Fpga-based Phase-shifting Profilometry Technology And Its Research In System Level

Surface structured light profilometry system is developing at high speed,high precision,integration and embedded.At present,high-speed structured light system mainly relies on GPU(Graphic Processing Unit)to do the calculation task of structured light decoding and 3D reconstruction.But the power consumption and volume of GPU are not suitable for the industry needs of integrated and embedded.FPGA(Field Programmable Gate Array)has excellent power consumption and computing power ratio because of its configurable hardware resources,which can be designed to a completely parallel and pipelined computing architecture,and is not limited by Von Neumann architecture.So,the heterogeneous computing platform which combines FPGA with soft core or hard core processor provides a new direction for embedded high-speed and high-precision structured light measurement system.Therefore,using FPGA to undertake or accelerate the calculation of structured light measurement system has become a new trend in the filed.In this paper,the Phase-Shifting structured light measurement technology and system implementation are studied.FPGA design is divided into calculation acceleration module,image buffering module and communication & control module,and the framework of software and hardware cooperation is adopted to give full play to the advantages of ARM +FPGA on Xilinx ZYNQ platform.A Phase-Shifting structured light measurement prototype system based on FPGA is built in this paper.In addition,the simulation and experimental verification are carried out.The research work of this paper is as follows1.Based on step-by-step backward phase unwrapping with the three frequency and four steps Phase-Shifting algorithm,the FPGA hardware structure light decoding module is designed to realize the parallel processing of the input 12 channel image data.2.Aiming at the parallel input requirement of FPGA Phase-Shifting decoding module,a multi-frame ping-pong image buffering control architecture based on AXI4 Xilinx MIG(Memory Interface Generator)is designed and implemented.The whole buffering architecture realizes the jump of read-write control state,switch of read-write ping-pong address and multchannel output.It can meet the requirements that system run single measurement or continuous dynamic measurement.3.From the point of view of hardware and software cooperation,the camera and projector are controlled in ZYNQ PS(processing subsystem),and the communication module between ZYNQ PL(programmable logic)and PS for small amount of data or large bandwidth data transmission is designed,which provides necessary support for FPGA embedded structured light measurement system to work independently.4.The PC platform and FPGA platform of structured light measurement system are built respectively,and the related experimental research is carried out.The system calibration is completed on PC platform,and the measurement experiments are carried out based on two experimental platforms.The accuracy of the FPGA Phase-Shifting profilometry system is verified.