Variable Block-Size 4D Light Field Compression
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Solution Overview
Problem
Current light field compression methods are inefficient in exploiting four-dimensional redundancy, often relying on depth maps and view synthesis, which are computationally costly and not always available, leading to non-uniform quality of decoded views and high storage requirements.
Innovation Solution
The method employs variable block-size four-dimensional transforms and hexadeca-tree bit-plane decomposition to compress light field data, eliminating the need for depth maps and view synthesis by partitioning four-dimensional blocks into sub-blocks based on a rate-distortion criterion and encoding using an arithmetic coder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If depth maps and view synthesis are used for light field compression, then compression efficiency is improved, but computational cost increases and quality uniformity deteriorates
Solution Approach 1:
The light field data is divided into four-dimensional blocks that are further partitioned into sub-blocks based on rate-distortion criteria. This segmentation allows different regions to be processed independently with appropriate complexity, avoiding the need for global depth map computation while maintaining compression efficiency.
Solution Approach 2:
The method uses variable block sizes and adapts the transformation parameters based on rate-distortion analysis. By changing block dimensions and transformation parameters dynamically, the system achieves efficient compression without requiring computationally intensive depth estimation algorithms.
2Productivity
If depth maps and view synthesis are used for light field compression, then compression efficiency is improved, but quality uniformity across views deteriorates
Solution Approach 1:
The method applies different compression strategies to different four-dimensional blocks based on their rate-distortion characteristics. By analyzing local rate-distortion profiles, the system ensures uniform quality across views while maintaining compression efficiency, as each region is processed according to its specific characteristics rather than applying a uniform approach.
3Ease of manufacture
If fixed block size transforms are used, then implementation simplicity is improved, but compression efficiency deteriorates
Solution Approach 1:
The method transitions from fixed block sizes to variable block sizes that are dynamically selected based on rate-distortion analysis. This dynamic adaptation allows the system to achieve higher compression efficiency by selecting optimal block dimensions for each four-dimensional block, while maintaining relative implementation simplicity through automated selection processes.
4Productivity
If four-dimensional transforms are applied to the entire light field, then compression efficiency is improved, but processing time increases
Solution Approach 1:
The entire light field is segmented into multiple four-dimensional blocks that can be processed in parallel. This segmentation reduces the processing time for each individual block while maintaining the compression efficiency benefits of four-dimensional transforms, as blocks can be transformed and encoded simultaneously rather than sequentially.
Data Source
AI summary
A method for compressing light field data using variable block-size four-dimensional transform and bit-plane hexadeca-tree decomposition, the method including: partitioning a four-dimensional pixel data of a light field into four-dimensional blocks of independent fixed size; partitioning the four-dimensional blocks in a set of four-dimensional non-overlapping sub-blocks of different sizes according to a rate-distortion criterion; independently transforming the four-dimensional sub-blocks generated in the previous operation, using a four-dimensional transform; quantizing by bit-planes the sub-blocks transformed by the four-dimensional transform according to Rate-Distortion optimized hexadeca-tree structure; and encoding the four-dimensional quantized data generated through an arithmetic encoder to produce a compressed representation of the light field.