TapSense: Enhancing Finger Interaction on Touch Surfaces, created by Chris Harrison, the same guy who brought us Omnitouch, the technology "doubles the bandwidth" when it comes to touch interaction.
"TapSense, an enhancement to touch interaction that allows conventional surfaces to identify the type of object being used for input. This is achieved by segmenting and classifying sounds resulting from an object's impact. For example, the diverse anatomy of a human finger allows different parts to be recognized -- including the tip, pad, nail and knuckle -- without having to instrument the user," reads the video description.
Adding, "This opens several new and powerful interaction opportunities for touch input, especially in mobile devices, where input is extremely constrained. Our system can also identify differ-ent sets of passive tools."
"We conclude with a comprehen-sive investigation of classification accuracy and training implications. Results show our proof-of-concept system can support sets with four input types at around 95% accu-racy. Small, but useful input sets of two (e.g., pen and fin-ger discrimination) can operate in excess of 99% accuracy."