wpt(a,b,f,[o,[i]]) Returns the
wavelet packet transform of the array a
with respect to basis or level b
by the wavelet filter f. f can have an offset o
and negation i .
iwpt(w,b,f,[o,[i]]) Returns
the inverse wavelet packet transform of the array w
with respect to basis b by the
wavelet filter f. f
can have an offset o and negation
i .
Arguments:
a is a vector
or matrix. The length of a must be divisible by 2level if it is a vector. The number of rows
and columns of a must be divisible by 2level if it is a matrix.
b represents
a level or a packet basis. For wpt,
b is an integer or a 2- or 3-column
matrix representing a packet basis. For iwpt,
b must be a 2- or 3-column matrix
representing a packet basis.
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.