Adaptive Loop Filtering for Image Coding Regions
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Solution Overview
Problem
The increasing demand for high-resolution and high-quality images in various fields leads to diverse image quality support across devices and network environments, necessitating an adaptive image filtering method to enhance subjective and objective image quality while improving coding efficiency.
Innovation Solution
A picture filtering method that adaptively determines whether to apply a filter, selects a filter shape, and sets filter coefficients based on image characteristics for each region, allowing for efficient filtering and improved inter-prediction efficiency by using the filtered picture as a reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If adaptive loop filtering is applied to enhance image quality, then subjective and objective picture quality is improved, but coding efficiency and processing complexity increase
Solution Approach 1:
The patent divides the picture into multiple regions and applies different filtering operations to each region based on local characteristics. Each region can have its own filter coefficients, filter shape, and filtering strength, allowing the system to enhance picture quality where needed while avoiding unnecessary processing in regions that don't benefit from filtering.
Solution Approach 2:
The filtering process is segmented into distinct regions with independent control parameters. The picture is partitioned into multiple regions, and filtering is applied independently to each region, enabling selective enhancement and reducing overall processing complexity by focusing computational resources only where beneficial.
2Productivity
If region-based adaptive filtering is implemented, then filtering efficiency is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent changes filtering parameters (filter coefficients, filter shape, filtering strength) based on regional characteristics. Each region can have optimized parameters that match its specific image content, improving filtering efficiency while the parameter adaptation is driven by automated analysis of regional features.
3Manufacturing precision
If filter coefficients and shapes are adaptively determined for each region, then picture quality enhancement is optimized, but processing time and computational load increase
Solution Approach 1:
Filter parameters such as coefficients and shapes are determined in advance for each region based on regional characteristics, before the actual filtering operation is applied. This preliminary determination allows the filtering process to proceed efficiently with pre-computed parameters, reducing real-time processing time while maintaining optimized picture quality enhancement.
Data Source
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AI summary
A picture filtering method performed by an encoding device, according to the present invention, comprises the steps of: deriving, from a current picture, regions for adaptive loop filtering (ALF); deciding ALF coefficients by picture unit or region unit; on the basis of the ALF coefficients, determining, by region unit, whether ALF is usable; re-deciding ALF coefficients for an ALF-usable first region; deriving a filter shape for the first region; on the basis of the re-decided ALF coefficients, determining, by unit of coding units (CUs) in the first region, whether ALF is usable; performing filtering for ALF-usable CUs on the basis of the derived filter shape and the re-decided ALF coefficients; and transmitting at least one among information on the ALF-usable first region and information on the ALF-usable CUs. According to the present invention, efficient filtering appropriate for image properties per region may be applied.