Digital PSF Pre-Compensation for Dual Modulation Projectors
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Solution Overview
Problem
Dual modulation projectors face challenges in achieving uniform contrast and brightness due to sub-optimal point spread functions (PSFs) in the relay optics between modulators, leading to artifacts and limited spatial frequency resolution.
Innovation Solution
The implementation of a digital PSF that pre-compensates for variations and imperfections in the light path by modifying the image sent to the pre-modulator, synchronizing bit sequences between pre- and primary modulators, and using multiple halftones per frame to produce a compensation image that reduces errors caused by sub-optimal PSFs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay optics are used to transfer light between modulators, then light transfer is achieved, but non-uniform PSF and artifacts are introduced
Solution Approach 1:
The patent applies preliminary action by pre-compensating for the non-uniform PSF of relay optics through digital processing of the image data before it reaches the modulators. A pre-compensation filter is applied to the input image to counteract the expected distortions, ensuring uniform PSF at the output without requiring physical modification of the relay optics.
2Measurement precision
If dual modulation is used to improve image quality, then spatial frequency resolution is enhanced, but contrast uniformity deteriorates
Solution Approach 1:
The patent implements feedback by using the known PSF characteristics of the relay optics to guide the pre-compensation process. The system characterizes the optical path and uses this information to adjust the input image, creating a closed-loop approach where the output uniformity feedback informs the input correction strategy.
Solution Approach 2:
The patent applies parameter changes by modifying the digital image parameters (pixel values, spatial distribution) before modulation to compensate for optical imperfections. The pre-compensation filter adjusts image parameters to counteract the expected non-uniformities in the optical path, ensuring uniform contrast output.
3Manufacturing precision
If pre-compensation filtering is applied to correct PSF variations, then PSF uniformity is improved, but image processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-compensating for the non-uniform PSF of relay optics through digital processing of the image data before it reaches the modulators. A pre-compensation filter is applied to the input image to counteract the expected distortions, ensuring uniform PSF at the output without requiring physical modification of the relay optics.
Data Source
AI summary
A digital PSF for use in a dual modulation display. The invention allows the use of less than optimal point spread (PSF) functions in the optics between the pre-modulator and primary modulator of a dual modulation projection system. This technique uses multiple halftones per frame in the pre-modulator synchronized with a modified bit sequence in the primary modulator to produce a compensation image that reduces the errors produced by the sub-optimal PSF. The invention includes the application to dual modulation and dual modulated 3D viewing systems.