Projector Calibration Without a Calibration Plate
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Solution Overview
Problem
Existing projection methods require the preparation of both a projector and a calibration plate, which is time-consuming and effort-intensive for users.
Innovation Solution
A method involving projecting an image onto a projection surface, picking it up with a camera, generating correspondence relationships between pixel coordinates, estimating internal and external parameters of the optical system, and adjusting the projection based on these relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a calibration plate is used to calculate projector parameters, then measurement precision is improved, but device complexity and user effort increase
Solution Approach 1:
The invention extracts and removes the calibration plate from the parameter calculation process. Instead of requiring a separate calibration plate, the system uses the projection surface itself as the reference, eliminating unnecessary equipment while maintaining measurement precision through direct coordinate mapping between projected images and captured images
Solution Approach 2:
The projection surface serves multiple functions: it acts as both the display medium for the projection image and the reference object for coordinate mapping. This multi-functionality eliminates the need for dedicated calibration equipment, reducing device complexity while preserving the ability to accurately calculate projector parameters
2Measurement precision
If a calibration plate is prepared for parameter calculation, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system performs preliminary coordinate mapping by projecting a test pattern and capturing it with the camera before actual parameter calculation. This preliminary action establishes the correspondence relationship between projection coordinates and image coordinates, enabling accurate parameter calculation without requiring time-consuming calibration plate preparation during actual use
Solution Approach 2:
The system uses itself (the projector and camera combination) to perform the calibration function that would otherwise require external equipment. By projecting images and capturing them to establish coordinate relationships, the system self-calibrates without requiring user preparation of calibration plates, significantly reducing setup time while maintaining precision
Data Source
AI summary
A projection method includes: projecting a projection image onto projection surface from projector; acquiring picked-up image formed by picking up projection image with camera having a first internal parameter; generating a first correspondence relationship in which coordinates of a plurality of first pixels in picked-up image and coordinates of a plurality of second pixels on display panel of projector are associated with each other; acquiring state information indicating a state of an optical system of projector; estimating a second internal parameter of optical system, based on a second correspondence relationship in which the second internal parameter and the state of the optical system are associated with each other, and the state information; and estimating external parameter indicating one or both of a position and an attitude of the projector in relation to the camera, based on the first internal parameter, the first correspondence relationship, and the second internal parameter.