Real-time stroboscopic laser fringe-pattern projection system

A high-speed scanning real-time stroboscopic laser fringe-pattern projection system is designed. A high-speed rotating polygon mirror and a line-structured laser cooperate to produce stable and unambiguous stroboscopic fringe patterns. The system is realized by using field programmable gate array (FPGA) to monitor photoelectric-detector signal and control the output modulation signal of laser accurately in real time. The system combines the overall projection of grating with the high accuracy of the line-structured laser light source. The projected fringe patterns have high refresh rate and high precision. In addition, the intensity, frequency, pulse width and phase shift can be controlled in real time by dynamic programming. A small size device is measured by using the proposed system, and the corresponding accurate phase and characteristic points that can show the three-dimensional shape are obtained. The proposed system shows a broad application prospect for fast three-dimensional shape precision measurements, particularly in the industrial field of three-dimensional online detection for precision devices. ©, 2014, Chinese Optical Society. All right reserved.