This paper introduces a fully automatic method for registering satellite images to vector maps in urban area. The key idea is to automatically match the man-made objects extracted from satellite images against the corresponding objects in maps. The proposed method consists of two procedures: feature extraction for matching, and determination of mismatch. We use the normalized difference vegetation index as a spectral indicator to extract matching features. The index is well known to provide accurate differentiation of vegetation from man-made objects. In order to minimize registration mismatch, we apply the voting technique based on the generalized Hough transform. The experimental results show that our approach can register satellite images against maps accurately; the registration mismatch is just a few pixels. We also applied our method to the multitemporal satellite image registration. It also offers reliable image-to-image registration.

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SUMMARYThe "shape-from-contour method" reconstructs the 3D shape of the surface of an object by extracting its contour from each of a series of successive images of the object. This can be realized by using a CCD camera, and is a relatively accurate method of obtaining environmental information. However, to obtain an accurate result, many images must be processed. Therefore, it is important to select the images depending on their effect on the final result, particularly for high-speed processing.This paper proposes an adaptive image selection (AISE) method which depends on the required accuracy. The method has been applied to objects having various cross-sectional shapes. The errors in shape reconstruction and the number of images required in the conventional method and the proposed method are compared. The experimental results show that the proposed method requires fewer images than the conventional method, particularly when the surface curvature of the object has large variation. The theoretical relationship between the accuracy of the reconstructed shape and the number of images required is also derived.

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