Probabilistic mathematical formula recognition using a 2D context-free graph grammar

We present a probabilistic framework for the mathematical expression recognition problem. The developed system is flexible in that its grammar can be extended easily thanks to its graph grammar which eliminates the need for specifying rule precedence. It is also optimal in the sense that all possible interpretations of the expressions are expanded without making early commitments or hard decisions. In this paper, we give an overview of the whole system and describe in detail the graph grammar and the parsing process used in the system, along with some preliminary results on character, structure and expression recognition performances

Apprentissage de relations spatiales pour la reconnaissance d'expressions mathématiques manuscrites en-ligne

International audienceNous proposons dans cet article une nouvelle méthode d'analyse syntaxique et structurelle pour un système de reconnaissance d'expressions mathématiques manuscrites enligne. Une grammaire probabiliste est mise en place pour regrouper les hypothèses de segmentation/reconnaissance proposées par un segmenteur 2D. Les probabilités associés à la grammaire sont calculées à partir d'informations structurelles entre les symboles. Ces informations structurelles utilisent l'évaluation d'une relation spatiale entre les éléments intervenants dans chaque règle. L'apprentissage du système se fait en deux phases, d'abord l'apprentissage global du classifieur sans tenir compte de la grammaire, puis l'apprentissage des relations spatiales intervenant dans la grammaire. Ce système est entraîné et testé sur une large base synthétisée d'expressions, puis testé sur une base d'expressions réelles complexes

Interactive interpretation of structured documents: Application to the recognition of handwritten architectural plans

International audienceThis paper addresses a whole architecture, including the IMISketch method. IMISketch method incorporates two aspects: document analysis and interactivity. This paper describes a global vision of all the parts of the project. IMISketch is a generic method for an interactive interpretation of handwritten sketches. The analysis of complex documents requires the management of uncertainty. While, in practice the similar methods often induce a large combinatorics, IMISketch method presents several optimization strategies to reduce the combinatorics. The goal of these optimizations is to have a time analysis compatible with user expectations. The decision process is able to solicit the user in the case of strong ambiguity: when it is not sure to make the right decision, the user explicitly validates the right decision to avoid a fastidious a posteriori verification phase due to propagation of errors.This interaction requires solving two major problems: how interpretation results will be presented to the user, and how the user will interact with analysis process. We propose to study the effects of those two aspects. The experiments demonstrate that (i) a progressive presentation of the analysis results, (ii) user interventions during it and (iii) the user solicitation by the analysis process are an efficient strategy for the recognition of complex off-line documents.To validate this interactive analysis method, several experiments are reported on off-line handwritten 2D architectural floor plans

An Efficient Syntactic Approach to Structural Analysis of On-line Handwritten Mathematical Expressions

Machine recognition of mathematical expressions is not trivial even when all the individual characters and symbols in an expression can be recognized correctly. In this paper, we propose to use Definite Clause Grammar (DCG) as a formalism to define a set of replacement rules for parsing mathematical expressions. With DCG, we are not only able to define the replacement rules concisely, but their definitions are also in a readily executable form. However, a DCG parser is potentially inefficient due to its frequent use of backtracking. Thus we propose some methods here to increase the efficiency of the parsing process. Experiments done on some commonly seen mathematical expressions show that our proposed methods can achieve quite satisfactory speedup, making mathematical expression recognition more feasible for real-world applications. Keywords: Definite Clause Grammar, document processing, mathematical expression recognition, structural analysis 1 Introduction Many documents in scienti..

An Efficient Syntactic Approach to Structural Analysis of On-line Handwritten Mathematical Expressions

Machine recognition of mathematical expressions is not trivial even when all the individual characters and symbols in an expression can be recognized correctly. In this paper, we propose to use Definite Clause Grammar (DCG) as a formalism to define a set of replacement rules for parsing mathematical expressions. With DCG, we are not only able to define the replacement rules concisely, but their definitions are also in a readily executable form. However, a DCG parser is potentially inefficient due to its frequent use of backtracking. Thus we propose some methods here to increase the efficiency of the parsing process. Experiments done on some commonly seen mathematical expressions show that our proposed methods can achieve quite satisfactory speedup, making mathematical expression recognition more feasible for real-world applications. The Hong Kong University of Science & Technology Technical Report Series Department of Computer Science Contents 1 Introduction 1 2 Related Work 2 3 Pro..