Ultrasonic position measurement and its applications to human interface

This paper presents a position measuring method and its applications to human interface. It is based on the principle of ultrasonic position measurement by phase difference. In conventional method, position is computed with the absolute distance between sender and receiver, on the other hand, in our method, it is computed with the phase difference between the waves received by a pair of receivers. Any kinds of motor actions of users is available to screen pointing by the device, then it allows computer users various pointing styles including “mouse-like” and “pen-like” ones. Firstly, the principle and the formulae of ultrasonic position measurement by phase difference are introduced. Secondly, trial construction of the pointing system is described, and performance of the pointing system is investigated. Finally some examples of pointing devices with various pointing styles are realized, and experiments on the efficiency of pointing tasks with computer users are carried out to conclude that the pointing system is suitable for practical use