The Laser Weld Seam Visual Measuring System Research

Weld automatic tracking technology is the key to realize the welding automation. Compared with the method of the traditional welding detection based on electromagnetics and acoustics technology, welding seam tracking technology based on vision because of the characteristics of large amounts of information,high sensitivity and high precision measurement, strong resistance to electromagnetic interference and artifacts, so the technology of welding seam tracking gets the researchers' attention.This paper analyzes the current situation of welding seam tracking technology, designs the laser weld visual measurement system based on the CMOS camera as image acquisition unit, the semiconductor laser as an auxiliary light source and the FPGA as controller, which including optical system, image acquisition and processing system. Through the FPGA to accomplish the acquisition and transmission of image. The acquired image will be transmitted to the Industrial Personal Computer(IPC), then image filtering de-noising, threshold detection and binarization image processing by IPC, extracting the weld center position and getting the deviation information of weld seam.1. Based on the analysis and research the current situation of the weld seam tracking development in the domestic and foreign, this paper makes the plan of implementation based on vision laser weld measurement system, and discusses the classification of weld seam tracking system.2. The optical structure of the measuring system is designed and the selection of optical devices is completed.3. Setting up the hardware circuit of image acquisition. With FPGA as the main chip to design the related external circuit. It was designed image acquisition hardware logic platform, analyzing image acquisition and display of resource allocation, given the display of image acquisition.4. Researching the welding seam recognition algorithm. The image carries on filtering de-noising, binarization pretreatment process and so on, through the boundary tracking, edge extraction, Hough transform and the center line extraction methods so as to obtain characteristics of weld line and get the feature points of welding seam image, finally obtain the deviation value of these points.In this paper, the design of laser weld seam visual measuring system has carried on the preliminary experiment, the result shows that the design of the structure of the measuring system is simple and practical,and can obtain the deviation value of the weld position in real time.