High-speed shape measurements by fringe projection method: SOPRA 3D

Abstract

Accurate and high-speed three-dimensional (3D) shape measurements are becoming increasingly important in many industries. Recent advances in the development of high-resolution detectors, light sources, MEMS, and computational power are enabling the availability of noncontact and noninvasive optical methods, which can be applied to new and challenging applications requiring 3D and high-speed measurements. In this paper, we describe our recent advances in the development of a fringe projection-based system for high-speed 3D shape measurements, as part of the Surface Optical Profilometry Roadway Analysis (SOPRA) system for evaluation of the public road quality within the urban infrastructure. The system is mounted on a vehicle moving at speeds of up to 100 km per hour and it consists of a custom built structured light projector and a recording and analysis sub-system. Fast-Fourier Transform (FFT) and discrete wavelet transform (DWT) single frame methods as well as optimized spatial phase unwrapping methods have been developed as part of the analysis sub-system. We have also developed innovative Graphics Processing Unit (GPU) accelerated algorithms to improve the analysis and post-processing speeds to run live phase retrieval at up 40 fps. Automatic road curvature and crack detection algorithms quantify the road quality index. The system has been field tested for real-time road measurements in daylight conditions. © The Society for Experimental Mechanics, Inc. 2014.