An automatic 3D tracking system with a PC and a single TV camera

We developed a novel system, for tracking a freely moving object (animal) in a limited 3D space, based on a closed loop TV and PC. Instead of using a pair of TV cameras to capture the 3D scene through the pair of its orthogonal projections, the system captures these projections by using a single TV camera. The direct view of the scene (e.g. its ground plan, i.e. projection onto the x-y plane) is captured together with its side projection, (i.e. projection onto the z-x plane) observed in a slanted mirror. The system uses a simple detection algorithm and hardware that were originally developed for 2D tracking of a single, contrast object on a stable and homogeneous background. All three coordinates of the tracked object are evaluated, displayed and stored in real-time, at 25 interlaced frames (samples) per second. The system was implemented on an IBM PC enhanced by an universal I/O board (Kaminsky, Yu, Krekule, I. Universal multifunctional IBM PC I/O board for clinical examinations and experimental research in neuroscience. Physiol Res 1994;43:193-199) and tested by tracking a LED marker, a small living fish in a water tank and a pair of LED markers which were activated one at the time in alternating TV frames thereby demonstrating the ability to simultaneously track two or more objects in 3D.