  Abstract. Nowadays, interaction represents an attractive approach for deploying new forms of entertainment and art. Towards this aim, novel technologies can make possible advanced concepts of interaction, hence supporting complicated application scenarios. In this work, an interactive audiovisual installation is presented, which aims to make the participant interact with the stars in the space. Human gesture based interaction is employed in order to control the visual and audio reproduction in real time. Keywords: ambisonics, soundscape, interaction. I. INTRODUCTION HE desire of human to explore the stars and understand their environment, the space, was the basic idea that led us in the conception of the scenario described in this work. The space and the stars can be presented more accurately with the use of new technologies. By using these technologies we can achieve significantly better and authentic visual and audio representation of the universe. Additionally, interaction can have a decisive role in this essential approach in the immersion of space by giving the user the opportunity with his gestures to interact with the outer space and to establish a “virtual link” between himself and the universe. More specifically, through the use of interaction, an effort is made for the user to be able to observe the starry night and to additionally allow him to interact with the stars. This is performed in the context of an interactive audiovisual installation termed “ambiStar” [Fig. 1]. Fig 1. The ambiStart installation logo. Interactive audiovisual installations represent a new form for realizing complex human-oriented experiments that most commonly involve human-machine interactions, while they are also employed by modern artists as a new artistic expression approach [1]. Hence, new terms and ideas originating from the general concept of interaction are nowadays frequently used to provide novel means of audio and visual production, where the audience is actively participating in the production process [2], [3]. In this installation we have employed and combined advanced visual and three dimensional (3D) sound representation technologies for realizing the natural universe environment, as well as human gesture-based interaction. Focusing on the sound environment, the basic target was to realize an authentic soundscape, that is an imaginary (virtual) sound environment that corresponds to a specific place. Nowadays, we have the opportunity to create and describe an environment with sounds as well as to achieve the best sound reproduction in 3D space. Traditionally, the creation and playback of 3D sound is usually made with coding sound information in multiple channels, like 5.1 surround systems [4] or with more channels (i.e. wavefield synthesis [5]). During the last few years the research on this area has focused on developing methods of accurate modeling of the sound field in three dimensions, such as binaural processing [6] and ambisonics, who axe the need of having multiple sound channels. Beyond typical systems for home and professional sound reproduction in three dimensions, those techniques can be used for audiovisual installations and in new kind of interactive interfaces. With the use of visual projection and video compositing a realistic representation of the desired environment can be produced as well. Hence, the ambisonics [7] surround sound technology was employed here, which represents a very attractive and efficient form for realistic sound projection in 3D spaces and environments. The complete universe environment representation is achieved by the synchronous high-quality and resolution video projection of sky, appropriately synthesized and projected on a curved dome. As mentioned previously, within the installation context, the audiovisual universe representation is fully controlled by the user using gesture-based interaction. More specifically, the installation participant can control the audiovisual reproduction and context by simply moving his hand. This simplified approach was selected based on the fact that most humans usually observe the night sky during relaxing time intervals, without carrying special equipment. During this observation, it is also very common to focus on specific stars’ formations, allowing the development of a natural way of interacting with the visible star space. In the past several artists has used the features that the technology of reproducing sound in 3D space provides and they have made installations with original and complicated scenarios. Typical examples of such works ambiStar: A Virtual Space Representation sing 3D Human Interaction Nikolas Grigoriou 1 , Andreas Floros 2 1 Department of AudioVisual Arts - Ionian University, Greece, 2 Department of AudioVisual Arts - Ionian University, Greece, nikolas.grigoriou@me.com, floros@ionio.gr T 430 978-1-4244-7562-9/10/$26.00 ©2010 IEEE