Real-Time Analysis of Human Body Parts and Gesture-Activity Recognition in 3D - 3D Modeling and Animation: Synthesis and Analysis Techniques for the Human Body - page 157

Figure 14: Unattended object detection.
would improve the performance by alleviating the self-occlusion problem.
Another challenge is detecting multiple persons and recognizing their activities.
Figure 15 displays an example frame from security cameras in a test room. Note
that the algorithm can generate the 3D model of each body part, unless there is
occlusion because of the other person or because of another body-part. As it is
mentioned before, occlusion problems can be overcome by using multiple
cameras (more than two) and using a feedback scheme.
Figure 15: Multiple persons.