www.gusucode.com > wavelet工具箱matlab源码程序 > wavelet/wavelet/waverec3.m
function X = waverec3(wdec,varargin)
%WAVEREC3 Multilevel 3-D wavelet reconstruction.
% WAVEREC3 performs a multilevel 3-D wavelet reconstruction
% starting from a multilevel 3-D wavelet decomposition.
%
% X = WAVEREC3(WDEC) reconstructs the 3-D array X based
% on the multilevel wavelet decomposition structure WDEC.
%
% In addition, you can use WAVEREC3 to simply extract coefficients
% from a 3-D wavelet decomposition (see below).
%
% WDEC is a structure with the following fields:
% sizeINI: contains the size of the 3-D array X.
% level: contains the level of the decomposition.
% mode: contains the name of the wavelet transform extension mode.
% filters: is a structure with 4 fields LoD, HiD, LoR, HiR which
% contain the filters used for DWT.
% dec: is an N x 1 cell array containing the coefficients of the
% decomposition. N is equal to 7*WDEC.level+1. dec{1} contains
% the lowpass component (approximation) at the level of the
% decomposition. The approximation is equivalent to the
% filtering operations 'LLL'. dec{k+2},...,dec{k+8} with k =
% 0,7,14,...,7*(WDEC.level-1) contain the 3-D wavelet
% coefficients. The coefficients start with the coarsest level
% when k=0. For example, if WDEC.level=3, dec{2},...,dec{8}
% contain the wavelet coefficients for level 3 (k=0),
% dec{9},...,dec{15} contain the wavelet coefficients for
% level 2 (k=7), and dec{16},...,dec{22} contain the wavelet
% coefficients for level 1 (k=7*(WDEC.level-1)). At each
% level, the wavelet coefficients in dec{k+2},...,dec{k+8} are
% in the following order:
% 'HLL','LHL','HHL','LLH','HLH','LHH','HHH'. The strings give
% the order in which the separable filtering operations are
% applied from left to right. For example, suppose the order
% is 'LHH'. First, WAVEDEC3 applies the lowpass (scaling)
% filter with downsampling to the rows of X. Next, WAVEDEC3
% applies the highpass (wavelet) filter with downsampling to
% the columns of X and then to the 3rd dimension of X.
% sizes: contains the successive sizes of the decomposition
% components.
%
% C = WAVEREC3(WDEC,TYPE,N) reconstructs the multilevel
% components at level N of a 3-D wavelet decomposition. N must be
% a positive integer less or equal to the level of the decomposition.
% The valid values for TYPE are:
% - A group of 3 chars 'xyz', one per direction, with 'x','y' and 'z'
% in the set {'a','d','l','h'} or in the corresponding upper case
% set {'A','D','L','H'}), where 'A' (or 'L') stands for low pass
% filter and 'D' (or 'H') stands for high pass filter.
% - The char 'd' (or 'h' or 'D' or 'H') gives directly the sum of
% all the components different from the low pass one.
% - The char 'a' (or 'l' or 'A' or 'L') gives the low pass
% component (the approximation at level N).
%
% For extraction purpose, the valid values for TYPE are the same as
% above prefixed by 'c' or 'C'.
%
% X = WAVEREC3(WDEC,'a',0) or X = WAVEREC3(WDEC,'ca',0) is equivalent
% to X = WAVEREC3(WDEC).
%
% C = WAVEREC3(WDEC,TYPE) is equivalent to C = WAVEREC3(WDEC,TYPE,N)
% with N equal to the level of the decomposition.
%
% Examples:
% M = magic(8);
% X = repmat(M,[1 1 8]);
% wd = wavedec3(X,2,'db2','mode','per');
% XR = waverec3(wd);
% err1 = max(abs(X(:)-XR(:)))
% A = waverec3(wd,'aaa');
% CA = waverec3(wd,'ca');
% D = waverec3(wd,'d');
% err2 = max(abs(X(:)-A(:)-D(:)))
% A1 = waverec3(wd,'aaa',1);
% D1 = waverec3(wd,'d',1);
% err3 = max(abs(X(:)-A1(:)-D1(:)))
% DDD = waverec3(wd,'ddd',2);
% disp(DDD(:,:,1))
%
% See also idwt3, wavedec3, waveinfo.
% M. Misiti, Y. Misiti, G. Oppenheim, J.M. Poggi 09-Dec-2008.
% Last Revision: 20-Dec-2010.
% Copyright 1995-2010 The MathWorks, Inc.
% Check arguments.
nbIn = length(varargin);
% Initialization.
cfs = wdec.dec;
sizes = wdec.sizes;
level = wdec.level;
cfsFLAG = false;
nbREC_UP = level;
if nbIn>0
errorFLAG = false;
type = varargin{1};
nbChar = length(type);
if nbChar==2 || nbChar==4
if isequal(upper(type(1)),'C')
type(1) = []; nbChar = nbChar-1; cfsFLAG = true;
else
errorFLAG = true;
end
end
switch nbChar
case {1,3}
num = ones(1,3);
switch type
case {'a','l','A','L','1'} , num = Inf;
case {'d','h','D','H','0'} , num = -num;
otherwise
if nbChar==3
for k = 1:3
switch type(k)
case {'a','l','A','L','1'}
case {'d','h','D','H','0'} , num(k) = 2;
otherwise , errorFLAG = true;
end
end
else
errorFLAG = true;
end
end
otherwise , errorFLAG = true;
end
if isequal(num,[1 1 1]) , num = Inf; end
if errorFLAG
error(message('Wavelet:FunctionArgVal:Invalid_ArgVal'));
end
if nbIn>1
levREC = varargin{2};
OKval = isnumeric(levREC) && isequal(levREC,fix(levREC)) && ...
levREC<=level && (levREC>0 || ...
(levREC==0 && (isequal(num,[1 1 1]) || isinf(num))) );
if ~OKval
error(message('Wavelet:FunctionArgVal:Invalid_ArgVal'));
end
else
levREC = level;
end
if isinf(num)
First_toDEL = 2+7*(level-levREC);
for k = First_toDEL:(7*level+1) , cfs{k}(:) = 0; end
if cfsFLAG
if isequal(level,levREC) , X = cfs{1}; return; end
nbREC_UP = level-levREC;
end
elseif isequal(num,[-1,-1,-1])
cfs{1}(:) = 0;
for k = 1:(level-levREC)
for j = 1:7 , cfs{7*(k-1)+j+1}(:) = 0; end
end
if cfsFLAG , X = cfs; end
else
num(num==2) = 0;
Idx_toKeep = 1+7*(level-levREC+1) - bin2dec(dec2bin(num)');
if cfsFLAG
if (~isequal(num,[1,1,1]) || isequal(level,levREC))
X = cfs{Idx_toKeep};
return
elseif isequal(num,[1,1,1])
nbREC_UP = level-levREC;
end
end
for k = 1:(7*level+1)
if k~=Idx_toKeep , cfs{k}(:) = 0; end
end
end
end
idxBeg = 1;
for k=1:nbREC_UP
idxEnd = idxBeg+7;
wdec.dec = reshape(cfs(idxBeg:idxEnd),2,2,2);
X = idwt3(wdec,sizes(k+1,:));
cfs{idxEnd} = X;
idxBeg = idxEnd;
end