| Wavelet Toolbox | |
Inverse discrete stationary wavelet transform 2-D
Syntax
X = iswt2(SWC,'wname') X = iswt2(A,H,V,D,'wname') X = iswt2(SWC,Lo_R,Hi_R) X = iswt2(A,H,V,D,Lo_R,Hi_R)
Description
iswt2 performs a multilevel 2-D stationary wavelet reconstruction using either a specific orthogonal wavelet ('wname', see wfilters for more information) or specific reconstruction filters (Lo_R and Hi_R).
X = iswt2(SWC,'wname') or X = iswt2(A,H,V,D,'wname') or X = iswt2(A(:,:,end),H,V,D,'wname') reconstructs the signal X, based on the multilevel stationary wavelet decomposition structure SWC or [A,H,V,D] (see swt2).
X = iswt2(SWC,Lo_R,Hi_R) or X = iswt2(A,H,V,D,Lo_R,Hi_R) or X = iswt2(A(:,:,end),H,V,D,Lo_R,Hi_R) reconstructs as above, using filters that you specify.
Lo_R and Hi_R must be the same length.
Examples
% Load original image. load nbarb1; % Perform SWT decomposition % of X at level 3 using sym4. swc = swt2(X,3,'sym4'); % Second usage. [ca,chd,cvd,cdd] = swt2(X,3,'sym4'); % Reconstruct s from the stationary wavelet % decomposition structure swc. a0 = iswt2(swc,'sym4'); % Second usage. a0 = iswt2(ca,chd,cvd,cdd,'sym4'); % Check for perfect reconstruction. err = max(max(abs(X-a0))) ans = 2.3482e-010 errbis = max(max(abs(X-a0bis))) ans = 2.3482e-010
Algorithm
See the section "Stationary Wavelet Transform" in Chapter 6, "Advanced Concepts", of the User's Guide.
See Also
idwt2, swt2, waverec2
References
Nason, G.P.; B.W. Silverman (1995), "The stationary wavelet transform and some statistical applications," Lecture Notes in Statistics, 103, pp. 281-299.
Coifman, R.R.; Donoho D.L. (1995), "Translation invariant de-noising," Lecture Notes in Statistics, 103, pp. 125-150.
Pesquet, J.C.; H. Krim, H. Carfatan (1996), "Time-invariant orthonormal wavelet representations," IEEE Trans. Sign. Proc., vol. 44, 8, pp. 1964-1970.
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