HDR Tone Mapping With Segmented Spline Curves
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Solution Overview
Problem
Existing tone mapping methods for high dynamic range (HDR) images using N-power spline functions are inflexible, leading to poor display effects, especially in extra bright or dark regions, due to reliance on basic curves.
Innovation Solution
A tone mapping method that generates M N-power spline curves based on metadata, including mapping curve parameters and coordinates, allowing for flexible design and improved tone mapping effects by using different curves for various luminance ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If tone mapping is performed using a single N-power spline curve based on a basic curve, then the processing method is simple, but the mapping flexibility is insufficient and tone mapping effect in extra bright or dark regions is poor
Solution Approach 1:
The patent divides the luminance range into multiple segments (first luminance range and second luminance range) and applies different mapping curves to each segment. This segmentation allows each curve to be optimized for its specific luminance range, improving overall mapping flexibility and effect while managing complexity through structured division.
Solution Approach 2:
The patent applies different mapping characteristics to different luminance regions by using distinct mapping curves for bright and dark regions. Each curve can be independently optimized for its local luminance characteristics, achieving better tone mapping effect in extra bright or dark regions without requiring complete redesign of the entire mapping system.
2Manufacturing precision
If multiple mapping curves are used for different luminance ranges, then tone mapping effect is improved, but the metadata complexity and processing overhead increase
Solution Approach 1:
The metadata is segmented to include parameters for each mapping curve corresponding to different luminance ranges. This structured segmentation allows precise tone mapping for each region while organizing metadata in a manageable format that reduces unnecessary data redundancy.
Solution Approach 2:
The patent applies mapping curves selectively to different luminance ranges rather than using a single comprehensive curve for all luminance values. This partial application approach achieves improved precision where needed (in extra bright or dark regions) while keeping metadata quantity reasonable by not over-engineering regions that don't require specialized treatment.
Data Source
AI summary
Tone mapping methods and apparatus provide for receipt by a backend device may of metadata and an HDR image from a frontend device and the generation of a mapping curve based on feature parameters of the mapping curve included in the metadata. Tone mapping on the HDR image can be performed based on the mapping curve. The feature parameters of the mapping curve are determined by the frontend device based on a luminance distribution status of the HDR image. In this way, the mapping curve parameters are determined based on the luminance distribution status of the HDR image so that design of the mapping curve is more flexible, and display effect of the HDR image can be effectively improved.