Projection distortion analysis for flattened image mosaicing from straightuniform generalized cylinders

This paper presents a new approach for reconstructing images mapped or pain ted on straight uniform generalized cylinders (SUGC). A set of monocular im ages is taken from different viewpoints in order to be mosaiced and to repr esent the entire scene in detail. The expressions of the SUGC's projection axis are derived from two cross-sections projected onto the image plane. Ba sed on these axes we derive the SUGC localization in the camera coordinate system. We explain how we can find a virtual image representation when the intersection of the two axes is matched to the image center. We analyze the perspective distortions when flattening a scene which is mapped on a SUGC. We evaluate the lower and the upper bounds of the necessary number of view s in order to represent the entire scene from a SUGC, by considering the di stortions produced by perspective projection. A region matching based mosai cing method is proposed to be applied on the flattened images in order to o btain the complete scene. The mosaiced scene is visualized on a new synthet ic surface by a mapping procedure. The proposed algorithm is used for the r epresentation of mural paintings located on SUGCs with closed cross-section s (circles for columns), or opened cross-sections (ellipses or parabolas fo r vaults). (C) 2001 Pattern Recognition Society. Published by Elsevier Scie nce Ltd. All rights reserved.