TY CONF TI A Structural Approach to the Classification of the Letters in the Images KW optical character recognition KW digital text image KW digital font KW grapheme KW mathematical model KW medial representation KW aggregated skeleton graph JO 29th International Conference on Computer Graphics, Image Processing and Computer Vision, Visualization Systems and the Virtual Environment GraphiCon'2019 AU Lipkina, A.L. AU Mesteckiy, L.M. PY 2024 PB Bryansk State Technical University