Implementation of digital 3-D IIR filters for stream-processing applications

Presents an implementation structure for recursive three-dimensional digital filters, based on the filter design presented in Runze and Steffen (1996), which yields either recursive or non-recursive filters. The recursive design results have two interesting properties: the recurrence direction is oriented parallel to one coordinate axis (e.g. time axis in data-stream processing), and the transfer function itself is composed of separable systems. These properties can be exploited to build up the whole three-dimensional system, using only spatial shifts and time-directed one-dimensional recursive filters