Intra Prediction Using Weighted Reference Samples
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Solution Overview
Problem
Current video encoding and decoding technologies face inefficiencies in predicting sample values, particularly in high-definition and ultra-high-definition video processing, leading to degradation in image quality and coding efficiency due to increased prediction errors as distance from reconstructed neighboring samples increases.
Innovation Solution
An intra prediction method that derives a final prediction value for a current block by performing a weighting sum of directional and reference sample values using a weighting matrix, with the reference sample positioned based on neighboring block information and spatial variations, to reduce prediction errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If directional prediction using neighboring samples is used, then prediction can be performed using available reference information, but prediction errors increase as distance from neighboring samples increases
Solution Approach 1:
The patent introduces an internal reference sample within the current block as an intermediary to bridge the gap between distant neighboring samples and current block pixels. This internal reference sample serves as a local anchor point that reduces prediction error variation across the block, effectively mediating between the available neighboring sample information and the pixels that need to be predicted.
Solution Approach 2:
The patent changes the parameter of reference sample positioning from using only external neighboring samples to using an internal reference sample at a specific position within the current block. This parameter change allows the prediction system to adapt to different block characteristics and reduces the impact of distance-related prediction errors by selecting reference samples that are optimally positioned within each block.
2Ease of manufacture
If reference samples are positioned at fixed locations, then the positioning process is simple, but the prediction accuracy does not adapt to spatial variations in the block
Solution Approach 1:
The patent applies local quality by determining reference sample positions based on spatial variations within each current block. Instead of using a universal fixed position for all blocks, the method adapts the reference sample position to the local characteristics of each block, such as gradient directions and edge orientations. This allows the prediction to account for local structures while maintaining a relatively simple positioning mechanism.
3Measurement precision
If weighting sum with multiple prediction values is performed, then prediction accuracy improves, but computational complexity increases
Solution Approach 1:
The patent optimizes the weighting parameters in the weighting sum operation by determining weights based on the positions of reference samples and pixels rather than using fixed or extensively calculated weights. This parameter approach reduces computational complexity while maintaining improved prediction accuracy through the use of multiple prediction values, as the weights are derived from simple positional relationships rather than complex optimization.
Data Source
AI summary
An intra prediction method according to the present invention comprises the following steps: performing a directional prediction using at least one of a neighboring pixel of a current block and a left upper corner pixel positioned at a left upper corner of the current block so as to obtain a first prediction value for the current block; obtaining a second prediction value for the current block using the reference sample positioned in the current block; and weighted summing the first prediction value and the second prediction value using a weighting matrix so as to obtain a final prediction value for the current block. According to the present invention, image encoding/decoding efficiency may be improved.