The Weld Pool Surface Reconstruction Of TIG Welding Based On Vision Sensing And Processing Software Design

TIG welding is an important thermal processing technology, and is widely used in industrial production. As the rapid development of modem society, the traditional manual welding method can hardly meet the requirements of modern high-tech product manufacturing, welding process automation, intelligent welding technology have become the industry trends. Many studies have shown that the geometrical parameters of the front weld pool surface has a good relationship with penetration and welding forming, and the three-dimensional information such as the amount of collapsed pool surface can better reflect the penetration state, therefore, the detection and measurement of three-dimensional weld pool surface have become an increasing concern. By using visual sensing system to get the pool images of TIG welding, and reconstruct three-dimensional shape of weld pool surface. It can provided experimental verification for the numerical simulation of welding thermal process, but also lay a solid foundation for realization of intelligent control of welding process, such research has important theoretical significance and practical value.Firstly, several different weld pool image sensing systems are briefly introduced, and then the practical difficulties in capturing images and image features are analyzed by experiments. Due to the interference such as arc light, heat and other influence factors, the images captured by CCD always contain a lot of noise, therefore, image pre-processing is an essential step in the acquisition process of weld pool information. In the tests, the processing results of weld pool grating images are compared and analyzed, and a curve fitting algorithm to remove noise is designed; the characteristics and effects of different weighted filtering window are studied in base frequency filtering.For the raster images obtained by dual lens system, the principle of Fourier transform profilometry was adopted to reconstruct three-dimensional shape of weld pool surface. In actual operation, the phase processing algorithms have a direct impact on the result of three-dimensional reconstruction and efficiency. This paper introduces the traditional unwrapping algorithm and quality map oriented algorithm, and a centerline of bright strips segmentation algorithm along with several phase correction algorithm for dealing with phase lines are designed, then the characteristics and effects of each processing algorithms are analyzed by simulation tests. The algorithms are applied in the three-dimensional reconstruction of weld pool surface in TIG welding, then by the reconstruction results and time-consuming of fact, the feasibility and applicability of each algorithm are analyzed.Using Visual C++ and MATALAB programming developed a TIG welding image analysis and processing software, as well as some related soft wares. For all the software, the design and functions have been made a definite description, especially for the TIG welding grating image processing software, the process of design and programming is described in detail, and method of installation and use in the Windows XP system has presented.