Three-Dimension Reconstruction Technology Research Of Inner Crack Defect Based On Characteristic Parameters

A series of slice-images which comprise the defect information can be obtained with CT scan, but it needs experience and spatial visualization of engineer to estimate the 3D information of defect, have great limitation. In order to get the further information of the slice-images, such as the defect space position, size, shape, density distribution and so on. It is necessary to reconstruct 3D model. This paper takes this as a background and carries on a series of research for the 3D reconstruction algorithm of slice-images for inner crack defect of component systematically.Firstly, aimed at the edge detection method mostly cannot detect crack edge accurately because of crack ripped and irregular, the edge image and contour obtained vague relatively, area boundary searching algorithm based on seed fill is proposed. Above all find a seedpoint in the crack where the grayscale is zero, then searched along a fixed direction, find a pixel whose grayscale is different from the seedpoint, at last starting from that point, searching along eight directions, until back to that point, achieve the search of the crack edge pixels.Secondly, due to space information of defect can not be exactly estimated in non-destructive testing of industrial CT, this article proposes the reconstruction algorithm of component containing inner crack defect. The algorithm aimed at the limitation of traditional MC method, Using surface tracking, meta-surface growing and meta-surface triangulation of Growing -cube algorithm to complete the extraction of iso-surface, get the reconstruction model of component, thus achieving the observation to 3D space shape.Finally, in the VisualC++6.0 development platform to develop using OpenGL, 3D display the reconstructed crack model. The system provides preview window to display all CT images, tow-dimensional image pre-processing window, 3D window OpenGL supported, and so on. It could observe and measure inner crack defect of component from different degree and direction by means of the 3D display of model.