Multi-Projector Alignment Refinement Using Embedded Calibration Patterns
Solution Overview
Problem
Current multi-projector systems require significant manual effort for alignment and are prone to misalignment due to physical movements and environmental factors, with existing automatic alignment methods being slow and visible to viewers.
Innovation Solution
The Alignment Refinement Projection System (ARPS) decodes overlapping 2D ruler images to determine projector positions, embeds calibration patterns within the content image, and uses camera projections to refine alignment without additional calibration frames, ensuring continuous automatic alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual alignment procedures are used to achieve precise projector alignment, then alignment accuracy is improved, but the time and labor required for alignment increases significantly
Solution Approach 1:
The system performs automatic alignment refinement by having the projectors continuously project calibration patterns and the system automatically captures, processes, and adjusts alignment based on captured images, eliminating the need for manual intervention in the alignment process while maintaining high precision
Solution Approach 2:
The system captures images of projected calibration patterns, processes these images to determine alignment accuracy, and uses this feedback to automatically adjust projector positions and orientations, creating a closed-loop control system that refines alignment iteratively
2Measurement precision
If traditional calibration patterns are projected for alignment refinement, then alignment precision is improved, but the calibration process becomes slow and requires multiple frames to be captured and processed
Solution Approach 1:
The system continuously projects calibration patterns and continuously captures images for processing, performing alignment refinement as an ongoing process rather than a discrete multi-step procedure, thereby maintaining both precision and speed through uninterrupted calibration cycles
3Reliability
If calibration patterns are displayed during content projection, then continuous alignment is maintained, but the calibration patterns become visible to viewers
Solution Approach 1:
The system projects calibration patterns at different brightness levels in different regions - using lower brightness in viewer-visible areas and higher brightness in overlap regions where calibration data is captured, thereby maintaining continuous alignment while minimizing viewer perception of calibration patterns
Solution Approach 2:
The system alternates between projecting calibration patterns at different intensities and capturing images at different time points, using periodic modulation of calibration pattern visibility to maintain alignment data collection while reducing continuous visibility to viewers
Data Source
AI summary
A method of aligning two portions of an image, the portions being projected by projectors on a surface to form respective projected portions of the image, a calibration pattern being embedded in each of the two portions, the method comprising capturing from the surface an image of the pattern from the projected portions, the calibration pattern extending across a combined projection area of the projectors; locating an overlap area according to locations of calibration points; determining projector image coordinates dependent upon locations in the overlap area; and aligning the two portions of the image according to the locations of control points and the locations in the overlap area.