Signatures are among the dynamic biometric features. The way people sign, how the pressure is distributed, the acceleration and speed with which the entire stroke and individual passages or letters are written.
Signature recognition also distinguishes the steepness of the letters and the length of breaks within the signature. These are characteristic features that cannot be imitated by others. While the acceptance of signature recognition systems is very high, their invariance is not good and the uniqueness is also relatively low at about 1 in 10,000.
Graphics tablets or touchscreens are used to record the signature or even for character recognition. Since only the static features of the signature are captured, special styluses with built-in sensors are used for the dynamic features.