Interactive Mechanism Modeling From Muti-view Images

Three-dimensional modeling has been a hot issue in the field of computer graphics research. 3D models are widely used in reverse engineering, television and entertainment, virtual reality, scientific research, military, heritage, three-dimensional printing etc. Three-dimensional modeling has several decades of history. In recent years, new interactive modeling methods are constantly proposed, which indicates that the issue still faces great difficulties and challenges and is a very active area. One of the most commonly used 3D modeling methods is manually creating models by interactive software such as MAYA, 3D Studio Max, Soft Image and CATIA etc. The other is reconstructing three-dimensional models through the data of objects’ surface obtained by instruments such as three-dimensional scanners, digital cameras, CT etc. For instance, multi-view based modeling first take a group of scene photos by a digital camera and then get a three-dimensional model of the scene from random image sequences.This thesis is mainly about mechanical modeling. Mechanical models generally consist of some simple mechanical model primitives such as gear, cylindrical, rectangular and flat etc. Primitive members are mechanically assembled and form complex mechanical systems. Repeating primitives are often seen in mechanical systems. There are strong motion links among primitives, so geometrical relationships exist among the primitive components such as parallel, perpendicular, and coplanar collinear. Mechanical model is generally complex and the occlusion issues of primitives make the problem more difficult. This thesis effectively solves the occlusion issue among primitive components through the method of three-dimensional modeling based on multi-view approach. The bottleneck of mechanical modeling is that designers have to spend a lot of time and efforts to create high-quality 3D models. Although mechanical modeling is also affected by other factors, this article focuses on fast, efficient mechanical modeling.This thesis proposes an image-based interactive mechanism modeling system. The input to our system is the multi-view images of a mechanism so as to handle the occlusions between its mechanical parts in the 3D modeling. In interactive modeling, users only need to draw several strokes to extract single part from a selected view. An alignment optimization is performed to improve the model quality after all parts are modeled separately. The generated 3D mechanism models contain not only the basic geometry information but also the motion structure of the real mechanism. Experimental results show that the system can be applied to the modeling simple mechanical toys and real mechanism objects.