Real-time 3-dimensional recursive digital filter for video signals

The design and implementation of a real-time 3D digital filter for video signals is described. The filter implements a completely general 3D, first-order, recursive, discrete-time transfer function at NTSC video-rates (480/spl times/512 pixels, 30 f/s). A fully-parallel systolic structure is chosen based on its short critical path, regularity, local interconnectivity, internal overflow immunity, minimized memory requirements and expandability. The implementation is carried out with discrete logic on PCBs and consists of 634 ICs distributed over 12 modules. A comprehensive workstation-based GUI, which includes a 3D filter-design facility, directly communicates with the filter to control its numerous parameters. The hardware can be further expanded to implement higher orders and 3D real-time adaptive filter algorithms. To our knowledge, this is the first such filter to be reported in the literature.