Research On High Speed Fringe Structured Light Projection System And Design Based On DMD Technique

High speed structured light projection system is one of the key techniques for 3D measuring system to achieve high efficiency and real-time measurement. The traditional phase shifting grating system demands high accuracy mechanical movement devices which is rather structure complicated and is difficult to adjust the parameters of the fringe patterns. The traditional business projector is large in volume and is difficult to adapt to the embedded systems without triggers and fast rates, and could not realize real-time control. After researching Digital Lighting Processing(DLP) technology,we designed a high-speed structured light projection system which has a research value and practical significance in phase 3D profile measurement system based on Digital Micro-mirror Device(DMD) IC.This thesis is sponsored by projects entitled “High accuracy 3D measurement technique based on telecentric imaging and general S transformation”(E051102) and “Research of key techniques in high accuracy and high speed 3D measurement”(No. 2011125). The major research content and contributions of this paper include: 1. Researched the DLP projected techniques and analysed the importance of projection sequence and acquisition sequence for the quality of sinusoidal patterns based on the principle of Binary Pulse Width Modulation(BPWM) grayscale modulation. Proposed a way to design a high-speed structured light projection system which has synchronization of projecting and capturing to achieve high-speed and fine 3D profile. 2. Based on DLP4500 FQE, we developed a fringe structured light projector system with synchronous trigger and high-speed rates which include image acquisition and processing module, FLASH storage module,synchronous trigger function module,USB module and LED light driver module. Furthermore,the system can work off-line instead of connecting to computer. Associated with camera,it can synchronous carry out the fringes of projecting and collecting. It has high speed pattern sequence mode, 1-Bit binary pattern rates to 2130 Hz and 8-Bit grayscale pattern rates to 117 Hz. 3. Following the DLPC350 ZFF operating principle, we proposed a method that only blue LED light is used for illumination and three RGB channels load stripe structured light patterns respectively. The number of the patterns decreased to 6 from 16 which enable the RGB channels to response identically. 4. Testing the high-speed stripe structure light projector system in the ordinal embedded 3D measuring system, it carried out the synchronized control of the stripes projecting and collecting. It achieved a fine 3D profile as well.