Last-Position CABAC Context Switching for Image Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image coding techniques face difficulties in accurately switching contexts during context adaptive binary arithmetic coding and decoding of last position information, leading to decreased coding efficiency due to inappropriate context selection for bit positions with different symbol occurrence probabilities.
Innovation Solution
An image coding method that binarizes last position information to generate signals with variable lengths, allowing for context switching among multiple contexts based on bit positions and using a fixed probability for certain signals, ensuring the binary symbol at the last bit position is coded with a context exclusive to that position, thereby improving coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If context adaptive binary arithmetic coding is used for last position information, then coding efficiency is improved, but appropriate context switching becomes difficult when symbols have significantly different occurrence probabilities
Solution Approach 1:
The patent segments the binary signal into a first signal (coded with context switching) and a second signal (coded with fixed probability). This segmentation allows different coding strategies to be applied to different parts of the data, resolving the contradiction by enabling context switching only where beneficial while using simpler fixed probability coding elsewhere.
Solution Approach 2:
The patent applies local quality by using context switching coding specifically for the first signal where it provides benefit, and fixed probability coding for the second signal. This localized application of different coding qualities optimizes overall performance while managing complexity.
2Device complexity
If the same context is used for binary symbols with significantly different probabilities, then device complexity is reduced, but coding efficiency decreases
Solution Approach 1:
The patent divides the binary signal into segments (first and second signals) that can be coded with different strategies. This allows the system to use context switching only for portions where it improves efficiency, rather than uniformly across all symbols, thus balancing complexity and efficiency.
Solution Approach 2:
The patent changes the coding parameter (from fixed context to switched context) based on the signal portion being coded. By dynamically adjusting the coding approach based on signal characteristics, the system optimizes efficiency without uniformly increasing complexity.
3Measurement precision
If context switching is implemented for all binary symbols, then coding accuracy is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent segments the coding process into two parts: first signal coded with context switching for high accuracy, and second signal coded with fixed probability for simplicity. This segmentation achieves high prediction accuracy where needed while controlling overall system complexity.
Solution Approach 2:
The patent applies context switching partially rather than universally - only to the first signal portion where it provides the most benefit. This partial application achieves sufficient accuracy improvement without the full complexity cost of universal context switching.
Data Source
AI summary
An image coding method including: binarizing last position information to generate (i) a binary signal which includes a first signal having a length smaller than or equal to a predetermined maximum length and does not include a second signal or (ii) a binary signal which includes the first signal having the predetermined maximum length and the second signal; first coding for arithmetically coding each of binary symbols included in the first signal using a context switched among a plurality of contexts according to a bit position of the binary symbol; and second coding for arithmetically coding the second signal using a fixed probability when the binary signal includes the second signal, wherein in the first coding, a binary symbol at a last bit position of the first signal is arithmetically coded using a context exclusive to the last bit position, when the first signal has the predetermined maximum length.