PROCESSING OF OFF-LINE HANDWRITTEN TEXT - POLYGONAL-APPROXIMATION ANDENFORCEMENT OF TEMPORAL INFORMATION

Algorithms to process off-line Arabic handwriting prior to recognition are presented. The first algorithm converts smoothed and thinned imag es into polygonal approximations. The second algorithm determines the start vertex of writing. The third algorithm enforces temporal informa tion by traversing the graph of the stroke in an order consistent with Arabic handwriting. It implements the following heuristic rule: the m inimum distance path that traverses the stroke's polygon from the star t vertex to the end vertex has its vertices ordered as they were gener ated when the stroke was written. This third algorithm is developed fr om a standard solution of the Chinese postman's problem applied to the graph of the stroke. Special rules to enforce temporal information on the stroke to obtain the most likely traversal that is consistent wit h Arabic handwriting are applied. Unconstrained handwritten strokes wr itten by five subjects, (n = 4065) were used in testing. In 92.6% of t he samples, the proposed algorithms restored the actual temporal infor mation. (c) 1994 Academic Press, Inc.