Effect of the tactile array density on the discrimination of edge patterns: Implications for tactile systems design

Tactile arrays are devices that can provide spatially distributed cutaneous signals delivering important information during haptic exploration and manipulation procedures. One of the key specifications to design a tactile array is the density of the array elements that is believed to directly affect the effectiveness of the device. Most of the systems developed so far use the generally accepted standard that matches the array density to the spatial resolution in the human fingertip. This work investigates the effect of the array density on the human capacity to discriminate edge patterns. Psychophysical experiments were performed to quantify subjects´ tactile discrimination capacity and indicate that within this perception context, tactile arrays with lower spatial resolution than the one indicated in the fingertip are able to transmit pattern information accurately. This will allow the design of array systems with lower complexity (smaller number of elements) and still effective in conveying tactile cues of certain contexts.