Multi-Modulator Projector Local Dimming With Misalignment Correction
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Solution Overview
Problem
Dual and multi-modulator projector display systems face challenges in achieving improved image rendering performance and efficiency due to limitations in light processing and alignment requirements between modulators, leading to issues like bright and dark clipping, halos, and misalignment drift.
Innovation Solution
The system employs a dual or multi-modulator architecture with a light source, controller, first modulator for halftone image rendering, and a second modulator for pulse-width modulation, using a blurring optical system and light field modeling to correct for misalignment and calibrate the system, ensuring improved image rendering by creating a binary halftone image, blurring it, and projecting a pulse-width modulated image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a dual or multi-modulator projector system is used to improve image rendering performance and light efficiency, then dynamic range and light utilization are enhanced, but alignment precision and system complexity increase
Solution Approach 1:
The system divides the modulation function into multiple independent modulators (first modulator for spatial modulation, second modulator for temporal/PWM modulation). Each modulator handles a specific aspect of image rendering, allowing them to be optimized independently while working together to achieve high light efficiency and dynamic range.
Solution Approach 2:
The system incorporates feedback mechanisms where the controller receives information about the actual light output and modulator states, then adjusts control signals to maintain proper alignment and compensate for drift. This closed-loop control ensures alignment precision is maintained despite system complexity.
2Illumination intensity
If multiple modulators are employed to achieve high dynamic range, then image rendering performance improves, but system complexity and alignment requirements worsen
Solution Approach 1:
The modulation task is segmented across multiple devices: the first modulator handles spatial light distribution while the second modulator handles temporal modulation. This segmentation allows each component to be simpler while the combination achieves high dynamic range.
Solution Approach 2:
The controller serves multiple functions: generating control signals for both modulators, processing input image data, and coordinating the timing and alignment between different modulators. This multi-functionality reduces overall system complexity by centralizing control.
3Illumination intensity
If halftone images are rendered by the first modulator and blurred by the optical system, then light distribution is improved, but misalignment and halo artifacts increase
Solution Approach 1:
The blurring optical system acts as an intermediary between the first modulator's halftone image and the second modulator. It softly transitions the light distribution, preventing sharp edges that cause halo artifacts while maintaining proper light flow to the second modulator.
Solution Approach 2:
The system changes the spatial distribution parameter of light by introducing controlled blur. This parameter change transforms the sharp halftone pattern into a softer light distribution that reduces halo effects while maintaining image fidelity.
4Reliability
If iterative calibration and correction processes are implemented, then image quality is maintained over time, but processing time and system complexity increase
Solution Approach 1:
The system performs preliminary calibration during manufacturing or initial setup, establishing baseline alignment parameters and PSF models. This preliminary action reduces the need for frequent iterative calibration during normal operation, minimizing time loss while maintaining image quality.
Solution Approach 2:
The system incorporates self-calibration capabilities where the controller automatically adjusts alignment parameters based on feedback from the modulators' performance. This self-service approach maintains image quality stability without requiring external intervention or extensive processing time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances contrast ratio, reduces visual artifacts, and improves image rendering performance by avoiding alignment requirements, achieving high contrast ratios and minimizing bright and dark clipping, while allowing for continuous calibration and refinement.
Implementation Method 1
a blurring optical system with a Point Spread Function (PSF)
Data Source
AI summary
Dual and multi-modulator projector display systems and techniques are disclosed. In one embodiment, a projector display system comprises a light source; a controller, a first modulator, receiving light from the light source and rendering a halftone image of said the input image; a blurring optical system that blurs said halftone image with a Point Spread Function (PSF); and a second modulator receiving the blurred halftone image and rendering a pulse width modulated image which may be projected to form the desired screen image. Systems and techniques for forming a binary halftone image from input image, correcting for misalignment between the first and second modulators and calibrating the projector system—e.g. over time—for continuous image improvement are also disclosed.