In recent years we have seen a proliferation of musical tables. Believing that this is not just the result of a tabletop trend, in this paper we first discuss several of the reasons for which live music performance and HCI in general, and musical instruments and tabletop interfaces in particular, can lead to a fertile two-way cross-pollination that can equally benefit both fields. After that, we present the reacTable, a musical instrument based on a tabletop interface that exemplifies several of these potential achievements. Author Keywords Tangible interfaces, tabletop interfaces, musical instrument, musical performance, design, interaction techniques. ACM Classification Keywords H.5.2 [User Interfaces]: interaction styles, input devices and strategies J.5: [Arts and Humanities]: performing arts.

Abstract. In this article we present Tuio, a simple yet versatile protocol designed specifically to meet the requirements of table-top tangible user interfaces. Inspired by the idea of interconnecting various existing table interfaces such as the reacTable * [1], being developed in Barcelona and the tDesk [2] from Bielefeld, this protocol defines common properties of controller objects on the table surface as well as of finger and hand gestures performed by the user. Currently this protocol has been implemented within a fiducial marker-based computer vision engine developed for the reacTable * project. This fast and robust computer vision engine is based on the original d-touch concept [3], which is also included as an alternative to the newer fiducial tracking engine. The computer vision framework has been implemented on various standard platforms and can be extended with additional sensor components. We are currently working on the tracking of finger-tips for gestural control within the table interface. The Tuio protocol has been implemented using OpenSound

The reacTable * is a novel multi-user electro-acoustic musical instrument with a tabletop tangible user interface. In this paper we will focus on the various collaborative aspects of this new instrument as well as on some of the related technical details such as the networking infrastructure. The instrument can be played both in local and remote collaborative scenarios and was designed from the very beginning to serve as a musical instrument for several simultaneous players. 1 The reacTable* The reacTable*, is a novel multi-user electro-acoustic musical instrument with a tabletop tangible user interface. Several simultaneous performers share complete control over the instrument by moving physical artefacts on the

The reacTIVision system is software for tracking specially designed fiducials (markers) in a real-time video stream. ReacTIVision was designed to enable expressive gestural control of musical sound, and can track many markers at a high frame rate. The development of reacTIVision involved not only computer vision algorithms, but also the design of a new marker system. We co-designed the computer vision system and markers, applying evolutionary computation to minimise marker size while meeting geometric constraints required to efficiently compute the location and 2D orientation of the markers. The computer vision techniques adopted would not have been practical had the genetic algorithms not been able to solve these constraints. This paper focuses on the design and evolution of the markers, the computer vision aspects of reacTIVision are documented elsewhere. 1.

In this paper we study the potential and the challenges posed by multi-user instruments, as tools that can facilitate interaction and responsiveness not only between performers and their instrument but also between performers as well. Several previous studies and taxonomies are mentioned, after what different paradigms exposed with examples based on traditional mechanical acoustic instruments. In the final part, several existing systems and implementations, now in the digital domain, are described and identified according to the models and paradigms previously introduced.

In this paper we describe object design considerations for the reacTable* project, a novel tangible musical instrument, developed at the Audiovisual Institute at the Universiat Pompeu Fabra. The work presented in this paper is the result of a collaboration with the Palpable Machines Group at Media Lab Europe, which focussed on haptic design aspects of the reacTable* instrument. We present a simple haptic encoding scheme for the mapping of abstract sound synthesis objects onto tangible proxy objects.

In recent years we have seen a proliferation of musical tables. Believing that this is not just the result of a tabletop trend, in this paper I first discuss the reasons that make tabletop interfaces promising musical interfaces. After that, I present the reactable, a musical instrument based on a tabletop interface that exemplifies several of these potential achievements. Author Keywords Reactable, tangible interfaces, tabletop interfaces, musical instrument, musical performance, design, interaction techniques. ACM Classification Keywords H.5.2 [User Interfaces]: interaction styles, input devices and strategies J.5: [Arts and Humanities]: performing arts.

We present the Pin&Play&Perform system: an interface in the form of a tablet on which a number of physical controls can be added, removed and arranged on the fly. These controls can easily be mapped to existing music sofware using the MIDI protocol. The interface provides a mechanism for direct manipulation of application parameters and events through a set of familiar controls, while also encouraging a high degree of customisation through the ability to arrange, rearrange and annotate the spatial layout of the interface components on the surface of the tablet.

ChucK is a programming language for real-time sound synthesis. It provides generalized audio abstractions and precise control over timing and concurrency - combining the rapid-prototyping advantages of high-level programming tools, such as Pure Data, with the flexibility and controllability of lower-level, text-based languages like C/C++. In this paper, we present a new time-based paradigm for programming controllers with ChucK. In addition to real-time control over sound synthesis, we show how features such as dynamic patching, on-the-fly controller mapping, multiple control rates, and precisely-timed recording and playback of sensors can be employed under the ChucK programming model. Using this framework, composers, programmers, and performers can quickly write (and read/debug) complex controller/synthesis programs, and experiment with controller mapping on-the-fly.

We present the Pin&Play&Perform system: an interface in the form of a tablet on which a number of physical controls can be added, removed and arranged on the fly. These controls can easily be mapped to existing music sofware using the MIDI protocol. The interface provides a mechanism for direct manipulation of application parameters and events through a set of familiar controls, while also encouraging a high degree of customisation through the ability to arrange, rearrange and annotate the spatial layout of the interface components on the surface of the tablet. The paper