Components

Hard drive: 1 GB of memory

Operating system: Ubuntu 7.10 (GNU/Linux distribution, free and secure operating system)

ASUS processor

This computer replaces the two original “sound” and “video” computers (migration, February 2008)

Software created by the artist and programmed with GridFow and Pure Data freeware.

The artist and the programmer made slight modifications during the installation of the work in February 2008:

Installation of the following Ubuntu packages: Puredata, Libraby, ruby, g++, ruby 1.8-dev, libjpeg62-dev, libpug12=dev, libx11-dev, nasm, libxext-dev, libxt-dev.

Video and sound parts of the program were joined together (migration).

Description

The work is an interactive video installation. The visitor moves through a passage into a dark room. Once in the room, the visitor sees his/her silhouette superimposed on a series of images projected on a wall. Depending on the intensity of the visitor’s movements, his/her silhouette changes and images representing foliage, water and fire change from green, to blue, to red. The amplitude and frequency of the samples from the soundtrack vary more or less perceptibly.

Surveillance video camera (passage)

The surveillance video camera is set up on the floor in the projection room. Fitted with a wide angle lens, it captures the visitor’s image and movements in real time. The captured image is sent to a computer in the control room.

Computer and software

The computer is equipped with software that analyzes motion and the synthesis of animated sequences using a motion capture algorithm programmed with GridFlow and Pure Data freeware. Only the visitor’s silhouette is kept and modified by the code.

- GridFow: multidimensional data processing bank for Pure Data, specialized in image and video.

- Pure Data: real-time graphic programming environment for audio, video and graphics.

Projection

The captured image is not projected immediately. The silhouette is inverted, creating a mirror effect, and superimposed on a series of images projected on a wall in the room. Depending on the intensity of the movements of the visitors in the room, the silhouette is transformed and images roll past, changing from green (no movement), to blue (limited movement), to red (on-going movement).

Sound

The soundtrack consists of five levels of intensity is submitted to a motion-based random generator, which vary the amplitude and frequency of samples from the soundtrack more or less perceptibly. Abundant movement may lead to a stretch of silence, whereas an extended lack of movement results in the sound stopping.

Lighting

The back wall is lit with secondary lighting.

Visitors

There is no maximum number of visitors permitted in the room, but the presence of over 20 visitors at once may cause a saturation of silhouettes on the series of projected images.

1- It is important for the back wall to be painted white to ensure that no light is reflected on the projection wall.

2- The floor must be a colour other than grey so that the visitor’s silhouette stands out.

3- Set up the computer in the control room.

4- Connect the power supply for the surveillance video camera and connect it to the computer. Install the camera on the ground near the projection wall.

5- Set up the secondary lighting and point it at the back wall.

6- Suspend the projector very high from the ceiling. Place the projector as far as possible from the projection wall depending on the available space and connect it to the computer and to a power outlet.

7- Plug in and install the speakers (sound: about 70 dB).

8- Once all the equipment is installed and connected, start the computer and perform the following checks:

- adjust the camera angle;

- set the projection parameters (Brightness, Contrast, Transparences and Contours);

- adjust speaker volume.