Keyboards without Keyboards: A Survey of Virtual Keyboards

Input to small devices is becoming an increasingly crucial factor indevelopment for the ever-more powerful embedded market. Speech inputpromises to become a feasible alternative to tiny keypads, yet itslimited reliability, robustness, and flexibility render it unsuitablefor certain tasks and/or environments. Various attempts have been madeto provide the common keyboard metaphor without the physical keyboard,to build \"virtual keyboards\". This promises to leverage ourfamiliarity with the device without incurring the constraints of thebulky physics.This paper surveys technologies for alphanumeric input devices andmethods with a strong focus on touch-typing. We analyze thecharacteristics of the keyboard modality and show how they contributeto making it a necessary complement to speech recognition rather thana competitor.