In this paper, we propose an infinite impulse response (IIR)
filtering with complex coefficients for Euclid distance based
filtering, e.g. bilateral filtering. Recursive filtering of edgepreserving
filtering is the most efficient filtering. Recursive
bilateral filtering and domain transform filtering belong to
this type. These filters measure the difference between pixel
intensities by geodesic distance. Also, these filters do not
have separability. The aspects make the filter sensitive to
noises. Bilateral filtering does not have these issues, but it is
time-consuming. In this paper, edge-preserving filtering with
the complex exponential function is proposed. The resulting
stack of these IIR filtering is merged to approximated edgepreserving
in FIR filtering, which includes bilateral filtering.
For bilateral filtering, a raised-cosine function is used for efficient
approximation. The experimental results show that the
proposed filter, named IIR bilateral filter, approximates well
and the computational cost is low