On the localization of objects using an FSR pressure pad transducer

The force sensing resistor (FSR) is a relatively new and inexpensive device; however, to date its practical application has been limited. This paper introduces a novel technique that shows how a pressure pad made of a 16×16 array of FSRs can be used to locate and describe objects. In this initial study, we focus on circular objects and use the pad to measure both the geometric center and the radius. The force distributions on the array are treated as a “tactile” image that is pre-processed using thresholding and morphological smoothing. A circle is then fit to the convex hull of the result using a least-squares technique. The errors in the center position and the radius are typically around 50% of the FSR element width