Image Display Signal Processing for Adaptive Grayscale Tone Mapping
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Solution Overview
Problem
Existing image display apparatuses struggle to effectively enhance grayscale expression, particularly at mid and high gray levels, in images with varying peak luminances.
Innovation Solution
The image display apparatus incorporates a signal processing device that performs tone mapping by combining first and second tone mappings based on input and reference peak luminances, adjusting the ratio and amount of luminance change according to the gray level and peak luminance differences, to enhance grayscale expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If tone mapping is performed based on input peak luminance, then image brightness is preserved, but grayscale expression at mid and high gray levels deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the tone mapping curve based on the input peak luminance. When the input peak luminance is low, the system switches to a different tone mapping curve that enhances grayscale expression at mid and high gray levels, while maintaining appropriate brightness. This parameter adaptation resolves the contradiction by selecting the optimal tone mapping parameters according to the input image characteristics.
Solution Approach 2:
The system implements dynamics by making the tone mapping process adaptive rather than fixed. The signal processing device determines whether to use first or second tone mapping based on the input peak luminance threshold, creating a dynamic response that adjusts to different input conditions. This dynamic adaptation allows the system to optimize grayscale expression without sacrificing brightness.
2Manufacturing precision
If tone mapping curve is adjusted for low peak luminance, then grayscale expression is enhanced, but image brightness is reduced
Solution Approach 1:
The patent uses parameter changes to select between different tone mapping curves based on input peak luminance. For low peak luminance images, the system applies a specific tone mapping curve that enhances grayscale expression while maintaining brightness through careful parameter selection. This resolves the contradiction by adapting the mapping parameters to balance both grayscale expression and brightness preservation.
Data Source
AI summary
An image display apparatus is disclosed. The image display apparatus according to an embodiment of the present disclosure includes: a display; and a signal processing device to output an image signal to the display, wherein, in response to an input peak luminance of an input image being equal to or lower than a reference peak luminance, the signal processing device is configured to perform third tone mapping, based on a combination of first tone mapping corresponding to the input peak luminance and second tone mapping corresponding to the reference peak luminance, and output a signal corresponding to the third tone mapping. Accordingly, grayscale expression can be enhanced.