Unified Tree Coding for Luminance-Chrominance Block Flags

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Solution Overview

Problem

In image coding and decoding methods, there is a demand to reduce the data amount stored in memory for temporarily holding data used in coding or decoding, particularly due to the increased data requirements for managing transform sizes and coefficients.

Innovation Solution

The method involves splitting an input image signal into coding units, performing orthogonal transform and quantization on prediction error signals, and coding management information and quantization coefficients into a tree structure, where each transform unit corresponds to a leaf node, allowing for continuous coding of management information and quantization coefficients, reducing the need to store information from other transform units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If management information and transform coefficients are coded into separate tree structures, then the flexibility in selecting transform sizes is improved, but the data amount in memory for temporarily holding data increases

Engineering Contradiction:
Improveflexibility in selecting transform sizesVSAvoiddata amount in memory
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent combines the coding of management information (CBFs) and transform coefficients into a single unified tree structure. By merging these two previously separate coding processes, the patent eliminates the need to store management information of other transform units in memory, thereby reducing memory data amount while preserving the flexibility to select different transform sizes through the tree structure's inherent adaptability

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If management information of all transform units is stored in memory, then the coding accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improvecoding accuracyVSAvoidmemory storage requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the necessary transform coefficients from the coded stream and processes them immediately without storing all management information in memory. By taking out only the essential data needed for accurate coding and processing it on-the-fly, the patent maintains coding accuracy while significantly reducing memory storage requirements and device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If separate tree structures are used for management information and transform coefficients, then the reliability of decoding is improved, but the loss of time in processing increases

Engineering Contradiction:
Improvedecoding reliabilityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements continuous coding of management information and transform coefficients in a single unified tree traversal process. This continuous action eliminates the need for separate processing stages and intermediate storage operations, thereby maintaining decoding reliability through complete data processing while reducing overall processing time by eliminating redundant operations

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3598754B1Signaling of luminance-chrominance coded block flags (CBF) in video coding
Publication Date: 2021.03.17 TAGIVAN II
  • EP3598754B1 patent drawingFigure 1
  • EP3598754B1 patent drawingFigure 2
  • EP3598754B1 patent drawingFigure 3

AI summary

An image coding method, comprising: subtracting a prediction signal (181) from the input image signal (191) for each coding unit (CU), thereby generating respective prediction error signals (111); performing orthogonal transform and quantization on a corresponding one of the prediction error signals (111) for each transform unit (TU), eventually generating quantization coefficients (131); and coding pieces of management information indicating a structure of the transform units (TU) and the quantization coefficients (131) into a tree structure. Each of the transform units corresponds to a corresponding one of leaf nodes in the tree structure. In the coding, for each leaf node, management information and a quantization coefficient (131) are coded, eventually generating a coded signal (191) in which the coded management information and the coded quantization coefficient are arranged in succession for each leaf node.