"Shape Representation and Similarity for Image Databases", Call for Papers: Special Issue of Pattern Recognition on "Shape Representation and Similarity for Image Databases" The recent increased use of image and multimedia databases has motivated research in developing and applying shape similarity measures. In a sense this continues the long history of work in both shape representation and similarity. However, since in image databases the object classes are generally unknown a priori, a global, non-parametric shape representation is often necessary. By this we mean approaches in which the entire object shape is described uniformly in accord with our visual perception. Such a representation should permit the differentiation of perceptually similar objects that are not mathematically identical. This involves the use of shape representation based on visual parts, multiscale contour approximations, Hausdorff distances, skeleton based representations, curvature scale spaces, reaction-diffusion spaces, and deformable shapes. Methods based on vectors of shape parameters like area, perimeter, elongation (major axis / minor axis), etc. are excluded. Vectors of shape parameters may be very useful for shape classification, but not as a basis for shape similarity measures, since in order to recognize common shapes, hundreds of parameters must be represented explicitly, and most of these parameters are probably unknown. Such a representation also excludes parametric methods that describe certain object classes, e.g., B-spline surface patches of car prototypes, since they require explicit assumptions about the category of objects to be represented. We seek papers on global, non-parametric shape representations and shape similarity measures that are useful tools for retrieval of similar objects in image data bases and for other tasks related to image indexing, e.g., finding repeated patterns and symmetry groups. Papers on comparison and analysis of different approaches with respect to shape related tasks in image databases are also welcome. For example, what representations are most functional for a system that needs to reason about shape, find similar shapes fast under a given set of allowable transformations, or determine whether a given shape satisfies a set of user-related queries. Please submit five copies of a manuscript to one of the guest editors. The deadline for submission is June 30, 1999. Guest Editors: Ari Gross, Department of Computer Science Queens College, Flushing, NY 11367, USA Email: ari@vision.cs.qc.edu Longin Jan Lateckim, Department of Applied Mathematics University of Hamburg, Bundesstr. 55, 20146 Hamburg, Germany Email: latecki@math.uni-hamburg.de Robert Melter, Department of Mathematics Long Island University, Southampton, NY 11968, USA Email: RMelter@aol.com