Projection Device Luminance Control via Frame Segmentation
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Solution Overview
Problem
Existing projection devices face challenges in maintaining the color purity of a black background due to increased luminance when brighter objects are present, which affects the contrast ratio and overall image quality.
Innovation Solution
A projection device with a frame determination unit that analyzes gray level distributions to identify dark-like frames and sub-frames, adjusting luminance accordingly to ignore non-dark-like sub-frames and compute luminance reference values based on unignored areas, thereby maintaining the color purity of the black background.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the luminance of the light source is adjusted according to global image detection to enhance dynamic contrast, then the contrast ratio is improved, but the color purity of the black background deteriorates when brighter objects appear
Solution Approach 1:
The patent divides the image frame into multiple sub-frames and further segments each sub-frame into multiple regions. By analyzing the gray level distribution in each region separately, the system can identify dark-like regions and calculate luminance reference values based only on those regions, excluding brighter objects that would otherwise contaminate the calculation. This segmentation approach resolves the contradiction by enabling contrast enhancement without compromising black background purity.
Solution Approach 2:
The patent applies different processing strategies to different regions of the image. Dark-like regions are used for luminance reference calculation while brighter regions are excluded. This local quality approach ensures that the luminance adjustment is based purely on dark background characteristics, maintaining color purity while still enabling dynamic contrast enhancement through localized analysis.
2Illumination intensity
If the luminance of the projection light source is raised to accommodate brighter objects in the image, then the visibility of brighter objects is improved, but the color purity of the black background is compromised
Solution Approach 1:
By segmenting the image into sub-frames and regions, the system can calculate luminance reference values based exclusively on dark-like regions, ignoring brighter objects. This allows the projection light luminance to be adjusted according to the actual black background requirements rather than being constrained by the presence of brighter objects, thus maintaining color purity while ensuring adequate illumination.
Solution Approach 2:
The patent calculates luminance reference values using only a subset of regions (dark-like regions) rather than the entire frame. This partial action approach ensures that the luminance setting is optimized for black background purity without being influenced by brighter objects, resolving the contradiction between illumination intensity and color purity.
Data Source
AI summary
A projection device and a luminance control method of a frame are provided. The luminance control method of the frame includes the following steps. Whether the frame is a dark-like frame or not is determined according to a gray level distribution of the frame and whether at least one sub-frame of the frame is a dark-like sub-frame or not is determined according to a gray level distribution of the sub-frame. When the frame is the dark-like frame and the sub-frame is not the dark-like sub-frame, a corresponding area of the sub-frame is ignored and a reference value of luminance is computed according to a part corresponding to the unignored area in the frame. The luminance of a projection light of the projection device is adjusted according to the reference value of luminance.