A study on the epipolarity of linear pushbroom images

Abstract

Although epipolar geometry is a very useful clue in processing stereo images, it has not been thoroughly examined previously for linear pushbroom images. Some have assumed that epipolar geometry would be the same for pushbroom images as for perspective images. Some do not use this geometry at all because it is not fully understood. The purpose of this paper is to provide a theoretical basis for the epipolar geometry of linear pushbroom images and to discuss the practical implications of this geometry in processing such images. We show that epipolarity for linear pushbroom images is different from that for perspective images. We also derive an equation for epipolar curves of linear pushbroom images, which are not lines but hyperbola-like non-linear curves. Through analyses of the properties of these curves, we conclude that these curves can be approximated as piece-wise linear segments and that any closely located points on one epipolar curve are mapped onto a common epipolar curve.