Image Processing Apparatus Tone Mapping Based on Luminance Metadata
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Solution Overview
Problem
Display devices struggle to accurately reproduce images with dynamic ranges that exceed their capabilities, leading to distortion of the original image intent due to insufficient consideration of luminance characteristics during tone mapping processes.
Innovation Solution
An image processing apparatus that receives metadata indicating the maximum display luminance values of both a mastering and target display, allowing it to divide images into scenes, obtain luminance characteristics, and perform tone mapping based on these values to adjust the dynamic range accordingly, ensuring the image is displayed with the intended brightness and saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If tone mapping is performed without considering luminance characteristics, then processing complexity is reduced, but color reproduction accuracy and image intent preservation deteriorate
Solution Approach 1:
The patent applies preliminary action by obtaining luminance characteristics metadata before performing tone mapping. The system retrieves maximum display luminance values and other luminance-related parameters from metadata associated with the image content, then uses these pre-obtained characteristics to guide the subsequent tone mapping process, ensuring accurate color reproduction without excessive processing complexity
Solution Approach 2:
The patent uses luminance characteristics metadata as an intermediary between the input image and the tone mapping process. This metadata acts as a mediator that conveys information about the intended luminance presentation, allowing the system to perform accurate tone mapping by referencing these intermediate luminance parameters rather than performing complex real-time analysis
2Manufacturing precision
If dynamic range is increased to match mastering display, then image quality is improved, but compatibility with target displays deteriorates
Solution Approach 1:
The patent applies dynamics by enabling adaptive tone mapping that adjusts the dynamic range transformation based on the specific target display's capabilities. The system dynamically selects and applies appropriate tone mapping curves and parameters by comparing the mastered luminance characteristics with the target display characteristics, allowing the same content to be optimally displayed across different display devices with varying dynamic ranges
Solution Approach 2:
The patent uses parameter changes by modifying tone mapping parameters such as maximum luminance values, contrast ratios, and transfer curves based on the target display capabilities. The system changes these parameters dynamically to ensure that high-quality image reproduction on mastering displays translates effectively to displays with different dynamic range capabilities, maintaining image intent while ensuring compatibility
Data Source
AI summary
Provided are an image processing apparatus and method, which use a maximum display luminance value of a mastering display and a maximum display luminance value of a target display according to luminance characteristics of a current scene of an encoded image.