Display Luminance Mapping Curve Parameters for Accurate Tone Adjustment
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Solution Overview
Problem
Existing dynamic-range mapping methods, such as static and dynamic mapping, fail to accurately adjust tone on display devices with varying luminance, leading to information loss in certain scenes and increased data requirements.
Innovation Solution
A method and apparatus for obtaining a mapping curve parameter set by adjusting parameters based on display luminance, maximum target system display luminance, and adjustment coefficients, allowing for more accurate tone adjustment on devices with different luminance capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a static mapping method is used with a single mapping curve for all scenes, then the image needs to carry less data and the processing procedure is simple, but information may be lost in some scenes because the same mapping curve is used for TM in all scenes
Solution Approach 1:
The patent applies dynamics by transitioning from a static mapping curve to a dynamic mapping curve that adapts to different luminance conditions. The mapping curve parameters are adjusted in real-time based on the actual luminance of the display device, allowing the system to optimize tone mapping for each specific scene while maintaining manageable complexity through automated adaptation.
Solution Approach 2:
The patent implements parameter changes by modifying the mapping curve parameters (such as slope, intercept, and curvature) based on the display device's luminance characteristics. This allows the same base mapping curve to be adapted to different luminance conditions by changing its parameters dynamically, thereby preserving image information across various scenes without requiring completely different curves for each scenario.
2Loss of information
If a dynamic mapping method is used with a mapping curve adjusted for each scene or frame, then differentiated processing can be implemented for different scenes, but the image needs to carry a large amount of data because related scene information needs to be carried in each frame or scene
Solution Approach 1:
The patent extracts only the essential luminance parameter from the scene information and uses it to adjust the mapping curve. Instead of carrying complete scene information or multiple full mapping curves, the system extracts the key luminance characteristic and applies it to a base mapping curve, significantly reducing the data quantity while maintaining the benefits of scene-adaptive processing.
Solution Approach 2:
The patent performs preliminary action by pre-defining a base mapping curve and preparing adjustment parameters in advance. Rather than generating complete scene-specific mapping curves on-the-fly, the system prepares the base curve and luminance adjustment parameters beforehand, then applies them efficiently during playback, reducing the real-time data processing burden.
3Device complexity
If tone mapping is performed without considering display luminance capabilities, then the processing is simpler, but accurate tone adjustment cannot be achieved on display devices with different luminance
Solution Approach 1:
The patent applies local quality by tailoring the mapping curve parameters to the specific luminance characteristics of each display device. Instead of using a universal mapping curve for all devices, the system adjusts the curve's local properties (slope, curvature, intercept) to match the luminance capabilities of the target display, ensuring accurate tone representation for each device type while maintaining a systematic approach to the adjustment process.
Data Source
AI summary
A mapping curve parameter obtaining method and apparatus are described. The method includes obtaining a first mapping curve parameter set and first maximum target system display luminance, and obtaining a display luminance parameter set, where the display luminance parameter set includes maximum display luminance and/or minimum display luminance of a display device. The method also includes obtaining an adjustment coefficient set, where the adjustment coefficient set includes one or more adjustment coefficients, and the one or more adjustment coefficients correspond to one or more parameters in the first mapping curve parameter set. Furthermore, the method includes adjusting the one or more parameters in the first mapping curve parameter set based on the display luminance parameter set, the first maximum target system display luminance, and the adjustment coefficient set to obtain a second mapping curve parameter set, where the second mapping curve parameter set includes one or more adjusted parameters.