The Computer Reconstruction Technology Research Of Three-dimensional Microstructure For Metalllic Materials

The acquisition and quantitative characterization of material 3D microstructure,which is one of the four major factors for the research in materials science and engineering disciplines,has been the research emphasis and difficulty in the field of materials science.In recent years,with the continuous development of computer technology,using computer technology to materials research has become the main development trend in the field of materials science,and three dimensional reconstruction technology has become the important way to gain the material microstructure.The 3D reconstruction technology is divided into surface rendering and volume rendering.This topic seems industrial pure iron as the research object,firstly,a series of continuous 2D cross section image are acquired with the serial sectioning method and suitable pretreatment method for each image is given.Pretreatment process includes image gray,image filtering,morphological reconstruction,shadow correction,image transformation and image segmentation.In the filtering,the method of median-method combine with the anisotropy is used,for the purpose of suppress image noise effectively On the basis of the guarantee grain edge information.In the segmentation,the improved watershed transformation method is used,which seems the binary image acquired by double threshold segmentation method as the lowest points and ridge test of grain edge image as the highest points.In order to effectively analyze material 3D microstructure,This topic complete 3D reconstruction of continuous 2D images respectively using the method of surface rendering and volume rendering After the completion of the preprocessing.In the study of surface rendering method,MC algorithm is improved in this topic,the watershed transformation method is adopted to replace the threshold method to realize the image segmentation to extract the grain boundary information accurately.Aiming at the problem of efficiency of the MC algorithm,”regional traversal method” is presented based on the theory of human organs connection,once unempty element within the triangles was determined,adjacent triangles in body is bound to be topology extension according to certain rules.In order to further reduce the amount of calculation,using middle points instead of linear interpolation method to calculate the intersection point.This promotes the overall efficiency of the algorithm.In the study of volume rendering method,grain structure has carried on the three-dimensional reconstruction respectively by the method of light projection and shear deformation.By contrast,the two methods have no obvious difference in reconstruction results,but the shear deformation method has obvious advantages in the reconstruction efficiency.Finally,carries on the quantitative analysis of 3D reconstruction results,to extract the characteristic value of grains,such as grain size,area,equivalent radius,with the comparison of characteristic values obtained by two-dimensional condition.By contrast,in terms of average multiple grains,the error of characteristic values obtained by two-dimensional conditionis is small,in terms of single grain,the error of characteristic values obtained by two-dimensional conditionis is big,a two-dimensional section of single grain is not accurate said its three-dimensional shape.