Multi-Projector Overlap Region Calibration Using Gray Code Segmentation
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Solution Overview
Problem
Existing multi-projection systems face challenges in achieving accurate and efficient calibration, particularly in overlap regions where images from multiple projectors intersect, leading to prolonged calibration times and reduced accuracy.
Innovation Solution
A projection system controlling method that identifies specific correspondences between pixels on the display surface and captured images for each projector, using a combination of calibration images and Gray code images projected in a time-division manner to enhance accuracy in overlap regions, allowing for more precise keystone correction and reduced calibration time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plurality of Gray code images are used in calibration, then calibration accuracy is improved, but calibration time increases
Solution Approach 1:
The patent divides the projection region into multiple regions (first projection region, second projection region, and overlap region) and applies different calibration strategies to each region. Gray code images are used only in the overlap region where high accuracy is critical, while other regions use standard calibration images, thus reducing overall calibration time while maintaining accuracy where needed.
Solution Approach 2:
The patent applies different calibration methods to different spatial locations: the overlap region receives enhanced calibration using Gray code images for maximum accuracy, while non-overlap regions use conventional calibration. This local differentiation optimizes the balance between accuracy and time consumption.
2Measurement precision
If calibration is performed across the entire projection region, then overall accuracy is improved, but time consumption increases
Solution Approach 1:
The patent segments the calibration process by identifying the overlap region between multiple projectors and applying enhanced calibration only to this specific area. The first projector calibrates its first projection region, the second projector calibrates its second projection region, and both work together to calibrate the overlap region with higher precision using Gray code images.
Solution Approach 2:
Instead of applying the most accurate but time-consuming Gray code calibration to the entire projection region, the patent applies it partially only to the overlap region where it is most needed. This partial action achieves the necessary accuracy improvement without the full time penalty of comprehensive high-precision calibration.
3Area of stationary object
If multiple projectors are used to create a tiled image, then display area is expanded, but calibration complexity increases
Solution Approach 1:
The patent divides the multi-projector system into independent calibration units (first projector with first imaging apparatus, second projector with second imaging apparatus) that can be calibrated separately. Each projector-calibration apparatus pair performs independent calibration on its designated region, simplifying the overall calibration process despite the expanded display area.
Solution Approach 2:
The patent creates a universal calibration framework that works for both single and multi-projector configurations. The same basic calibration process applies to each projector, with the addition of overlap region calibration using Gray code images. This multi-functional approach handles both individual projector calibration and coordinated multi-projector calibration uniformly.
Data Source
AI summary
A projection system controlling method includes identifying a first correspondence, identifying a second correspondence, identifying a third correspondence between a plurality of pixels corresponding to an overlap region in an image projected by a first projector, accuracy of the third correspondence is higher than accuracy of the first correspondence, identifying a fourth correspondence between a plurality of pixels corresponding to the overlap region in an image projected by a second projector, accuracy of the fourth correspondence is higher than accuracy of the second correspondence, projecting an image onto a region different from the overlap region based on the first correspondence, projecting an image onto the overlap region based on the third correspondence, projecting an image onto a region different from the overlap region based on the second correspondence, and projecting an image onto the overlap region based on the fourth correspondence.