How human age affects the signature’s curvature, density and amplitude to wavelength ratio and its potential application for countering document falsification
Elfi Yuliza, Nadya Amalia, Handika Dany Rahmayanti, Muhammad Miftahul Munir, Khairurrijal Khairurrijal, Mikrajuddin Abdullah · Australian Journal of Forensic Sciences · 2019
By comprehensive investigating of 3540 signatures from 86 males and 23 females over a specific period, we identified that a signature’s curvature and multiplication of density with time change exponentially with age, while the amplitude to wavelength ratio likely changes inversely with time. The subjects’ ages are between 30 and 63 for females and 36 and 68 for males and they had the same educational background, occupation and institution. Their signatures were collected from the same types of documents stored in several libraries. Combination of three characterizations enable in estimating the year when a document was signed. Ten signatures that have been randomly selected from two subjects showed that the bias in prediction of signing year was less than 3 years. The method is potential for countering the crime associated with falsification of documents created in the past by the same person, as a complement to the already standard methods.