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imwr.imwdc

Inverse two-dimensional discrete wavelet transform.

DESCRIPTION

This functions performs the reconstruction stage of Mallat's pyramid algorithm (i.e. the inverse discrete wavelet transform) for images.

USAGE:

imwr.imwdc(imwd, verbose=F)

REQUIRED ARGUMENTS:

imwd: An object of class imwdc. This type of object is returned by threshold.imwd and is a compress.imwd compressed version of an imwd object.

OPTIONAL ARGUMENTS:

verbose: If this argument is true then informative messages are printed detailing the computations to be performed
...: other arguments to supply to the imwr function which is called after uncompressing the imwdc object.

VALUE:

A matrix, of dimension determined by the original data set supplied to the initial decomposition (more precisely, determined by the nlevels component of the imwdc object). This matrix is the highest resolution level of the reconstruction.

SIDE EFFECTS:

None

DETAILS:

This function merely uncompresses the supplied imwdc object and passes the resultant imwd object to the imwr.imwd function.

This function is a method for the generic function imwr for class imwdc objects. It can be invoked by calling imwr for an object of the appropriate class, or directly by calling imwr.imwdc regardless of the class of the object.

RELEASE:

EXAMPLES:

#
# Do a decomposition, thresholding, then exact reconstruction
# Look at the error
#
# Test image is just some sort of  square matrix whose side length
# is a power of two.
#
max( abs(imwr(threshold(imwd(test.image))) - test.image))
# [1] 62.34
#
# The answer is not zero (see contrasting example in the help page for
# imwr.imwd because we have thresholded the
# 2D wavelet transform here.