Design And Implementation Of Portable Phase Measurement Profilometry System Based On FPGA

In recent years,Fringe Projection Profilometry(FPP)has received widespread attention and research under the background of rapid development of machine vision and optical measurement.As a typical representative of FPP,Phase Measurement Profilometry(PMP)is widely used in machine manufacturing,reverse engineering,rail traffic safety monitoring,medical diagnosis and other fields due to its advantages of high accuracy,fast speed and noncontact.The generation,projection,image acquisition,and image storage of fringe patterns in traditional measurement systems of PMP rely on computer control.This system is large in size,high in cost,low in integration,and inconvenient to carry in engineering applications.To solve this problem,a portable PMP system based on FPGA is studied and designed in this thesis.This system mainly consists of fringe patterns generation module,image acquisition module and image storage module.The fringe patterns generation module can generate sine fringe,ronchi fringe,composite fringe,composite dual-frequency fringe and color fringe with adjustable frequency,phase and style by FPGA in real time according to the different measurement object and environment.Besides,it connects the DLP projector with VGA video conversion interface to project the fringe patterns on the surface of the measured object.The selection input of fringe patterns frequency,phase,style and other parameters is realized through a matrix keyboard,but the specific parameters of the current output fringe patterns are displayed in real time through the LCD module.This kind of fringe patterns generation module is easy to operate and fast to project.Meanwhile,it improves the flexibility of fringe selection output.In order to realize the image acquisition and storage out of the control of the computer in the measurement,an image acquisition and storage module based on FPGA is designed.Firstly,the camera module OV5640 is driven by FPGA to acquire and cache the distorted fringe patterns information,which is highly modulated by the object.Next,combined with the SOPC Builder solution and the Nios II soft core processor,The acquired image data is encapsulated into BMP format with the help of Nios II IDE software platform.After that,the image is stored in the SD card through the transplanted FATFS file system.Finally,a experimental platform for portable PMP system based on FPGA is built.And the system calibration and actual object measurement experiments were carried out.Through experimental analysis,it can be concluded that the system can flexibly generate fringe patterns with adjustable frequency,phase and pattern,and the sine fringe has good sinusoidal property.On the other hand,it is feasible to use the portable PMP system to measure the contours of threedimensional objects,and the system integrates FPGA,projector,and camera.It has the advantages of small size,low cost,convenient carrying,strong specificity,and simple operation,which expands the application scenarios of PMP.