Accurate and flexible calibration method for a 3D microscopic structured light system with telecentric imaging and...

Area of Science:

• Optics and Photonics
• Metrology
• Precision Engineering

Background:

• Accurate 3D imaging of micro-structures is vital for advanced manufacturing and quality control.
• Existing methods often struggle with depth of field and measurement range limitations.

Purpose of the Study:

• To propose an accurate and flexible calibration method for a 3D microscopic structured light system.
• To enhance 3D imaging and metrology capabilities for complex micro-structures.

Main Methods:

• Development of a fringe projection 3D microscopy (FP-3DM) system using a telecentric camera and Scheimpflug projector.
• Implementation of a joint calibration method incorporating pinhole imaging and Scheimpflug distortion models.
• Utilizing optimized local homography and the perspective-n-point (PnP) method for accurate correspondence and 3D coordinate estimation.

Main Results:

• The developed FP-3DM system leverages telecentric imaging for an increased depth of field and measurement range.
• The calibration method achieved a re-projection error below 1µm.
• 3D repeated measurement error using feature fitting was less than 4µm within a 10x50x40mm volume.

Conclusions:

• The proposed calibration method enables high-resolution and high-precision 3D imaging for micro-structures.
• The system demonstrates significant improvements in accuracy and measurement range for industrial inspection.
• The validated performance supports its application in precision manufacturing and metrology.