Flexible and simple telecentric camera calibration method.

Area of Science:

• Optics and Photonics
• Metrology
• Computer Vision

Background:

• Telecentric imaging systems are vital for accurate dimensional measurements.
• Calibration accuracy directly impacts the reliability of telecentric measurements.
• Existing calibration methods can be complex or limited in flexibility.

Purpose of the Study:

• To develop a flexible and simple calibration method for telecentric cameras.
• To enhance the measurement accuracy and robustness of telecentric imaging systems.
• To address the challenges associated with telecentric camera calibration.

Main Methods:

• Utilized the orthogonality of the rotation matrix to determine magnification.
• Employed a telecentric imaging model to solve for external parameters and resolve sign ambiguity.
• Applied the Levenberg-Marquardt (LM) nonlinear optimization method for distortion parameter estimation.

Main Results:

• Achieved a reprojection error of 0.7 pixels, corresponding to an actual dimension of 6.37 µm.
• Validated the method using standard measuring blocks and real-world objects.
• Demonstrated high measurement accuracy and robustness of the proposed calibration technique.

Conclusions:

• The proposed calibration method is effective for telecentric cameras.
• The technique offers a significant improvement in measurement accuracy and reliability.
• This approach provides a robust solution for precise dimensional metrology using telecentric imaging.