Class-Guided Building Extraction from Ikonos Imagery

ofstereoIkonosimagery showsthat5-to10-mcontour linescan Recent high-resolution satellite images provide a valuable new bederivedwith thehighesttopographicstandard(Toutin etal., data source for geospatial information acquisition. This paper 2001). As forgeospatial feature extraction for topographicmapaddresses building extraction from Ikonos images in urban ping, Baltsaviaset al.(2001a) andFraser etal.(2001;2002) presareas. The proposed approach uses the classification results ent results on building extraction from Ikonos stereo images. A of Ikonos multispectral images to provide approximate loca- comparative study withthe results obtained fromaerial phototion and shape for candidate building objects. Their fine graphs concludes that about 15 percent of the building areas, as extraction is then carried out in the corresponding panchro- measured in aerial images, cannot be modeled using Ikonos matic image through segmentation and squaring. The ECHO images. An assessment based on 19 GPS surveyed check points classifier is used for supervised classification while the ISODATA atroofcorners suggeststhattheIkonos-derivedbuilding model algorithm is used for unsupervised classification and subse- can reach an accuracy of better than 1 meter both in planimetry quent image segmentation. The classification performance is and elevation (Baltsavias et al., 2001a). Sohn and Dowman evaluated using the classification confusion matrix, while the (2001) used a local Fourier transformation to analyze the domifinal building extraction results are assessed based on the nantorientation angleina buildingcluster andextractrectilinmanually delineated results. A building squaring approach ear building outlines from Ikonos imagery based on a binarybased on the Hough transformation is developed that detects space partitioning tree. Dial et al. (2001) present an investigaand forms the rectilinear building boundaries. A number of tion on automated road extraction in wide suburban roads. sample results are presented to illustrate the approach and Regarding the fundamental methodology in geospatial feademonstrate its efficiency. It is shown that about 64.4 percent ture extraction from aerial and space images, abundant experiof the buildings can be detected, extracted, and accurately ence hasbeen gainedin thepast few years.A collectionof stateformed through this process. Remaining difficulties are high of-the-art articles can be found in the periodical proceedings