An automated method for registration of remotely sensed images with adaptive generation of corresponding point pairs to local disparities

Abstract

AbstractImage registration is very important in analyzing multitemporal images. We have proposed an automated method, ARTSIM (Automated Registration meThod for Satellite IMages), for generating control point pairs on multitemporal images. Since we used spatial correlation as the index of point pair correspondence, the positions and numbers of the control point pair depended on the image quality. This tended to generate fewer pairs of control points in regions having larger spatial discrepancy and to yield insufficient registration accuracy. In this paper, we propose a new method, ARTOFL (Automated Registration Technique using Optical FLow), which measures local disparities between images to be registered and generates the minimum number of control point pairs in adequate positions so as to achieve the desired accuracy of the registration. In the method, we regard the two images to be registered as sequential shots in a movie scene. Optical flow is introduced as a tool for measuring local disparities. A new control point is generated at the point having the maximum length of the optical flow vector. Since images may have severe distortion and/or temporal changes in pixel density, some compensations are required so that larger disparities yield larger optical flow vectors. These procedures are repeated until the maximum length of the optical flow vector falls below a threshold, so that the accuracy of the registration is ensured. The validity of ARTOFL was confirmed by numerical simulation and processing of real remote sensing images. ARTOFL generated fewer control point pairs but provided higher accuracy than ARTSIM. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(1): 38–47, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10034