Shenzhen University

Sichen Yan

Dong Li

Yong Tian

Jindong Tian

A calibration method is described for a telecentric imaging 3D shape measurement system, including step Sestablishing a telecentric 3D shape measurement system; Scontrolling a telecentric projection equipment to project a sinusoidal fringe pattern to a translation stage, and collecting the sinusoidal fringe pattern by a telecentric camera equipment; moving the translation stage to different depth, then obtaining absolute phase values of a pixel for calibration by a phase-shifting method; and conducting linear fitting on the series of absolute phase values of the pixel and the corresponding depths to obtain a phase-depth conversion of the measurement system; and Stransforming pixel coordinates on the image plane of the telecentric camera equipment into world coordinates through calibrating parameters of the telecentric camera equipment. A relationship between phase and depth herein is linear, and only needs to calibrate the linearity of one pixel. Therefore, the phase-depth calibration is of small complexity, high precision, good operability and strong practical applicability. Moreover, an orthographic transformation model of camera with bilateral telecentric lens is provided, which simplifies the calibration process.

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Shenzhen, China

Sichen Yan