Classification of forms with handwritten fields by planar hidden Markov models

In this article, we present a method for modelling physical structure of forms with handwritten fields, by means of pseudo-bidimensional hidden Markov models (PHMMs). This description is then used for automatic classification of types of forms. With the nature of the document, which comprises handwritten fields, position and dimensions of significant rectangles are variable. Moreover, the phenomena of merging and fragmentation, induce an additional variability in the number of rectangles. They characterize the physical structure of a class of forms. Modelling by PHMMs is developed and appears as a suitable tool to solve the problems of the 2D random variability arising from automatic classification of forms.