Display Device Dynamic Range Expansion Grayscale Clustering
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Solution Overview
Problem
Conventional contrast enhancement technologies fail to fully utilize increased output bits, leading to grayscale clustering and contour occurrence when expanding the dynamic range of images, especially when the number of output bits exceeds the number of input bits.
Innovation Solution
A display apparatus and method that generate a second image with an expanded dynamic range by applying a first and second gain to an input image, then apply a degradation model to modify pixel values based on difference values, minimizing grayscale clustering and contour occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the number of output bits is increased to expand dynamic range, then contrast enhancement is improved, but grayscale clustering and contour occurrence are caused
Solution Approach 1:
The patent applies a preliminary gamma correction to the input image before contrast enhancement, and performs bit filling in advance to prepare the image data for expanded dynamic range processing. This preliminary preparation prevents grayscale clustering and contour artifacts from occurring during the contrast enhancement process.
Solution Approach 2:
The patent changes the bit depth parameter from the original input bit depth to an expanded output bit depth, and applies gamma correction parameters to transform the image data. By adjusting these parameters systematically, the patent achieves expanded dynamic range while maintaining grayscale precision and avoiding artifacts.
2Device complexity
If conventional transfer function is used for contrast enhancement, then processing simplicity is maintained, but output bits are not fully utilized
Solution Approach 1:
The patent performs preliminary gamma correction and bit filling operations before the main contrast enhancement process. This preliminary action prepares the image data in a format that enables full utilization of output bits while keeping the main processing pipeline relatively simple and systematic.
Solution Approach 2:
The patent implements a continuous processing pipeline that includes gamma correction, contrast enhancement with expanded bit depth, and bit filling operations. This continuous chain of useful actions ensures that the increased number of output bits are fully utilized throughout the entire processing flow, rather than being wasted.
Data Source
AI summary
A display apparatus is provided. The display apparatus according to an exemplary embodiment includes a display, and a processor configured to generate a second image and a third image where a dynamic range is expanded by respectively applying a first gain and a second gain to an input first image, generate a degraded image of the second image by applying a predetermined degradation model to the second image, based on a difference value between a pixel of the degraded second image and a pixel of the third image satisfying a predetermined condition, modify a pixel value of the second image based on the difference value, and output the second image where the pixel value is modified through the display.