3-D Surface Reconstruction And Feature Analysis Of High Power Disk Laser Welding Molten Pool Image

Laser welding is an important technique of bonding techniques among different meterials, which has advantages of less material using, high-speed welding, good welding quality. It has been used popularly in the industry productions. Because high power disk laser welding have obvious advantages of higher power laser, better laser beam, smaller heat affected zone, deeper fusion welding and better joint strength, it has been a researching hot spot of laser welding. Under the background of higher demands in the industry automation and joint quality, it will has important research value and practice significance to capture molten pool image on time during laser welding using high speed camera instead of human eyes, analyse the relationship between molten pool shape and its characteristics, bulid weld width prediction model of molten pool shape and its characteristics and weld width.Shape from shading (SFS) has been proved to realize3D reconstruction effectively, which has advantages of simple equipment, low cost, fast reconstruction. In the paper slant and tilt are estimated, molten pools are reconstructed using local analysis method of SFS.Neural network can be used to build prediction model between feature inputs and targets. Molten pool shading characteristics can reflect the corresponding molten pool information to some extent. The width variation of shading can obviously reflect the height variation of welding molten pool. Molten pool characteristic information can be gotten by image graying, auto-threshold gray binary processing and morphologic processing. BP neural network prediction model can be built between shading characteristics of molten pool and weld width. Test result proves that the model can effectively predict the weld width according to the shading characteristics of molten pool.