Research On 3D Reconstruction Of Electric Melting Material Increating Products Surface Based On Heterogeneous Image Sensor

Wire Arc Additive Manufacture(WA-AM),using welding arc as the heat source to melting metal wire,fabricates parts by accumulating deposited metal according to the set path,which can forge large-sized parts in a rapid way.During the process of WA-AM,the heat input is directly affected by arc voltage,welding current and deposit velocity while it can further affect weld pool shape in each deposited metal layer,temperature distribution and solidification time,which are important influence factors in weld formation stability,deformation and surface quality in the working process.By taking the reconstruction of three-dimensional surface during the large additive manufacturing process with multi-heat sources as the study object,this thesis designs the joint calibration method of visible light camera and thermal infrared imager as well as the method of three-dimensional reconstruction of infrared thermal imagery based on the principle model of binocular stereo vision,calibration,correction,stereo matching algorithm and the three-dimensional reconstruction in computer vision,and aims to reach the data of position,size,temperature of the three-dimensional surface units with some complicated or profound changes.First of all,the study and realization of visible light binocular stereo vision is presented in the vision development platform provided by the Intel Open CV,including the software and hardware platform construction,cameras calibration,binocular correction,binocular stereo correspondence,three-dimensional reconstruction and its precision analysis as well as the contrastive analysis combined with MATLAB,the accuracy of the re-projection error is not more than 0.5 pixels,the error of threedimensional reconstruction is about 4mm.On the basis of above analysis,binocular stereo vision and thermal imager are combined to reconstruct the three-dimensional visual system for the three-dimensional reconstruction of infrared imagery.According to the imaging characteristics of thermal infrared imager,then this thesis designs the joint calibration method of visible light binocular stereo vision and thermal imager with trinocular camera,and the method is simple and convenient to operate and its precision can satisfy the practical application requirements,re-projection error of not more than 1 pixel.At last,on the ground of the projection matrix and other parameters generated by the joint calibration,point cloud of the reconstruction of visible binocular image is projected to the imaging plane of infrared thermal imager to realize the three-dimensional reconstruction of infrared imagery,the error of three-dimensional reconstruction is about 30 mm.