Display Driver APL Filtering for Contrast Edge Discontinuities
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display technologies face issues with discontinuities at edges of areas in contrast correction based on image characteristics, leading to undesirable effects like block noise and halo effects, particularly when applying local contrast correction techniques.
Innovation Solution
A display device and method that includes a driver configured to perform APL-calculating and square-mean-calculating filtering processes to generate area characterization data and pixel-specific characterization data, which are used for correction calculations to reduce discontinuities and suppress halo effects by modifying the gamma curve for each pixel based on its position and adjacent areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local contrast correction is performed based on image characteristics of each area, then contrast enhancement is improved, but discontinuities occur at boundaries between adjacent areas causing block noise
Solution Approach 1:
The patent introduces a boundary region between adjacent areas where the gamma value is determined through interpolation between the gamma values of the respective areas. This intermediary approach prevents abrupt transitions at area boundaries, eliminating block noise while maintaining contrast enhancement benefits.
Solution Approach 2:
The patent dynamically adjusts the gamma value parameter based on the spatial position within areas and boundary regions. By continuously modifying the gamma parameter rather than applying fixed values to entire areas, the system achieves smooth transitions and prevents discontinuities at area boundaries.
2Manufacturing precision
If the input-output relation is continuously modified to resolve discontinuities at area boundaries, then image continuity is improved, but halo effects occur near image edges
Solution Approach 1:
The patent applies different gamma correction strategies to different spatial locations: within areas, boundary regions, and near image edges. By making the correction characteristics location-dependent, the system resolves discontinuities without creating halo effects in constant-color regions.
Solution Approach 2:
The patent divides the display region into distinct zones (areas, boundary regions, and edge regions) and applies appropriate gamma correction to each segment. This segmentation allows the system to address discontinuities at area boundaries while preventing halo effects near image edges through targeted correction.
3Illumination intensity
If strong contrast enhancement is performed on the entire image, then overall image quality is improved, but the number of representable grayscale levels is reduced causing blocked up shadows and clipped white
Solution Approach 1:
The patent applies different gamma values to different areas based on their local image characteristics rather than using a single gamma value for the entire image. This localized approach preserves grayscale levels in dark and bright regions while enhancing contrast in mid-tone regions, preventing blocked up shadows and clipped white.
Data Source
AI summary
A display device includes a display panel and a driver. The driver generates APL-calculation image data corresponding to an APL-calculation luminance image through an APL-calculation filtering process on the input usage data, calculates area characterization data including first APL data of each area in the APL-calculation luminance image and calculates second APL data depending on the position of each pixel and the first APL data of the area characterization data associated with the area in which each pixel is located and with the adjacent areas to generate pixel-specific characterization data including the second APL data. The driver generates output image data on the basis of the second APL data of the pixel-specific image data and drives each pixel in response to the output image data. The APL-calculating filtering process involves setting a luminance value of the target pixel in the APL-calculation luminance image to a specific APL-calculation alternative luminance value.