Gamma Correction Circuit Using Cubic Polynomial Approximation
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Solution Overview
Problem
Conventional display systems face challenges in applying digital image processing to gamma-corrected data due to analog output from the panel gamma block, leading to truncation of small luminance values and resulting in artifacts like dark shadows and gradients rendered entirely black, and also struggle with high gate count requirements for implementing gamma correction functions.
Innovation Solution
Implementing a display system with a gamma preconditioning circuit applying a first gamma function, followed by a processing circuit for image processing, and an output gamma circuit using a third-order polynomial function to cancel the panel's gamma function, thereby reducing gate count and avoiding truncation issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single panel gamma block is used to apply gamma function to input image data, then the display can correctly display sRGB images, but digital image processing cannot be applied to the gamma-corrected data because the output is analog, causing truncation of small luminance values and artifacts
Solution Approach 1:
The system divides the gamma correction process into two separate stages: an input gamma block that processes input image data and an output gamma block that processes processed image data. This segmentation allows digital image processing to occur on digital data while maintaining proper gamma correction, eliminating the truncation problem that occurred when processing analog data.
Solution Approach 2:
The patent introduces an output gamma block as an intermediary component between the digital image processing block and the display. This intermediary converts the processed digital image data back to the appropriate gamma encoding, enabling seamless integration of digital processing with analog display output without data loss.
2Measurement precision
If conventional gamma correction functions are implemented, then accurate gamma correction can be achieved, but the gate count requirement becomes excessively high
Solution Approach 1:
The patent changes the mathematical parameters of the gamma correction function from a traditional power function to a cubic polynomial function. This parameter change maintains the accuracy of gamma correction while significantly reducing the computational complexity and gate count required for implementation in digital circuitry.
Solution Approach 2:
The patent replaces the traditional power function-based gamma correction mechanism with a polynomial-based mechanism that is more suitable for digital implementation. This substitution maintains the essential function of gamma correction while reducing hardware complexity through more efficient mathematical operations.
Data Source
AI summary
A cubic, or other polynomial, approximation to a panel's gamma function. Embodiments contemplate a display system configured to apply a panel gamma function that is a third-order polynomial function, as well as its substantial inverse. This third order function is often easier to implement, and yields lower gate count than current power law gamma functions.