Robust and Fully Automated Image Registration Using Invariant Features

This paper introduces a novel method for affine invariant matching using Zwickels that is especially well suited for images of man-made structures. Zwickels are sections defined by two intersecting line segments, dividing the neighborhood around the intersection point into two sectors. The information inside the smaller sector is used to compute an affine invariant representation. We rectify the sector using the line information and compute a histogram of the edge orientations as a description vector. The descriptor combines the advantage of accurate point localization through line intersection as well as higher descriptivity through use of a larger image region compared to descriptors computed around the points. Compared to other affine invariant descriptors we demonstrate that our method avoids the problem of depth discontinuities. In several matching experiments we show that our features are insensitive against viewpoint changes as well as illumination changes. Results are presented for aerial and terrestrial images as well.