The Research And Implementation Of Center Extraction Technology Of Line Structured Light Based On ZYNQ

With the rapid development of industrial manufacturing,computer-aided technology and the increasing complexity of industrial product modeling.The information extracted by the traditional2 D image measurement system can not meet the needs of industrial production,manufacturing and inspection.At the same time,the entire industrial manufacturing system is also making continuous progress in the direction of intelligence and automation,which also puts forward higher requirements for measurement technology.The 3D measurement technology of line structured light is a non-contact,efficient,flexible,and accurate measurement method,which is widely used in industrial production to measure the surface contour of parts.Based on the 3D measurement technology of line structured light,according to the requirements analysis,this thesis designs a preprocessing and centerline extraction module that meets the requirements.The main research contents are as follows:(1)Research related technologies of FPGA algorithm implementation.The structure of 3D measurement system,the data flow of each module in ZYNQ and the general mapping method involved in the implementation of complex algorithms using FPGA are analyzed.According to the data processing and transmission requirements of the system,the modules in the system are divided reasonably.For the FPGA algorithm mapping technology,the problems that need to be paid attention to in the process of algorithm conversion are explained from three aspects: system structure,storage and computing technology.(2)In order to improve the quality of the laser fringe image captured by the CMOS sensor,the preprocessing module has been constructed on the basis of the original image acquisition channel,which includes filtering and threshold segmentation operations on the image.According to the characteristics of the light fringe itself,the filtering part uses the two-dimensional Gaussian filtering algorithm,which is realized by FPGA.In addition,in order to avoid the difference in reflectance of different analyte surfaces on the segmentation threshold,a dynamic threshold segmentation algorithm is used to adapt to the surface of the measured object with different reflectivity.(3)The Steger algorithm is implemented based on FPGA,which is used for subpixel extraction of the centerline of the line structured light stripe.In the FPGA implementation structure,the algorithm is divided into four modules: Multi-channel integration,Gaussian differential convolution,Hessian matrix eigenvalue and Eigenvector solution,Sub-pixel center point solution.It also analyzes and optimizes the using resources of Steger algorithm and the timing after placement and routing.Through the software and hardware collaborative debugging,it is finally verified that the extraction accuracy of the Steger algorithm based on the FPGA is less than 0.2 pixels in the 3D measurement system.The extraction speed has been greatly improved compared to the software.In the measurement range of width and height less than 40 mm,the measurement error of the threedimensional measurement system is ±0.1mm.