Reverse LUT Data Translation for Nonlinear Video Transfer Curves
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Solution Overview
Problem
Existing video compression methods, such as RAM-based look up tables 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, with the M bit memory content containing input video group information and (2**N) addresses representing 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 is used for video compression, then the transfer function can be accurately implemented, but the memory size grows exponentially as the number of input video bits increases
Solution Approach 1:
The patent inverts the conventional LUT approach by swapping addresses and data. Instead of using input video bits as addresses to retrieve output values, the system uses output video levels as addresses to store input video group information. This inversion fundamentally changes the memory access pattern and reduces memory requirements from exponential to linear growth with respect to input bits.
Solution Approach 2:
The patent segments the input video range into multiple groups, where each group maps to a specific output level. The memory stores the starting and ending values of each input group rather than individual input-output mappings. This segmentation allows the system to represent complex nonlinear transfer curves using fewer memory locations by capturing only the boundary points of each segment.
2Device complexity
If piecewise linear approximation is used to reduce memory size, then the circuit complexity is reduced, but the resolution is compromised for highly nonlinear transfer curves
Solution Approach 1:
By inverting the LUT structure, the patent enables storage of detailed input group boundaries for each output level without requiring complex interpolation circuits. The memory directly stores the precise input value ranges that map to each output level, allowing accurate representation of highly nonlinear transfer curves while maintaining relatively simple circuitry.
Solution Approach 2:
The patent changes the parameters stored in memory from output values (conventional approach) to input group boundary values (inverted approach). This parameter transformation allows the system to achieve high resolution for nonlinear transfer curves by storing critical boundary information rather than approximate linear interpolation data.
3Manufacturing precision
If the number of input video bits increases to improve resolution, then the video quality is improved, but the conventional LUT memory size increases exponentially
Solution Approach 1:
The inverted LUT structure fundamentally changes how resolution scaling works. Instead of requiring 2^M memory locations for M input bits, the system requires only proportional to M memory locations to store input group boundaries. This allows high-resolution video processing (e.g., 14-bit or 16-bit input) without exponential memory growth, as the memory stores compact group boundary information rather than complete input-output mappings.
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.