Image Processing Device Iterative Histogram Clipping for Brightness Control
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Solution Overview
Problem
Existing image enhancement methods, such as classical histogram equalization, often over-enhance image noise and overall brightness, failing to effectively improve image brightness, contrast, and detail for applications like video surveillance and facial recognition.
Innovation Solution
An image processing method and device that receive a to-be-processed image, calculate its target brightness, create a histogram curve, clip it according to a clipping value, obtain a mapping function, and adjust the clipping value iteratively until the difference between the target and average brightness is less than a threshold, ensuring optimal image enhancement without over-enhancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If classical histogram equalization is used for image enhancement, then image brightness and contrast are improved, but image noise is over-enhanced
Solution Approach 1:
The patent modifies the traditional histogram equalization algorithm by introducing a clipping mechanism that changes the parameter range of histogram processing. By clipping the histogram curve at specific thresholds, the method selectively enhances certain brightness ranges while suppressing noise in other ranges, thus improving brightness without over-enhancing noise
Solution Approach 2:
The patent implements an iterative feedback mechanism where the clipping values are dynamically adjusted based on the comparison between target brightness and actual average brightness of the enhanced image. This feedback loop allows the system to automatically optimize the enhancement parameters to achieve desired brightness while controlling noise amplification
2Illumination intensity
If classical histogram equalization is used for image enhancement, then overall brightness is improved, but brightness uniformity deteriorates
Solution Approach 1:
The patent introduces clipping parameters that modify the histogram distribution shape, transforming the aggressive equalization curve into a more controlled mapping function. This parameter adjustment ensures brightness improvement while maintaining more uniform distribution across different regions of the image
3Manufacturing precision
If iterative adjustment of clipping value is implemented, then image enhancement quality is improved, but processing time increases
Solution Approach 1:
The patent uses a feedback-based iterative adjustment mechanism that compares the actual average brightness with the target brightness and dynamically modifies clipping values accordingly. This structured feedback approach converges to an optimal solution efficiently, balancing enhancement quality with processing time by avoiding unnecessary iterations
Solution Approach 2:
The patent implements a threshold-based stopping criterion that terminates the iterative process when the brightness difference falls below a predetermined threshold. This partial action principle prevents excessive iterations, achieving sufficient enhancement quality while limiting processing time
Data Source
AI summary
An image processing method includes: (a) receiving a to-be-processed image; (b) obtaining a target brightness of the to-be-processed image; (c) creating a histogram curve of the to-be-processed image; (d) clipping the histogram curve according to a clipping value; (e) obtaining a mapping function of the clipped histogram curve; (f) obtaining a mapped image mapped according to the mapping function; (g) obtaining an average brightness of the mapped image; (h) obtaining a difference between the target brightness and the average brightness; and (i) if the difference is greater than a threshold, adjusting the clipping value and repeating steps (d) to (i) until the difference is less than the threshold. Thus, if the to-be-processed image does not reach the target brightness, the image processing device automatically repeats steps (c) to (i) until the to-be-processed image reaches the target brightness.