Image Processing Circuit Sub Frame Signal Generation for HDR Grayscale
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Solution Overview
Problem
Existing HDR image processing techniques face limitations in expressing the full dynamic range due to video format, signal transmission interface, and monitor expression performance, resulting in inadequate grayscale representation and incorrect subject reflectance in screen luminance.
Innovation Solution
An image processing circuit and method that generates video signals for a display device by controlling the light emission time of light emission elements for each sub frame based on exposure conditions, allowing for the effective reproduction of grayscale information and accurate representation of subject reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple images are combined to extend dynamic range, then the number of expressible grayscales increases, but the dynamic range is reduced due to video format and signal transmission interface limitations
Solution Approach 1:
The patent divides the display period into multiple sub-frames, with each sub-frame displaying an image captured under specific exposure conditions. This temporal segmentation allows the display to present multiple dynamic range levels simultaneously without combining them in a way that limits the expressible grayscale quantity, thereby resolving the contradiction between the number of grayscales and dynamic range.
2Quantity of substance
If multiple images are simply displayed as sub frames, then the number of display grayscales increases, but information of the subject is displayed in an overlapping manner and luminance fails to correctly express subject reflectance
Solution Approach 1:
The patent applies different exposure condition images to different sub-frames with specific local quality characteristics. Each sub-frame is assigned an image captured under corresponding exposure conditions, ensuring that the luminance of each sub-frame accurately represents the subject reflectance for that specific exposure level, thereby preventing information overlap and maintaining subject accuracy.
Solution Approach 2:
The patent changes the exposure condition parameter for each sub-frame image capture. By capturing images under different exposure conditions and assigning them to different sub-frames, the system maintains accurate subject reflectance representation while increasing the number of display grayscales, thus resolving the contradiction between grayscale quantity and information accuracy.
3Measurement precision
If HDR technology is implemented with multiple exposure conditions, then the dynamic range is extended, but the complexity of the combining process increases
Solution Approach 1:
Instead of combining multiple exposure images through complex processing, the patent segments the display time into sub-frames and assigns different exposure condition images to each sub-frame. This temporal segmentation approach extends dynamic range while avoiding the complexity of image combining processes, as each sub-frame simply displays its assigned image without requiring complex integration.
Data Source
AI summary
There is provided an image processing circuit including a sub frame signal generation unit configured to receive n pieces of image information of n images which are obtained by photographing the same scene under n (n is a natural number equal to or greater than 2) exposure conditions and the n exposure conditions at the time of the photographing as input. When a display video of one scene is constituted by a maximum of n sub frames, the sub frame signal generation unit generates video signals of the maximum of n sub frames by controlling a light emission time of light emission elements for each sub frame according to the n exposure conditions.