RealScape: Metropolitan Fixed Assets Change Judgment by Pixel-by-pixel Stereo Processing of Aerial Photographs

(FACJ) system and its core tool, RealScape. RealScape automatically detects changes in the height and color of buildings based on three-dimensional analysis of aerial photographs. The three-dimensional analysis employs a pixel-by-pixel stereo processing method that calculates the height of each pixel in aerial photographs and thus enables precise difference detection between previous and current aerial photographs. The FACJ system reduces the labor costs to one third of the traditional approach and the required judgment duration to about two weeks per 100 km2. The FACJ system was experimentally used by the Tokyo Metropolitan Government for the first time in 2005. Since then, it has been used at its tax bureau every year to calculate the municipality’s fixed-asset tax. After the success in Tokyo, other major city governments, including Osaka and Sapporo, have followed suit.