Simple and effective multi-word query spotting in handwritten text images

Abstract

Keyword spotting techniques are becoming cost-effective solutions for information retrieval in handwritten documents. We explore the extension of the single-word, line-level probabilistic indexing approach described in [1, 2] to allow page-level Boolean combinations of several single-keyword queries. We propose heuristic rules to combine the single-word relevance probabilities into probabilistically consistent confidence scores of the multi-word boolean combinations. As a preliminary study, this paper focuses on evaluating the search performance of word-pair queries involving just one OR or AND Boolean operation. Empirical results of this study support the proposed approach and clearly show its effectiveness.