C09EDF computes the inverse two-dimensional multi-level discrete wavelet transform (DWT). This routine reconstructs data from (possibly filtered or otherwise manipulated) wavelet transform coefficients calculated by C09ECF
from an original input matrix. The initialization routine C09ABF
must be called first to set up the DWT options.
C09EDF performs the inverse operation of C09ECF
. That is, given a set of wavelet coefficients, computed by C09ECF
using a DWT as set up by the initialization routine C09ABF
, on a real matrix,
, C09EDF will reconstruct
. The reconstructed matrix is referred to as
in the following since it will not be identical to
when the DWT coefficients have been filtered or otherwise manipulated prior to reconstruction. If the original input matrix is level
, then it is possible to terminate reconstruction at a higher level by specifying fewer than the number of levels used in the call to C09ECF
. This results in a partial reconstruction.
If on entry
, explanatory error messages are output on the current error message unit (as defined by X04AAF
The accuracy of the wavelet transform depends only on the floating point operations used in the convolution and downsampling and should thus be close to machine precision.