iwa2sym.m

This package is a free collection of Matlab routines for computing wave atom transforms in one, two

function x = iwa2sym(res,pat,tp)
% iwa2sym - 2D inverse wave atom transform (symmetric version)
% -----------------
% INPUT
% --
% res is an array containing all the wave atom coefficients. If
% tp=='ortho', then res is of size N-by-N. If tp=='
% If tp=='directional', then res is of size N-by-N-by-2. If tp=='complex',
% then res is of size N-by-N-by-4.
% --
% pat specifies the type of frequency partition which satsifies
% parabolic scaling relationship. pat can either be 'p' or 'q'.
% --
% tp is the type of tranform.
% 	'ortho': orthobasis
% 	'directional': real-valued frame with single oscillation direction
% 	'complex': complex-valued frame
% -----------------
% OUTPUT
% --
% x is a real N-by-N matrix. N is a power of 2.
% -----------------
% Written by Lexing Ying and Laurent Demanet, 2007

  
  if( ismember(tp, {'ortho','directional','complex'})==0 | ismember(pat, {'p','q','u'})==0 )    error('wrong');  end
  
  N = size(res,1);
  H = N/2;
  lst = freq_pat(H,pat);
  red = size(res,3);
  
  call = cell(length(lst),red);
  for i=1:red
    y = res(:,:,i);
    c = cell(length(lst),1);
    for s=1:length(lst)
      B = 2^(s-1);    D = 2*B;
      nw = length(lst{s});
      c{s} = cell(nw,nw);
      for I=0:nw-1
        for J=0:nw-1
          if(lst{s}(I+1)==0 & lst{s}(J+1)==0)
            c{s}{I+1,J+1} = [];
          else
            c{s}{I+1,J+1} = y( I*D+[1:D], J*D+[1:D] );
          end
        end
      end
    end
    call(:,i) = c;
  end
  x = iwa2(call,pat,tp);