Camera Auto-Focusing with Dynamic Light Source Correction
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Solution Overview
Problem
Existing auto-focusing methods in cameras with dynamic light sources are affected by changes in brightness, leading to inaccurate focusing evaluation functions and image blurring, as evidenced by multiple peaks in the focusing evaluation curve rather than a single peak, which compromises image clarity.
Innovation Solution
The method involves dividing the image into sub-regions, calculating focusing evaluation values and their changing rates, and correcting values affected by dynamic light sources using a correction factor based on adjacent regions to ensure a single peak in the focusing evaluation curve, thereby minimizing the influence of dynamic light sources on the auto-focusing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a focusing evaluation function is designed to maximize image information and details, then image clarity is improved, but the evaluation function becomes sensitive to brightness changes from dynamic light sources, causing multiple peaks in the evaluation curve
Solution Approach 1:
The patent divides the image into multiple sub-regions (e.g., left, right, center regions) and calculates focusing evaluation values separately for each sub-region. This segmentation allows the system to identify and exclude regions affected by dynamic light sources from the overall evaluation, preventing brightness changes from creating false peaks in the focusing evaluation curve.
Solution Approach 2:
The patent applies different evaluation strategies to different regions of the image based on their local characteristics. Regions with dynamic light sources are identified and handled differently (through exclusion or correction) compared to stable regions, allowing each region to contribute appropriately to the overall focusing evaluation without being skewed by local brightness variations.
2Ease of operation
If the focusing evaluation function uses brightness information to determine focus quality, then focus detection is simplified, but dynamic light sources create false peaks that reduce focusing accuracy
Solution Approach 1:
By segmenting the image into sub-regions and calculating focusing evaluation values independently for each region, the system maintains the simplicity of brightness-based evaluation while preventing dynamic light sources from creating false peaks. The segmented approach allows selective inclusion or exclusion of regions based on their stability.
Solution Approach 2:
The patent incorporates feedback mechanisms to detect and correct the influence of dynamic light sources. By monitoring brightness changes and comparing them with focusing evaluation values, the system can identify when dynamic light sources are present and adjust the evaluation accordingly, maintaining both simplicity and accuracy.
3Productivity
If the entire image is used for focusing evaluation, then the evaluation process is simple and fast, but regions affected by dynamic light sources distort the evaluation curve
Solution Approach 1:
The patent segments the image into multiple sub-regions and calculates focusing evaluation values for each segment independently. This segmentation enables the system to process the image in parallel and maintain speed while filtering out the distorting influence of dynamic light sources from regions that would otherwise corrupt the overall evaluation.
Solution Approach 2:
The patent extracts or removes regions affected by dynamic light sources from the overall focusing evaluation. By identifying these regions and excluding them or applying correction factors, the system maintains evaluation reliability without sacrificing the speed of processing the entire image.
Data Source
AI summary
The present disclosure provides a method for calculating a focusing evaluation value. The method may be applied in a scene having a dynamic light source and include: dividing an image region of a camera into a plurality of sub-regions; selecting a first sub-region which is affected by a dynamic light source from the plurality of sub-regions; correcting a focusing evaluation value of the first sub-region with the focusing evaluation value of each of sub-regions adjacent to the first sub-region; and calculating a focusing evaluation value of the whole image region based on the focusing evaluation value of each of the sub-regions. The present disclosure improves the performance of auto-focusing in a scene having a dynamic light source.