This paper introduces an interactive browsing system that efficiently supports the reliable distribution of 3D GIS data including 3D urban models with texture, attributes and aerial/satellite images. Our approach uses the view-dependent simplification to reduce the number of primitives distributed and rendered. We apply to make preparations for only visible primitives concerning with each 3D viewpoint and direction in advance. This approach will make it possible to distribute only the visible data, that is, no occlusion culling in rendering. Additionally, we suggest a compression concept to control the increase in the supposed view sets. Experimental results show that our approach is stable and reliable enough to make the distribution and rendering of 3D GIS data possible.

Creating three-dimensional (3-D) models of real urban objects is an important goal in a wide variety of applications. This paper describes a method that utilizes airborne laser elevation images and aerial images for the 3-D reconstruction of urban objects. Our modeling approach uses the vertical geometric pattern analysis of elevation images. These patterns correspond to object contours and, thus, enable the extraction of the object. In addition, to provide realistic textured details, textures are cut from aerial images and mapped onto 3-D models. Our texture-mapping approach can avoid geometry mismatching and enable the automatic registration to determine the most reliable correspondence between projected outlines of 3-D models and contours of real objects shown in aerial images. Edge pairs, which are matched with projected outlines, are detected from aerial images. In order to minimize mismatching, we apply the voting technique based on the generalized Hough transform. Experimental results show that 3-D reconstruction of urban objects is generally successful.

A personal multimedia-multipoint teleconference (PMTC) system is described that allows teleconferences using voice, full-motion video and graphics to be established with up to 20 terminals through a mesh type multipoint configuration using a broadband ISDN. PMTC service concepts are discussed, especially conference environments called conference spaces for sharing the same information among participants, and communication control methods for multipoint communication. The hardware architecture of a prototype PMTC terminal based on an existing general purpose workstation is also described.>