Enabling 3D Tele-Immersion with Live Reconstructed Mesh Geometry with Fast Mesh Compression and Linear Rateless Coding

3D Tele-immersion enables participants in remote locations to share, in real-time, an activity. It offers users interactive and immersive experiences, but it challenges current media streaming solutions. Work in the past has mainly focused on the efficient delivery of image-based 3D videos and on realistic rendering and reconstruction of geometry-based 3D objects. The contribution of this paper is a real-time streaming component for 3D Tele-Immersion with dynamic reconstructed geometry. This component includes both a novel fast compression method and a rateless packet protection scheme specifically designed towards the requirements imposed by real time transmission of live-reconstructed mesh geometry. Tests on a large dataset show an encoding speed-up upto 10 times at comparable compression ratio and quality, when compared to the high-end MPEG-4 SC3DMC mesh encoders. The implemented rateless code ensures complete packet loss protection of the triangle mesh object and a delivery delay within interactive bounds. Contrary to most linear fountain codes, the designed codec enables real time progressive decoding allowing partial decoding each time a packet is received. This approach is compared to transmission over TCP in packet loss rates and latencies, typical in managed WAN and MAN networks, and heavily outperforms it in terms of end-to-end delay. The streaming component has been integrated into a larger 3D Tele-Immersive environment that includes state of the art 3D reconstruction and rendering modules. This resulted in a prototype that can capture, compress transmit and render triangle mesh geometry in real-time in realistic internet conditions as shown in experiments. Compared to alternative methods, lower interactive end-to-end delay and frame rates over 3 times higher are achieved.