Four-Path Tree Vector Quantization for Efficient Codebook Search
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Solution Overview
Problem
Conventional dynamic two-path tree structured vector quantization methods are inefficient and slow, especially with high-definition video data, as they often get stuck in unsuitable paths, increasing error and calculation time.
Innovation Solution
Implementing dynamic four-path tree structured vector quantization, where codebook vectors are arranged in a tree structure with upper nodes averaged from four adjacent nodes, and thresholds are calculated to select paths based on mean square errors, allowing for more efficient codebook search by considering multiple paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If dynamic two-path tree structured vector quantization is used, then codebook search is performed with reduced calculation time compared to full search, but the method gets stuck in unsuitable paths and increases error
Solution Approach 1:
The codebook search is segmented into multiple independent paths (four paths instead of two), allowing the system to explore multiple potential solutions simultaneously rather than being constrained to a single path. This segmentation enables the algorithm to divide the search space into parallel trajectories, each evaluating different codebook candidates, thereby reducing the risk of getting stuck in local optima while maintaining efficient search throughput.
Solution Approach 2:
The patent implements dynamic path selection by calculating thresholds based on mean square errors and adaptively determining which paths to follow at each node. The system dynamically adjusts the number of active paths (between 1-4 paths) based on the calculated threshold value, allowing flexible adaptation to different search conditions and data characteristics, thus improving both search efficiency and accuracy.
2Productivity
If conventional two-path tree structured vector quantization is used, then calculation time is reduced from 256 comparisons to 16 comparisons, but calculation time increases to 510 for high-definition video data
Solution Approach 1:
The patent introduces an additional dimension to the traditional two-path tree structure by implementing a four-path configuration. This dimensional expansion adds more search trajectories (from 2 to 4 paths) through the codebook tree, enabling parallel exploration of more codebook candidates. The four-path structure effectively doubles the search capacity compared to two-path methods, reducing calculation time for high-definition video data from 510 to 310 while maintaining systematic search organization.
3Reliability
If full search is performed comparing all codebook data with video data, then the most similar codebook is guaranteed to be found, but the method takes much time with 256 comparisons required
Solution Approach 1:
The patent applies partial action by evaluating only a selected subset of codebook paths (up to 4 paths) rather than performing exhaustive comparison with all 256 codebooks. By using threshold-based dynamic path selection, the system performs sufficient comparisons to achieve high accuracy without the complete overhead of full search, reducing comparison operations from 256 to a manageable subset while maintaining reliable codebook matching.
Data Source
AI summary
Disclosed is a method for four-path tree structured vector quantization, comprising: (a) placing codebook vectors where magnitudes of vectors are arranged in order at lowermost nodes; (b) configuring upper nodes by averaging vector values of the lowermost adjacent four nodes; (c) calculating mean square errors to paths of the upper nodes (A, B, C, and D) corresponding to four paths from an input vector ‘X’; (d) presetting a threshold between 0 and 1 after the ‘(c)’; (e) calculating thresholds between the input vector ‘X’ and four paths ‘A’, ‘B’, ‘C’, and ‘D’, based on the mean square errors; and (f) comparing the thresholds calculated in the ‘(d)’ with the preset threshold to select a path having a threshold greater than the preset threshold, in which dynamic four-path tree structured vector quantization is used instead of conventional dynamic two-path tree structured vector quantization, thereby more efficiently and quickly searching a codebook.