Dynamic Metadata HDR Gamut Mapping for SDR Displays

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Solution Overview

Problem

Standard television sets and display devices struggle to accurately reproduce high dynamic range (HDR) images due to their lower brightness levels and gamut range, leading to color-clipping and hue-shift, as they use static algorithms that fail to account for differences between HDR content and display capabilities.

Innovation Solution

A method that dynamically adjusts luminance and brightness levels, and performs gamut mapping using dynamic metadata, which involves analyzing image distributions to generate scene information and applying adaptive processing techniques such as signed clip, color correction, tone mapping, and gamut mapping to ensure accurate representation of HDR images on SDR displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If static algorithms are used for gamut mapping and luminance adjustment, then device complexity is reduced, but image quality deteriorates due to color-clipping and hue-shift

Engineering Contradiction:
Improveimage qualityVSAvoidprocessing algorithm complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transforming static gamut mapping and luminance adjustment algorithms into dynamic ones that adapt to different scenes. The system generates scene information (dynamic metadata) that characterizes each scene's luminance distribution and color characteristics, then uses this information to dynamically adjust processing parameters such as tone mapping curves and color correction matrices, eliminating color-clipping and hue-shift while maintaining algorithmic efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes processing parameters dynamically based on scene characteristics. Specifically, it adjusts luminance mapping parameters, color gamut compression ratios, and tone mapping curve parameters according to the generated scene information, allowing the same processing pipeline to optimize for different content types without increasing hardware complexity

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If HDR images are displayed on SDR television sets, then compatibility is improved, but image quality deteriorates due to lower brightness level and gamut range

Engineering Contradiction:
Improvedisplay compatibilityVSAvoidimage quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent dynamically adjusts processing parameters based on the target display's SDR capabilities and the source HDR content characteristics. By generating scene information that captures the luminance distribution and color gamut of the HDR content, the system adapts tone mapping and gamut mapping parameters to preserve maximum image quality while ensuring compatibility with SDR displays

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces scene information (dynamic metadata) as an intermediary between HDR content and SDR display. This intermediary carries essential characteristics of the HDR scene, enabling the processing system to make informed decisions about luminance mapping and color transformation, thereby bridging the gap between HDR source and SDR display capabilities

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If conventional static gamut mapping is applied to HDR images, then processing speed is maintained, but image quality deteriorates due to color-clipping and hue-shift

Engineering Contradiction:
Improvecolor accuracyVSAvoidprocessing algorithm complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary analysis of the HDR image to generate scene information before applying gamut mapping. This preliminary action characterizes the luminance distribution and color characteristics of the input scene, enabling subsequent processing stages to apply optimized transformation parameters that prevent color-clipping and hue-shift while maintaining efficient processing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by using the generated scene information to continuously optimize processing parameters. The scene characteristics feed back into the gamut mapping and luminance adjustment algorithms, allowing them to adapt their behavior based on the actual content being processed, thereby improving color accuracy without requiring complex hardware

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS10019785B2Method of processing high dynamic range images using dynamic metadata
Publication Date: 2018.07.10 NOVATEK MICROELECTRONICS CORP
  • US10019785B2 patent drawing
  • US10019785B2 patent drawing
  • US10019785B2 patent drawing

AI summary

A method of performing luminance/brightness adjustment and gamut mapping to high dynamic range images for a display device includes receiving an input image to analyze an image distribution of the input image, generating a scene information of the input image according to the image distribution, and performing luminance/brightness adjustment and gamut mapping to the input image according to the scene information, to generate an output image corresponding to the input image, wherein the scene information is regarded as dynamic metadata of the input image.