WO2020038069A1

WO2020038069A1 - Exposure control method and device, and electronic apparatus

Info

Publication number: WO2020038069A1
Application number: PCT/CN2019/090146
Authority: WO
Inventors: 胡孔勇
Original assignee: Oppo广东移动通信有限公司
Priority date: 2018-08-22
Filing date: 2019-06-05
Publication date: 2020-02-27
Also published as: CN109068067B; CN109068067A

Abstract

The present invention provides an exposure control method and device, and an electronic apparatus, relating to the technical field of mobile terminals. The method comprises: determining that a current shooting scenario is a night scenario; performing face region recognition on a preview image, and identifying, according to whether a face region is recognized, an applicable night mode for the current shooting scenario; determining, according to the night mode, an exposure parameter of each frame of an image to be acquired; using the exposure parameter to perform exposure control; dynamically adjusting the applicable night mode by identifying whether a person is in the night scenario; and using a corresponding exposure parameter to perform exposure control on the image to be acquired. The invention improves imaging quality of an image in a night scenario, and resolves the technical issue of low imaging quality caused by using only one type of shooting mode when shooting a night scenario.

Description

Exposure control method, device and electronic equipment

Cross-reference to related applications

This application claims the priority of Chinese Patent Application No. “201810963326.2” filed by OPPO Guangdong Mobile Communication Co., Ltd. on August 22, 2018, with the application name “Exposure Control Method, Device and Electronic Equipment”.

Technical field

The present application relates to the technical field of mobile terminals, and in particular, to an exposure control method, device, and electronic device.

Background technique

With the development of mobile terminal technology and image processing technology, people have higher and higher requirements for shooting. Even at night when the ambient light is dark, they also hope to obtain high-quality images. However, night scenes are more complicated and changeable than daytime scenes due to the intensity and location of the light source. Therefore, the shooting mode needs to be flexibly adjusted according to different night scenes to obtain high-quality images.

Summary of the Invention

This application is intended to solve at least one of the technical problems in the related technology.

For this reason, this application proposes an exposure control method that dynamically adjusts the applicable night scene mode by identifying whether there is a portrait in the night scene, and uses the corresponding exposure parameters to perform exposure control of the image to be acquired, which improves the image in the night scene. Imaging quality.

The application proposes an exposure control device.

The present application proposes an electronic device.

The present application proposes a computer-readable storage medium.

An embodiment of one aspect of the present application provides an exposure control method, including:

Determine that the current shooting scene is a night scene;

Perform face area recognition on the preview image, and identify the night scene mode applicable to the current shooting scene based on whether the face area is recognized;

Determining an exposure parameter of an image to be acquired in each frame according to the night scene mode;

The exposure parameter is used for exposure control.

An embodiment of another aspect of the present application provides an exposure control device, including:

A scene determination module, configured to determine that a current shooting scene belongs to a night scene scene;

A recognition module for recognizing a face area of a preview image, and identifying a night scene mode applicable to a current shooting scene according to whether a face area is recognized;

A parameter determining module, configured to determine an exposure parameter of an image to be acquired in each frame according to the night scene mode;

A control module, configured to perform exposure control by using the exposure parameter.

An embodiment of another aspect of the present application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the implementation is implemented as described above. Aspect of the exposure control method.

An embodiment of yet another aspect of the present application provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the exposure control method according to the foregoing aspect is implemented.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and / or additional aspects and advantages of this application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic flowchart of an exposure control method according to an embodiment of the present application;

2 is a schematic flowchart of another exposure control method according to an embodiment of the present application;

3 is a schematic flowchart of another exposure control method according to an embodiment of the present application;

4 is a schematic flowchart of still another exposure control method according to an embodiment of the present application;

5 is a schematic structural diagram of an exposure control apparatus according to an embodiment of the present application;

FIG. 6 is a schematic diagram of the internal structure of the electronic device 200 in one embodiment; and

FIG. 7 is a schematic diagram of an image processing circuit 90 in one embodiment.

detailed description

Hereinafter, embodiments of the present application will be described in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary, and are intended to explain the present application, and should not be construed as limiting the present application.

The exposure control method, device and electronic equipment according to the embodiments of the present application will be described below with reference to the drawings.

At present, in night scenes, most mobile terminals use a single night scene mode for shooting, but a single night scene mode cannot be applied to all night scenes, resulting in a problem of lower imaging quality. To this end, this application proposes an exposure control method, determining that the current shooting scene belongs to a night scene, performing face area recognition on the preview image, identifying whether a face area is recognized, identifying a night scene mode applicable to the current shooting scene, and according to the night scene mode, Determine the exposure parameters of the images to be collected for each frame, use the exposure parameters for exposure control, dynamically adjust the applicable night scene mode by identifying whether there is a portrait in the night scene, and use the corresponding exposure parameters for exposure control of the images to be collected, which improves the Imaging quality of images in night scenes.

FIG. 1 is a schematic flowchart of an exposure control method according to an embodiment of the present application.

As shown in Figure 1, the method includes the following steps:

Step 101: Determine that the current shooting scene belongs to a night scene.

As a possible implementation method, according to the current shooting scene, an image acquisition module is used to obtain a preview graphic of the current scene, image feature extraction is performed on the preview image, the extracted image features are input to a recognition model, and the current scene is determined according to the type of scene output by the recognition model. The shooting scene is a night scene, where the recognition model has learned to obtain the correspondence between the image features and the scene type.

As another possible implementation manner, a user operation for scene switching is detected, and when a user operation switched to a night scene is detected, the ambient brightness is detected to obtain brightness information. As a possible implementation manner, electronic The built-in light metering module detects the current ambient brightness and determines the brightness information of the current environment. According to the brightness information, it is determined that the current shooting scene belongs to a night scene. For example, the brightness index Lix_index can be used to measure the brightness level. The greater the value of the brightness information, the lower the brightness of the current scene. The ratio of the obtained brightness information to the preset brightness value is Yes, if the obtained brightness information is greater than a preset brightness value, it is determined that the current shooting scene belongs to a night scene. Further, if the obtained brightness information is less than a preset brightness value, it is determined that the current shooting scene belongs to a non-night scene, and in a non-night scene, imaging is performed in a high dynamic range mode, where high dynamic range imaging can be performed by setting different Exposure compensation value, to obtain a higher dynamic range. For example, 3 frames of images can be acquired, and the interval of the exposure compensation value is [-4, +1].

Step 102: Perform face area recognition on the preview image, and identify a night scene mode applicable to the current shooting scene according to whether the face area is recognized.

Specifically, face area recognition is performed on the preview image to identify whether the preview image contains a human face. As a possible implementation manner, a face detection algorithm may be adopted, for example, a skin detection-based face detection algorithm or a facial feature feature Face detection algorithm, etc., to detect the face interest area FACE ROI, identify the face area in the preview image, if there is a face area, the face interest area FACE ROI box is displayed, if it is not recognized, it is not displayed The face interest area FACE ROI box determines whether there is a face area in the preview image according to the recognition result.

Furthermore, if a face area is recognized, a night portrait mode is determined. If a face area is not recognized, a non-night portrait mode is determined. The portrait night mode and the non-night night mode use different exposure compensation values. This is because when the image processor performs post-processing on the image, it will increase the brightness of the face area based on the face brightening related algorithm. If the exposure is collected with normal exposure, the image will be superimposed with the later face brightening effect. The final image will have face brightness distortion. Therefore, in order to avoid this kind of brightness distortion, a lower exposure compensation value can be used in portrait night scene mode to offset all or part of the face brightening effect in the later stage.

Step 103: Determine the exposure parameters of the images to be collected in each frame according to the night scene mode.

Among them, the exposure parameters include exposure compensation value, sensitivity and exposure time.

Specifically, in the portrait night scene mode, the preset exposure compensation value of each frame to be acquired is determined from the corresponding first value range, and in the non portrait night scene mode, each frame is determined from the corresponding second value range. Preset exposure compensation value for the image to be acquired. The upper limit of the first value range is smaller than the upper limit of the second value range.

Further, according to the night scene mode, the preset sensitivity of each frame to be acquired is determined, the reference exposure amount is determined based on the brightness information of the preview image, and each frame is determined based on the reference exposure amount and the preset exposure compensation value of each frame to be acquired image. The target exposure of the image to be acquired is determined according to the target exposure of the image to be acquired in each frame and the preset sensitivity of the image to be acquired in each frame to determine the exposure time of the image to be acquired in each frame.

Step 104: Use exposure parameters to perform exposure control.

Specifically, according to the determined night scene mode, the exposure control is performed using the determined exposure parameters of the images to be acquired in each frame.

In the exposure control method in the embodiment of the present application, it is determined that the current shooting scene belongs to a night scene, and face area recognition is performed on the preview image. According to whether a face area is recognized, a night scene mode applicable to the current shooting scene is identified, and each of the night scene modes is determined according to the night scene mode. The exposure parameters of the frame to be captured are adjusted by using the exposure parameters. The night scene is identified to dynamically adjust the applicable night scene mode. The corresponding exposure parameters are used to control the exposure of the image to be collected, which improves the night scene. Imaging quality of the lower image.

Based on the previous embodiment, this embodiment provides another exposure control method, which illustrates that before the face area recognition of the preview image, the night scene mode needs to be determined according to the degree of jitter of the imaging device. FIG. 2 is the implementation of this application. The flow chart of another exposure control method provided by the example is shown in FIG. 2. Before step 102, the method may further include the following steps:

Step 201: Obtain the degree of shaking of the imaging device, and determine the night scene mode according to the degree of shaking.

The night scene mode determined according to the degree of shaking includes a portrait night scene mode or a non-portrait night scene mode, a single-frame night scene mode, and a tripod night scene mode.

Specifically, the collected displacement information is acquired from a sensor provided in the imaging device, and the degree of jitter of the imaging device is determined according to the displacement information. As a possible implementation manner, the sensor may be a gyroscope, and the gyroscope may output displacement information of three axes of x, y, and z. By acquiring the displacement information of the three axes of the gyroscope, the corresponding displacement of the three axes is obtained. The information takes an absolute value and is added and summed. The sum of the displacement information corresponding to the three axes is represented by S. The value of the displacement information S is used to indicate the degree of jitter of the imaging device.

In the embodiment of the present application, a preset dither threshold is determined, and the obtained dither degree is compared with a preset threshold to determine the current night scene mode. In order to distinguish the night scene mode, the dither threshold is divided into a first dither threshold and a second dither threshold. , Wherein the first jitter threshold is greater than the second jitter threshold. The night scene mode is determined according to the shake threshold, specifically: if the degree of shake is less than the first shake threshold and greater than the second shake threshold, the night scene mode may be determined according to the degree of shake using a portrait night scene mode or a non-portrait night scene mode; if the shake degree is greater than or equal to The first jitter threshold is determined to adopt a single-frame night scene mode; if the degree of jitter is less than or equal to the second jitter threshold, it is determined to use a tripod night scene mode. Among them, the number of frames of the image to be collected in the night scene mode is larger than the number of frames in the portrait night mode or the non-portrait night scene mode, and the number of frames of the image to be collected in the single frame night scene mode is less than that in the portrait night scene mode or the non-portrait night scene mode. number.

It should be noted that after determining the current night scene mode based on the degree of dithering, a portrait night scene mode or a non-portrait night scene mode can be used, and then the face image area can be further identified by identifying whether the preview image contains a face night scene mode or a non-night night scene mode. For details, refer to step 102 in the previous embodiment, and details are not described herein again. When the night scene mode can be determined by the degree of jitter, the tripod night scene mode can be used, because the tripod night scene mode has very little jitter, and the imaging device itself has an anti-shake elimination strategy, such as Optical Image Stabilization (OIS), etc. Therefore, the jitter in the tripod night scene mode is very small, so it can take a long time to obtain a high-quality picture, such as 1 minute. Even if a person appears in the image, it can't stay still for 1 minute. It does not distinguish whether or not a face area is included, that is, no special processing is performed even if a portrait is included. When the night scene mode is determined by the degree of dithering, the single-frame night scene mode can be used. Due to the large jitter, the single-frame night scene mode only uses a single frame acquisition and a single exposure measurement to shorten the exposure time and avoid blurs and ghosts. Therefore, It does not distinguish whether or not a face region is included.

In the exposure control method of the embodiment of the present application, it is determined that the current shooting scene belongs to a night scene, and the current night scene mode is determined according to the jitter situation. When it is determined that the current night scene mode is a portrait night scene mode or a non-portrait night scene mode, the preview is further performed. The image performs face area recognition, according to whether the face area is recognized, and the night scene mode applicable to the current shooting scene, and according to the night scene mode, the exposure parameters of each frame to be collected are determined, and the exposure parameters are used for exposure control. Whether there is a portrait, to dynamically adjust the applicable night scene mode and use the corresponding exposure parameters to control the exposure of the image to be collected, improving the imaging quality of the image in the night scene.

Based on the above embodiments, an embodiment of the present application further proposes an exposure control method, which further clearly explains how to determine the exposure parameters of the images to be collected in each frame according to the determined night scene mode or portrait night scene mode. 3 is a schematic flowchart of another exposure control method provided by an embodiment of the present application. As shown in FIG. 3, step 103 may further include the following sub-steps:

Step 1031, according to the night scene mode, determine the preset sensitivity of the image to be collected for each frame.

In the embodiment of the present application, the night scene mode is a portrait night scene mode or a non-portrait night scene mode, and the preset sensitivity iso of each image to be acquired in each frame in the portrait night scene mode or the non-portrait night scene mode is determined, for example, the preset sensitivity is 200 iso. The preset sensitivity value is small to prevent more noise from appearing in the captured image and improve the imaging quality of the image.

It should be noted that in this embodiment, the preset sensitivities of the images to be collected in each frame in the portrait night scene mode or the non-portrait night scene mode may be completely the same, or there may be minor differences. For example, in the portrait night scene mode, The preset sensitivity of each frame to be collected is 200iso, or the preset sensitivity of the first frame is 200iso, and subsequent frames are incremented by 5iso per frame. The value of the preset sensitivity is not limited in this embodiment.

Step 1032: Determine a preset exposure compensation value for each frame of the image to be acquired according to the night scene mode.

Specifically, based on different night scene modes, different preset exposure compensation values for each frame of the standby image are determined.

In one scene, if the night scene mode is portrait night scene mode, the preset exposure compensation value of each frame to be acquired is determined from the corresponding first value range. For example, in portrait night scene mode, the image to be acquired is set It is set to 7 frames, and the first value range corresponding to the exposure compensation value EV (Exposure Compensation Value) is [-6,0] EV, so that the preset exposure compensation values of the images to be collected for each frame are determined as: [-6 , -4, -2,0,0,0,0] EV.

In another scenario, if the night scene mode is a non-portrait night scene mode, the preset exposure compensation value of each frame to be acquired is determined from the corresponding second value range. For example, in a non-portrait night scene mode, the The acquired image is set to 7 frames, and the range of the exposure compensation value is set to [-6, + 1] EV. For example, for the 7 frames of image to be acquired, the corresponding exposure compensation value can be [-6, -3 , 0, + 1, + 1, + 1, + 1] EV.

It should be noted that in actual applications, the exposure compensation value can also be changed according to the ambient brightness and the captured image, and the exposure range can be reduced. For example, in the non-portrait night scene mode, the range of the exposure compensation value can be adjusted to [-5, + 1] EV.

Step 1033: Determine a reference exposure amount according to the brightness information of the preview image.

Specifically, the reference exposure amount is determined according to the brightness information of the preview image. As a possible implementation manner, the brightness information of the preview image corresponding to the current shooting scene is measured by the photometry module in the electronic device, and the set comparison value is used. Low sensitivity, convert the measured brightness information, determine the reference exposure, and set it to EVO. For example, the sensitivity measured by the photometry module is 500iso, the exposure time is 50 milliseconds (ms), and the target sensitivity If it is 100iso, the sensitivity obtained after conversion is 100iso, the exposure time is 250ms, and the sensitivity is 100iso and the exposure time is 250ms as the reference exposure amount EVO.

It should be noted that EVO is the reference exposure that is most suitable for the current night scene environment, but the reference exposure EVO is not a fixed value, but a value that changes according to the brightness information of the preview image. When the environment brightness changes, the preview The brightness information of the image will change, and the reference exposure EV0 will also change.

It should be noted that there is no timing difference between the execution of the

above steps

1031, 1032, and 1033.

Step 1034: Determine the target exposure amount of the image to be acquired for each frame according to the reference exposure amount and the preset exposure compensation value of the image to be acquired for each frame.

For example, in the portrait night scene mode, the corresponding preset exposure compensation values for the 7 frames of images to be acquired are -6EV, -4EV, -2EV, 0EV, 0EV, 0EV, and 0EV, respectively, where "+" indicates that it is being measured. Increase the exposure based on the reference exposure set by the light. "-" Means decrease exposure. The corresponding number is the number of steps to compensate for the exposure. According to the preset exposure compensation value and reference exposure for each frame of the image to be collected, determine the frame to be collected. Target exposure of the image. For example, if the exposure compensation value of a frame of image is -6EV, the number -6 is the number of steps to compensate the exposure, and the reference exposure is EVO, then the target exposure of the frame image is determined as EVO * 2 ^-6 , that is, EVO / 64, that is, reducing the brightness of the frame image acquisition; if the exposure compensation value of a frame image is 0EV, and the reference exposure is EVO, the target exposure of the frame image is determined as EVO * 1, that It is EVO, that is, the exposure is performed based on the reference exposure amount. Similarly, the method for confirming the target exposure amount of the images to be collected in other frames is the same, which is not listed here.

It should be noted that, in the non-portrait night scene mode, the determination method of the target exposure amount of the images to be collected in each frame is the same, and is not repeated here.

Step 1035: Determine the exposure duration of the image to be acquired in each frame according to the target exposure of the image to be acquired in each frame and the preset sensitivity of the image to be acquired in each frame.

In the embodiment of the present application, in the night scene mode, the aperture value is fixed when collecting each frame of images. For each image to be collected, the target exposure amount is determined by the sensitivity and the exposure duration. When the sensitivity is determined, The corresponding exposure time can be determined.

For example, the sensitivity IOS value and exposure time corresponding to the reference exposure are divided into: 100iso and 250ms, the preset sensitivity of a frame to be captured is 100iso, and the exposure compensation value is -4EV. Target exposure time is

That is 16ms, which means that the exposure time is reduced. Similarly, when the exposure compensation value is EV, the obtained exposure time is 250ms. Similarly, the exposure time of each frame can be determined. By setting a wider dynamic range, each frame of images to be collected is acquired with different exposure durations, so that the details of each part of the image can be clearly imaged under the control of different exposure durations, thereby improving Imaging effect.

In the embodiment of the present application, the minimum exposure duration supported by the shutter is 10 milliseconds (ms). In one possible scenario, when a relatively large amount of light illuminates the camera in the shooting scene, the metering device may mistakenly assume that the current scene light Brighter, so that the determined reference exposure is smaller, that is, the exposure duration corresponding to the reference exposure is shorter. Furthermore, when the exposure duration of each frame to be captured is calculated by using the reference exposure as EVO, it is easy to correspond to the exposure compensation value − At 6E, the calculated exposure time may be lower than the preset minimum exposure time of 10ms, such as 8ms, then increase the exposure time from 8ms to 10ms, and determine to increase the corresponding magnification compensation value to ensure that the darkest There is a certain shooting brightness in one frame. At the same time, the images to be collected in each frame are increased according to this magnification compensation value, so that the brightness of the obtained images to be collected increases linearly, so that the acquired images are synthesized in subsequent images. As a result, the transition of the halo is natural, improving the effect of the synthesized image.

In another possible scenario, when the environment is very dark, the maximum exposure duration of a single frame calculated with the reference exposure amount may be greater than the maximum value set for the exposure duration, for example, 5 seconds, for example, the The sensitivity is 100iso and the exposure time is 4 seconds. When the corresponding exposure compensation value is + 1EV, the preset sensitivity of the image to be captured is also 100iso. The calculated exposure time is 8 seconds, which exceeds the preset maximum of 5 Seconds, you need to reduce the exposure time of the frame to a preset maximum of 5 seconds, determine the reduction ratio, and adjust the sensitivity at this ratio to prevent the exposure time from being too long. After the longest exposure time is compressed If you also need to adjust the exposure amount during exposure, you can only increase the brightness of the shooting by appropriately increasing the sensitivity value, and the sensitivity value cannot exceed the upper limit of the preset sensitivity value, such as 550iso. Setting a larger sensitivity will increase the noise in the picture and reduce the imaging quality.

In the exposure control method in the embodiment of the present application, according to the night scene mode being a portrait night scene mode or a non-portrait night scene mode, a preset sensitivity and a preset exposure compensation value of each frame to be collected are determined, and the brightness information of the preview image is used to determine The reference exposure amount, according to the reference exposure amount, determines the target exposure amount corresponding to the image to be collected for each frame, and determines the exposure duration according to the target exposure amount and the preset sensitivity of the preset image to be collected for each frame, thereby determining each frame to be collected The exposure parameters of the image, by setting different exposure parameters in portrait night scene mode or non-portrait night scene mode, realize the dynamic adjustment of the exposure parameters when shooting night scenes, and improve the imaging quality of night scenes.

Based on the above embodiments, an embodiment of the present application further proposes an exposure control method. FIG. 4 is a schematic flowchart of another exposure control method provided by an embodiment of the present application. As shown in FIG. 4, after step 104, the method It can also include the following steps:

Step 401: Acquire each frame image collected under exposure control, and synthesize each frame image to obtain an imaging image.

Specifically, according to the determined exposure parameters of the images to be acquired for each frame, each frame image acquired under the control of the corresponding exposure parameter is acquired, and the acquired images are aligned to eliminate the influence of jitter, and at the same time, the image The moving objects in the image are detected to eliminate ghosting, and then the corresponding pixels in each frame image are weighted and synthesized to obtain a corresponding one frame target image. Because the exposure parameters used for each frame of the image acquired are different and correspond to different exposure durations, by combining the images of each frame, the dark portion of the final output imaging image can be obtained from the corresponding pixel information in the image with the longer exposure duration. For compensation, the bright part can be suppressed by the corresponding pixel information in the image with a shorter exposure time. Therefore, there is no over-exposed area and under-exposed area in the final composite imaging image, and the brightness of the image is excessively uniform, which has better imaging. effect. At the same time, during the synthesis process, the amplitude and position of the noise generated by the current are random. Therefore, when multiple images are superimposed and synthesized, the noise can be canceled each other, thereby improving the imaging quality.

In the exposure control method in the embodiment of the present application, it is determined that the current shooting scene belongs to a night scene, and face area recognition is performed on the preview image. According to whether a face area is recognized, a night scene mode applicable to the current shooting scene is identified, and each of the night scene modes is determined according to the night scene mode. The exposure parameters of the frame to be captured are adjusted by using the exposure parameters. The night scene is identified to dynamically adjust the applicable night scene mode. The corresponding exposure parameters are used to control the exposure of the image to be collected, which improves the night scene. The image quality of the image is reduced, and at the same time, multiple frames of image are synthesized to preserve the details of the highlights and the corresponding transitions, which improves the imaging effect.

In order to implement the above embodiments, the present application also proposes an exposure control device.

FIG. 5 is a schematic structural diagram of an exposure control apparatus according to an embodiment of the present application.

As shown in FIG. 5, the device includes a scene determination module 51, an identification module 52, a parameter determination module 53, and a control module 54.

The scene determining module 51 is configured to determine that a current shooting scene belongs to a night scene.

The recognition module 52 is configured to recognize a face area of the preview image, and identify a night scene mode applicable to the current shooting scene according to whether the face area is recognized.

A parameter determining module 53 is configured to determine an exposure parameter of an image to be acquired in each frame according to a night scene mode.

The control module 54 is configured to perform exposure control by using an exposure parameter.

Further, in a possible implementation manner of the embodiment of the present application, the apparatus further includes a determination module and a synthesis module.

The determining module is configured to obtain the degree of jitter of the imaging device, and determine that the degree of jitter is less than the first jitter threshold and greater than the second jitter threshold, where the first jitter threshold is greater than the second jitter threshold.

As a possible implementation manner, the determining module is further used for:

If the degree of jitter is greater than or equal to the first jitter threshold, it is determined that a single-frame night scene mode is adopted;

If the degree of jitter is less than or equal to the second jitter threshold, determine that a tripod night scene mode is adopted;

Among them, the number of frames of the image to be acquired in the tripod night scene mode is greater than the number of frames in the portrait night scene mode or the non-portrait night scene mode;

The number of frames to be captured in the single-frame night scene mode is smaller than the number of frames in the portrait night scene mode or the non-portrait night scene mode.

As a possible implementation manner, the determining module is further specifically used to:

Obtain the collected displacement information from the sensors set on the imaging device; and determine the degree of jitter of the imaging device based on the displacement information.

A synthesizing module is configured to acquire each frame image collected under exposure control; and synthesize each frame image to obtain an imaging image.

As a possible implementation manner, the foregoing identification module 52 is specifically configured to:

If a face area is identified, a portrait night scene mode is determined;

If no face area is identified, a non-portrait night scene mode is determined;

Among them, night portrait mode and non-night portrait mode use different exposure compensation values.

As a possible implementation manner, the parameter determining module 53 is specifically configured to:

In portrait night scene mode, the preset exposure compensation value of each frame to be acquired is determined from the corresponding first value range;

In the non-portrait night scene mode, the preset exposure compensation value of each frame to be acquired is determined from the corresponding second value range;

The upper limit of the first value range is smaller than the upper limit of the second value range.

Further, as a possible implementation manner, the above-mentioned parameter determining module 53 is further specifically configured to:

Determine the preset sensitivity of the image to be collected for each frame according to the night scene mode;

Determine the reference exposure based on the brightness information of the preview image;

Determining the target exposure amount of the image to be acquired for each frame according to the reference exposure amount and the preset exposure compensation value of the image to be acquired for each frame;

According to the target exposure amount of the images to be acquired in each frame and the preset sensitivity of the images to be acquired in each frame, the exposure time of the images to be acquired in each frame is determined.

As a possible implementation manner, the foregoing scenario determining module 51 is specifically configured to:

Detecting a user operation for scene switching; when detecting a user operation switching to a night scene, detecting the ambient brightness to obtain brightness information; and according to the brightness information, determining that the current shooting scene belongs to a night scene.

As a possible implementation manner, the foregoing scene determination module 51 is further specifically configured to: if it is determined that the current shooting scene belongs to a non-night scene according to the brightness information, and use a high dynamic range mode for imaging.

As another possible implementation manner, the foregoing scenario determination module 51 is further specifically configured to:

Extract the image features of the preview image; input the extracted image features into the recognition model, and determine that the current shooting scene belongs to the night scene according to the type of scene output by the recognition model; wherein the recognition model has learned to obtain the correspondence between the image features and the scene type.

It should be noted that the foregoing explanation of the method embodiment is also applicable to the device in this embodiment, and details are not described herein again.

In the exposure control device of the embodiment of the present application, it is determined that the current shooting scene belongs to a night scene, and the current night scene mode is determined through the shake situation, and the face area recognition is performed on the preview image. The night scene mode applicable to the shooting scene, according to the night scene mode, determine the exposure parameters of the frames to be captured, use the exposure parameters to perform exposure control, and dynamically adjust the applicable night scene mode by identifying whether there is a portrait in the night scene and use the corresponding exposure. The parameter controls the exposure of the image to be collected, which improves the imaging quality of the image in the night scene. At the same time, it combines multiple frames of images to retain the details of the highlights and the corresponding transitions, which improves the imaging effect.

In order to implement the foregoing embodiments, an embodiment of the present application further provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, The exposure control method according to the foregoing method embodiment is implemented.

FIG. 6 is a schematic diagram of the internal structure of the electronic device 200 in one embodiment. The electronic device 200 includes a processor 60, a memory 50 (for example, a non-volatile storage medium), an internal memory 82, a display screen 83, and an input device 84 connected through a system bus 81. The memory 50 of the electronic device 200 stores an operating system and computer-readable instructions. The computer-readable instructions can be executed by the processor 60 to implement the control method in the embodiment of the present application. The processor 60 is used to provide computing and control capabilities to support the operation of the entire electronic device 200. The internal memory 50 of the electronic device 200 provides an environment for execution of computer-readable instructions in the memory 52. The display screen 83 of the electronic device 200 may be a liquid crystal display or an electronic ink display. The input device 84 may be a touch layer covered on the display screen 83, or may be a button, a trackball, or a touch button provided on the housing of the electronic device 200. Board, which can also be an external keyboard, trackpad, or mouse. The electronic device 200 may be a mobile phone, a tablet computer, a notebook computer, a personal digital assistant, or a wearable device (for example, a smart bracelet, a smart watch, a smart helmet, or smart glasses). Those skilled in the art can understand that the structure shown in FIG. 6 is only a schematic diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the electronic device 200 to which the solution of the present application is applied. The specific electronic device 200 may include more or fewer components than shown in the figure, or some components may be combined, or have different component arrangements.

Please refer to FIG. 7. The electronic device 200 according to the embodiment of the present application includes an image processing circuit 90. The image processing circuit 90 may be implemented by using hardware and / or software components, including various types of defining an ISP (Image Signal Processing) pipeline. Processing unit. FIG. 7 is a schematic diagram of an image processing circuit 90 in one embodiment. As shown in FIG. 7, for ease of description, only aspects of the image processing technology related to the embodiments of the present application are shown.

As shown in FIG. 7, the image processing circuit 90 includes an ISP processor 91 (the ISP processor 91 may be the processor 60) and a control logic 92. The image data captured by the camera 93 is first processed by the ISP processor 91. The ISP processor 91 analyzes the image data to capture image statistical information that can be used to determine one or more control parameters of the camera 93. The camera 93 may include one or more lenses 932 and an image sensor 934. The image sensor 934 may include a color filter array (such as a Bayer filter). The image sensor 934 may obtain light intensity and wavelength information captured by each imaging pixel, and provide a set of raw image data that can be processed by the ISP processor 91. The sensor 94 (such as a gyroscope) may provide parameters (such as image stabilization parameters) of the acquired image processing to the ISP processor 91 based on the interface type of the sensor 94. The sensor 94 interface may be a SMIA (Standard Mobile Imaging Architecture) interface, other serial or parallel camera interfaces, or a combination of the foregoing interfaces.

In addition, the image sensor 934 may also send the original image data to the sensor 94. The sensor 94 may provide the original image data to the ISP processor 91 based on the interface type of the sensor 94, or the sensor 94 stores the original image data into the image memory 95.

The ISP processor 91 processes the original image data pixel by pixel in a variety of formats. For example, each image pixel may have a bit depth of 8, 10, 12, or 14 bits, and the ISP processor 91 may perform one or more image processing operations on the original image data and collect statistical information about the image data. The image processing operations may be performed with the same or different bit depth accuracy.

The ISP processor 91 may also receive image data from the image memory 95. For example, the sensor 94 interface sends the original image data to the image memory 95, and the original image data in the image memory 95 is then provided to the ISP processor 91 for processing. The image memory 95 may be an independent dedicated memory in the memory 50, a part of the memory 50, a storage device, or an electronic device, and may include a DMA (Direct Memory Access) feature.

When receiving raw image data from the image sensor 934 interface or from the sensor 94 interface or from the image memory 95, the ISP processor 91 may perform one or more image processing operations, such as time-domain filtering. The processed image data may be sent to the image memory 95 for further processing before being displayed. The ISP processor 91 receives processing data from the image memory 95, and performs processing on the image data in the original domain and in the RGB and YCbCr color spaces. The image data processed by the ISP processor 91 may be output to a display 97 (the display 97 may include a display screen 83) for viewing by a user and / or further processing by a graphics engine or a GPU (Graphics Processing Unit). In addition, the output of the ISP processor 91 can also be sent to the image memory 95, and the display 97 can read image data from the image memory 95. In one embodiment, the image memory 95 may be configured to implement one or more frame buffers. In addition, the output of the ISP processor 91 may be sent to an encoder / decoder 96 to encode / decode image data. The encoded image data can be saved and decompressed before being displayed on the display 97 device. The encoder / decoder 96 may be implemented by a CPU or a GPU or a coprocessor.

The statistical data determined by the ISP processor 91 may be sent to the control logic unit 92. For example, the statistical data may include image information of the image sensor 934 such as auto exposure, auto white balance, auto focus, flicker detection, black level compensation, and lens 932 shading correction. The control logic 92 may include a processing element and / or a microcontroller that executes one or more routines (such as firmware). The one or more routines may determine the control parameters of the camera 93 and the ISP processor according to the received statistical data. 91 control parameters. For example, the control parameters of the camera 93 may include sensor 94 control parameters (such as gain, integration time for exposure control, anti-shake parameters, etc.), camera flash control parameters, lens 932 control parameters (such as focus distance for focusing or zooming), or these parameters The combination. The ISP control parameters may include gain levels and color correction matrices for automatic white balance and color adjustment (eg, during RGB processing), and lens 932 shading correction parameters.

For example, the following are the steps of implementing the exposure control method by using the processor 60 in FIG. 6 or the image processing circuit 90 (specifically, the ISP processor 91) in FIG. 7:

01: Make sure the current shooting scene belongs to night scene;

02: Perform face area recognition on the preview image, and identify the night scene mode applicable to the current shooting scene based on whether the face area is recognized;

03: Determine the exposure parameters of the images to be collected in each frame according to the night scene mode;

04: Use exposure parameters for exposure control.

In order to implement the foregoing embodiment, an embodiment of the present application further provides a computer-readable storage medium on which a computer program is stored. When instructions in the storage medium are executed by a processor, the implementation is implemented as in the foregoing method embodiment. The exposure control method described above.

In the description of this specification, the description with reference to the terms “one embodiment”, “some embodiments”, “examples”, “specific examples”, or “some examples” and the like means specific features described in conjunction with the embodiments or examples , Structure, material, or characteristic is included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. In addition, without any contradiction, those skilled in the art may combine and combine different embodiments or examples and features of the different embodiments or examples described in this specification.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality" is at least two, for example, two, three, etc., unless it is specifically and specifically defined otherwise.

Any process or method description in a flowchart or otherwise described herein can be understood as representing a module, fragment, or portion of code that includes one or more executable instructions for implementing steps of a custom logic function or process And, the scope of the preferred embodiments of this application includes additional implementations in which the functions may be performed out of the order shown or discussed, including performing the functions in a substantially simultaneous manner or in the reverse order according to the functions involved. It is understood by those skilled in the art to which the embodiments of the present application pertain.

Logic and / or steps represented in a flowchart or otherwise described herein, for example, a sequenced list of executable instructions that may be considered to implement a logical function, may be embodied in any computer-readable medium, For use by, or in combination with, an instruction execution system, device, or device (such as a computer-based system, a system that includes a processor, or another system that can fetch and execute instructions from an instruction execution system, device, or device) Or equipment. For the purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: electrical connections (electronic devices) with one or more wirings, portable computer disk cartridges (magnetic devices), random access memory (RAM), Read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program can be printed, because, for example, by optically scanning the paper or other medium, followed by editing, interpretation, or other suitable Processing to obtain the program electronically and then store it in computer memory.

It should be understood that each part of the application may be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods may be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it may be implemented using any one or a combination of the following techniques known in the art: Discrete logic circuits with logic gates for implementing logic functions on data signals Logic circuits, ASICs with suitable combinational logic gate circuits, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc.

A person of ordinary skill in the art can understand that all or part of the steps carried by the methods in the foregoing embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium. The program is When executed, one or a combination of the steps of the method embodiment is included.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing module, or each unit may exist separately physically, or two or more units may be integrated into one module. The above integrated modules may be implemented in the form of hardware or software functional modules. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

The aforementioned storage medium may be a read-only memory, a magnetic disk, or an optical disk. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limitations on the present application. Those skilled in the art may, within the scope of the present application, understand the above. Embodiments are subject to change, modification, substitution, and modification.

Claims

An exposure control method, characterized in that the method includes the following steps:

Determine that the current shooting scene is a night scene;

Perform face area recognition on the preview image, and identify the night scene mode applicable to the current shooting scene based on whether the face area is recognized;

Determining an exposure parameter of an image to be acquired in each frame according to the night scene mode;

The exposure parameter is used for exposure control.
The exposure control method according to claim 1, wherein the identifying a night scene mode applicable to a current shooting scene according to whether a human face area is recognized comprises:

If a face area is identified, a portrait night scene mode is determined;

If no face area is identified, a non-portrait night scene mode is determined;

Wherein, the portrait night scene mode and the non- portrait night scene mode use different exposure compensation values.
The exposure control method according to claim 2, wherein the exposure parameter includes an exposure compensation value, and determining the exposure parameter of each frame to be acquired according to the night scene mode comprises:

In the portrait night scene mode, determining a preset exposure compensation value for each frame of images to be acquired from a corresponding first value range;

In the non-portrait night scene mode, determining a preset exposure compensation value for each frame of images to be acquired from a corresponding second value range;

The upper limit of the first value range is smaller than the upper limit of the second value range.
The exposure control method according to any one of claims 1 to 3, wherein before performing face area recognition on the preview image, further comprising:

Obtain the degree of jitter of the imaging device;

Determining that the degree of jitter is less than a first jitter threshold and greater than a second jitter threshold;

The first jitter threshold is greater than the second jitter threshold.
The exposure control method according to claim 4, wherein after the obtaining the degree of jitter of the imaging device, further comprising:

If the degree of jitter is greater than or equal to the first jitter threshold, determining that a single-frame night scene mode is adopted;

If the degree of jitter is less than or equal to the second jitter threshold, determining to use a tripod night scene mode;

Wherein, the number of frames of the image to be collected in the tripod night scene mode is greater than the number of frames in the portrait night scene mode or the non-personal night scene mode;

The number of frames of the image to be collected in the single-frame night scene mode is smaller than the number of frames in the portrait night scene mode or the non-personal night scene mode.
The method for controlling exposure according to claim 3, wherein determining an exposure parameter of an image to be acquired in each frame according to the night scene mode further comprises:

Determining, according to the night scene mode, a preset sensitivity of the image to be collected in each frame;

Determining a reference exposure amount according to the brightness information of the preview image;

Determining the target exposure amount of the image to be acquired for each frame according to the reference exposure amount and the preset exposure compensation value of the image to be acquired for each frame;

According to the target exposure amount of the images to be acquired in each frame and the preset sensitivity of the images to be acquired in each frame, the exposure time of the images to be acquired in each frame is determined.
The exposure control method according to claim 4 or 5, wherein the obtaining the degree of jitter of the imaging device comprises:

Obtain the collected displacement information from the sensors set by the imaging equipment;

According to the displacement information, a degree of shaking of the imaging device is determined.
The exposure control method according to any one of claims 1 to 7, wherein after the performing exposure control by using the exposure parameter, further comprising:

Acquiring each frame image acquired under the exposure control;

The images of each frame are synthesized to obtain an imaging image.
The exposure control method according to any one of claims 1 to 7, wherein the determining that a current shooting scene belongs to a night scene scene comprises:

Performing image feature extraction on the preview image;

The extracted image features are input to a recognition model, and the current shooting scene is determined to be a night scene according to the type of scene output by the recognition model; wherein the recognition model has learned to obtain the correspondence between the image features and the scene type.
The exposure control method according to any one of claims 1 to 7, wherein the determining that a current shooting scene belongs to a night scene scene comprises:

Detect user operations for scene switching;

When a user operation that switches to a night scene is detected, the ambient brightness is detected to obtain brightness information;

According to the brightness information, it is determined that the current shooting scene belongs to a night scene.
The exposure control method according to claim 10, wherein after detecting the ambient brightness to obtain the brightness information, the method further comprises:

If it is determined that the current shooting scene belongs to a non-night scene according to the brightness information, imaging is performed in a high dynamic range mode.
An exposure control device, characterized in that the device includes:

A scene determination module, configured to determine that a current shooting scene belongs to a night scene scene;

A recognition module for recognizing a face area of a preview image, and identifying a night scene mode applicable to a current shooting scene according to whether a face area is recognized;

A parameter determining module, configured to determine an exposure parameter of an image to be acquired in each frame according to the night scene mode;

A control module, configured to perform exposure control by using the exposure parameter.
The exposure control device according to claim 12, wherein the identification module is specifically configured to:

If a face area is identified, a portrait night scene mode is determined;

If no face area is identified, a non-portrait night scene mode is determined;

Wherein, the portrait night scene mode and the non- portrait night scene mode use different exposure compensation values.
The exposure control device according to claim 13, wherein the exposure parameter includes an exposure compensation value, and the parameter determination module is specifically configured to:

In the portrait night scene mode, determining a preset exposure compensation value for each frame of images to be acquired from a corresponding first value range;

In the non-portrait night scene mode, determining a preset exposure compensation value for each frame of images to be acquired from a corresponding second value range;

The upper limit of the first value range is smaller than the upper limit of the second value range.
The exposure control device according to any one of claims 12 to 14, wherein the device further comprises:

A determining module is configured to obtain a degree of jitter of the imaging device; determine that the degree of jitter is less than a first jitter threshold and greater than a second jitter threshold; wherein the first jitter threshold is greater than the second jitter threshold.
The exposure control device according to claim 15, wherein the determining module is further configured to:

If the degree of jitter is greater than or equal to the first jitter threshold, determining that a single-frame night scene mode is adopted;

If the degree of jitter is less than or equal to the second jitter threshold, determining to use a tripod night scene mode;

Wherein, the number of frames of the image to be collected in the tripod night scene mode is greater than the number of frames in the portrait night scene mode or the non-personal night scene mode;

The number of frames of the image to be collected in the single-frame night scene mode is smaller than the number of frames in the portrait night scene mode or the non-personal night scene mode.
The exposure control device according to claim 14, wherein the parameter determining module is further configured to:

Determining, according to the night scene mode, a preset sensitivity of the image to be collected in each frame;

Determining a reference exposure amount according to the brightness information of the preview image;

Determining the target exposure amount of the image to be acquired for each frame according to the reference exposure amount and the preset exposure compensation value of the image to be acquired for each frame;

According to the target exposure of the image to be acquired in each frame and the preset sensitivity of the image to be acquired in each frame, the exposure time of the image to be acquired in each frame is determined.
The exposure control device according to claim 15 or 16, wherein the determining module is further configured to:

Obtain the collected displacement information from the sensors set by the imaging equipment;

According to the displacement information, a degree of shaking of the imaging device is determined.
An electronic device, comprising: a memory, a processor, and a computer program stored in the memory and operable on the processor. When the processor executes the program, the processor implements any of claims 1-11. A method for controlling exposure.
A computer-readable storage medium having stored thereon a computer program, characterized in that when the program is executed by a processor, the exposure control method according to any one of claims 1-11 is implemented.