Smooth scene transition for virtual tour on the World Wide Web

This paper presents a robust image registration technique for creating smooth scene transitions for a Web-based virtual tour system. Easy and effective virtual tour (EEVT). EEVT has advantages over traditional geometry-based 3D rendering approach in that it does not require labor intensive 3D modeling process or high bandwidth for realistic virtual tour yet provides a virtual tour with free navigation and immersive experience through the WWW. EEVT constructs virtual tour from a set of images. It uses several snap shots of conventional photos without special tools, builds a simple 3D space within each photo using the spidery mesh technique, and expands the virtual spaces by connecting each space together. The connection between images is achieved by image registration, which finds correspondences automatically and estimates transformations. The image registration process is crucial for virtual tour applications in order to compose smooth transitional scenes between two views so that virtual tourists perceive continuous scenes during navigation. Our registration method uses a parametric approach and it includes the following key features for robust and accurate computation: 1) coarse-to-fine hierarchical estimation; 2) fast computation based on image feature-correspondences; 3) FFT-based global matching, 4) automatic outlier removal by RANSAC. The expanded virtual space creates a sense of navigational freedom for virtual tourists with less distorted viewing.