Web Photogrammemetry : Stereoscopic Measurement System over Www

As digital photogrammetric system developed, we became able to measure three-dimensional objects on a generic personal computer. And recently aerial photograph is easily obtained, for example we can get aerial photograph through internet at a low price in Japan. But three-dimensional measurement using by photogrammetry is not popular. One of this cause is that digital mapping system requires photogrammetric knowledge and experience for calculation of orientation parameters and construction of stereo pair models. So we developed a three-dimensional measurement system on network, Web Photogrammetry. This system consists of server and clients. Aerial photographs, these orientation parameters and three-dimensional feature data are stored on a server. Clients are connected with a server by a network and have stereoscopic display. When we access a server by WWW browser, we are able to browse aerial photographs stereoscopically that are retrieved from server. Stereoscopic image are shown on WWW browser and measure three-dimensional objects over there. If three-dimensional feature data are stored on this server, these are shown stereoscopically over the aerial photographs. We can store measured data on a server and share these data with other users. It is important to implement this system that stereo image are shown on WWW browser so quickly. So stereo image is generated at a client and server delivers stereo par aerial photographs and these orientation parameters to clients. Then to realize enough response for measurement environment, clients communicate asynchronously with a server and parts of aerial photograph image data are cached at a client.We believe that anyone having stereoscopic display and network can measure three-dimensional objects without photogrammetric knowledge and experiences by using this system. As a result three-dimensional spatial data will be used in more variously field. In addition we can deliver aerial photograph quickly by this system for photo interpretation, for example when disaster happened.