nag_wav_3d_coeff_ext (c09fyc) extracts a selected set of discrete wavelet transform (DWT) coefficients from the full set of coefficients stored in compact form, as computed by
nag_dwt_3d (c09fac) (single level three-dimensional DWT) or
nag_mldwt_3d (c09fcc) (multi-level three-dimensional DWT).
nag_wav_3d_coeff_ext (c09fyc) is intended to be used after a call to either
nag_dwt_3d (c09fac) (single level three-dimensional DWT) or
nag_mldwt_3d (c09fcc) (multi-level three-dimensional DWT), either of which must be preceded by a call to
nag_wfilt_3d (c09acc) (three-dimensional wavelet filter initialization). Given an initial three-dimensional data set
, a prior call to
nag_dwt_3d (c09fac) or
nag_mldwt_3d (c09fcc) computes the approximation coefficients (at the highest requested level in the case of
nag_mldwt_3d (c09fcc)) and seven sets of detail coefficients (at all levels in the case of
nag_mldwt_3d (c09fcc)) and stores these in compact form in a one-dimensional array
c.
nag_wav_3d_coeff_ext (c09fyc) can then extract either the approximation coefficients or one of the sets of detail coefficients (at one of the levels following
nag_mldwt_3d (c09fcc)) into a three-dimensional data set stored in
d.
If a multi-level DWT was performed by a prior call to
nag_mldwt_3d (c09fcc) then the dimensions of the three-dimensional data stored in
d depend on the level extracted and are available from the arrays
dwtlvm,
dwtlvn and
dwtlvfr as returned by
nag_mldwt_3d (c09fcc) which contain the first, second and third dimensions respectively.
If a single level DWT was performed by a prior call to
nag_dwt_3d (c09fac) then the dimensions of the three-dimensional data stored in
d can be determined from
nwct,
nwcn and
nwcfr as returned by the setup function
nag_wfilt_3d (c09acc).
See
Section 2.1 in the c09 Chapter Introduction for a discussion of the three-dimensional DWT.
None.
Note: the following notation is used in this section:
Not applicable.
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