Embedded Structured Light 3D Scanning System Based On DLP

3D scanning Optical technology is a set of optical, mechanical, electrical and computer technology in one of the intelligent and visible high technology. It has been widely studied and applied in some area, such as automated testing, industrial design, biomedical, virtual reality, and some reverse engineering. In recent years,3D scanner is in a hot spot, especially, the fast and portable 3D scanners.This paper studies this situation, introduces the principles and prcesses of the 3D scanning structured light projection in detail, design the DMD(digital micromirror device) as a generator of the structured light, and using FPGA as the master chip of the device to achieve high-speed DMD camera control and synchronization acquisition. According to the design ideas, build a 3D scanning system on the optical platform, and apply the four-step phase shift method to complete 3D scanning experiments. Specific research work is as follows:(1) This article design and implement the DMD based structured light generator. The system uses TI's DLP Discovery 4100 development kit, including 0.7XGA 2xLVDS A class DMD, Xilinx Virtex-5 FPGA as the main chip, as well as Micron's 64 SO-DIMM for DDR2 SDRAM. By PWM modulation, system complete the high speed DMD grayscale display, can generate sinusoidal fringe structured light of different direction and different cycles, according to the user's demand, and can be clearly and quickly projection display.(2) This paper using the main chip FPGA synchronous DMD display refresh and camera capture exposure, to complete the synchronous triggering and acquisition of sinusoidal fringe projection with high-speed camera. This system use JAI's RM series of high-speed camera whis a resolution of 640×480, the maximum can be 200Hz frame rate. By controlling the JAI camera, capture the real-time full-speed sinusoidal fringe grayscale projection for the subsequent 3D scanning experiments.(3) This paper, combined with the principle of structured light projection 3D scanning, according to the hardware design of this article, complete based on traditional four-step phase shift 3D structured light. This system can project sinusoidal fringe structured light with specified direction and period, according to the user's demand, acquire image synchronously, then using the design of software to complete the pre-processing of the captured images, phase demodulation, expand the software design phase, phase- height mapping reduced to give a 3Ddepth information and modelingThis design of the system can complete up to 464.8 per second in the different directions and periods of the sinusoidal fringe structure light show, and complete the camera trigger acquisition with 194 frames per second, and finally get a clear 3D scanning image with abundant depth information, and rebuild the 3Ddepth information.