Realistic 3-D scene modeling from uncalibrated image sequences
This paper addresses the problem of obtaining photo-realistic 3D models of a scene from images alone with a structure-from-motion approach. The 3D scene is observed from multiple viewpoints by freely moving a camera around the object. No restrictions on camera movement and interval camera parameters like zoom are imposed, as the camera pose and intrinsic parameters are calibrated from the sequence. The only restrictions on the scene content are the rigidity of the scene objects and opaque, piecewise smooth object surfaces. The approach operates independently of object scale and requires only a single low-cost consumer photo or video camera. The modeling system described here uses a three-step approach. First, the camera pose and intrinsic parameters are calibrated on-line by tracking salient feature points between the different views. Next, consecutive images of the sequence are treated as stereoscopic image pairs and dense correspondence maps are computed by area matching. Finally, dense and accurate depth maps are computed by linking together all correspondences over the viewpoints. The depth maps are converted to triangular surfaces meshes that are texture mapped for photo-realistic appearance. The resulting surface models are stored in VRML-format for easy exchange and visualization. The feasibility of the approach has been tested extensively and will be illustrated on several real scenes. In particular we will demonstrate the generation of realistic 3D models for a virtual exhibition of the archaeological excavation site in Sagalassos, Turkey.