The International Gesture Workshops (GW) are interdisciplinary events for those researching gesture-based communication across the disciplines. The focus of these events is a shared interest in understanding gestures and sign language in their many facets, and using them for advancing human-machine interaction. Since 1996, International Gesture Workshops have been held roughly every second year, with fully reviewed proceedings published by Springer. The International Gesture Workshop GW 2009 was hosted by Bielefeld University's Center for Interdisciplinary Research (ZiF - Zentrum für interdisziplinäre Forschung) during February 25-27, 2009. Like its predecessors, GW 2009 aimed to provide a platform for participants to share, discuss, and criticize recent and novel research with a multidisciplinary audience. More than 70 computer scientists, linguistics, psychologists, neuroscientists as well as dance and music scientists from 16 countries met to present and exchange their newest results under the umbrella theme "Gesture in Embodied Communication and Human-Computer Interaction. " Consistent with the steady growth of research activity in this area, a large number of high-quality submissions were received, which made GW 2009 an exciting and important event for anyone interested in gesture-related technological research relevant to human-computer interaction. In line with the practice of previous gesture workshops, presenters were invited to submit theirs papers for publication in a subsequent peer-reviewed publication of high quality. The present book is the outcome of this effort. Representing the research work from eight countries, it contains a selection of 28 thoroughly reviewed articles.

Analysis of Gesture.- The Role of Iconic Gestures in Production and Comprehension of Language: Evidence from Brain and Behavior.- Speakers' Use of Interactive Gestures as Markers of Common Ground.- Gesture Space and Gesture Choreography in European Portuguese and African Portuguese Interactions: A Pilot Study of Two Cases.- Concepts of Gesture.- The Embodied Morphemes of Gaze.- On Factoring Out a Gesture Typology from the Bielefeld Speech-and-Gesture-Alignment Corpus (SAGA).- Function and Form of Gestures in a Collaborative Design Meeting.- Gesture Recognition.- Continuous Realtime Gesture Following and Recognition.- Multiscale Detection of Gesture Patterns in Continuous Motion Trajectories.- Recognition of Gesture Sequences in Real-Time Flow, Context of Virtual Theater.- Deictic Gestures with a Time-of-Flight Camera.- Gesture Processing.- Towards Analysis of Expressive Gesture in Groups of Users: Computational Models of Expressive Social Interaction.- On Gestural Variation and Coarticulation Effects in Sound Control.- Gesture Saliency: A Context-Aware Analysis.- Towards a Gesture-Sound Cross-Modal Analysis.- Methods for Effective Sonification of Clarinetists' Ancillary Gestures.- Gesture Simulation.- Systematicity and Idiosyncrasy in Iconic Gesture Use: Empirical Analysis and Computational Modeling.- To Beat or Not to Beat: Beat Gestures in Direction Giving.- Requirements for a Gesture Specification Language.- Statistical Gesture Models for 3D Motion Capture from a Library of Gestures with Variants.- Modeling Joint Synergies to Synthesize Realistic Movements.- Gesture and Multimodal Interfaces.- Multimodal Interfaces in Support of Human-Human Interaction.- Gestures for Large Display Control.- Gestural Attributions as Semantics in User Interface Sound Design.-Gestural Interfaces for Elderly Users: Help or Hindrance?.- Gestures in Human-Computer Interaction - Just Another Modality?.- Sign Language.- Body Posture Estimation in Sign Language Videos.- Influence of Handshape Information on Automatic Sign Language Recognition.- Towards Interactive Web-Based Virtual Signers: First Step, a Platform for Experimentation Design.- Toward Modeling Sign Language Coarticulation.