  Removing noise in computer tomography (CT) data for real-time 3D
visualization is vital to improving the quality of the final display. However,
the CT noise cannot be removed by straight averaging because the noise has a
broadband spatial frequency that is overlapping with the interesting signal
frequencies. To improve the display of structures and features contained in the
data, we present spatially variant filtering that performs averaging of
sub-regions around a central region. We compare our filter with four other
similar spatially variant filters regarding entropy and processing time. The
results demonstrate significant improvement of the visual quality with
processing time still within the millisecond range.
