Projector Calibration Unit for 3D Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image projection devices require extensive manual adjustment and calibration, leading to inefficiencies in three-dimensional measurement and parameter estimation, particularly due to the challenges of lens distortion and the reliance on camera calibration results for projector calibration.
Innovation Solution
The image projection device incorporates a projector calibration unit that performs ray tracing and distortion correction using a known checker pattern, estimating parameters with sub-pixel accuracy and considering lens distortion, allowing for independent projector calibration without relying on camera calibration results, and utilizes the Levenberg-Marquardt method for nonlinear optimization to estimate perspective projection matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional calibration methods are used for projector and camera, then calibration can be performed, but extensive manual adjustment and long man-hours are required
Solution Approach 1:
The system performs automatic calibration where the projector and camera self-calibrate using captured images and coordinate correspondence. The computer automatically calculates calibration parameters without requiring manual adjustment, making the system self-sufficient in the calibration process.
Solution Approach 2:
The calibration pattern is displayed on a calibration object before the actual measurement process. This preliminary display of known patterns allows the system to pre-capture images and pre-calculate coordinate correspondences, establishing calibration parameters in advance.
2Measurement precision
If calibration is performed using camera results, then projector calibration can be achieved, but accuracy is compromised due to lens distortion and dependency on camera calibration
Solution Approach 1:
The calibration process is segmented into independent steps: camera calibration, projector calibration, and 3D measurement. Each component is calibrated independently using its own captured images and coordinate correspondences, allowing separate optimization and reducing error propagation between components.
Solution Approach 2:
The system changes the calibration approach by using direct coordinate correspondence between projector and world coordinates, rather than relying on camera-mediated calibration. This parameter change in the calibration methodology improves reliability by eliminating dependency on camera calibration results.
3Measurement precision
If extensive manual adjustment is performed for high accuracy calibration, then parameter estimation improves, but productivity decreases
Solution Approach 1:
The manual mechanical adjustment process is replaced with an automated computational system. The computer automatically captures images, calculates coordinate correspondences, and determines calibration parameters through algorithms, substituting manual mechanical adjustment with automated digital processing.
Solution Approach 2:
The system uses feedback from captured images to automatically adjust and refine calibration parameters. The computer analyzes the correspondence between known calibration pattern coordinates and captured image coordinates, using this feedback to calculate and optimize projector and camera parameters automatically.
Data Source
AI summary
There is provided an image projection device including a camera, a projector configured to project an image, a camera calibration unit configured to perform calibration of the camera, a projector calibration unit configured to perform calibration of the projector, and an image correction unit configured to correct the image projected from the projector based on a result of the calibration. The projector calibration unit performs ray tracing of a known checker pattern on which structural light is projected by the projector, and estimates parameters by acquiring correspondence relation between a lattice point of the checker pattern and projector coordinates.