WO2022067496A1

WO2022067496A1 - Fast auto-exposure method for camera, and storage medium

Info

Publication number: WO2022067496A1
Application number: PCT/CN2020/118798
Authority: WO
Inventors: 李泽飞; 吴伟霖; 胡涛
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2020-09-29
Filing date: 2020-09-29
Publication date: 2022-04-07

Abstract

Provided are a fast auto-exposure method for a camera and a storage medium. The method comprises: according to historical brightness data of prior camera exposures, predicting the ambient brightness the next time a camera is started up; according to the predicted ambient brightness, setting a brightness sequence for performing exposure testing, and, according to the brightness sequence, setting within the camera an exposure parameter corresponding to the brightness sequence; after the camera is started up, sequentially performing exposure according to the set exposure parameter, and obtaining corresponding images; determining, according to the images obtained by exposure, whether exposure testing is successful, and obtaining a first exposure parameter corresponding to successful exposure testing; and calculating an actual exposure parameter according to the first exposure parameter so as to perform photographing. By means of the described method, the time spent on the whole process from camera startup to completing photographing can be controlled within 1S, reaching an industry-leading level.

Description

A method for fast automatic exposure of a camera and a storage medium

technical field

The present invention generally relates to the field of cameras, and more particularly, to a method for rapid automatic exposure of a camera and a storage medium.

Background technique

When the camera is in use, the brightness of the exposure needs to be adjusted. Auto exposure uses the appropriate exposure parameters according to the brightness of the scene to avoid overexposed or dark images. Exposure test convergence is usually performed by automatic exposure to get the best shot brightness.

Since it takes a long time for the exposure test to converge from the start of the camera to the automatic exposure (AE), for example, it takes 15-40 frames in many application scenarios. will be very long.

For some high-speed motion scenes, the camera is in a standby energy-saving state when it is not shooting (the camera sensor does not take pictures, and the Image Signal Processing (ISP) does not work). , to quickly capture wonderful moments, but the current camera takes too long from startup to complete auto exposure to achieve the above goals.

Therefore, the current automatic exposure method needs to be improved to overcome the above problems.

SUMMARY OF THE INVENTION

The present invention has been made to solve at least one of the above-mentioned problems. A first aspect of the present invention provides a method for fast automatic exposure of a camera, the method comprising:

According to the historical brightness data of the previous exposure of the camera, predict the ambient brightness when the camera is activated next time;

Setting a brightness sequence for exposure testing according to the predicted ambient brightness, and setting exposure parameters corresponding to the brightness sequence in the camera according to the brightness sequence;

After the camera is started, exposure is performed in sequence according to the set exposure parameters and corresponding images are obtained;

Determine whether the exposure test is successful according to the image obtained by the exposure, and obtain the first exposure parameter corresponding to the successful exposure test;

Actual exposure parameters are calculated according to the first exposure parameters for taking pictures.

A second aspect of the present invention provides a storage medium on which a computer program is stored, and the computer program executes the aforementioned method when running.

The invention provides a method for fast automatic exposure of a camera. In the method, before the camera is started, the environment brightness when the camera is started is predicted, and the brightness sequence used for exposure test is set according to the environment brightness. Before exposing the image, the exposure parameters corresponding to the set brightness sequence are sequentially exposed, and finally the actual exposure parameters are obtained. The method can shorten the time consumed by automatic exposure and photographing after the camera is started, and solve the problem that the current product takes too much time from starting to completing automatic exposure. long question. Through the method, the time-consuming and energy-consuming of the entire process from the start of the camera to the completion of taking pictures can be controlled within 1S, which reaches the industry-leading level.

Description of drawings

1 shows a schematic flowchart of a method for fast automatic exposure of a camera provided by the present invention;

FIG. 2 shows a schematic block diagram of a method for fast automatic exposure of a camera provided in an embodiment of the present invention.

Detailed ways

In order to make the objects, technical solutions and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of the embodiments of the present invention, and it should be understood that the present invention is not limited by the example embodiments described herein. Based on the embodiments of the present invention described in the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without one or more of these details. In other instances, some technical features known in the art have not been described in order to avoid obscuring the present invention.

It should be understood that the present invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the/the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should also be understood that the terms "compose" and/or "include", when used in this specification, identify the presence of stated features, integers, steps, operations, elements and/or components, but do not exclude one or more other The presence or addition of features, integers, steps, operations, elements, parts and/or groups. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

For a thorough understanding of the present invention, detailed steps and detailed structures will be proposed in the following description to explain the technical solutions proposed by the present invention. Preferred embodiments of the present invention are described in detail below, however, the present invention may have other embodiments in addition to these detailed descriptions.

In order to solve the aforementioned problems, a first aspect of the present invention provides a method for fast automatic exposure of a camera, as shown in FIG. 1 , the method includes:

Step S1: Predict the ambient brightness when the camera is activated next time according to the historical brightness data exposed by the camera before;

Step S2: setting a brightness sequence for exposure testing according to the predicted ambient brightness, and setting exposure parameters corresponding to the brightness sequence in the camera according to the brightness sequence;

Step S3: After the camera is started, exposure is performed in sequence according to the set exposure parameters and corresponding images are obtained;

Step S4: judging whether the exposure test is successful according to the image obtained by the exposure, and obtaining the first exposure parameter corresponding to the successful exposure test;

Step S5: Calculate actual exposure parameters according to the first exposure parameters, so as to be used for taking pictures.

The preparation method will be described in detail below with reference to FIG. 2 , wherein FIG. 2 shows a schematic block diagram of a method for fast automatic exposure of a camera provided in an embodiment of the present invention.

It should be noted that the fast automatic exposure method described in this application can be applied to all types of digital cameras, and is not limited to a certain one. For example, the camera can be a motion camera. The time from camera startup to taking a picture is sensitive. The camera may also be a professional camera, wherein faster automatic exposure in a professional camera means less power consumption and increased standby time. In the time-lapse photography with super long interval time, it can effectively increase the standby time.

In addition, in addition to being applied to the camera field, the automatic exposure method of the present application can also be applied to all application scenarios that require quick exposure after startup. The automatic exposure method described in the present application will be described in detail below by taking a camera as an example.

In the step S1, in the conventional automatic exposure method, the convergence of the exposure test is usually directly performed to obtain the optimal exposure brightness, which takes too long. In the automatic exposure method of the present application, before the camera is started , First, according to the historical brightness data of the previous exposure of the camera, the ambient brightness when the camera is started next time is predicted and stored in the camera, so as to avoid the problem that the exposure parameter setting is too different from the current ambient brightness, resulting in a long automatic exposure time.

Specifically, in the automatic exposure process, if the exposure parameter is preset to a high value, there will be a lot of overexposure in the camera picture, and the automatic exposure (AE) cannot judge how bright the scene is, and the metering fails. If the exposure parameter is set low, there will be many dark parts of the screen, and the automatic exposure (AE) statistics will be affected by dark current and noise, and the metering will also fail.

The method described in this application makes use of the law of changes in ambient brightness, and by fitting historical brightness data, to predict the ambient brightness when the camera is activated next time, and then if the exposure parameters of the first frame are set properly, automatic exposure can be completed in one frame. The exposure test of AE can reduce the time of exposure test, and then obtain the actual exposure parameters obtained more quickly, and shorten the time consumed by automatic exposure and photography after the camera is started.

Wherein, the historical brightness data refers to fitting the historical brightness previously exposed by the camera to obtain historical brightness data after each time the camera takes a photo and before entering standby. The fitting refers to fitting the historical brightness previously exposed by the camera to a parameter corresponding to the historical brightness, wherein the parameter corresponding to the historical brightness includes time and/or position.

In an embodiment of the present application, when fitting exposure brightness and exposure time, a time-exposure brightness point set or curve is established with the time as the abscissa and the corresponding exposure brightness as the ordinate, so as to obtain the historical luminance data.

In another embodiment of the present application, when fitting the exposure brightness and the location during exposure, take the location as the abscissa and the corresponding exposure brightness as the ordinate to establish a location-exposure brightness point set or curve, with Obtain the historical luminance data. Wherein, the location can be obtained according to GPS or other means, which is not limited herein.

In addition, it is also possible to fit the exposure brightness, exposure time, and exposure location to obtain a three-dimensional curved surface.

Among them, when performing data fitting and sampling, the sampling time interval can be set. If the sampling time is greater than a certain threshold (for example, 5S), the collected data is fitted to predict the ambient brightness when the next startup is turned on.

Among them, the method of fitting the sampling data can be cubic spline fitting. In this application, the sampling result is to draw an approximate curve according to some data obtained by observation, that is, some discrete points on the plane. These discrete points are called for the control point. When fitting, it is required that the curve does not necessarily pass through all control points, but approximates these points in some way to obtain the fitted curve.

Specifically, a fitting curve is constructed after sampling. In addition to the least squares method, a piecewise fitting method can also be used in this application, that is, in each segment, a low-order polynomial is used as the fitting curve of the segment, Moreover, these piecewise polynomial curves also have a certain degree of smoothness at the demarcation point for spline fitting. Through the spline, the above-mentioned time-exposure brightness or time-exposure location and other smooth curves can be drawn according to the given control points. .

In an embodiment of the present application, as shown in FIG. 2 , the exposure brightness and corresponding parameters, as well as the historical brightness data obtained after fitting, have been stored in the camera during the last use of the camera, and then predicted The ambient brightness the next time the camera starts up.

Wherein, in the present application, after obtaining the historical brightness data previously exposed by the camera, the environmental brightness in the next shooting is predicted according to the historical brightness data. Specifically, the method includes predicting the ambient brightness at the next shooting according to the parameters at the next shooting in combination with the historical brightness data.

For example, in an embodiment of the present application, the shooting time can be obtained in the next shooting, and then according to the time-exposure brightness point set or curve, the brightness corresponding to the time can be obtained on the point set or curve , as the ambient brightness for the next shooting.

In another embodiment of the present application, the shooting location may be acquired during the next shooting, and then, according to the location-exposure brightness point set or curve, the brightness corresponding to the location is obtained on the point set or curve , as the ambient brightness for the next shooting.

In addition, since the use of the camera is continuous within a period of time, the probability of the current use and the previous use is the same. Therefore, in order to speed up the exposure speed, the last exposure brightness of the camera can be directly used as the next shot. Exposure at ambient brightness.

In the step S2, before the camera is started, the brightness sequence used for the exposure test is set according to the ambient brightness predicted in the step S1, wherein the brightness sequence refers to a series of ambient brightness to be used in the subsequent steps. In the step, exposure parameters corresponding to the brightness sequence are set in the camera according to the brightness sequence.

Wherein, the method for setting a brightness sequence for exposure testing in the camera according to the predicted ambient brightness includes: centering on a brightness smaller than the predicted ambient brightness, increasing and decreasing with a fixed amplitude, to obtain the ambient brightness greater than the predicted, the predicted ambient brightness and the brightness sequence less than the predicted ambient brightness.

In an embodiment of the present application, as shown in FIG. 2 , the ambient brightness predicted in the step S1 is 0EV, and a brightness smaller than the predicted 0EV is used as the intermediate number, for example, -4EV is used as the intermediate number , Increment and decrement with 8EV as a fixed range, increase 8EV, get 4EV ambient brightness, decrease 8EV, get -12EV ambient brightness, the obtained ambient brightness sequence is (-4EV, 4EV, -12EV).

Wherein, the number of brightnesses set in the brightness sequence does not exceed 10. For example, in an embodiment of the present application, the number of brightnesses set in the brightness sequence is three. The number of brightnesses set in the brightness sequence is not limited to the above example, and can be selected according to actual needs.

Specifically, the number of brightnesses set in the brightness sequence is related to the lag time of images generated by the camera after exposure. If the images generated by the first group of exposures are obtained after N frames of exposure, the brightness set in the brightness sequence is The number is N-1, that is, the exposure test can be stopped after obtaining the images generated by the first set of exposures. At this time, N-1 sets of data have been exposed. Of course, the setting of the number of brightness in the brightness sequence is also exemplary. .

In the automatic exposure process in the present application, the exposure is continued regardless of whether the exposed image is generated or not, instead of each exposure, obtaining the exposure image, and performing the exposure detection in the current method, in the present application, after each exposure is completed, the camera is driven to Immediately enter the next exposure, not affected by the frame rate, without waiting for the image to be generated, and it takes less time to pass the set exposure test.

Wherein, in the step S2, exposure parameters corresponding to the brightness are set in the camera according to each brightness in the brightness sequence, wherein the methods of setting the exposure parameters include shutter, aperture (value) size, Sensitivity (ISO), etc.

Among them, the shutter speed is the time from the shutter opening to closing. The smaller the shutter speed value, the less time the shutter is open, the less the amount of incoming light, and the less the amount of light read by the photosensitive element; on the contrary, the larger the shutter speed value, the less the amount of light coming in. The amount of light read by the photosensitive element is also large. Shutter speed is generally 1/100s, 1/30s, 2s.

Among them, the aperture (value) has many lenses in the camera lens, and the light can penetrate to the end, and the multiple metal blades (after being folded) hidden in a certain position of the lens can control the amount of light entering on the lens. The larger the circular hole that the light surrounded by the aperture blade can enter, the more light will enter; on the contrary, the smaller the aperture, the less light will enter.

Among them, the sensitivity, also known as ISO, is the sensitivity of the photosensitive element to light: if the sensitivity is high, it is sensitive to light. If you give a little light, the photosensitive element can also feel it and the exposure is sufficient; if the sensitivity is low, you need to increase the sensitivity. .

The exposure parameters are set by adjusting one or more of shutter, aperture (value) size, and light sensitivity (ISO) in the camera, so that the brightness of the exposure during the exposure process is equal to the brightness in the set brightness sequence .

In the step S3, before the camera is started, the exposure parameters have been set in the steps S1 and S2, and after the camera is started, the set exposure parameters are sequentially performed in a certain order. Exposure is enough, and the corresponding image is obtained after exposure.

The methods for exposing and generating images are the same as the conventional methods, and are not repeated here.

In an embodiment of the present application, as shown in FIG. 2 , three brightness sequences are set in the brightness sequence, and the three brightness sequences are respectively exposed to obtain the first frame, the second frame and the third brightness sequence. Images obtained from three exposures.

In the step S4, an exposure test is performed according to the image obtained in the step S3, that is, it is verified whether any luminance in the luminance sequence meets the exposure requirement, as the first exposure parameter corresponding to the successful exposure test.

In the method for judging whether the exposure test is successful in this application, it is necessary to first obtain two data, one is the characterization of the current ambient brightness, and the other is the characterization of the brightness in the actual exposure process, and the two are compared. .

In an embodiment of the present application, the representation of the current ambient brightness may be an expected value of the image brightness in the camera calculated according to the current ambient brightness.

In an embodiment of the present application, the image exposure brightness can be obtained by performing statistics on the pixels in the image obtained after exposure; wherein, the image exposure brightness can be the average of all pixels in the image obtained after statistical exposure. The brightness can also be the brightness of a specific area in the image obtained after exposure, for example, it can also be the brightness of the central area of the image obtained after exposure, wherein the measurement of the exposure brightness of the image can be set according to actual needs and purposes, Not limited to the above examples.

When judging whether the exposure test is successful, it is necessary to compare the expected value with the image exposure brightness judgment exposure test. There are two situations in the comparison process, namely underexposure and overexposure. The following is for each situation. Detailed explanation.

First, when the exposure is insufficient, the exposure brightness of the image is less than or equal to the expected value of the brightness. At this time, there are dark parts in the exposed image. When the number of dark parts in the exposed image does not account for too much, the exposure Test success. Specifically, if the number of dark parts in the image is less than the set dark part threshold, the exposure test is successful. Wherein, the set dark part threshold can be set according to actual needs. For example, the threshold number of pixels in the dark part in the image can be set. When the actual dark part in the image is less than or equal to the threshold number of pixels, The exposure test is deemed successful.

In an embodiment of the present application, according to a statistical value generated by a preset exposure parameter, the average brightness of all pixels in the image can be obtained through the statistical value. When the average brightness of all pixels in the image is less than or equal to the expected value of brightness, and the number of dark parts in the image is less than the set dark part threshold, the exposure test is successful.

Second, when overexposed, the exposure brightness of the image is greater than the expected value of the brightness, at this time, there are bright parts in the exposed image, and when the number of bright parts in the exposed image does not account for too much, the exposure Test success. Specifically, if the number of bright parts in the image is less than the set bright part threshold, the exposure test is successful. The threshold value of the bright part can be set according to actual needs, for example, the threshold number of the pixels in the bright part in the image can be set. If the threshold number is exceeded, the exposure test is considered to be successful.

In the case of overexposure, since it is not known how bright the overexposed pixels are in automatic exposure, and it is unclear how much the exposure parameters are lowered so that these overexposed pixels will not be overexposed, accurate metering cannot be performed, so it is necessary to strictly control the The number of bright parts is less than the set bright part threshold to ensure that the exposure brightness meets the requirements.

In an embodiment of the present application, according to a statistical value generated by a preset exposure parameter, the average brightness of all pixels in the image can be obtained through the statistical value. When the average brightness of all pixels in the image is greater than the expected value of the brightness, and the number of bright parts in the image is less than the set bright part threshold, the exposure test is successful.

In the present application, the images obtained by exposure are judged in order to judge whether the exposure test of the exposure parameters is successful, and stop after obtaining the result of the successful exposure test, and no subsequent exposure images that have not been judged are judged. If all the images obtained by the exposure parameters fail the exposure test, abnormal processing will be performed.

In an embodiment of the present application, as shown in FIG. 2 , the delay of the exposure-generated image described in the present application is 4 frames, the set luminance sequence includes 3 luminances, and after exposure is performed in sequence, 3 frames of images are obtained respectively, The first frame of graphics, the second frame of images, and the third frame of images are respectively the first frame of images, the second frame of images, and the third frame of images, and exposure tests are performed on the three frames of images. Then, the detection of the exposure test is stopped, and the exposure description corresponding to the exposure of the first frame is the first brightness, which can be used for subsequent calculation of the actual brightness.

If the exposure test in the first frame of exposure image fails, continue to judge the exposure test of the second frame of exposure image, if the exposure test in the second frame of image is successful, stop the continuous exposure test detection, and the exposure corresponding to the second frame of exposure is explained. is the first brightness, which can be used for subsequent calculation of actual brightness.

If the exposure test in the second frame of exposure image fails, continue to judge the exposure test on the third frame of exposure image. If the exposure test in the third frame of image is successful, stop continuing the exposure test detection, and the exposure corresponding to the third frame of exposure is explained. is the first brightness, which can be used for subsequent calculation of actual brightness.

If the exposure test fails in the images of the third frame (that is, all exposed images), it means that the predicted ambient brightness and the brightness sequence set according to the predicted ambient brightness do not match the current ambient brightness, and the difference is large. For exception handling, for example, you can reset or add additional brightness sequences to continue exposure, or directly estimate a value according to the current situation to perform exposure.

In an embodiment of the present application, according to the conditions for the successful exposure test described above, the image exposure brightness needs to be moderate. According to experience, the expected value of the image brightness in the camera is set to [-8EV, 0EV], that is, at [-8EV] ,0EV] can be successfully metered.

Set the "estimated ambient brightness" as 0EV, take -4EV as the middle number, and take 8EV as the increment and decrement in a fixed range, the resulting metering sequence is [-4EV, -12EV, +4EV], then:

If the current ambient brightness is in the range of [-4,+4]EV, and the exposure parameter in the first frame of exposure is -4EV, then the current ambient brightness and the exposure brightness of the exposure parameter are superimposed to obtain the image brightness in the camera The expected value of -4EV and -4EV is -8EV, and -4EV and 4EV is superimposed as 0EV, then within the range of the expected value [-8EV, 0EV], the first frame metering is successful. When the exposure of the first frame is successful, the exposure test may not be continued.

In the same way, if the real ambient brightness is in the range of [+4, +12]EV, and the exposure parameter in the first frame of exposure is -12EV, then the current ambient brightness and the exposure brightness of the exposure parameter are superimposed to get the camera. The expected value of the picture brightness, that is, the superposition of 4EV and -12EV is -8EV, and the superposition of -12EV and 12EV is 0EV, if it is within the range of the expected value [-8EV, 0EV], the second frame metering is successful.

Similarly, if the real ambient brightness is in the [-12,-4]EV range, the third frame metering is successful.

Through the above three-frame metering sequence, the range that can be successfully metered is -12EV to 12EV, reaching 24EV, which is higher than the brightness range that the camera can encounter in outdoor natural conditions, and the data of the successful exposure test can be obtained. If the ambient light brightness exceeds This range can be handled by exception.

In the step S5, after determining the first brightness corresponding to the successful exposure, calculation needs to be performed according to the first brightness to obtain an actual exposure parameter that is closer to the current ambient brightness, thereby making the exposure brightness different from the current ambient brightness Smaller and better for taking pictures.

In this application, the calculation is performed according to the two situations of underexposure and overexposure in the step S4:

First, when the exposure is insufficient, that is, the exposure brightness of the image is less than or equal to the expected value of the brightness, the calculation is performed by an iterative method, so that the actual exposure parameter is closer to the expected value of the brightness, so that the The error between the actual exposure parameter and the expected value of the brightness is within a set error threshold.

In an embodiment of the present application, the actual exposure parameter can be wirelessly approached to the expected value of the brightness through an iterative method.

Second, when overexposed, the exposure amount in the first exposure parameter is A, then the exposure amount setting of the actual exposure parameter is determined according to the product of the ratio of A to image exposure brightness and the expected value .

In an embodiment of the present application, the exposure amount in the first exposure parameter is A, and the exposure amount of the actual exposure parameter is set according to the ratio of A to the average brightness of all pixels in the image and the expected value The product is determined.

In the process of executing the steps S1 to S5, the picture displayed by the camera is fixed to prevent discomfort to the user's vision, for example, the picture displayed by the camera is locked as the first exposure time screen.

In an example of the present application, as mentioned above, if the brightness sequence is [-4EV, -12EV, +4EV], when exposure parameters with brightness of -12EV and +4EV are used for exposure, the difference between brightness and darkness is very large. The picture displayed by the camera is the picture of the real exposure brightness at that time, which will cause the visual flickering and cause stimulation, so by fixing the picture, the user can have a better experience.

Optionally, in this application, in each step from step S1 to step S5, the data generated when each instruction is executed, including the historical brightness data, are stored in the storage medium, so that the user can find it when needed. .

The storage medium is a local storage medium in the camera. The local storage medium may include various forms of computer-readable storage medium, such as volatile memory and/or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and/or cache memory, or the like. The non-volatile memory may include, for example, read-only memory

(ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the camera-readable storage medium, and the program instructions may be executed to implement various steps in the foregoing embodiments of the present application. Various application programs and various data, such as various data used and/or generated by the application program, may also be stored in the camera-readable storage medium.

In addition, the present application also provides a storage medium, where program instructions are stored on the storage medium, and when the program instructions are run by a computer or a processor, the program instructions are used to execute the corresponding steps from step S1 to step S5 in the embodiment of the present application. operate. The storage medium may include, for example, a memory card of a camera, a storage unit of a tablet computer, a hard disk of a personal computer, a read only memory (ROM), an erasable programmable read only memory (EPROM), a portable compact disk read only memory ( CD-ROM), USB memory, or any combination of the above storage media. The computer-readable storage medium can be any combination of one or more computer-readable storage media.

Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above-described example embodiments are exemplary only, and are not intended to limit the scope of the invention thereto. Various changes and modifications can be made therein by those of ordinary skill in the art without departing from the scope and spirit of the invention. All such changes and modifications are intended to be included within the scope of the invention as claimed in the appended claims.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of the present invention.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or May be integrated into another device, or some features may be omitted, or not implemented.

In the description provided herein, numerous specific details are set forth. It will be understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it is to be understood that in the description of the exemplary embodiments of the invention, various features of the invention are sometimes grouped together , or in its description. However, this method of the invention should not be interpreted as reflecting the intention that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the corresponding claims reflect, the invention lies in the fact that the corresponding technical problem may be solved with less than all features of a single disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

It will be understood by those skilled in the art that all features disclosed in this specification (including the accompanying claims, abstract and drawings) and any method or apparatus so disclosed may be used in any combination, except that the features are mutually exclusive. Processes or units are combined. Each feature disclosed in this specification (including accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that although some of the embodiments described herein include certain features, but not others, included in other embodiments, that combinations of features of different embodiments are intended to be within the scope of the invention within and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

Various component embodiments of the present invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all of the functions of some modules according to the embodiments of the present invention. The present invention may also be implemented as apparatus programs (eg, computer programs and computer program products) for performing part or all of the methods described herein. Such a program implementing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such signals may be downloaded from Internet sites, or provided on carrier signals, or in any other form.

It should be noted that the above-described embodiments illustrate rather than limit the invention, and that alternative embodiments may be devised by those skilled in the art without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. do not denote any order. These words can be interpreted as names.

The above is only the specific embodiment of the present invention or the description of the specific embodiment, and the protection scope of the present invention is not limited thereto. Any changes or substitutions should be included within the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

A method for fast automatic exposure of a camera, characterized in that the method comprises:

According to the historical brightness data of the previous exposure of the camera, predict the ambient brightness when the camera is activated next time;

Setting a brightness sequence for exposure testing according to the predicted ambient brightness, and setting exposure parameters corresponding to the brightness sequence in the camera according to the brightness sequence;

After the camera is started, exposure is performed in sequence according to the set exposure parameters and corresponding images are obtained;

Determine whether the exposure test is successful according to the image obtained by the exposure, and obtain the first exposure parameter corresponding to the successful exposure test;

Actual exposure parameters are calculated according to the first exposure parameters for taking pictures.
The method according to claim 1, wherein the method for judging whether the exposure test is successful comprises:

Calculate the expected value of the screen brightness in the camera according to the current ambient brightness;

Count the pixels in the image obtained after exposure to obtain the image exposure brightness;

Whether the exposure test is successful is determined according to the expected value and the image exposure brightness.
The method according to claim 2, wherein the image exposure brightness is the average brightness of all pixels in the image.
The method according to claim 2, wherein the determining whether the exposure test is successful according to the expected value and the image exposure brightness comprises:

When the exposure brightness of the image is less than or equal to the expected value of the brightness, and the number of dark parts in the image is less than the set dark part threshold, the exposure test is successful.
The method according to claim 4, wherein iterating according to the first exposure parameter is performed to obtain the actual exposure parameter whose error is within a set error threshold.
The method according to claim 2, wherein the judging whether the exposure test is successful according to the expected value and the target brightness comprises:

When the exposure brightness of the image is greater than the expected value, and the number of bright parts in the image is less than the set bright part threshold, the exposure test is successful.
The method according to claim 6, wherein the exposure amount in the first exposure parameter is A, and the exposure amount of the actual exposure parameter is set according to the ratio of A to image exposure brightness and the expected value is determined by the product of .
The method according to claim 1, wherein the predicting the ambient brightness during the next shooting according to the historical brightness data previously exposed by the camera comprises:

Fitting the historical brightness previously exposed by the camera and the parameter corresponding to the historical brightness to obtain the historical brightness data;

According to the parameters at the next shooting time and the historical brightness data, the ambient brightness at the next shooting time is predicted.
The method according to claim 8, wherein the parameters corresponding to the historical brightness include time and/or location.
The method according to claim 1, wherein the predicting the ambient brightness during the next shooting according to the historical brightness data previously exposed by the camera comprises:

The ambient brightness at the next shooting is predicted according to the last exposure brightness of the camera.
The method according to claim 1, wherein the method for setting a brightness sequence in the camera for performing an exposure test according to the predicted ambient brightness comprises:

Taking a brightness smaller than the predicted ambient brightness as an intermediate number, increment and decrement are performed with a fixed amplitude, thereby obtaining a brightness sequence including a plurality of brightnesses.
The method according to claim 11, wherein the number of luminances set in the luminance sequence does not exceed 10.
The method according to claim 1, wherein whether the exposure test of the exposure parameters is successful is determined in sequence according to the images obtained by exposure, and the subsequent exposure parameters are no longer exposed until the exposure test successfully obtains the first brightness test judgment.
The method according to claim 13, characterized in that, if all the images obtained by the exposure parameters fail the exposure test, abnormal processing is performed.
The method according to claim 1, wherein in the process of sequentially exposing the camera to obtain corresponding images and judging whether the exposure test is successful according to the images obtained by exposure, the picture displayed by the camera is always the first image. The image at the second exposure.
The method according to claim 1, wherein the historical luminance data and the data information generated in each step of the method are stored in a storage medium.
The method according to claim 16, wherein the storage medium is a local storage medium.
A storage medium, characterized in that a computer program is stored on the storage medium, and the computer program executes the method according to any one of claims 1-17 when running.