This article describes the development of   LiteFoot, an interactive floor space that tracks dancers’ steps, converting human motion into sound and images. The system can also record steps for further analysis for use in dance research programmes, choreographic experimentation and training.

Introduction

In early 1997 a team of researchers at the University of Limerick started to discuss the prospects of recording traditional Irish dance electronically. We realised that an electronic recording device could also be made to add to, or enhance, performance through sound and visual representations of dance. If such a system could be created, it would potentially allow researchers in ethnochoreology to record and analyse the subtle movements of master dancers as well as allowing modern dancers to explore possibilities with a dancer making his or her own music in real-time. We initiated a project, first reviewing existing systems and technologies. We found that existing systems were either expensive, invasive or not fulfilling the requirements.

Designing LiteFoot

A number of issues had to be covered, both users’ requirements and technical requirements versus constraints such as budget and a definite deadline – UL’s 25th anniversary. The following requirements were identified as key elements for this design:

• The floor should be able to respond at a rate corresponding to at least 30 steps per second.

• The floor should have a reasonable spatial resolution (44 millimetres)

• The floor should be able to track multiple feet and dancers.

The LiteFoot prototype is a 1.76 meter square and 10 centimetres high floor element, filled with a matrix of 1,936 optical proximity sensors. When you stand on the floor the spatial locations of your feet are detected. An accelerometer detects the total impact force of the feet, providing a third dimension. Arbitrary mappings between the data coming from the floor and representations can be defined by the user. The visual representation has, so far, been a direct mapping of location to displayed groups of pixels, with the colour controlled by the impact force. For the auditory representation, the incoming data-stream controls the MIDI synthesizer of a standard sound card, with various musical scales in one dimension (X) and various sets of "instruments" in another dimension (Y). The impact force has been mapped to, for example, loudness (Z).

LiteFoot in Action

The LiteFoot premiere was in September 1997 in a performance in the University Concert Hall at UL. Both traditional Irish dance and improvised modern dance were performed, and several members of the audience reported the performance to be aesthetically and perceptually engaging. In January 1998 LiteFoot appeared in The Late Late Show as an example of new art and technology. Since then it has been demonstrated several times, including an international workshop on dance at the University of Limerick (Trath na gCos) and in an interactive exhibition in Limerick City (Infusion – a National Review of Live Art).

Continued Research

With the existing LiteFoot prototype, we can now evaluate its use to define the requirements for a second generation of LiteFoot. Some of our students, working on their final year projects, have extended our software libraries. There are many possibilities to be explored, for example, to use other kinds of mappings. Instead of direct mappings, orchestrations and sound, music or video sequences with parametric control could be mapped to areas of the floor. When several persons are active on the floor simultaneously, the level of "collaborative harmony" could be mapped to tonal harmony and temporal structures. As a play space, LiteFoot seems to be highly engaging, and there are also a number of possibilities to be evaluated with, for example, disabled people who might be able to extend their action range through training with different forms of auditory and visual feedback.

Acknowledgements

The LiteFoot team is an expanding interdisciplinary group and it is almost impossible to list all contributors to this project. The core of the group, so far, is Dr Niall Griffith (Department of Computer Science and Information Systems - CSIS), Dr Liam Bannon (Interaction Design Centre/ CSIS) and Dr Catherine Foley (Irish World Music Centre). I also would like to thank Prof. Kevin Ryan for his financial support and the Department of CSIS for financial support and the loan of equipment during the development.

Contact: Mikael Fernström, Interaction Design Centre,
Department of Computer Science
and Information Systems, University of Limerick.