  We proposed a new type of tactile sensor that is capable of determining the
surface morphology of skin lesions. The sensor consists of a brass cylinder
with an axial bore. Three peripheral bobbins were machined in the cylinder
around which three coils have been wound. An iron core can easily move inside
the bore. One of the coils acts as primary and the other two are secondary
coils. Change in the position of the core due to surface peaks and valleys
causes the induced voltage in the secondary coils to vary. This change in the
voltage is a measure of core position and reveals the morphological features of
the surface (surface profile). Experiments show that the proposed sensor is
capable of discriminating between the models of two different types of skin
lesions, namely, anetoderma and nodule, which resemble each other in visual
inspection but behave differently when being touched. Thus, this sensor could
be used as an assist device for diagnosis purposes in teledermatology systems.
