Multi-Projector Calibration via Multi-Viewpoint Luminance Integration
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Solution Overview
Problem
Multi-projector displays suffer from artifacts such as over-compensation and hot spotting, particularly on non-Lambertian surfaces and at varying viewing angles, leading to diminished image quality in front-projected, rear-projected, and stereoscopic 3-D displays.
Innovation Solution
A system and method that uses camera measurements from multiple viewpoints to integrate compensation parameters, remapping measured luminance profiles to a common coordinate system and applying weighted reflectance functions to reduce view-dependent artifacts and hot spotting across a wider range of viewing angles, incorporating head/gaze tracking for real-time adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If compensation parameters are estimated from camera measurements taken at only one viewpoint, then the calibration process is simple and fast, but significant artifacts in the form of over-compensation appear for screens that are non-Lambertian and for viewing angles different from the camera position
Solution Approach 1:
The calibration process is segmented into multiple viewpoint measurements rather than a single viewpoint. The system divides the calibration task into multiple discrete measurement positions around the display, collecting data from each position separately and then integrating the results to create a comprehensive compensation model that accounts for viewing angle dependencies.
Solution Approach 2:
The calibration approach transitions from a single-point measurement (0D/1D) to multi-point spatial measurements (3D volumetric sampling). By adding the spatial dimension of multiple measurement positions, the system captures the angular dependence of the display surface properties, enabling accurate compensation across different viewing angles.
2Manufacturing precision
If multiple cameras at multiple viewpoints are used to measure luminance profiles, then view-dependent artifacts and hot spotting are reduced, but the device complexity and measurement time increase
Solution Approach 1:
Multiple measurement datasets from different viewpoints are merged into a unified compensation model. The system combines the luminance profile data collected from multiple camera positions through coordinate transformations and weighted integration, creating a single comprehensive set of compensation parameters that account for all measured viewing angles.
Solution Approach 2:
A coordinate transformation and integration process acts as an intermediary between the multiple camera measurements and the final compensation parameters. This intermediary step reconciles the different viewpoint measurements by mapping them to a common reference frame and combining them through weighted averaging, producing unified compensation values.
3Manufacturing precision
If compensation is optimized for a specific camera position, then the image quality is excellent from that viewpoint, but the display exhibits hot spots and artifacts when viewed from other angles
Solution Approach 1:
The compensation model incorporates local quality variations across different viewing angles. Instead of applying a single uniform compensation value, the system determines location-dependent and angle-dependent compensation parameters that are tailored to specific regions of the display and specific viewing directions, optimizing image quality for each local condition.
Solution Approach 2:
The compensation parameters become dynamic rather than static, adapting to the viewer's position and angle. The system uses the multi-viewpoint measurement data to create a dynamic compensation model that can adjust compensation values based on the actual viewing conditions, making the display performance adaptable across a range of angles rather than optimized for a single fixed position.
Data Source
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AI summary
A method for reducing view-dependent artifacts in a multi-projector system includes the steps of measuring, from multiple viewpoints, projection characteristics of an image projected by a multi-projector system, estimating view-dependent projection parameters that can reduce view-dependent artifacts, and computing rendering parameters for each projector so as to reduce the view-dependent artifacts.