Original devices and strategies for man-machine interaction in music live performance

In this paper two originai man-machine interfaces and a special environment that allows algorithmic composition and interaction during the live performance, are described. The Light Baton consists of a special conductor baton with a small lamp on the tip, whose movements are detected by a CCD camera, digitized as light-point-position changes and properly stored in the computer memory where information from the correspondig paths are extracted. The Infrared Twin-Towers consists of a couple offour-infrared-sensors placed at the corners of two squares, and upword vertically active. Signals provided by each set of transducers are used to compute the position and the orientation of a performer's hands moving inside the active volumes. The RealTime Concurrent PascalMusic is a musicallanguage for algorithmic composition and interactive performance. Realtime means that a running program/composition issues MIDI messages that control synthetizers, and that the computation can be affected by incoming MIDI messages issued by performers playing MIDI controllers, or special devices such as the Light Baton or the Infrared Twin-Towers. Concurrent mans that many processes, i.e. many Pascal procedures, can run together.