Calibration of fish‐eye camera for acquisition of spherical image

Abstract

AbstractThis paper proposes a method for nonmetric calibration of a fish‐eye camera that utilizes the properties of vanishing points on lines in photo scenes to join together two images facing two sides front and rear, taken with a fish‐eye camera (for this paper, a camera mounting a fish‐eye conversion lens with a field of view extending to more than one hemisphere is called a fish‐eye camera), in order to acquire a full‐view spherical image. In this method, the geometric properties of vanishing points are first used to obtain initial estimates of the optical center and focal distance on the image, which are the internal parameters for the fish‐eye camera. Next, the photo images of the two sides are each mapped onto a spherical surface, and binding conditions, in which true parameter values are used to join the two resulting hemispherical images into a single spherical image, are used to perform fine adjustment of the parameters, based on image correlation of overlapping sections of the front and rear photo images. Experiments using actual still scene images showed the validity of the method, and the proposed method was used to build a system capable of shooting full‐view images in real time. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 10–20, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20631 Copyright © 2004 Wiley Periodicals, Inc.