Projector Calibration for Non-Pinhole Optical Systems
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Solution Overview
Problem
Existing projector calibration methods do not effectively calibrate projection units with non-pinhole optical systems, which emit multiple light rays from multiple points rather than a single specific point, limiting their calibration capabilities.
Innovation Solution
A calibration apparatus and method that includes a projection unit with a non-pinhole optical system, utilizing a calibration apparatus with a memory unit, imaging unit, location-and-attitude estimation unit, reflection-point estimation unit, and passing-point-and-direction identification unit to estimate and adjust the projection patterns, allowing for the calibration of both pinhole and non-pinhole optical systems by projecting patterns onto a surface, capturing images, and calculating the location, attitude, and direction of light rays for accurate 3D shape measurement and distortion adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing calibration methods are used, then pinhole optical systems can be calibrated, but non-pinhole optical systems cannot be calibrated
Solution Approach 1:
The calibration apparatus is designed to handle both pinhole and non-pinhole optical systems through a unified calibration flow. The system automatically detects the optical system type and applies appropriate calibration algorithms, making the apparatus universally applicable to different projection unit configurations without requiring separate calibration procedures.
Solution Approach 2:
The calibration method changes key parameters based on the optical system type detected. For non-pinhole systems, the system modifies the calibration parameters to account for multiple light emission points, adjusting the mathematical models and calculation methods to match the physical characteristics of the specific optical system being calibrated.
2Measurement precision
If non-pinhole optical systems are calibrated using existing methods, then calibration can be performed, but measurement precision deteriorates
Solution Approach 1:
The calibration apparatus applies different calibration strategies tailored to specific optical system characteristics. For non-pinhole systems, it uses specialized algorithms that account for the distributed light emission points, applying locally optimized calibration methods that match the physical properties of each optical system type to achieve high measurement precision.
3Reliability
If projection patterns are projected onto surfaces for calibration, then calibration data can be obtained, but distortion and measurement errors occur with non-pinhole systems
Solution Approach 1:
The system replaces traditional geometric assumption-based calibration with a physics-based approach that models actual light ray behavior in non-pinhole optical systems. By substituting simplified mechanical models with accurate optical models that account for multiple emission points and light propagation characteristics, the system achieves reliable calibration and precise reflection point measurement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the calibration of both pinhole and non-pinhole projection units, allowing for precise 3D shape measurement and geometric distortion adjustment, resulting in high-quality image projection with reduced distortion.
Implementation Method 1
reflection-point estimation unit for estimating a reflection point of each of the multiple light rays on the pattern forming surface
Data Source
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AI summary
A calibration apparatus for calibrating a projection unit projecting light-rays includes an imaging unit for taking an image of a surface of an object having a location and an attitude, the light-rays being projected onto the surface by the projection unit; a location-and-attitude estimation unit for estimating the location and the attitude of the surface based on the image; a reflection-point estimation unit for estimating, based on the estimated location and the attitude, a reflection point at which one of the light-rays is reflected by the surface; and an identification unit for identifying both a passing point that the one of the light-rays passes and a direction in which the one of the light-rays passes the passing point, or identifying only the direction, based on multiple reflection points that are obtained by the reflection-point estimation unit with respect to multiple different locations and/or multiple different attitudes of the surface.