Inter-Prediction Illumination Compensation for Block Boundary Error Reduction
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Solution Overview
Problem
High-resolution and high-quality image data requires efficient compression techniques to reduce transmission and storage costs, as conventional methods struggle with increased data amounts and prediction errors at block boundaries during inter-prediction.
Innovation Solution
The method employs illumination compensation-based inter-prediction by deriving motion vectors and reference blocks for current and neighboring blocks, generating prediction samples through weighted-sums, and encoding these for efficient data transmission while reducing prediction errors at block boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inter-prediction is used, then device complexity is low, but prediction error at block boundaries increases
Solution Approach 1:
The patent divides the current block into multiple sub-units (first sub-unit, second sub-unit, etc.) along the boundary direction. Each sub-unit is processed separately with its own reference block derivation, allowing independent optimization of prediction accuracy at different boundary regions without requiring complete redesign of the entire prediction system.
Solution Approach 2:
The patent applies different reference block derivation methods to different sub-units based on their specific boundary characteristics. For example, the first sub-unit uses a first reference block derived from motion vector of the current block, while the second sub-unit uses a second reference block derived from motion vector of a neighboring block. This localized approach improves prediction accuracy at specific boundary locations without increasing overall system complexity.
2Reliability
If illumination compensation is applied, then prediction error is reduced, but additional data requirements increase
Solution Approach 1:
The patent applies illumination compensation selectively only to the sub-units adjacent to boundaries where prediction errors occur, rather than applying it to the entire block. This partial application reduces the quantity of additional data needed while still achieving significant prediction accuracy improvement at the critical boundary regions.
Solution Approach 2:
The patent introduces illumination compensation as an intermediary processing step between motion compensation and final prediction generation. The illumination compensation unit processes the reference blocks to compensate for illumination differences before the prediction samples are generated, acting as a mediator that improves prediction accuracy without requiring fundamental changes to the core prediction architecture.
3Reliability
If multiple reference blocks are derived, then inter-prediction performance is enhanced, but processing time increases
Solution Approach 1:
The patent segments the prediction process into parallel operations for different sub-units. Multiple reference blocks are derived simultaneously for different sub-units using parallel motion compensation operations, and the illumination compensation can also be performed in parallel across different sub-units. This segmentation enables concurrent processing that reduces overall prediction processing time while maintaining enhanced prediction accuracy through multiple reference blocks.
Solution Approach 2:
The patent performs preliminary derivation of motion vectors and reference blocks before the final prediction generation. By pre-processing the reference blocks (including illumination compensation) before they are needed for prediction, the system can optimize prediction accuracy without adding significant delay to the overall encoding/decoding process, as the heavy computation is done in advance.
Data Source
AI summary
An inter-prediction method according to the present invention comprises the steps of: deriving a first motion vector of a current block; deriving a first reference block with respect to a current subunit of the current block on the basis of the first motion vector, the current subunit being adjacent to a target boundary of the current block; deriving a second reference block with respect to the current subunit on the basis of a second motion vector of a neighboring block adjacent to the target boundary; and generating prediction samples on the basis of an illumination compensation (IC)-based weighted sum of the first reference block and second reference block. The present invention enables reduction of the amount of data of additional information as well as efficient illumination compensation-based inter-prediction and block boundary error reduction.