
the results are then added to reconstruct c
jþ1
. Figure 7.6 illustrates this recon-
struction (synthesis) procedure, or the inverse DWT.
As is seen from Eq. 7.43, the same digital filters used in the analysis are used
for the synthesis, since we have defined orthonormal scaling and wavelet func-
tions. This type of transformation is known as an orthogonal (or, more specif-
ically, orthonormal ) discrete wavelet transform. If the analysis and synthesis
filters are different but the transform is invertible, then the transform is known
as a biorthogonal wavelet transform, as explained later in this chapter. Due
to this orthonormality, g
0
(n) ¼ h
0
(n) and