US-20260129305-A1 - METHODS AND SYSTEMS FOR VIDEO ACQUISITION

Abstract

Some embodiments of the present disclosure provide a method for video acquisition. The method may be implemented by a computing device including at least one processor and a storage device, and the method may include: obtaining a first exposure parameter corresponding to a first image frame acquired by a video acquisition device; obtaining a second exposure parameter used by the video acquisition device to acquire a second image frame, wherein the second exposure parameter is smaller than the first exposure parameter; adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device, wherein the target exposure parameter matches the first exposure parameter; and causing, based on the target exposure parameter, the video acquisition device to acquire a target image frame.

Inventors

• Lei Liu
• Jianmiao WANG
• Feiyue ZHU
• Guo Chen

Assignees

• ZHEJIANG DAHUA TECHNOLOGY CO., LTD.

Dates

Publication Date

20260507

Application Date

20251230

Priority Date

20230720

Claims (20)

1. 1 . A method implemented by a computing device including at least one processor and a storage device for video acquisition, comprising: obtaining a first exposure parameter of a video acquisition device when the video acquisition device acquires a first image frame; obtaining a second exposure parameter used by the video acquisition device to acquire a second image frame, wherein the second exposure parameter is smaller than the first exposure parameter; adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device, wherein the target exposure parameter matches the first exposure parameter; and causing, based on the target exposure parameter, the video acquisition device to acquire a target image frame.
2. 2 . The method of claim 1 , wherein the adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device includes: obtaining a step size for adjusting the exposure parameter lower limit of the video acquisition device; and adjusting the exposure parameter lower limit based on the step size.
3. 3 . The method of claim 2 , wherein the obtaining the step size for adjusting the exposure parameter lower limit of the video acquisition device includes: determining the step size based on a distance between a target subject entering into a monitoring region of the video acquisition device and the video acquisition device.
4. 4 . The method of claim 2 , wherein the obtaining the step size for adjusting the exposure parameter lower limit of the video acquisition device includes: determining, based on a reference image frame, a reflectivity level of a target subject entering into a monitoring region of the video acquisition device; and determining the step size based on the reflectivity level.
5. 5 . The method of claim 4 , wherein the determining, based on a reference image frame, a reflectivity level of a target subject entering into a monitoring region of the video acquisition device includes: determining the reflectivity level of the target subject based on pixel information of a region in the reference image frame corresponding to the target subject and/or pixel information of the reference image frame.
6. 6 . The method of claim 5 , wherein the determining the reflectivity level of the target subject based on pixel information of a region in the reference image frame corresponding to the target subject and/or pixel information of the reference image frame includes: dividing the reference image frame into at least one image block; determining one or more target image blocks to which the target subject belongs, wherein the one or more target image blocks corresponds to the region in the reference image frame corresponding to the target subject; and determining the reflectivity level of the target subject based on pixel information of the one or more target image blocks and/or the pixel information of the reference image frame.
7. 7 . The method of claim 6 , wherein the determining the reflectivity level of the target subject based on pixel information of the one or more target image blocks and/or the pixel information of the reference image frame includes: in response to determining that the reference image frame is a color image, determining a brightness variance of the one or more target image blocks based on the pixel information of the one or more target image blocks and the pixel information of the reference image frame; and determining the reflectivity level of the target subject based on the brightness variance of the one or more target image blocks.
8. 8 . The method of claim 6 , wherein the determining the reflectivity level of the target subject based on pixel information of the one or more target image blocks and/or the pixel information of the reference image frame includes: in response to determining that the reference image frame is a black and white image, determining a similarity level between pixel information of each of the one or more target image blocks and pixel information of the reference image frame under a pure infrared light source; and determining, based on a count of image blocks in the one or more target image blocks that satisfy a similarity condition and a count of the one or more target image blocks, the reflectivity level of the target subject.
9. 9 . The method of claim 1 , wherein the adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device includes: adjusting the exposure parameter of the video acquisition device from the second exposure parameter to the target exposure parameter by iteratively increasing the exposure parameter lower limit until a termination condition is satisfied, after each increase in the exposure parameter lower limit, an intermediate exposure parameter lower limit, an intermediate exposure parameter, and an intermediate image frame being determined, wherein the termination condition includes the intermediate exposure parameter being equal to the first exposure parameter, or a brightness of the intermediate image frame being equal to a brightness of the first image frame.
10. 10 . The method of claim 9 , wherein the second exposure parameter is greater than the exposure parameter lower limit, and the increase of the exposure parameter lower limit includes a first stage and a second stage; in the first stage, the intermediate exposure parameter lower limit is less than or equal to the second exposure parameter; and in the second stage, the intermediate exposure parameter lower limit is greater than the second exposure parameter, and a difference between two adjacent intermediate exposure parameter lower limits in the first stage is greater than a difference between two adjacent intermediate exposure parameter lower limits in the second stage.
11. 11 . The method of claim 1 , wherein the adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device includes: adjusting the exposure parameter of the video acquisition device from the second exposure parameter to the target exposure parameter by iteratively increasing the exposure parameter lower limit until a termination condition is satisfied, an intermediate exposure parameter lower limit and an intermediate exposure parameter being determined after each increase in the exposure parameter lower limit; wherein the method further comprises: after each increase in the exposure parameter lower limit, obtaining an intermediate image frame acquired by the video acquisition device based on the intermediate exposure parameter; determining whether a brightness of the intermediate image frame is greater than a target brightness of the video acquisition device; in response to determining that the brightness of the intermediate image frame is greater than the target brightness, reducing a brightness gain of the video acquisition device so that the brightness of the intermediate image frame is not greater than the target brightness.
12. 12 . The method of claim 11 , wherein the termination condition includes the brightness gain of the video acquisition device being equal to 0 dB.
13. 13 . The method of claim 1 , further comprising: determining whether the first exposure parameter is greater than a threshold; and in response to determining that the first exposure parameter is greater than the threshold, executing a method comprising: obtaining the second exposure parameter used by the video acquisition device to acquire the second image frame, wherein the second exposure parameter is smaller than the first exposure parameter; adjusting the exposure parameter of the video acquisition device from the second exposure parameter to the target exposure parameter by adjusting the exposure parameter lower limit of the video acquisition device, wherein the target exposure parameter matches the first exposure parameter; and causing, based on the target exposure parameter, the video acquisition device to acquire the target image frame.
14. 14 . The method of claim 1 , wherein a difference between a brightness of the target image frame and a brightness of the first image frame is less than a brightness threshold.
15. 15 . (canceled)
16. 16 . A device for video acquisition, comprising a processor, wherein the processor executes a recognition program, and the recognition program, when executed, performs the method for video acquisition, wherein the method includes: obtaining a first exposure parameter of a video acquisition device when the video acquisition device acquires a first image frame; obtaining a second exposure parameter used by the video acquisition device to acquire a second image frame, wherein the second exposure parameter is smaller than the first exposure parameter; adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device, wherein the target exposure parameter matches the first exposure parameter; and causing, based on the target exposure parameter, the video acquisition device to acquire a target image frame.
17. 17 . A non-transitory computer-readable storage medium storing one or more computer instructions, wherein when a computer reads the one or more computer instructions from the storage medium, the computer executes the method for video acquisition, wherein the method includes: obtaining a first exposure parameter of a video acquisition device when the video acquisition device acquires a first image frame; obtaining a second exposure parameter used by the video acquisition device to acquire a second image frame, wherein the second exposure parameter is smaller than the first exposure parameter; adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device, wherein the target exposure parameter matches the first exposure parameter; and causing, based on the target exposure parameter, the video acquisition device to acquire a target image frame.
18. 18 . The method of claim 1 , wherein the first exposure parameter and the second exposure parameter are values of the exposure parameter of the video acquisition device at different time periods.
19. 19 . The method of claim 2 , wherein the step size refers to the amount of adjustment for each adjustment of the exposure parameter lower limit.
20. 20 . The method of claim 3 , wherein the distance between the target subject entering into the monitoring region of the video acquisition device and the video acquisition device is directly proportional to the step size.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Continuation of International Application No. PCT/CN2024/091548, filed on May 7, 2024, which claims priority of Chinese Patent Application No. 202310897660.3 filed on Jul. 20, 2023, the entire contents of each of which are hereby incorporated by reference. TECHNICAL FIELD The present disclosure relates to the field of video surveillance, and in particular, to methods and systems for video acquisition. BACKGROUND With the development of video acquisition devices, more and more monitoring functions have been developed. A video acquisition device may detect an intruding object in a monitoring region and control a flashlight to flash to alert against the intruding object. However, the flashing of the flashlight may also interfere with an image acquisition process of the video acquisition device. A current solution for eliminating the interference of the flashing of the flashlight may be to shorten an exposure time and increase an exposure interval between two adjacent image frames of the video acquisition device, allowing the flashlight to flash during the exposure interval to prevent the video acquisition device from capturing the flashing of the flashlight during exposure. However, shortening the exposure time may result in a subsequent image frame being darker than previous image frames acquired before flashing of the flashlight. Even though conventional methods for exposure recovery may increase the brightness gain of the current image or adjust the exposure time of the video acquisition device, it is difficult to avoid reducing the quality of the subsequent image frame. Therefore, it is desirable to provide a method and a system for video acquisition to ensure image quality while achieving exposure recovery and improving video acquisition effectiveness. SUMMARY One embodiment of the present disclosure provides a method for video acquisition. The method may be implemented by a computing device including at least one processor and a storage device, and the method may include: obtaining a first exposure parameter of a video acquisition device when the video acquisition device acquires a first image frame; obtaining a second exposure parameter used by the video acquisition device to acquire a second image frame, wherein the second exposure parameter is smaller than the first exposure parameter; adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device, wherein the target exposure parameter matches the first exposure parameter; and causing, based on the target exposure parameter, the video acquisition device to acquire a target image frame. In some embodiments, the adjusting an exposure parameter of the video acquisition device from the second exposure parameter to a target exposure parameter by adjusting an exposure parameter lower limit of the video acquisition device may include: obtaining a step size for adjusting the exposure parameter lower limit of the video acquisition device, and adjusting the exposure parameter lower limit based on the step size. In some embodiments, the obtaining the step size for adjusting the exposure parameter lower limit of the video acquisition device may include: determining the step size based on a distance between a target subject entering into a monitoring region of the video acquisition device and the video acquisition device. In some embodiments, the obtaining the step size for adjusting the exposure parameter lower limit of the video acquisition device may include: determining, based on a reference image frame, a reflectivity level of a target subject entering into a monitoring region of the video acquisition device, and determining the step size based on the reflectivity level. In some embodiments, the determining, based on a reference image frame, a reflectivity level of a target subject entering into a monitoring region of the video acquisition device may include: determining the reflectivity level of the target subject based on pixel information of a region in the reference image frame corresponding to the target subject and/or pixel information of the reference image frame. In some embodiments, the determining the reflectivity level of the target subject based on pixel information of a region in the reference image frame corresponding to the target subject and/or pixel information of the reference image frame may include: dividing the reference image frame into at least one image block; determining one or more target image blocks to which the target subject belongs, wherein the one or more target image blocks corresponds to the region in the reference image frame corresponding to the target subject; and determining the reflectivity level of the target subject based on pixel information of the one or more target image blocks and/or the pixel information of th