title: Iconic indexing by 2-d strings.
abstract: In this paper, we describe a new way of representing a symbolic picture by a two-dimensional string. A picture query can also be specified as a 2-D string. The problem of pictorial information retrieval then becomes a problem of 2-D subsequence matching. We present algorithms for encoding a symbolic picture into its 2-D string representation, reconstructing a picture from its 2-D string representation, and matching a 2-D string with another 2-D string. We also prove the necessary and sufficient conditions to characterize ambiguous pictures for reduced 2-D strings as well as normal 2-D strings. This approach thus allows an efficient and natural way to construct iconic indexes for pictures.
authors.affiliation: Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, IL 60616; Department of Computer Science, University of Pittsburgh, Pittsburgh, PA 152.
authors.forename: S K
authors.initials: SK
authors.lastname: Chang
authors.forename: Q Y
authors.initials: QY
authors.lastname: Shi
authors.forename: C W
authors.initials: CW
authors.lastname: Yan