Investigation of Fingertip Blobs on Optical Multitouch Screen

Recently, multi-touch tabletop displays provided the Natural User Interface (NUI). Humans use the bare finger as a pointing device for manipulation of interactive elements on multi-touch surface. However, fingertip size occupies the large space instead of appropriate target point and creates ambiguity in touch detection. To overcome issue possibly, we develop an optical multi-touch screen using the Frustrated Total Internal Reflection (FTIR) sensing technique for investigation of the fingertip blobs. In order to conduct the experiment we specify the interaction mechanism which provides the stability in finger touch detection. When users touch with the multi-touch screen using their fingers, we obtain the fingertip blobs that are used for investigation. We take each fingertip blob as an image and compute its relative pixel intensity values using the image processing tool. The investigation exhibits the variation in pixel values each fingertip blobs. The unit variance in intensity of pixel values helps in identifying the error rate in finger touch detection. The study identifies the factors that generate the error rate and ambiguity in finger touch detection. Our study may support for avoiding the error rate and enhancing the finger touch detection. It may also helpful for achieving the accuracy in finger touch detection and for designing and implementing the interactive elements for multi-touch screens.