Luminance Correction Apparatus for Dynamic Range Expansion
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Solution Overview
Problem
Existing image processing technologies face challenges in performing dynamic range expansion without removing overshoot and undershoot from video signals, leading to luminance crushing and insufficient dynamic expansion.
Innovation Solution
An image processing apparatus that generates a second image through predetermined processing on an input image, determines a luminance correction range based on high and low luminance ranges, and corrects luminance values within this range to prevent luminance crushing while allowing for suitable dynamic expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dynamic range expansion is uniformly performed after removing overshoot and undershoot from a video signal, then luminance correction can be applied, but the luminance of shoot areas may fall outside the displayable range causing luminance crushing
Solution Approach 1:
The patent applies different luminance correction strategies to different regions of the image. Shoot areas (identified by saturation threshold) receive one type of correction while non-shoot areas receive another type, preventing luminance crushing in saturated regions while maintaining dynamic range expansion in other areas.
Solution Approach 2:
The patent dynamically adjusts luminance correction parameters based on image content analysis. By detecting saturation levels and calculating appropriate correction amounts, the system adapts the luminance correction to prevent crushing while achieving desired dynamic range expansion.
2Object-affected harmful factors
If dynamic range expansion is performed without removing overshoot and undershoot from the video signal, then luminance crushing can be avoided, but sufficient dynamic expansion cannot be achieved
Solution Approach 1:
The patent selectively removes overshoot and undershoot only in shoot areas where saturation is detected, while preserving them in non-shoot areas. This localized approach prevents luminance crushing in saturated regions while maintaining dynamic expansion effectiveness in other parts of the image.
Solution Approach 2:
Instead of completely removing overshoot and undershoot or applying uniform correction, the patent applies partial correction only where necessary (in shoot areas with saturation). This partial action approach achieves the minimum necessary correction to prevent crushing while preserving dynamic expansion in other areas.
3Device complexity
If a fixed luminance correction approach is applied to all image regions, then processing is simple, but the correction cannot adapt to different image content causing luminance crushing in shoot areas
Solution Approach 1:
The patent performs preliminary analysis of the image to identify shoot areas and saturated pixels before applying luminance correction. By detecting saturation levels and calculating correction parameters in advance, the system prepares region-specific correction strategies that prevent luminance crushing while maintaining simplicity in the actual correction application.
Data Source
AI summary
An image processing apparatus includes an image processing unit configured to generate a second image obtained by performing predetermined image processing on a first image representing an input image, a determination unit configured to determine a luminance correction range on the basis of image information in one of a high luminance range and a low luminance range determined in accordance with the image processing, and a luminance correction unit configured to correct a luminance value in the luminance correction range determined by the determination unit for the second image.