Projector Bitplane Coordination for Blend Zone Brightness Uniformity
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Solution Overview
Problem
In multiple digital projector systems, the overlap of images from different projectors often results in uneven brightness in blend zones, leading to visible bands of brightness and darkness, which distract from the image and reveal the multiple projectors used, due to the simultaneous projection of bitplanes by multiple projectors.
Innovation Solution
The projectors are coordinated to project bitplanes in a sequence such that only one projector is projecting a given bitplane at any time, with the bitplanes being distributed between projectors in a synchronized manner to ensure that each pixel receives light from only one projector at a time, eliminating the overlap of bitplanes and thus reducing banding artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple projectors simultaneously project bitplanes in overlap regions, then projection coverage is improved, but brightness uniformity deteriorates causing visible bands
Solution Approach 1:
The patent applies periodic action by sequentially projecting bitplanes from different projectors in a time-multiplexed manner. Instead of simultaneous projection, each projector projects its assigned bitplanes in alternating time slots, creating a periodic projection pattern that eliminates overlapping light exposure and achieves uniform brightness perception
Solution Approach 2:
The system dynamically assigns different bitplanes to different projectors based on their projection capabilities and timing. The projection sequence is dynamically coordinated so that at any given moment, only one projector is active for a specific bitplane, allowing flexible adaptation to maintain brightness uniformity across the projection area
2Illumination intensity
If electronic blending is used to adjust brightness in blend zones, then brightness uniformity is improved, but visual artifacts worsen due to banding effects
Solution Approach 1:
The patent extracts the blending function from the projection process itself and replaces it with a temporal separation approach. By removing the simultaneous projection of overlapping bitplanes and replacing it with sequential projection, the harmful blending artifacts are eliminated while maintaining brightness uniformity through proper timing coordination
Solution Approach 2:
The patent substitutes the electronic blending mechanism (which adjusts brightness through electronic control of overlapping projections) with a temporal sequencing mechanism. Instead of using electronic blending to manage overlap, the system uses time-multiplexed projection where each projector takes turns projecting its bitplanes, eliminating the need for electronic blending and its associated artifacts
Data Source
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AI summary
Techniques for reducing blend artifacts in a multiple digital projector system are provided, including a first and second projector, having respective projection fields which overlap in a blend zone and one or more control devices configured to: for a given pixel of a common image frame projected by both the first projector and the second projector in the blend zone, the given pixel of the common image frame comprising a plurality of bitplanes arranged in a sequence, control the first projector to project a first portion of the plurality of bitplanes according to the sequence; and control the second projector to project a second portion of the plurality of bitplanes according to the sequence, the second portion complementary to the first portion, such that in the common image frame only one of the first projector and the second projector projects any given bitplane of the plurality of bitplanes.