Handwriting Classification of Byzantine Codices via Geometric Transformations Induced by Curvature Deformations

In the present paper, we propose a methodology of general applicability for matching, comparing and grouping planar shapes, under a unified framework. This is achieved by interpreting shapes’ grouping as a result of the hypothesis that shapes of the same class come from the same implicit family of curves. In order to render the analysis independent of the functional form of the curves families’ implicit function, we have formalized the shapes’ comparison in terms of the implicit curvature function. The implementation of the methodology targets towards automatic writer identification and the corresponding information system has been applied to the identification of the writer of Byzantine codices that preserve Iliad. The shapes in hand are the alphabet symbols appearing in the documents’ images to be classified. The realizations of each alphabet symbol are compared pairwise, modulo affine transformations. The statistical compatibility of these comparisons inside the same document and between different documents determines the likelihood of attributing different documents to the same hand. By maximizing the joint likelihood for all alphabet symbols, common in all documents we determine the most probable classification of the given documents into writing hands. Application of the methodology to 25 images of Byzantine codices’ pages indicated that these pages have been written by 4 hands in full accordance with experts’ opinion and knowledge.