Ink-deposition model: the relation of writing and ink deposition processes

The paper describes our studies on the influence of physical and biomechanical processes on the ink trace and aims at providing a solid foundation for enhanced signature analysis procedures. By means of a writing robot, simulated human handwriting movements are considered to study the relation between writing process characteristics and ink deposit on paper. Since the robot is able to take up different writing instruments like pencil, ballpoint or fine line pen, the type of inking pen was also varied in the experiments. The results of analyzing these artificial ink traces contribute to a better understanding of the underlying interaction processes and allow for the formulation of a so-called ink-deposition model (IDM). Particularly, we present IDMs that analytically describe the relation of applied pen tip force and relative ink intensity distribution for solid, viscous and fluid ink types. These IDMs might be employed in computer-based analysis of ink trace line quality to recognize skilled forgeries.