dwt(a,n,f,[o,[i]]) Returns the
n-level wavelet transform of
the array a by the wavelet filter
f. f
can have an offset o and negation
i .
idwt(a,n,f,[o,[i]]) Returns
the n-level inverse wavelet transform
of the array a by the wavelet
filter f.
f can have an offset o
and negation i .
Arguments:
a is a vector
whose length is divisible by 2n,
or a is an array, the number of
rows and columns of which is divisible by 2n.
n is an integer.
f is a vector
of low pass filter coefficients for an orthonormal filter. Alternatively, for a biorthogonal filter, f is
a 2-column matrix whose first column contains the low pass filter coefficients and whose second column contains the inverse low pass filter coefficients. f is the result from a function, such as daublet or Bspline, that creates the filter coefficients for a particular wavelet or f is an array of user-defined filter coefficients.
o (optional)
is a real scalar, for an orthonormal filter, or a 1 x 2 matrix of real scalars for a biorthogonal filter. o
is the offset(s) corresponding to the filter f.
If not specified, o is a default
offset.
i (optional)
is zero or one for an orthonormal filter or, for a biorthogonal filter, i is a 1 x 2 matrix whose elements
are zero or one. i = 0 specifies
no negation of the default high pass coefficients; i = 1 specifies negation. If not specified, i = 0.