Mutual Gaze Support in Videoconferencing Reviewed

Videoconferencing allows geographically dispersed parties to communicate by simultaneous audio and video transmissions. It is used in a variety of application scenarios with a wide range of coordination needs and efforts, such as private chat, discussion meetings, and negotiation tasks. In particular, in scenarios requiring certain levels of trust and judgement non-verbal communication, cues are highly important for effective communication. Mutual gaze support plays a central role in those high coordination need scenarios but generally lacks adequate technical support from videoconferencing systems. In this paper, we review technical concepts and implementations for mutual gaze support in videoconferencing, classify them, evaluate them according to a defined set of criteria, and give recommendations for future developments. Our review gives decision makers, researchers, and developers a tool to systematically apply and further develop videoconferencing systems in serious settings requiring mutual gaze. This should lead to well-informed decisions regarding the use and development of this technology and to a more widespread exploitation of the benefits of videoconferencing in general. For example, if videoconferencing systems supported high-quality mutual gaze in an easy-to-set-up and easy-to-use way, we could hold more effective and efficient recruitment interviews, court hearings, or contract negotiations

Unsynchronized 4D Barcodes

We present a novel technique for optical data transfer between public displays and mobile devices based on unsynchronized 4D barcodes. We assume that no direct (electromagnetic or other) connection between the devices can exist. Time-multiplexed, 2D color barcodes are displayed on screens and recorded with camera equipped mobile phones. This allows to transmit information optically between both devices. Our approach maximizes the data throughput and the robustness of the barcode recognition, while no immediate synchronization exists. Although the transfer rate is much smaller than it can be achieved with electromagnetic techniques (e.g., Bluetooth or WiFi), we envision to apply such a technique wherever no direct connection is available. 4D barcodes can, for instance, be integrated into public web-pages, movie sequences or advertisement presentations, and they encode and transmit more information than possible with single 2D or 3D barcodes

Unsynchronized 4D Barcodes Coding and Decoding Time-Multiplexed 2D Colorcodes

Abstract. We present a novel technique for optical data transfer between public displays and mobile devices based on unsynchronized 4D barcodes. We assume that no direct (electromagnetic or other) connection between the devices can exist. Time-multiplexed, 2D color barcodes are displayed on screens and recorded with camera equipped mobile phones. This allows to transmit information optically between both devices. Our approach maximizes the data throughput and the robustness of the barcode recognition, while no immediate synchronization exists. Although the transfer rate is much smaller than it can be achieved with electromagnetic techniques (e.g., Bluetooth or WiFi), we envision to apply such a technique wherever no direct connection is available. 4D barcodes can, for instance, be integrated into public web-pages, movie sequences, advertisement presentations or information displays, and they encode and transmit more information than possible with single 2D or 3D barcodes.

Passive-Active Geometric Calibration for View-Dependent Projections onto Arbitrary Surfaces

In this paper we present a hybrid technique for correcting distortions that appear when projecting images onto geometrically complex, colored and textured surfaces. It analyzes the optical flow that results from perspective distortions during motions of the observer and tries to use this information for computing the correct image warping. If this fails due to an unreliable optical flow, an accurate -but slower and visiblestructured light projection is automatically triggered. Together with an appropriate radiometric compensation, view-dependent content can be projected onto arbitrary everyday surfaces. An implementation mainly on the GPU ensures fast frame rates