Off-Line Signature Verification - Comparison of Stroke Extraction Methods

Stroke extraction is a necessary part of the majority of semantic based off-line signature verification systems. This paper discusses some stroke extraction variants which can be efficiently used in such environments. First the different aspects and problems of signature verification are discussed in conjunction with off-line analysis methods. It is shown, that on-line analysis methods perform usually better than offline methods because they can make use of the temporal information (and thereby get a better perception of the semantics of the signature). To improve the accuracy of off-line signature verification methods the extraction of semantic information is necessary. Three different approaches are introduced to reconstruct the original strokes of a signature. One purely based on simple image processing algorithms, one with some more intelligent processing and one with a pen model. The methods are examined and compared with regard to their benefits and drawbacks on further signature processing.