Nicola Ranieri

Multi-Layered Automultiscopic Displays

Our hybrid display model combines multiple automultiscopic elements volumetrically to support horizontal and vertical parallax at a larger depth of field and better accommodation cues compared to single layer elements. In this paper, we introduce a framework to analyze the bandwidth of such display devices. Based on this analysis, we show that multiple layers can achieve a wider depth of field using less bandwidth compared to single layer displays. We present a simple algorithm to distribute an input light field to multiple layers, and devise an efficient ray tracing algorithm for synthetic scenes. We demonstrate the effectiveness of our approach by both software simulation and two corresponding hardware prototypes.

Towards next generation 3D teleconferencing systems

Teleconferencing is becoming more and more important and popular in todays society and is mostly accomplished using 2D video conferencing systems. However, we believe there is a lot of room for improving the communication experience: one crucial aspect is to add 3D information, but also freeing the user from sitting in front of a computer. With these improvements, we aim at eventually creating a fully immersive 3D telepresence system that might improve the way we communicate over long distances. In this paper we review and analyze existing technology to achieve this goal and present a proof-of-concept, but fully functional prototype.

An Immersive Bidirectional System for Life-size 3D Communication

Telecommunication and video conferencing are an integral part of modern society with implications in many aspects of everyday life. However, compared to a meeting in person, the sense of presence is still limited in electronic communication. In this paper, we present a novel system for life-size 3D telecommunication. It is designed to create an immersive user experience by seamlessly embedding a remote conversation partner into the local environment. To achieve this, users are captured in 3D by hybrid (color+depth) sensors and displayed on a life-size transparent 3D display. We have built two instances of this system in Zurich and Singapore. They form a complete and fully functional prototype enabling bidirectional communication in real-time over a long distance. We further demonstrate alternative hardware setups, which make our system flexible and adaptable to different usage scenarios.

Vision-based calibration of parallax barrier displays

Static and dynamic parallax barrier displays became very popular over the past years. Especially for single viewer applications like tablets, phones and other hand-held devices, parallax barriers provide a convenient solution to render stereoscopic content. In our work we present a computer vision based calibration approach to relate image layer and barrier layer of parallax barrier displays with unknown display geometry for static or dynamic viewer positions using homographies. We provide the math and methods to compose the required homographies on the fly and present a way to compute the barrier without the need of any iteration. Our GPU implementation is stable and general and can be used to reduce latency and increase refresh rate of existing and upcoming barrier methods.

Transparent stereoscopic display and application

Augmented reality has become important to our society as it can enrich the actual world with virtual information. Transparent screens offer one possibility to overlay rendered scenes with the environment, acting both as display and window. In this work, we review existing transparent back-projection screens for the use with active and passive stereo. Advantages and limitations are described and, based on these insights, a passive stereoscopic system using an anisotropic back-projection foil is proposed. To increase realism, we adapt rendered content to the viewers position using a Kinect tracking system, which adds motion parallax to the binocular cues. A technique well known in control engineering is used to decrease latency and increase frequency of the tracker. Our transparent stereoscopic display prototype provides immersive viewing experience and is suitable for many augmented reality applications.