A Case Study of the Relationship between Local Pen Action and Three Dimensional Shapes of Handwritten Strokes

Abstract

In this article, we performed a case study of the relationship between local pen action and three dimensional shapes of handwritten strokes on paper sheet. The purpose of the study is to enrich the knowledge effective for forensic handwriting examination. Samples for analysis were one Japanese Hiragana character written by one participant. Online and offline handwritings were captured simultaneously by using ink pen tablet. The type of pen was ballpoint pen, and characters were written on paper for plain copy placed on the tablet. The position and pen pressure information were captured at 200 Hz. The precision of pen position was 0.25 mm, and the pen pressure information was at 15 bit. Experimental results showed that the depth information of overall area of character was related with the density of handwritten strokes. On the other hand, the local shape of handwritten stroke was considered to be related with local pen action. As the pen pressure increased, the depth and the width of handwritten strokes increased. In addition, the influence of pen pressure spread widely around handwritten strokes. However, the local shape was not only dependent on pen pressure but also on pen speed.