We implemented a Direct Volume Rendering (DVR) approach for visualizing video sequences. The idea is based on the scientific paper "Visualising Video Sequences Using Direct Volume Rendering" by Daniel and Chen (Proc. of the 1st International Conference on Vision, Video and Graphics (VVG2003), 103-110, Eurographics/ACM Workshop Series, Bath, July 2003.).

Video sequences are summarized by visualising the whole sequence as a three dimensional object, where time is specified as the third dimension. Direct volume rendering is used to enable insights into the volumetric video block. Thus, a reasonable way to set the opacity of each voxel value has to be found. Our implementation offers 3 different options:

• Background Subtraction (non-changing background elements are set transparent, OpenCV BackgroundSubtractorMOG model was used)
• Saliency Detection (only salient areas in each frame are set opaque, http://www.samontab.com/web/saliency/)
• Hue Selection (transparency based on specified hue value)