Automatic Exposure Control Using Multi-Frame Luminance Analysis
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Solution Overview
Problem
Existing automatic exposure control methods in video surveillance systems often result in inappropriate exposure parameters for frames other than the one evaluated, leading to increased synthetic noise and poor image quality due to the use of constant exposure ratios that do not match different scenes.
Innovation Solution
A system and method that adjust exposure parameters by analyzing both a long-exposure frame and a short-exposure frame, determining dynamic range based on the brightest and darkest regions of each, and calculating total luminance to set appropriate exposure parameters for both frames, reducing synthetic noise and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only one frame of the current scene is used for evaluating luminance, then the evaluation process is simple, but the exposure parameters are only appropriate for that one frame and inappropriate for other frames
Solution Approach 1:
The patent combines multiple frames (first frame and second frame with different exposure times) into a unified exposure evaluation process. By merging the luminance information from both frames, the system determines exposure parameters that are appropriate for the entire sequence of frames rather than just a single frame, resolving the contradiction between simplicity and adaptability.
Solution Approach 2:
The patent introduces dynamic adjustment of exposure parameters based on the luminance characteristics of multiple frames. The exposure parameters are dynamically determined considering the luminance of both the first and second frames, allowing the system to adapt to different scene conditions while maintaining a relatively simple evaluation process.
2Device complexity
If a constant exposure ratio of long-exposure frame to short-exposure frame is used, then the determination process is simple, but the constant exposure ratio cannot match with different scenes and results in increasing synthetic noise and poor image quality
Solution Approach 1:
The patent changes the exposure ratio parameter dynamically based on scene luminance characteristics. Instead of using a constant exposure ratio, the system determines an optimal exposure ratio by evaluating the luminance of multiple frames and their darkest/brightest regions, thereby matching different scene conditions and reducing synthetic noise while maintaining reasonable determination process complexity.
Data Source
AI summary
The present disclosure relates to systems and methods for automatic exposure control. The methods may include obtaining a first frame and a second frame of a current scene from a camera, wherein a ratio of a first exposure time of the first frame to a second exposure time of the second frame is a first exposure ratio; obtaining a first average luminance of a brightest region in the second frame; obtaining a second average luminance of a darkest region in the first frame; and determining a dynamic range of the current scene based on the first exposure ratio, the first average luminance, and the second average luminance.