On the epipolar geometry of the crossed-slits projection

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 pinhole 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.