Hierarchical Graph-Grammar Model for Secure and Efficient Handwritten Signatures Classification

Marcin Piekarczyk (Pedagogical University of Krakow, Poland)

Marek R. Ogiela (AGH University of Science and Technology, Poland)

Abstract: One important subject associated with personal authentication capabilities is the analysis of handwritten signatures. Among the many known techniques, algorithms based on linguistic formalisms are also possible. However, such techniques require a number of algorithms for intelligent image analysis to be applied, allowing the development of new solutions in the field of personal authentication and building modern security systems based on the advanced recognition of such patterns. The article presents the approach based on the usage of syntactic methods for the static analysis of handwritten signatures. The graph linguistic formalisms applied, such as the IE graph and ETPL(k) grammar, are characterised by considerable descriptive strength and a polynomial membership problem of the syntactic analysis. For the purposes of representing the analysed handwritten signatures, new hierarchical (two-layer) HIE graph structures based on IE graphs have been defined. The two-layer graph description makes it possible to take into consideration both local and global features of the signature. The usage of attributed graphs enables the storage of additional semantic information describing the properties of individual signature strokes. The verification and recognition of a signature consists in analysing the affiliation of its graph description to the language describing the specimen database. Initial assessments display a precision of the method at a average level of under 75%.

Keywords: biometric security, handwritten signature verification, hierarchical attributed random graph, intelligent computing, secure verification, signature-based authentication

Categories: F.4.2, F.4.3, I.2.10, I.2.4, I.4.10, I.4.8, I.5.1