Variations of handwritten signatures with time: A sigma-lognormal analysis

The variation of dynamic signatures with time is analysed for the first time using the Kinematic Theory, following a general, consistent and fully reproducible protocol. Experiments are carried out on a new long-term database captured in 6 sessions uniformly distributed over a 15 month time span, under almost identical conditions. Signatures are represented with the Sigma Log-Normal model, which takes into account the effects of body ageing closely related to handwriting, such as neuromuscular response times. After studying the evolution of signatures with time, an analysis on age groups based on the model parameters is carried out.