The Cover Lens Visual Inspection System Based On Linux In Laser Soldering

The laser welding technique applied to the modern process would cause much welding spatter which fell on the cover len of laser welding head randomly in nowaday automobile manufacturing production.The light path of laser beam might be blocked because of the metal spatter on the cover len and it would give rise to the unevenly heating of the welding body.At present,there is no effective methods of visual detection to the cover lens because of the difficulty in specular detection.In the meantime,the system based on ARM embedded platform has the characteristics of high integration,high real-time property and system simplification and it applies to image processing systems mostly.This paper is on the basis of the requirements above and a cover lens visual inspection system based on Linux in laser soldering has been designed.It employs the design scheme which transplants Linux on AM437 X made by Texas Instruments and designs the visual detection algorithm which is applied to the cover lens in laser soldering.At the same time,the hardware drivers of CMOS digital image sensor,MT9M031,made by Aptina and other equipment related has been transplanted.Firstly,the problems of cover lens in laser welding on the current automobile production line were analyzed by extensive field research and literature review.The innovation and applied value of this system was also emphasized.Secondly,this paper illustrated the whole structural frame and design schemes of the light path and hardware according to the requirement of embedded system's function.Thirdly,the whole system for cover lens visual inspection based on Linux in Laser soldering was built including the design of light path,the design of embedded system hardware,the platform construction of embedded system development,the transplantation of Linux kernel,the transplantation of OpenCV library to ARM platform,the hardware drivers transplantation of CMOS digital image sensor and other equipment related,the design of image collection application,the design of the localization algorithm of cover lens and the design of the recognition algorithm of the defects on the cover lens.Then,the problem of black noise in the images was researched and solved.Lastly,the algorithms for images was combined with the program of image collection application and the embedded system had the function of visual recognitionof images.The feasibility of the system was proved by the experiment's results and the problem encountered during the research and design was expounded.So was the improvable parts.This system was the first embedded system on domestic automobile production line for cover lens visual inspection in laser soldering and it gave extremely significant direction for the embedded system with function of visual inspection on the area of automobile production equipment maintenance.