Electronic Mottling Compensation for High-Contrast Projector Screens
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Solution Overview
Problem
Visual displays in simulators with high contrast projectors exhibit brightness variations (mottling) due to non-uniform paint coatings, distracting users and degrading the training experience.
Innovation Solution
A method and system using a processor to apply spatial frequency filters to captured images, determining and outputting projector-space compensation filters to adjust image brightness, compensating for brightness variations on the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high contrast projection is used to improve display quality, then image contrast is improved, but brightness variations (mottling) become visible and distracting
Solution Approach 1:
The patent applies local quality by creating a spatially varying compensation filter that adjusts brightness on a pixel-by-pixel basis across the screen. The filter is generated by capturing an image of a uniform reference projection, analyzing the actual brightness distribution, and creating compensation values tailored to each specific location on the screen to counteract the mottling effect.
Solution Approach 2:
The patent changes the brightness parameter locally across different regions of the projected image. By modifying the intensity values in the compensation filter based on the captured screen image, the system adjusts the illumination intensity parameter to compensate for non-uniformities while preserving the overall high contrast characteristics of the display.
2Manufacturing precision
If uniform paint coating is improved to reduce mottling, then manufacturing complexity increases, but brightness uniformity improves
Solution Approach 1:
The patent replaces the mechanical painting system with a digital compensation system. Instead of relying on complex robotic painting arms to achieve perfect uniformity, the system uses computational methods to analyze the actual screen brightness distribution and generate a digital filter that compensates for the non-uniformities, substituting mechanical precision requirements with software-based correction.
Solution Approach 2:
The patent creates a digital copy of the screen's brightness characteristics by capturing an image of a uniform reference projection. This captured image serves as a model of the actual screen non-uniformities, which is then processed to generate the compensation filter, allowing the system to work with a digital representation rather than physically reworking the screen.
3Manufacturing precision
If spatial frequency filtering is applied to compensate for mottling, then brightness uniformity improves, but processing complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating the compensation filter before actual projection. The system captures a reference image, processes it through spatial frequency filtering to remove mottling artifacts, and generates the compensation filter in advance. This pre-processing approach allows the actual projection to use a simple lookup and application of pre-computed correction values rather than performing complex filtering in real-time.
Data Source
AI summary
A method for generating a digital filter for adjusting a brightness of a screen, the method being executed by a processor, the method comprising: receiving a captured image of a screen on which a reference image is projected by a projector, the captured image being captured by a camera; applying a spatial frequency filter to the captured image, thereby obtaining a spatially filtered image; determining a projector-space compensation filter based on the spatially filtered image, the projector-space compensation filter being configured for adjusting a brightness of the acquired image; and outputting the projector-space compensation filter.