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idwt3

Single-level inverse discrete 3-D wavelet transform

Syntax

X = idwt3(WT)
C = idwt3(WT,TYPE)

Description

The idwt3 command performs a single-level three-dimensional wavelet reconstruction starting from a single-level three-dimensional wavelet decomposition.

X = idwt3(WT) computes the single-level reconstructed 3-D array X, based on the three-dimensional wavelet decomposition stored in the WT structure. This structure contains the following fields.

sizeINI

Size of the three-dimensional array X.

mode

Name of the wavelet transform extension mode.

filters

Structure with 4 fields, LoD, HiD, LoR, HiR, which contain the filters used for DWT.

dec

2 x 2 x 2 cell array containing the coefficients of the decomposition.

dec{i,j,k}, i,j,k = 1 or 2 contains the coefficients obtained by low-pass filtering (for i or j or k = 1) or high-pass filtering (for i or j or k = 2).

C = idwt3(WT,TYPE) computes the single-level reconstructed component based on the three-dimensional wavelet decomposition. Valid values for TYPE are:

  • A group of three characters 'xyz', one per direction, with 'x','y' and 'z' selected in the set {'a','d','l','h'} or in the corresponding uppercase set {'A','D','L','H'}), where 'A' (or 'L') specifies low-pass filter and 'D' (or 'H') specifies high-pass filter.

  • The char 'd' (or 'h' or 'D' or 'H') which specifies the sum of all the components different from the low-pass component.

Examples

% Define original 3D data.
X  = reshape(1:64,4,4,4);

% Decompose X using db1.
wt = dwt3(X,'db1');

% Reconstruct X from coefficients.
XR = idwt3(wt);

% Compute reconstructed approximation, i.e. the 
% low-pass component.
A  = idwt3(wt,'aaa');

% Compute the sum of all the components different
% from the low-pass component.
D  = idwt3(wt,'d');

% Reconstruct the component associated with low-pass in the
% X and Z directions and high-pass in the Y direction.
ADA  = idwt3(wt,'ada');

See Also

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