  A method for constructing non-uniform filter banks is presented. Starting
from a uniform system of translates, generated by a prototype filter, a
non-uniform covering of the frequency axis is obtained by composition with a
warping function. The warping function is a $\mathcal C^1$-diffeomorphism that
determines the frequency progression and can be chosen freely, apart from minor
technical restrictions. The resulting functions are interpreted as filter
frequency responses. Combined with appropriately chosen decimation factors, a
non-uniform analysis filter bank is obtained. Classical Gabor and wavelet
filter banks are special cases of the proposed construction. Beyond the
state-of-the-art, we construct a filter bank adapted to a frequency scale
derived from human auditory perception and families of filter banks that can be
interpreted as an interpolation between linear (Gabor) and logarithmic
(wavelet) frequency scales. We derive straightforward conditions on the
prototype filter decay and the decimation factors, such that the resulting
warped filter bank forms a frame. In particular, a simple and constructive
method for obtaining tight frames with bandlimited filters is derived by
invoking previous results on generalized shift-invariant systems.
