Color Sequential Display Dithering for Artifact Reduction
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Solution Overview
Problem
Traditional micro-mirror displays and other projection technologies suffer from artifacts such as color break-up, motion contour, static contour, and jitter, particularly in areas of high contrast and when objects with gradual color gradations move, due to limitations in bit width and dithering speed.
Innovation Solution
The method involves generating and displaying a sequence of dithered sub-frames instead of traditional frames, using dither patterns that group pixel data into sub-groups across color channels, and modifying bit weights to reduce artifacts like color break-up, motion contour, and jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dither patterns are applied to reduce static contour, then manufacturing precision is improved, but device complexity increases due to the need for multiple dither patterns and frame sequences
Solution Approach 1:
The patent divides the display frame into multiple sub-frames and applies different dither patterns to each sub-frame. This segmentation allows the system to reduce static contour artifacts by distributing the dithering across multiple temporal segments, thereby improving manufacturing precision without requiring a single complex dither pattern for the entire frame
Solution Approach 2:
The patent employs periodic dither patterns that are applied in a repeating sequence across multiple frames. By using periodic action with carefully selected pattern sequences, the system achieves effective static contour reduction while maintaining manageable device complexity through the regular, predictable nature of the pattern repetition
2Reliability
If dithering speed is increased to reduce jitter, then reliability is improved, but device complexity increases due to faster switching requirements
Solution Approach 1:
The patent dynamically adjusts the dithering process by applying different dither patterns to different sub-frames within the same frame period. This dynamic approach allows the system to achieve effective jitter reduction through rapid pattern switching without requiring uniformly high dithering speeds across all pixels, thereby improving reliability while managing device complexity
Solution Approach 2:
The patent pre-calculates and stores multiple dither patterns in advance, selecting and applying them in a predetermined sequence. This preliminary preparation of dither patterns allows the display system to achieve fast effective dithering for jitter reduction without requiring complex real-time pattern generation, thus improving reliability while keeping the actual display operation simpler
3Measurement precision
If bit width is increased to reduce color break-up, then measurement precision is improved, but loss of substance increases due to higher data requirements
Solution Approach 1:
The patent changes the temporal parameter of color projection by displaying multiple sub-frames with different dither patterns instead of increasing the spatial bit width. This parameter change allows the system to achieve better color representation accuracy and reduce color break-up artifacts without proportionally increasing data bandwidth consumption, as the improvement comes from temporal dithering rather than higher resolution color data
4Manufacturing precision
If the number of dither patterns is increased to reduce motion contour, then manufacturing precision is improved, but productivity decreases due to more frames to process
Solution Approach 1:
The patent segments each display frame into multiple sub-frames, each processed with a different dither pattern. This segmentation allows motion contour reduction to be achieved through the combined effect of multiple simpler sub-frames rather than requiring one complex high-resolution frame, thereby improving manufacturing precision while maintaining better productivity compared to processing fewer, more complex frames
Solution Approach 2:
The patent applies dither patterns at a level that exceeds what would be needed for a single frame, distributing the dithering action across multiple sub-frames. This partial action approach, where each sub-frame uses a simpler dither pattern, collectively achieves superior motion contour reduction while maintaining processing throughput, as each sub-frame can be processed more quickly than a single complex frame would require
Data Source
AI summary
Methods, systems, and apparatus, including computer program products, for reducing artifacts in a color sequential display system. A frame of a digital image is displayed by receiving frame data, determining dither patterns, applying the dither patterns to the data, and displaying the dithered data. Each pixel of a frame of a digital image is displayed by receiving pixel data, grouping the pixel data for the color channels of the image into a plurality of sub-groups of pixel data; and displaying the pixel according to a sequence that separates each pair of sub-groups for a color channel by a sub-group for another color channel. Modified pixel data can be generated by replacing parent bits in the pixel data with corresponding pluralities of divided child bits, where all the child bits for a given parent bit have a divided weight that adds up to the parent bit's weight.