Image Signal Decoding With Adaptive Weight Prediction for Brightness Changes
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Solution Overview
Problem
Existing video encoding technologies face inefficiencies in inter prediction due to brightness changes between images, particularly in scenarios with multiple light sources or local brightness changes, leading to inaccurate predictions and increased residual signal energy.
Innovation Solution
The method and apparatus utilize weight prediction parameters to adaptively determine and apply weights based on brightness changes between images, using first and second weight prediction parameters for reference and local regions, respectively, to enhance inter prediction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inter prediction is performed using conventional methods without weight adaptation, then the encoding process is simple, but prediction accuracy deteriorates when brightness changes occur between images
Solution Approach 1:
The patent applies dynamics by making the weight parameter adaptive rather than fixed. The weight prediction unit dynamically adjusts the weight value based on brightness changes between the current picture and reference picture, allowing the prediction mechanism to respond to varying lighting conditions while maintaining encoding efficiency through automated adaptation.
Solution Approach 2:
The patent changes the parameter of weight value from a constant to a variable that adapts to brightness changes. By calculating weight prediction parameters based on luminance differences between pictures and applying these to prediction blocks, the system optimizes prediction accuracy for different lighting scenarios without requiring complex manual intervention.
2Measurement precision
If a single weight prediction parameter is used for the entire reference image, then the encoding process is simple, but prediction accuracy deteriorates when local brightness changes occur
Solution Approach 1:
The patent applies local quality by enabling different weight prediction parameters for different regions or blocks within the picture. The weight prediction unit can determine separate weight values for current blocks based on local brightness characteristics, allowing precise adaptation to local lighting variations such as fade-in/fade-out effects while maintaining simplicity in regions without brightness changes.
3Loss of energy
If weight prediction is not applied, then the encoding/decoding process is fast, but residual signal energy increases due to brightness mismatches
Solution Approach 1:
The patent applies preliminary action by calculating and applying weight prediction parameters before the actual prediction and encoding processes. The weight prediction unit pre-computes the weight values based on brightness differences, and these pre-calculated weights are then used in the prediction stage, reducing residual energy before the main encoding pipeline processes the data.
Data Source
AI summary
A method for decoding an image signal according to the present invention may comprise the steps of: determining whether there is a brightness change between a current image including a current block and a reference image of the current image; if it is determined that there is a brightness change between the current image and the reference image, determining weight prediction parameter candidates for the current block; determining a weight prediction parameter for the current block on the basis of index information which specifies any one of the weight prediction parameter candidates; and performing a prediction on the current block on the basis of the weight prediction parameter.