Reverse LUT Video Compression for Nonlinear Transfer Curves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video compression methods, such as RAM-based look up tables (LUTs) and piecewise linear approximation, face challenges in handling complex, nonlinear transfer curves without compromising resolution, and suffer from exponential memory growth and high circuit complexity.
Innovation Solution
A reverse look up table approach is implemented, using (2**N)×M bit memory instead of the conventional (2**M)×N bit memory, where the M bit memory content contains input video group information and (2**N) addresses represent output levels, allowing for optimal transfer curve fitting and significant circuit size savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional RAM-based look up table (LUT) is used for video compression, then the transfer function can be accurately implemented, but the memory size grows exponentially with the number of input video bits
Solution Approach 1:
The patent inverts the conventional LUT approach by using output video bits as addresses instead of input video bits. This reverse LUT maps output levels to input break points, fundamentally changing the address-to-data relationship and reducing memory requirements from exponential to linear growth with respect to input bit depth.
Solution Approach 2:
The patent segments the input video range into multiple sections using break points, where each section is mapped to a specific output display level. This segmentation allows the transfer function to be implemented in discrete steps rather than requiring continuous memory coverage of all input combinations.
2Device complexity
If piecewise linear approximation is used for video compression, then circuit complexity is reduced, but the method cannot handle highly non-linear transfer curves without loss of resolution
Solution Approach 1:
By inverting the LUT approach and using output levels as addresses, the patent achieves both simplicity and accuracy. The reverse LUT with break point storage provides exact transfer function implementation without requiring complex interpolation logic, while maintaining the ability to represent highly non-linear curves through appropriate break point selection.
3Manufacturing precision
If the number of break points is increased to improve transfer curve fitting, then resolution is improved, but the memory requirements and circuit complexity increase
Solution Approach 1:
The inverted LUT structure stores break points at output levels rather than mapping all input combinations, allowing the number of stored values to equal the number of break points without exponential growth. This enables high-resolution transfer curve fitting with manageable memory requirements.
Data Source
AI summary
A data translation system and method. This invention provides a reverse approach to implement a M bit input to N bit output cumulative/monotonic transfer function, (where M>N) by a (2**N)×M bit memory instead of the conventional (2**M)×N bit memory. The invention offers substantial circuit size savings without compromising on transfer function resolution and is independent of transfer function mapping algorithms. The M bit memory content of the reverse LUT contains input video group information for each output level and the (2**N) addresses of the reverse LUT represent the corresponding transfer function output levels. This data to address representation of the input to output relationship is exactly opposite to the conventional address to data format. Search and compare methods are employed to locate the input video group that the incoming video belongs to and the associated address of the reverse LUT represents the output.