Intra Prediction Edge Detection for Image Coding Efficiency
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Solution Overview
Problem
Conventional video coding standards face inefficiencies in coding sharp linear edges, leading to increased coded data or distortion due to limited prediction directions, which result in suboptimal coding efficiency and increased bit usage for high-frequency components.
Innovation Solution
The method involves detecting the direction of edges in surrounding blocks to generate a predicted block, using a weighted sum of pixel values and selecting appropriate prediction modes, such as edge prediction modes, to reduce prediction residuals and improve coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional prediction directions (8 directions) are used for intra-frame prediction, then the coding process is simple and fast, but the coding efficiency is poor for sharp linear edges leading to increased bit usage
Solution Approach 1:
The patent implements dynamic prediction by detecting edge directions in the current block and adaptively selecting prediction modes based on detected edges. Instead of using fixed 8 prediction directions, the system dynamically determines prediction directions that match the actual edge orientations in the image, thereby improving coding efficiency for sharp linear edges while maintaining manageable complexity through automated edge detection algorithms
Solution Approach 2:
The patent changes the prediction mode parameters by introducing edge detection-based prediction directions alongside the conventional 8 directions. When edges are detected, the system modifies the prediction approach to align with detected edge orientations, allowing flexible adaptation to different image content characteristics without requiring a complete redesign of the prediction framework
2Manufacturing precision
If conventional intra-frame prediction with limited directions is used, then the processing is computationally efficient, but distortion occurs in coded images with sharp edges
Solution Approach 1:
The patent applies preliminary edge detection to the current block before performing prediction. By detecting edges in advance and determining their directions, the system prepares the optimal prediction mode selection beforehand, ensuring high prediction accuracy for sharp edges. This preliminary action allows the main prediction process to proceed efficiently with pre-determined parameters
3Loss of information
If conventional prediction modes are used, then the amount of coded data increases for blocks with sharp edges, but implementing edge detection increases processing complexity
Solution Approach 1:
The patent implements self-service by having the encoder perform edge detection and determine optimal prediction modes autonomously. The system uses the same edge detection capability at both encoder and decoder sides, allowing the decoder to reconstruct images with high accuracy without requiring additional information transmission. This self-service approach minimizes information loss while keeping the complexity manageable through symmetric processing at both ends
Data Source
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AI summary
Provided is an image coding method for performing intra prediction achieving higher coding efficiency. The method for coding image data on a block-by-block basis includes: generating a predicted block by predicting a current block; computing a difference between the current block and the predicted block; coding the difference computed in the computing; decoding the difference coded in the coding; and adding the difference decoded in the decoding to the predicted block to generate a decoded block, wherein the generating includes: detecting an edge in a previously decoded block corresponding to a block adjacent to the current block; and extrapolating or interpolating previously decoded image data corresponding to a pixel included in the block adjacent to the current block, along a direction of the edge detected in the detecting to generate the predicted block.