Experimental Evidence of Lateral Skin Strain During Tactile Exploration

This paper describes an experimental platform for the study of stretch and compression of the human fingerpad skin during tactile exploration. A digital camera records the sequence of patterns created by a fingertip as it slides over a transparent surface with simple geometrical features. Skin deformation is measured with high temporal and spatial resolution by tracking anatomical landmarks on the fingertip. Techniques adapted from the field of online fingerprinting are used to acquire highcontrast fingerprint images and extract salient features (pores, valley endings, and valley bifurcations). The results of experiments performed with surfaces with a bump or hole and flat surfaces are presented. This work is motivated by the need to provide meaningful ‘tactile movies’ for a tactile display that uses distributed lateral skin stretch.