title: Regular expressions for decoding of neural network outputs.
abstract: This article proposes a convenient tool for decoding the output of neural networks trained by Connectionist Temporal Classification (CTC) for handwritten text recognition. We use regular expressions to describe the complex structures expected in the writing. The corresponding finite automata are employed to build a decoder. We analyze theoretically which calculations are relevant and which can be avoided. A great speed-up results from an approximation. We conclude that the approximation most likely fails if the regular expression does not match the ground truth which is not harmful for many applications since the low probability will be even underestimated. The proposed decoder is very efficient compared to other decoding methods. The variety of applications reaches from information retrieval to full text recognition. We refer to applications where we integrated the proposed decoder successfully.
authors.affiliation: Department of Mathematics, University of Rostock, Rostock, Germany. Electronic address: tobias.strauss@uni-rostock.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Strauß
authors.affiliation: Department of Mathematics, University of Rostock, Rostock, Germany. Electronic address: gundram.leifert@uni-rostock.de.
authors.forename: Gundram
authors.initials: G
authors.lastname: Leifert
authors.affiliation: Department of Mathematics, University of Rostock, Rostock, Germany. Electronic address: tobias.gruening@uni-rostock.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Grüning
authors.affiliation: Department of Mathematics, University of Rostock, Rostock, Germany. Electronic address: roger.labahn@uni-rostock.de.
authors.forename: Roger
authors.initials: R
authors.lastname: Labahn
mesh_terms: D006236:Handwriting; D006801:Humans; D016247:Information Storage and Retrieval / Q000379:methods*; D016571:Neural Networks, Computer; D011336:Probability
keywords: Connectionist Temporal Classification; Decoding; Handwriting recognition; Regular expressions