On Mosaicing Of 3D Complex Shape And Restoration Of Fragmented Objects

Shape macthing is widely used in many disciplines, such as archaeology, 3D reconstruction, and so on. Neighboring fragments with shape matching is reassembled to make broken objects restoration. Shape matching and Mosaicing of broken objects relate to computer graphics, graphics and images fusion, computer visualization technology. Shape features of fragments extracting and representing, shape matching, mosaicing fragmens, methods of repairing errors techniques are researched. Some techniques of shape matching and fragments mosaicing are presented. The main research works and contributions are concluded as follows.1. Fragments digitalization, mesh simplification, extracting mesh outlines, representation of contour curves and feature are researched. Segmenting Method Based on wavelet transform adaptive threshold is presented.2. Two dimension Fourier contour descriptors at multiscales are researched. A novel 2D curves matching method based on multiscale Fourier descriptors is presented. Contour curves are filtered by Gaussian filter at different scale. Eigenvectors are consisted of real and imaginary part of Fourier transformation coefficients to realize contour matching and objects mosaicing through comparing feature vectors. This approach has advantage of simple, accuracy and fastness.3. Curve represented by B spline is researched. Local coordinate system is built to calculate direction angle. Calculating method of Direction angles used to constructe eigenvectors and 3D curve matching algorithm based on direction angle are presented to complete fragments mosaicing.4. Calculating method of multiscale wavelet contour descriptors is researched. Methods of Extracting contour curves features at multiscale and technique of mosaicing 3D fragmented objects based on multiscale analysis are presented. Spatial contour curves are transformed by wavelet at an appropriate scale. The curvatures and torsions of smoothed contour by wavelet transform at a scale are calculated. Eigenvectors is consisted of Curvatures and torsions. Contour curves matching and fragments mosaicing through similarity measuring are completed. The problem of matching starting point based on wavelet contour descriptors is researched. Decision method of matching curve segment is presented. Time complexity of the algorithm is estimated. Experimental results show that method is accuracy, effectiveness and robustness.5. Surface representation, characteristics of surface are analyzed. Objects surface segmentation technique are researched. Directed eigenvector and undirected eigenvector consisting of directed footprints and undirected footprints of points on surface respectively are presented. Surface matching method by coarse matching and fine matching is presented to complete fractured surface mosaicing. Mosaicing methods, mosaicing errors processing and holes repairing technique are researched.6. Shape mosaicing techniques is applied in development of Computer-aided broken objects recovering system based on theory analysis. Functions analysis, data structure, technique characteristic and development process are introduced.