  We investigate the transduction of tactile information during active
exploration of finely textured surfaces using a novel tactile sensor mimicking
the human fingertip. The sensor has been designed by integrating a linear array
of 10 micro-force sensors in an elastomer layer. We measure the sensors'
response to the passage of elementary topographical features in the form of a
small hole on a flat substrate. The response is found to strongly depend on the
relative location of the sensor with respect to the substrate/skin contact
zone. This result can be quantitatively interpreted within the scope of a
linear model of mechanical transduction, taking into account both the intrinsic
response of individual sensors and the context-dependent interfacial stress
field within the contact zone. Consequences on robotics of touch are briefly
discussed.
