Variable Length Coding Circuit for Lossless Image Compression
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Solution Overview
Problem
Existing image compression algorithms, such as JPEG, require high computing power and result in loss of pixel values, which is not acceptable in all applications, and do not efficiently reduce data rate while maintaining high quality.
Innovation Solution
A high-performance variable length coding method that represents the differential value between adjacent pixels by dividing it by a predicted divisor, with the quotient and remainder coded using binary codes, allowing for parallel calculation and reduced bit number, thereby reducing data rate and computation power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional image compression algorithms like JPEG are used, then compression is achieved, but high computing power is required and pixel values are lost
Solution Approach 1:
The patent segments the pixel data processing by separating the compression of different color components (Y, U, V) and processing them independently. Each component is compressed separately using the variable length coding method, which divides the computation into manageable segments and reduces overall computing power requirements while maintaining compression efficiency.
Solution Approach 2:
The patent employs dynamic variable length coding where the code length adapts based on the differential value magnitude. By using a predicted divisor that can be updated based on previous differential values, the system dynamically adjusts the compression strategy to match the actual data characteristics, reducing computing power while maintaining high compression ratios.
2Quantity of substance
If traditional image compression algorithms like JPEG are used, then compression is achieved, but pixel values are not the same as original which is not acceptable in some applications
Solution Approach 1:
The patent extracts only the essential information by encoding the differential value between adjacent pixels rather than compressing the absolute pixel values. By representing only the change (difference) between pixels, the method achieves compression while preserving the ability to perfectly reconstruct original pixel values through simple addition, eliminating information loss.
Solution Approach 2:
Instead of directly compressing pixel values as traditional methods do, the patent inverts the approach by compressing the differential values (differences between adjacent pixels). This inversion transforms the compression problem into a form where lossless reconstruction is naturally achieved, as the original values can be recovered by accumulating the differential values.
3Quantity of substance
If variable length coding with predicted divisor is used, then data rate is reduced and computation power is lowered, but parallel calculation complexity increases
Solution Approach 1:
The patent segments the parallel calculation by processing each color component (Y, U, V) independently and simultaneously. Each component has its own parallel calculation pipeline that operates on the same algorithm, which simplifies the overall complexity by breaking down the complex parallel processing into multiple independent but identical simpler pipelines.
Solution Approach 2:
The patent creates a universal compression pipeline that can process any color component using the same algorithm and hardware structure. The predicted divisor calculation and variable length coding mechanism serve multiple functions across different color components, reducing overall device complexity through reuse of the same computational blocks for Y, U, and V components.
4Device complexity
If compression is done in series for each pixel component, then device complexity is reduced, but productivity decreases
Solution Approach 1:
The patent implements a dynamic architecture that can switch between series and parallel processing modes based on the input data characteristics and performance requirements. The system can dynamically activate parallel pipelines for high-speed processing when needed, or fall back to series processing for simpler cases, providing flexibility to balance device complexity and productivity.
Solution Approach 2:
The patent performs preliminary preparation by calculating predicted divisors in advance based on previous differential values. This preliminary action allows the main compression pipeline to operate more efficiently by using pre-computed reference values, reducing the critical path delay and enabling faster parallel processing without proportionally increasing device complexity.
Data Source
AI summary
The differential value of the adjacent pixels is calculated firstly and is coded by a VLC coding. The VLC coding includes codes representing the Quotient and Remainder with a marker bit inserted in between. The divider is predicted with no code in the coded data stream. If three pixel components are presented in the same clock time, three VLC encoders and three VLD decoders are applied to encode and decode one pixel at a time. During encoding, both Remainder and Quotient of the same pixel component are encoded in parallel followed. During decoding, both Remainder and Quotient of the same pixel component are decoded in parallel and the results of the first pixel component are used a reference to decode the second pixel component which adopts the same decoding procedure and the decoded results of the second pixel component is used as reference to decode the third pixel component.