Vision-ray-calibration-based monocular deflectometry with a curved screen as its display

Area of Science:

• Optical metrology
• Surface characterization
• 3D reconstruction

Background:

• Phase measuring deflectometry (PMD) is effective for surface measurement.
• Nonplanar illumination offers advantages for curved mirror testing in PMD.
• Existing methods face limitations in measurement range and accuracy for complex surfaces.

Purpose of the Study:

• To propose a monocular deflectometry system using nonplanar illumination for enhanced curved mirror measurement.
• To develop a high-accuracy curved screen modeling method.
• To implement and validate Vision Ray Calibration (VRC) for ray distribution calibration.

Main Methods:

• A monocular deflectometry system with a camera and curved screen was designed.
• A novel curved screen modeling technique was introduced for accurate transformations.
• Vision Ray Calibration (VRC) was applied in two steps and one integrated step.
• Two screen models were integrated into the PMD system.

Main Results:

• The proposed method successfully models curved screens, enabling accurate transformations.
• VRC effectively calibrated ray distributions in the monocular PMD system.
• Simulated and actual measurements demonstrated high accuracy, repeatability, and stability for various specular surfaces.

Conclusions:

• Nonplanar illumination in monocular PMD significantly enhances measurement range and accuracy for curved mirrors.
• The developed curved screen modeling and VRC techniques provide a robust framework for specular surface reconstruction.
• This approach offers a promising solution for precise metrology of complex optical components.