Development of soft tribo-sensor using PVDF film for skin surface contour measurement

This paper is concerned with a basic experimental study on the development of a tactile sensor for skin surface contour measurement. The sensor, imitating the finger, was constructed from an aluminum pipe as the digital phalanx, a sponge rubber sheet as the digital pulp and PVDF film as the sensory receptor. Furthermore, the sensor was covered with cellophane tape or a piece of gauze, which seemed to be an effective substitution for a fingerprint. The sensor is supposed to be moved directly along the skin surface and the skin texture would be estimated by measuring the output of the sensor. Since the signals from sensor are complex, three data processing methods, so-called Ten-point Average, Symmetrized Dot Pattern and Wavelet Transform, were introduced to evaluate the surface roughness both qualitatively and quantitatively. The experimental results obtained on some different types of paper and some parts of skin are presented. Furthermore, an efficient visual display technique and a quantitative evaluation method were proposed for the determination of skin roughness. The proposed tactile sensor shows great potential for skin surface contour measurement.