setf06.m

Sparse Signal Representation using Overlapping Frames (matlab toolbox)

function ErrCode=SetF06(FrameFile,wname,Level,a)
% SetF06    Set F as a general filter bank, using initial values from a wavelet
%           tree structured filter bank. The wavelet is made by GetWave.m
% The FrameFile will be of Type 'g'
% Also we will always have K==N (corresponds to critically sampled filter bank)
%
% ErrCode=SetF06(FrameFile,wname,Level,a);
% -----------------------------------------------------------------------------------
% Arguments:
%  ErrCode   - 0 is returned if the function execute without error
%              1 an 'unexpected' error occurred, lasterr may explain it
%              2 or larger, another error occurred, 
%  FrameFile - the name of the mat-file used to store the frame
%  wname     - name of the wavelet filter, as used in wfilters.m 
%              also 'db79' for Daubechies 7-9 biorthogonal filter is possible
%              Used as argument in GetWave.m
%  Level     - number of levels to use, use Level=1 to return just
%              the synthesis filters
%              Used as argument in GetWave.m
%  a         - indicate the kind of structure imposed on the filter bank
%              this affect the G matrix
%              0  - all non-zero variables are free, but zeros are fixed
%              a  - a is a real number and 0<a<1, then [F,G]=BuildG(Fg,a)
%                   a should be small!
%              1  - all filter coefficients are free, mut equal filters are 
%                   kept equal.
%              a  - a is a real number and 1<a<2, then BuildG(Fg,a-1) is used
%                   but filters are kept equal, (a-1) should be small!
% -----------------------------------------------------------------------------------

%----------------------------------------------------------------------
% Copyright (c) 2001.  Karl Skretting.  All rights reserved.
% Hogskolen in Stavanger (Stavanger University), Signal Processing Group
% Mail:  [e-mail]   Homepage:  http://www.ux.his.no/~karlsk/
% 
% HISTORY:  dd.mm.yyyy
% Ver. 1.0  10.01.2001  KS: function made
% Ver. 1.1  03.12.2002  KS: moved from ..\Frames to ..\FrameTools
%----------------------------------------------------------------------

Mfile='SetF06';

ErrCode=0; 

if (nargin < 4); a=0; end;   % the default
if (nargin < 3)
   disp([Mfile,': wrong number of arguments, see help.']);
   ErrCode=2;
   return
end
try
   if exist([FrameFile,'.mat'])
      disp([Mfile,': ',FrameFile,'.mat already exists, it will be overwritten.']);
   end
catch
   ErrCode=3;
   return
end

% initialize the variable in FrameFile
Class='';
Type='g';
Mdim=1;
F=[];
G=[];Dtab=[];Ctab=[];  
Fbest=F;
Savg=0;
Mdat=0;
PreProc=struct('Prog1','','Prog2','','Method',[],'arg1',[],'arg2',[],'arg3',[]);
VecSel=struct('Prog1','','arg1',[],'arg2',[],'arg3',[],'arg4',[],'arg5',[]);
InitialF=struct('Prog1',Mfile,'arg1',FrameFile,'arg2',wname,'arg3',Level,'arg4',...
   a,'arg5',[]);
History='';
SNRtot=[];

% now set the variables to the wanted values
try
   Fg=GetWave(wname,Level);              % size is NPxK
catch
   disp([Mfile,': error calling GetWave.']);
   ErrCode=4;
   return
end

[NP,K]=size(Fg);
N=K;
P=NP/N;
if rem(P,1)
   disp([Mfile,': P is not integer.']);
   ErrCode=5;
   return
end

if a<1
   [F,G]=BuildG(Fg,a);          % F is now Qx1, and G is NPxK
elseif a<2
   % let each filter be equal
   G=zeros(size(Fg));
   [F,G(:,1)]=BuildG(Fg(:,1),a-1);
   Q=size(F,1);
   for k=1:log2(K)
      k1=2^(k-1)+1;k2=2^k;
      % the vectors k1:k2 in Fg should be equal!
      [f,G(:,k1:k2)]=BuildG(Fg(:,k1:k2),a-1);
      if a==1
         q=size(f,1)/(k2-k1+1);
      else
         q=size(f,1);
      end
      if rem(q,1)
         disp([Mfile,': non-integer value of q.']);
         q=ceil(q);
      end
      F=[F;f(1:q)];
      G(:,k1:k2)=sign(G(:,k1:k2)).*(abs(G(:,k1:k2))+Q);
      Q=Q+q;
      I=find(abs(G)>Q);
      while length(I)
         G(I)=sign(G(I)).*(abs(G(I))-q);
         I=find(abs(G)>Q);
      end
   end
else
   disp([Mfile,': strange value of fourth argument, a.']);
   ErrCode=6;
   return
end
[Q,temp]=size(F);
if temp~=1
   disp([Mfile,': possible logical error, size(F) is not correct']);
   ErrCode=7;
   return
end
if max(G(:))~=Q
   disp([Mfile,': possible logical error, max(G(:))~=Q.']);
   ErrCode=8;
   return
end

% reshape G from NPxK to NxKxP
temp=G;G=zeros(N,K,P);
for p=1:P; G(:,:,p)=temp((1:N)+(p-1)*N,:); end;

% find Ctab and Dtab and SizeF
[Ctab,Dtab]=MapCD(G);
SizeF=size(G);
Fbest=F;
History=char([Mfile,' ',datestr(now),', initialized the frame ',FrameFile],...
   ['using wavlet ',wname,' ',int2str(Level),' levels, giving N=K=',...
    int2str(N),' P=',int2str(P),' Q=',int2str(Q)]);
% save the frame in a file 
try
   save(FrameFile,'Class','Type','Mdim','F','SizeF','G','Ctab','Dtab',...
        'Fbest','Savg','Mdat','PreProc','VecSel','InitialF','History','SNRtot');
catch
   disp([Mfile,': error saving ',FrameFile,'.']);
   ErrCode=9;
   return
end

return


% testing
clear all
FrameFile='test';
wname='db79';
Level=3;
a=1;    
ErrCode=SetF06(FrameFile,wname,Level,a);
load(FrameFile);
Fg=BuildFg(F,G);
disp(['The value of Q is ',int2str(max(G(:))),'==',int2str(size(F,1))]);
SizeF
PlotF(Fg);