Display Device Gamma Curve Control for Middle Luminance
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Solution Overview
Problem
Conventional image processing devices cannot control luminance in the middle luminance region of an image, as they only generate gamma curves for near-black and near-white ranges, leaving the middle luminance region unmanaged.
Innovation Solution
A display device and method that acquire input luminances for three reference points (low, high, and middle luminance regions) to generate a gamma curve, allowing for luminance conversion that adjusts the slope between these points to control luminance in the middle region, enabling effective luminance management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional image processing devices generate gamma curves only for near-black and near-white ranges, then contrast in extreme luminance regions is improved, but luminance control in the middle luminance region is lost
Solution Approach 1:
The patent segments the luminance range into three distinct regions (low, middle, and high luminance) and generates separate gamma curves for each region. This is achieved by dividing the luminance histogram into multiple ranges and calculating different gamma values for each range, thereby enabling independent control of luminance in each segment while maintaining overall image quality.
Solution Approach 2:
The patent applies local quality by optimizing gamma correction specifically for the middle luminance region where most image data is concentrated. By calculating a dedicated gamma value for the middle luminance range based on the histogram distribution, the system enhances local image quality in the most critical region without compromising other luminance ranges.
2Manufacturing precision
If gamma curves are optimized for black-end and white-end ranges, then contrast in extreme regions is enhanced, but the middle luminance region remains uncontrolled
Solution Approach 1:
The patent implements dynamic gamma curve generation that adapts to the specific luminance distribution of each input image. By analyzing the histogram and dynamically determining appropriate gamma values for different luminance ranges, the system achieves precise luminance control without requiring complex pre-defined gamma curves for all possible image types.
Solution Approach 2:
The patent changes the gamma parameter based on the luminance range being processed. Different gamma values are applied to different luminance ranges (low, middle, high), allowing precise control over luminance transformation characteristics for each region while maintaining a relatively simple overall processing framework.
Data Source
AI summary
A display device (101) includes: an output luminance calculation section (83) configured to generate an output luminance for an input luminance for a first reference point residing in a low luminance region, an output luminance for an input luminance for a second reference point residing in a high luminance region, and an output luminance for an input luminance for a third reference point residing between the first and second reference points in such a manner that a straight line connecting the first and third reference points has a different slope than does a straight line connecting the third and second reference points; and a luminance conversion section (85) configured to convert input luminances in the input image to output luminances based on a gamma curve specified using the input and output luminances for the first, second, and third reference points, to output the output image.