dtcwt.q

Computation of 1D and 2D discrete Dual-Tree complex wavelet transforms.

This file contains a basic implementation of the following references

  • [1] I.  Daubechies, “Ten Lectures on Wavelets,” CBMS-NSF Lecture Notes nr.  61, SIAM, 1992.
  • [2] N G Kingsbury, “Complex wavelets for shift invariant analysis and filtering of signals,” Journal of Applied and Computational Harmonic Analysis, vol 10, no 3, May 2001, pp.  234-253.
  • [3] I.  W. Selesnick.  “The design of approximate Hilbert transform pairs of wavelet bases,” IEEE Trans. on Signal Processing, 50(5):1144-1152, May 2002.
Summary
dtcwt.qComputation of 1D and 2D discrete Dual-Tree complex wavelet transforms.
Constants
Complex wavelets
Functions
dtcwt2dPerforms a dual-tree complex wavelet transform
idtcwt2dPerforms the backward dual-tree complex wavelet transform
pdtcwtPerforms a packet dual-tree complex wavelet transform
pidtcwtComputes the inverse packet dual-tree complex wavelet transform

Constants

Complex wavelets

filtercoeff_selcwvarious precomputed filter coefficients for Selesnicks’ complex wavelets
filtercoeff_selcw = cell(6,6)
filtercoeff_farrasFarras Abdelnour’s complex wavelet filters (for the first scale of the complex wavelet transform)
filtercoeff_dualfiltKingsbury’s 6-tap Q-Shift filters

Functions

dtcwt2d

Performs a dual-tree complex wavelet transform

function bands = dtcwt2d(x, w1, w2, J)

Parameters

xinput image
w1filters for the first scale
w2filters for the other scales
Jnumber of scales

idtcwt2d

Performs the backward dual-tree complex wavelet transform

function y = idtcwt2d(bands, w1, w2, J)

Parameters

bandsa cell vector with complex wavelet subbands
w1filters for the first scale
w2filters for the other scales
Jnumber of scales

pdtcwt

Performs a packet dual-tree complex wavelet transform

function b = pdtcwt(x, w1, w2, J, cplx=1, rev=0)

Parameters

xinput image
w1filters for the first scale
w2filters for the other scales
Jnumber of scales
cplxcompute the complex coefficients (by applying the complex phase modulation)
revreverse the highpass filter coefficients (for demosaicing purposes)

pidtcwt

Computes the inverse packet dual-tree complex wavelet transform

function y = pidtcwt(b, w1, w2, J, cplx=1)

Parameters

ba cell vector with complex wavelet subbands
w1filters for the first scale
w2filters for the other scales
Jnumber of scales
cplxcompute the complex coefficients (by applying the complex phase modulation)
Close