Alphabet independent two dimensional matching
STOC '92 Proceedings of the twenty-fourth annual ACM symposium on Theory of computing
A Generalization of the Suffix Tree to Square Matrices, with Applications
SIAM Journal on Computing
A sublinear algorithm for two-dimensional string matching
Pattern Recognition Letters
On the construction of classes of suffix trees for square matrices: algorithms and applications
Information and Computation
Two and higher dimensional pattern matching in optimal expected time
SODA '94 Proceedings of the fifth annual ACM-SIAM symposium on Discrete algorithms
Combinatorial methods for approximate image matching under translations and rotations
Pattern Recognition Letters - Special issue on pattern recognition in practice VI
A Rotation Invariant Filter for Two-Dimensional String Matching
CPM '98 Proceedings of the 9th Annual Symposium on Combinatorial Pattern Matching
Truly alphabet-independent two-dimensional pattern matching
SFCS '92 Proceedings of the 33rd Annual Symposium on Foundations of Computer Science
Optimal Exact and Fast Approximate Two Dimensional Pattern Matching Allowing Rotations
CPM '02 Proceedings of the 13th Annual Symposium on Combinatorial Pattern Matching
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We present an index to search a two-dimensional pattern of size m × m in a two-dimensional text of size n × n, even when the pattern appears rotated in the text. The index is based on (path compressed) tries. By using O(n2) (i.e. linear) space the index can search the pattern in O((logσ n)5/2) time on average, where σ is the alphabet size. We also consider various schemes for approximate matching, for which we obtain either O(polylogσ n) or O(n2λ) search time, where λ O(n2(logσ n)3/2) yields an average time of O(logσ n) for the simplest matching model. The algorithms have applications e.g. in content based information retrieval from image databases.