Chao-Yaug Liao

Fast and accurate triangular model generation for the shape-from-silhouette technique

ABSTRACTIn this study, we propose a method for generating triangular meshes of objects based on the shape-from-silhouette (SFS) technique. The proposed algorithm uses the direct intersection of multiple sets of infinite polygons from the silhouettes of two-dimensional (2D) images to acquire the surface points of an object. The surface points are then triangulated according to the topological relationship of the obtained points and the polygons corresponding to each of the points. In addition, a comprehensive study between the proposed method and the marching-cubes method was conducted. The main advantages of the proposed method are that all 3D points are precisely located on the silhouettes of 2D images, and that the number of vertices on the triangular model is very efficient compared to that for the results from the marching-cubes method. In contrast, the marching-cubes method faces noise and resolution problems, where the former is because the vertices are interpolated, and the latter is because the ma...

Generation and quality improvement of 3D models from silhouettes of 2D images

Abstract The shape-from-silhouette (SFS) method has been widely used in 3D shape reconstruction. It uses silhouettes of a series of 2D images captured from multiple viewpoints of an object to generate a 3D model that describes the visual hull of the object. The SFS method faces an inherent problem that virtual features appear all over the model. In addition, concavities on the object may wrongly be modeled as convex shapes because they are invisible on image silhouettes. The purpose of this study is to propose a method to generate a 3D model from silhouettes of multiple images and propose a quality improvement method to overcome the above-mentioned problems. The 3D modeling method focuses on accurate evaluation of 3D points intersected by all polyhedra from different views and the removal of poor meshes on triangulation. The quality improvement method is essentially an iterative procedure, which for smoothing the model and eliminating virtual features and artifacts, while preserving the consistency of all silhouettes. The proposed method is to be used for product presentations in e-commerce, in which the 3D model must be covered with color texture of an object. Several examples are presented to illustrate the capability of the proposed method.

Editable texture map generation and optimization technique for 3D visualization presentation

ABSTRACTThe mesh parameterization method has been widely used in computational geometry. It maps a three-dimensional (3D) model onto the parametric (UV) domain, on which various applications can be developed, such as texture mapping. The texture mapping technique is commonly used to create the 3D color model of an object by combining a 3D model with the objects texture map. However, the resolution and quality of the texture on the color model is important and requires careful consideration. The purpose of this study is to develop an integrated method for generating the 3D color model of an object based on the conformal mesh parameterization and a technique for direct texture mapping from the object images. Furthermore, an optimization process in texture mapping is developed to maintain the photo consistency at the transition of different images on the 3D color model. The proposed 3D color model is integrated with a 3D visualization method for a new easier and smoother presentation mode for 3D product pre...

Quality improvement of 3D models reconstructed from silhouettes of multiple images

ABSTRACTShape-from-Silhouette (SFS) is a technique for estimating the shape of an object from images of its silhouette. It is a simple but effective technique for obtaining a three-dimensional (3D) model of an object by using two-dimensional (2D) images of the object in different views. The inherent problem with this method is visual features or irregularities, such as sharp edges, corners, and artifacts. These affect not only the outline shape of a model, but also the accuracy of texture mapping, which is essential for creating a 3D color model. The objective of this study is to propose a quality improvement method to address the aforementioned problems for the SFS method. The proposed quality improvement method is a multiple-step iteration procedure combining a re-meshing process and a mesh smoothing process to remove virtual features and artifacts on the original model, while preserving the image silhouettes and the smoothness of the model. Two algorithms based on regular and irregular meshes, respecti...