Mllltiple matching of rectangular patterns

Abstract

We describe the first efficient algorithm for simultaneously matching multiple rectangular patterns of varying sizes and aspect ratios in a rectangular text. Efficient means significantly better asymptotically than known algorithms that handle one height, width, or aspect ratio at a time. Our algorithm features an interesting use of multidimensional range searching, as well as new adaptations of several known techniques for two dimensional string matching. We also extend our algorithm to a dynamic setting where the set of patterns can change over time.