On the Epipolar Geometry of the Crossed-Slits Projection

Abstract

The Crossed-Slits (X-Slits) camera is defined by two nonintersecting slits, which replace the pinhole in the common perspective camera. Each point in space is projected to the image plane by a ray which passes through the point and the two slits. The X-Slits projection model includes the pushbroom camera as a special case. In addition, it describes a certain class of panoramic images, which are generated from sequences obtained by translating pinhole cameras. In this paper we develop the epipolar geometry of the X-Slits projection model. We show an object which is similar to the fundamental matrix; our matrix, however, describes a quadratic relation between corresponding image points (using the Veronese mapping). Similarly the equivalent of epipolar lines are conics in the image plane. Unlike the pin-hole case, epipolar surfaces do not usually exist in the sense that matching epipolar lines lie on a single surface; we analyze the cases when epipolar surfaces exist, and characterize their properties. Finally, we demonstrate the matching of points in pairs of X-Slits panoramic images.