Dynamic Range Compression Device Saturation Detection Circuit
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Solution Overview
Problem
Existing HDR compression devices fail to maintain luminance values when extreme deviations in RGB colors occur, leading to decreased luminance and potential black spots in images due to overflow issues during data compression.
Innovation Solution
A dynamic range compression device with a saturation detection circuit and data distribution circuit that redistributes pixel values to maintain luminance by detecting saturation and redistributing data from saturated to non-saturated pixels, preventing luminance decrease during HDR compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If data compression is performed by converting luminance value Y into luminance value Y1 using only luminance information, then data compression ratio is improved, but luminance value significantly decreases when extreme deviation in RGB colors is present
Solution Approach 1:
The saturation detection circuit performs preliminary detection of color saturation in the RGB image before luminance conversion. By identifying pixels with extreme color deviations in advance, the system can apply appropriate correction measures during the compression process, preventing luminance value degradation before it occurs.
Solution Approach 2:
The patent introduces an intermediate processing step where pixels detected as saturated are handled differently during luminance conversion. Instead of directly converting all pixels using the same formula, saturated pixels are routed through a special processing path that maintains their luminance values, acting as an intermediary mechanism between standard compression and quality preservation.
2Loss of substance
If pixel values of RGB data are recalculated based on converted luminance value Y1, then data compression is achieved, but ratio between pixel values between RGB data is not maintained
Solution Approach 1:
The patent applies different processing qualities to different regions of the image based on local color characteristics. Saturated pixels (those with extreme color deviations) receive special handling to preserve their RGB ratios, while non-saturated pixels undergo standard luminance-based compression. This local differentiation maintains color accuracy where needed while achieving compression overall.
3Device complexity
If only luminance value of one specific color is large while other colors have low pixel values, then color data compression is simplified, but overflow occurs in internal register and luminance value becomes extremely decreased
Solution Approach 1:
The saturation detection circuit performs preliminary identification of pixels that are likely to cause overflow issues. By detecting extreme color deviations before the compression and recalculation process, the system can prepare appropriate handling strategies, such as applying gain compensation or alternative conversion formulas, to prevent register overflow and luminance degradation.
Solution Approach 2:
The patent implements a protective mechanism by detecting saturated pixels in advance and applying corrective measures during compression. This beforehand cushioning prevents the harmful effect of overflow and extreme luminance decrease from occurring, ensuring reliable luminance values even for pixels with extreme color deviations.
Data Source
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AI summary
According to one embodiment, there is provided a dynamic range compression device which includes a saturation detection circuit that detects saturation of each color data for each pixel depending on whether a value of the each color data for each pixel in a frame image converted from color data corresponding to a first luminance dynamic range to color data corresponding to a second luminance dynamic range exceeds a predetermined saturation value or not and a data distribution circuit that calculates a data amount necessary for the pixel in which saturation is detected to maintain a luminance value in a state of not being saturated and distributes and outputs the calculated data amount to other non-saturated color data which is not saturated other than saturated color data in which saturation is detected in the pixels in which saturation is detected.