  The latest developments in 3D capturing, processing, and rendering provide
means to unlock novel 3D application pathways. The main elements of an
integrated platform, which target tele-immersion and future 3D applications,
are described in this paper, addressing the tasks of real-time capturing,
robust 3D human shape/appearance reconstruction, and skeleton-based motion
tracking. More specifically, initially, the details of a multiple RGB-depth
(RGB-D) capturing system are given, along with a novel sensors' calibration
method. A robust, fast reconstruction method from multiple RGB-D streams is
then proposed, based on an enhanced variation of the volumetric Fourier
transform-based method, parallelized on the Graphics Processing Unit, and
accompanied with an appropriate texture-mapping algorithm. On top of that,
given the lack of relevant objective evaluation methods, a novel framework is
proposed for the quantitative evaluation of real-time 3D reconstruction
systems. Finally, a generic, multiple depth stream-based method for accurate
real-time human skeleton tracking is proposed. Detailed experimental results
with multi-Kinect2 data sets verify the validity of our arguments and the
effectiveness of the proposed system and methodologies.
