Adaptive Pixel Segment Filtering for Blocking Artifact Removal
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Solution Overview
Problem
Conventional methods for removing blocking effects in image encoding, such as those used in DCT-based codecs, are unsuitable for low complexity applications like mobile terminals and often corrupt high-frequency elements like edges, especially in limited bandwidth scenarios like mobile broadcasting.
Innovation Solution
A blocking effect removal system that extracts homogeneous pixel segments, determines a filtering mode based on segment size, and applies a direction vector to filter adjacent pixels, ensuring minimal smoothing and preservation of edge areas by filtering in the same direction across block boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low pass filter is applied to smooth block boundaries, then blocking artifacts are reduced, but high-frequency elements such as edges are corrupted
Solution Approach 1:
The patent applies different filtering strengths to different regions: strong filtering is applied to homogeneous regions (smooth pairs) where blocking artifacts are prominent, while weak or no filtering is applied to detailed regions (edge areas) where high-frequency information must be preserved. This is achieved by classifying pixel pairs as smooth or detailed and selectively applying filtering based on this classification.
Solution Approach 2:
The patent segments the image into different regions (smooth pairs and detailed pairs) based on local characteristics, and applies different filtering strategies to each segment. This allows the filtering operation to be adapted to local image content, reducing blocking artifacts in appropriate regions while preserving edges in other regions.
2Object-affected harmful factors
If conventional deblocking methods are used, then blocking effects are reduced, but computational complexity and memory usage increase
Solution Approach 1:
The patent extracts only the necessary information for filtering decisions (pixel values and their differences) and processes only the relevant pixel pairs adjacent to block boundaries. This avoids the need for complex global processing while still achieving effective deblocking, thereby reducing computational complexity and memory usage.
3Object-affected harmful factors
If strong filtering is applied to remove blocking artifacts, then visual quality improves, but additional smoothing artifacts are introduced
Solution Approach 1:
The patent applies strong filtering only to homogeneous regions where blocking artifacts are visible and no important image details exist, while applying weak or no filtering to regions containing edges or detailed information. This local adaptation prevents the introduction of smoothing artifacts in regions where they would be harmful, while still effectively removing blocking artifacts in appropriate regions.
Data Source
AI summary
A blocking effect removal system and method is provided. A blocking effect removal system, including: a pixel segment extraction unit to extract a pixel segment which satisfies a homogeneity with respect to each pixel group adjacent to a block boundary of an image; a filtering mode determination unit to determine a filtering mode corresponding to a filtering direction by considering a size of the extracted pixel segment; a direction vector determination unit to determine a direction vector which is applied to pixels adjacent to the block boundary considering the filtering mode; and a pixel segment filtering unit to filter an entire area of the pixel segment, adjacent to the block boundary, according to the filtering direction.