Suppressing Pixel Coloration Errors in HDR Video Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High dynamic range (HDR) video systems experience quality degradation due to amplified quantization errors during color space conversions, PQ encoding, and subsampling, leading to visible artifacts on displays.
Innovation Solution
A method for suppressing pixel color component noise in HDR signals by converting color values to a less precise representation, calculating a noise threshold, and reducing noise levels using pixel-level clamping, which can be implemented as a separate step or integrated with existing processes like color space conversion or PQ encoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If FP16 pixel values are converted to PQ encoded RGB or YCbCr HDR signals through color space conversions and encoding, then the HDR display can be driven with standard encoded signals, but quantization errors are amplified creating visible artifacts that lower display quality
Solution Approach 1:
The patent applies dithering noise before the quantization process to randomize and distribute quantization errors. By introducing this preliminary random noise pattern, the subsequent quantization errors become less correlated and more visually acceptable, preventing the amplification of structured artifacts through the color space conversions and PQ encoding process.
Solution Approach 2:
The patent converts the harmful deterministic quantization errors into beneficial random noise patterns through dithering. The quantization error, which would normally create visible banding and artifacts, is transformed into a random noise pattern that is less perceptible to the human visual system, thereby turning a quality-degrading factor into an acceptable characteristic.
2Quantity of substance
If quantization is applied during color space conversion and PQ encoding, then bandwidth and storage requirements are reduced, but noise accumulation increases creating visible artifacts on HDR displays
Solution Approach 1:
The patent converts the harmful deterministic quantization errors into beneficial random noise patterns through dithering. The quantization error, which would normally create visible banding and artifacts, is transformed into a random noise pattern that is less perceptible to the human visual system, thereby turning a quality-degrading factor into an acceptable characteristic.
Solution Approach 2:
The dithering noise acts as an intermediary element between the original FP16 signal and the quantized output. This intermediate random noise pattern modifies the quantization process itself, causing the quantization errors to be distributed in a more visually acceptable manner without requiring changes to the quantization algorithm or hardware.
3Quantity of substance
If chroma filtering and subsampling are applied during PQ encoding, then the encoded signal size is reduced, but quantization errors are further amplified resulting in visible artifacts
Solution Approach 1:
The patent applies dithering noise before the quantization process to randomize and distribute quantization errors. By introducing this preliminary random noise pattern, the subsequent quantization errors become less correlated and more visually acceptable, preventing the amplification of structured artifacts through the color space conversions and PQ encoding process.
Data Source
AI summary
The present disclosure is directed to a process to partially or fully suppress, or limit, pixel coloration errors. These pixel coloration errors, represented by small noise values, can be introduced during signal processing of high dynamic range (HDR) video signals. Converting visual content to a half precision floating point representation, for example, FP16, can introduce small amounts of signal noise due to value rounding. The noise can be multiplied and accumulated during HDR signal processing resulting in visual artifacts and degraded image quality. The disclosure can detect these noise amounts in pixel color component values, and suppress, or partially suppress, the noise to prevent the noise from accumulating during subsequent HDR signal processing.