A single scan longitudinal calibration technique for fringe projection profilometry

Fringe projection profilometry is an efficient approach for shape reconstruction. An essential step in fringe projection profilometry is the calibration of both the transverse (axial) and longitudinal (depth) directions. In the present work, a longitudinal calibration method for fringe projection profilometry is proposed. In the proposed approach a stepped board is used to calibrate the measurement system in a single scan. Each step of the board represents a different position and therefore only a single scan is required to calibrate the measurement system. The proposed approach neither requires a translating stage nor taking multiple scans of a reference board at various positions, as in traditional techniques. The proposed approach was validated by reconstructing a real object and evaluating its main dimension. Experimental results show the reliability and effectiveness of the proposed method. Measurement errors evaluated for a system calibrated using the proposed approach are relatively smaller than those obtained using a traditional calibration approach. The proposed approach is considerably faster than traditional calibration methods besides being much simpler to implement for onsite measurements.