Development of three-dimensional pavement texture measurement technique using surface structured light projection

To realize active, non-contact, high-precision and full-field measurement of pavement texture, an innovative surface structured light projection (SSLP) based technique is developed in this paper. Firstly, the sinusoidal intensity encoded surface structured light is projected through the optical fiber interference, and the highresolution industrial camera is used to capture the deformed fringe pattern modulated by the measured pavement. Then, a pre-processing method is proposed to suppress the noise and uneven background illumination in the captured fringe image. After that, a two-dimensional continuous wavelet transform method (2D-CWTM) is executed, and the wrapped phase can be demodulated accurately from the wavelet ridge. Finally, the 2 pi steps in the wrapped phase are removed by a phase unwrapper, and the measured pavement texture elevation can be obtained according to the phase-height mapping relationship. Both laboratory and field tests demonstrate the functionality and effectiveness of the proposed SSLP technique in pavement texture measurement.