Image Contrast Enhancement Using Gray Level Difference Analysis
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Solution Overview
Problem
Conventional image processing methods for enhancing contrast often result in unnatural images and image glittering, especially when dealing with frames that have significant gray level differences, such as those found in DVD films, which can lead to poor quality enhancements.
Innovation Solution
A method that calculates the original gray level differences between adjacent pixels, generates a transfer function, and adjusts gray levels using a Gamma curve to enhance contrast while maintaining image stability, by selectively adding to gray levels based on differences and using previous frame data to smooth adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the conventional image processing method enhances the contrast of the frame including black bands, then the contrast enhancement is applied uniformly across the entire frame, but the resulting image appears unnatural due to including gray levels in the black frame areas
Solution Approach 1:
The patent divides the frame into effective image areas and black band areas based on gray level distribution. By segmenting the frame according to actual image content boundaries rather than treating the entire frame uniformly, the method applies contrast enhancement only to effective image areas, avoiding unnatural appearance in black band regions while maintaining contrast enhancement benefits in actual image content
Solution Approach 2:
The patent applies different processing strategies to different regions of the frame. Effective image areas undergo contrast enhancement based on their local gray level characteristics, while black band areas are excluded from enhancement. This local differentiation ensures that contrast enhancement improves image quality where needed without introducing artifacts in regions where it is inappropriate
2Illumination intensity
If the gray level curve of the current frame widely differs from the previous frame, then the conventional method adjusts contrast significantly, but this results in image glittering
Solution Approach 1:
The patent compares the gray level curve of the current frame with the previous frame and uses this feedback to control the contrast enhancement process. When significant differences are detected, the method adjusts the enhancement parameters accordingly or skips enhancement for that frame, preventing excessive contrast changes that would cause image glittering while still allowing contrast improvement when conditions are appropriate
Solution Approach 2:
The patent makes the contrast enhancement process dynamic by adapting to frame-to-frame variations. The enhancement parameters are adjusted based on the degree of difference between consecutive frames, allowing the system to respond to changing image characteristics while maintaining stability when differences are large and preventing glittering effects
Data Source
AI summary
A method for processing an image is provided. The method is to calculate the amount of original gray levels in a frame according to the original gray level difference between each pixel and an adjacent pixel thereof and adjusts the contrast of the frame according to the calculated amount of gray levels and the contrast difference between the current frame and the previous frame.