Abstract

Method and apparatus are disclosed for verifying a sample signature based on comparison of the dynamics of a reference and a sample signature. More particularly, second derivative values of pen displacements (i.e. acceleration) and continuous pressure pattern signals are periodically sampled for both a reference and sample signature and a comparison of these second derivative values and pressure patterns is made. To effect the comparisons the two groups (reference and sample) of both second derivative and pressure pattern signals are segmented and corresponding segments are individually correlated. Successive comparisons of the same segment pairs are performed utilizing successive shifting of the phases between the two segments being correlated to find regions of highest possible correlation. A running account of the maximum cross correlation values for all of the segment pairs of the two signatures are kept. Finally, these maximum values obtained for each segment pair comparison are combined and this resultant correlation value is utilized as a verification indicator.