratio or the ratio of over darkness to the target over dark ratio The difference is estimated, the corrected exposure adjustment index is estimated (step c3-2); the correction weight array is calculated according to the corrected exposure adjustment index (step c3-3); and the preview image is calculated according to the correction weight array and the ordering of the blocks Weighting the average brightness and performing automatic exposure according to the result, obtaining a corrected automatic exposure picture (step c3-4); determining whether the over-exposure ratio in the brightness histogram of the corrected automatic exposure picture falls within a desired over-exposure interval (step c3-5); And if the overexposure ratio in the luminance histogram of the corrected auto exposure screen falls within the desired overexposure interval, the correction weight array is not adjusted (step c3-6). It should be noted that, in step c3-5, if the overexposure ratio in the luminance histogram of the corrected auto exposure screen does not fall within the expected overexposure interval, execution is again performed by step c3-1 to continue to adjust the correction weight. Array.

As shown in FIG. 3, it is assumed that the module having the photographing function in the electronic device has a preset weight array, and the preset exposure adjustment index N1 corresponding to the preset weight array is 70. Furthermore, it is assumed that the luminance histogram of the auto exposure screen generated by the preset weight array is as shown in FIG. 4A, and the overexposure ratio B1 (corresponding to the overexposure ratio B1 in FIG. 3) is 60%; The overexposure ratio BT is 30%.

In step c3-1, the difference between the overexposure ratio B1 and the target overexposure ratio BT, that is, -30%, is first calculated. Next, in step c3-2, the corrected exposure adjustment index N2 is estimated based on the difference between the overexposure ratio B1 and the target overexposure ratio BT. Further, since there is a difference of -30% between the overexposure ratio B1 and the target overexposure ratio BT, the corrected exposure adjustment index N2 smaller than the preset exposure adjustment index N1 is estimated according to the difference (as shown in FIG. 3). , assuming that the corrected exposure adjustment index N2 is 60). Finally, in step c3-3, the correction weight array will be calculated based on the corrected exposure adjustment index N2. It should be noted that, in step c3-2, according to the difference between the overexposure ratio B1 and the target overexposure ratio BT, an exposure adjustment index offset is first estimated, and then the exposure adjustment index offset is added. The preset exposure adjustment index N1 is preset by the preset exposure adjustment index N1 of the weight array. That is, the corrected exposure adjustment index N2 is the sum of the exposure adjustment index offset and the preset exposure adjustment index N1 of the preset weight array. It is worth noting that there are many methods for estimating the exposure adjustment index offset. In this embodiment, the k times the difference between the overexposed ratio B1 and the target overexposure ratio BT is used as the exposure adjustment index. The amount of shift (where k > 0), but the invention is not limited thereto.

In step c3-3, the correction weight array is obtained by using two of the aforementioned low light priority re-array, average weight array, and high light priority re-array. In the above example, since the corrected exposure adjustment index N2 estimated in step c3-2 is 60, at this time, in step c3-3, the low light priority re-array (corresponding to N=100) and the average weight array (corresponding to N=50) Interpolation calculates a correction weight array with an exposure adjustment index of 60.

Next, in step c3-4, the weighted average brightness of the preview image is calculated according to the correction weight array whose exposure adjustment index is 60 calculated in step c-3, and the automatic exposure is performed according to the automatic exposure. Picture. Notably, at this time, since the weight array is reset, the luminance histogram of the corrected auto exposure screen will also change. Here, assuming that the preset weight array is subjected to the first correction, the brightness histogram of the corrected automatic exposure picture is as shown in FIG. 4B, and the overexposure ratio B2 of the corrected automatic exposure picture obtained according to the brightness histogram is 53%. (corresponding to the overexposure ratio B2 in Fig. 3).

In order to confirm whether the correction weight array generated after the first correction can make the overexposure ratio B2 of the corrected auto exposure screen reach the target overexposure ratio BT (ie, 30%), in step c3-5, the correction is automatically performed according to the correction. The brightness histogram of the exposure screen determines whether the overexposure ratio B2 of the corrected auto exposure screen falls within a desired overexposure interval. Assume that the overexposure interval is expected to be BT±3% of the target overexposure ratio. In this case, the overexposure interval is expected to be 27%~33%, so the overexposure ratio B2 of the corrected auto exposure screen does not fall into 27%~33. %. Thus, execution is again performed by step c3-1 to continue adjusting the correction weight array.

Another corrected exposure adjustment index N3 will be obtained after performing the aforementioned steps c3-1 and c3-2 again. The corrected exposure adjustment index N3 is a sum of the estimated exposure adjustment index offset and the corrected exposure adjustment index N2 of the current correction weight array. It is assumed that the sum of the estimated exposure adjustment index offset and the corrected exposure adjustment index N2 of the current correction weight array is 40 (i.e., the corrected exposure adjustment index N3 = 40). Thus, in step c3-3, a correction weight array having an exposure adjustment index of 40 is calculated by interpolating the highlight priority array (corresponding to N=0) and the average weight array (corresponding to N=50). Then, in step c3-4, the weighted average brightness of the preview image is calculated again according to the correction weight array whose exposure adjustment index is 40 calculated in step c3-3, and the automatic exposure is performed according to the automatic exposure, and a new correction automatic is obtained. Exposure screen. At this time, since the weight array is reset again, the brightness histogram of the corrected auto exposure screen will also change. Chemical. Here, assuming that the preset weight array is subjected to the second correction, the overexposure ratio B3 obtained by correcting the luminance histogram of the automatic exposure screen is 32%.

In order to reconfirm whether the correction weight array generated after the second correction can make the overexposure ratio B3 of the corrected auto exposure screen reach the target overexposure ratio BT (ie, 30%), in step c3-5, according to the correction The brightness histogram of the auto exposure screen again determines whether the overexposure ratio B3 falls within the desired overexposure interval (ie, 27% to 33%). At this time, since the overexposure ratio B3 of the corrected auto exposure screen is 32%, it can be regarded as having reached the target overexposure ratio BT, and then the adjustment of the correction weight array is stopped in step c3-6.

Notably, in the present embodiment, the execution details of steps c3-1 to c3-6 of the automatic exposure control method in the day mode are similar to steps c3-1 to c3 of the automatic exposure control method in the night mode. The execution details of -6, but the difference between the two is that in the day mode, in steps c3-1 to c3-3, the correction weight array is calculated according to the darkness ratio in the luminance histogram of the automatic exposure screen. For example, k times the difference between the ratio of the darkness ratio and the target darkness ratio may be used as the exposure adjustment index offset (where k<0), but the invention is not limited thereto. In addition, in step c3-5 to step c3-6, it is judged whether or not the over-dark ratio in the luminance histogram of the corrected auto-exposure picture falls within the desired over-dark interval to decide whether to adjust the correction weight array. Therefore, regarding the execution details of the steps c3-1 to c3-6 of the automatic exposure control method in the day mode, reference may be made to the foregoing description, and the darkness ratio in the luminance histogram of the automatic exposure screen described herein may be referred to. The over-dark ratios D1 and D2 indicated in the luminance histograms of Figures 4A and 4B.

It is also worth noting that the luminance histograms in FIGS. 4A and 4B, the weight arrays in FIGS. 5A to 5C, and the exposure adjustment index, overexposure ratio, and over-dark ratio values in FIG. 3 are only used to describe The details of the execution of steps c to e are not intended to limit the invention.

After the adjustment of the correction weight array is completed, the process proceeds to step d to calculate the weighted average brightness of the preview picture according to the correction weight array and the order of the blocks. Perform automatic exposure to get the target auto exposure screen. It should be noted that if the preset weight array does not need to be corrected in step c, then in step d, the weighted average brightness of the preview picture is calculated according to the preset weight array and the order of the blocks, and the automatic exposure is performed accordingly. , get the target auto exposure screen.

Finally, after the processing from step a to step d, the overexposure ratio or the over dark ratio of the target auto exposure screen has met the requirements, but it is still necessary to check whether the overall brightness is appropriate, so step e will be performed. In step e, it is determined whether the overall brightness of the target auto-exposure screen falls within a desired brightness interval, to determine whether the control photography module performs photography according to the preset weight array or the correction weight array determined in step c, or further fine-tunes step c. Preset weight array or correction weight array.

Please refer to FIG. 1D. FIG. 1D is a flowchart of step e in the automatic exposure control method according to an exemplary embodiment of the present invention.

As shown in FIG. 1D, in the embodiment, step e includes: determining whether the overall brightness of the target auto exposure screen falls within a desired brightness interval (step e1); if the overall brightness of the target auto exposure screen falls within a desired brightness interval, Controlling the photography module to perform photography according to the preset weight array or the correction weight array determined in step c (step e2); and adjusting at least one brightness control of the photography module if the overall brightness of the target automatic exposure screen does not fall within the desired brightness interval The parameters are again executed by step b to fine tune the preset weight array or the correction weight array determined in step c (step e3).

It should be noted that, in step e3, at least one brightness control parameter of the camera module, such as the photosensitive element photosensitive value, exposure time, etc., is first adjusted. However, once the photosensitive element or exposure time of the photosensitive element of the photographic module is adjusted, the brightness of each block in the preview picture will also change accordingly, so that it needs to be executed again by step b to achieve the fine adjustment step c. Preset the weight array or correct the purpose of the weight array.

It should be noted that the details of the preset weight array or the correction weight array determined by the step b again to further fine tune the step c are the same as the details of adjusting the preset weight array or the correction weight array, so there is no other difference. Narration.

[An embodiment of an electronic device]

Please refer to FIG. 6. FIG. 6 is a flow chart of an electronic device according to an exemplary embodiment of the invention.

As shown in FIG. 6, the electronic device 1 provided in this embodiment includes a camera module 10, a memory 20, and a controller 30. The memory 20 is arranged to store an automatic exposure control program 20a. The controller 30 is connected to the camera module 10 and the memory 20, and is configured to execute the automatic exposure control program 20a to control the camera module 10 to perform photography according to a dynamic weight array generated after the automatic exposure control program 20a is executed.

For example, the electronic device 1 provided in this embodiment can be implemented by any electronic device having a photographic function, such as a mobile phone, a tablet computer, a monitoring device, etc., and the camera module 10 can be any electronic device having a photographic function. A photographic device such as a mobile phone, a tablet computer, a monitoring device, or the like. It should be noted that, in this embodiment, the operation performed by the controller 30 to execute the automatic exposure control program 20a is the steps in the automatic exposure control program method provided by the foregoing embodiment.

[Possible efficacy of the embodiment]

In summary, with the automatic exposure control method of the present invention, once the camera module of the electronic device is activated, the weight array for calculating the weighted average brightness of the preview image can be dynamically adjusted.

Different from traditionally setting a fixed luminance weight value to all the blocks in the picture and traditionally giving different brightness weight values to different blocks in the picture according to different brightness threshold intervals, regardless of the photography mode of the electronic device. The group operates in day mode and night mode, and the automatic exposure control method of the present invention can dynamically adjust the brightness weight value of each block in the preview picture until it reaches an appropriate value (ie, makes the automatic exposure picture Achieve the target too dark ratio or target overexposure ratio).

Further, in the automatic exposure control method of the present invention, the dynamic weight array is no longer corrected as long as it is judged that the excessive darkness ratio of the automatic exposure screen falls within the desired over dark interval or the overexposure ratio falls within the desired overexposure interval. This method can avoid the phenomenon that the brightness weight value of each block in the preview picture is adjusted too frequently to cause the picture to flicker.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

Claims (9)

An automatic exposure control method is applicable to an electronic device, the electronic device includes a camera module and a controller, and the controller executes the automatic exposure control method to control the camera module to perform photography according to a weight array of dynamic changes. The automatic exposure control method includes: step a: obtaining a preview picture, and cutting the preview picture into a plurality of blocks; and step b: sorting the blocks according to the brightness, and sorting according to the blocks Calculating a weighted average brightness of the preview picture with a preset weight array to perform automatic exposure to obtain an automatic exposure picture; and step c: determining whether an over-exposure ratio in one of the brightness histograms of the automatic exposure picture falls within Whether a desired overexposure interval or an over dark ratio falls within an expected over dark interval to determine whether to correct the preset weight array of the photographic module to obtain a correction weight array; step d: according to the preset weight array or The correction weight array and the ordering of the blocks, calculating the weighted average brightness of the preview picture for automatic exposure to obtain a target And exposing the screen; and step e: determining whether an overall brightness of the target auto exposure screen falls within a desired brightness interval, to determine to control the camera module to perform photography according to the preset weight array or the correction weight array, or fine tune the Predetermining a weight array or the correction weight array; wherein the correction weight array is obtained by a high light priority re-array and an average weight array interpolation calculation, or is calculated by interpolating a low-light priority re-array and the average weight array Obtained. The automatic exposure control method according to claim 1, wherein in the step b, the blocks are sorted by the block of the highest brightness to the block of the lowest brightness, or the block of the lowest brightness is sorted to the highest. The block of brightness. The automatic exposure control method of claim 1, wherein the step c comprises: step c1: determining whether the overexposure ratio in the luminance histogram of the auto exposure screen falls within the expected overexposure interval or whether the over dark ratio is Falling into the desired over dark interval; step c2: if the overexposure ratio in the luminance histogram of the auto exposure screen falls within the expected overexposure interval or the over dark ratio falls within the expected over dark interval, then no correction The preset weight array; and step c3: if the overexposure ratio in the luminance histogram of the auto exposure screen does not fall within the expected overexposure interval or the over dark ratio does not fall within the expected over dark interval, then the correction The preset weight array obtains the correction weight array. The automatic exposure control method of claim 1, wherein the camera module of the electronic device operates in a day mode and a night mode, and in step c, determining the brightness of the automatic exposure screen in the day mode Whether the over-dark ratio in the histogram falls within the desired over-dark interval to determine whether to correct the preset weight array of the photographic module to obtain the correction weight array, and in the night mode, determine the automatic exposure screen Whether the overexposure ratio in the luminance histogram falls within the desired overexposure interval to determine whether to correct the preset weight array of the photographic module to obtain the correction weight array. The automatic exposure control method of claim 3, wherein the step c3 comprises: step c3-1: calculating a difference between the overexposure ratio and a target overexposure ratio or a difference between the over dark ratio and a target over dark ratio Step c3-2: estimating an exposure adjustment index offset according to a difference between the overexposure ratio and the target overexposure ratio or a difference between the over dark ratio and the target over dark ratio, and the exposure adjustment index Offset plus one preset exposure adjustment index of the preset weight array to obtain a corrected exposure adjustment index; and step c3-3: calculating the correction weight matrix according to the corrected exposure adjustment index Column. The automatic exposure control method of claim 5, wherein the target overexposure ratio falls within the desired overexposure interval, and the target overexposure ratio falls within the desired over dark interval. The automatic exposure control method of claim 5, wherein the step c3 further comprises: step c3-4: calculating the weighted average brightness of the preview picture according to the correction weight array and the ordering of the blocks Performing automatic exposure to obtain a corrected automatic exposure screen; step c3-5: determining whether the overexposure ratio in the brightness histogram of the corrected automatic exposure screen falls within the desired overexposure interval or whether the over dark ratio falls The expected dark interval; and the step c3-6: if the overexposure ratio in the luminance histogram of the corrected auto exposure screen falls within the desired overexposure interval or the over dark ratio falls within the desired over dark interval, then The correction weight array is not adjusted; wherein, in step c3-5, if the overexposure ratio in the brightness histogram of the corrected auto exposure screen does not fall within the expected overexposure interval or the over dark ratio does not fall into the The dark interval is expected to be performed again by step c3-1 to adjust the correction weight array; wherein, in step c3-2, the corrected exposure adjustment index is the exposure adjustment index offset and the preset weight matrix Of the predetermined index and the exposure adjustment, index or adjusting the current offset correction of the correction weight of a positive weight n array indices and exposure adjustment for the exposure. The automatic exposure control method of claim 1, wherein the step e comprises: step e1: determining whether the overall brightness of the target automatic exposure screen falls within the desired brightness interval; step e2: if the target automatically exposes the image The brightness falls within the desired brightness interval, and then the camera module is controlled according to the preset weight array or the correction right Performing photography by the re-array; and step e3: if the overall brightness of the target auto-exposure screen does not fall within the desired brightness interval, adjusting at least one brightness control parameter of the camera module, and starting again by step b, to fine-tune The preset weight array or the correction weight array, wherein the brightness control parameter includes an exposure degree and a light sensing time. An electronic device comprising: a camera module; and a memory configured to store an automatic exposure control program; a controller coupled to the camera module and the memory, and configured to execute the automatic exposure control program The camera module is controlled to perform photography according to a dynamic weight array, wherein the controller operates the automatic exposure control program to perform the automatic exposure control method according to any one of claims 1 to 8.