[f1ff16]: / comp / comp_idgt_fac.m  Maximize  Restore  History

Download this file

138 lines (108 with data), 2.3 kB

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
function f=comp_idgt_fac(coef,gf,L,a,M)
%COMP_IDGT_FAC Full-window factorization of a Gabor matrix.
% Usage: f=comp_idgt_fac(c,g,a,M)
%
% Input parameters:
% c : M x N array of coefficients.
% gf : Factorization of window (from facgabm).
% a : Length of time shift.
% M : Number of frequency shifts.
% Output parameters:
% f : Reconstructed signal.
%
% Do not call this function directly, use IDGT.
% This function does not check input parameters!
%
% If input is a matrix, the transformation is applied to
% each column.
%
% This function does not handle multidimensional data, take care before
% you call it.
%
% References: so07-2 st98-8
% AUTHOR : Peter L. Søndergaard.
% TESTING: OK
% REFERENCE: OK
% Calculate the parameters that was not specified.
N=L/a;
b=L/M;
R=prod(size(gf))/L;
W=prod(size(coef))/(M*N*R);
N=L/a;
b=L/M;
[c,h_a,h_m]=gcd(a,M);
h_a=-h_a;
p=a/c;
q=M/c;
d=N/q;
ff=zeros(p,q*W,c,d,assert_classname(coef,gf));
C=zeros(q*R,q*W,c,d,assert_classname(coef,gf));
f=zeros(L,W,assert_classname(coef,gf));
% Apply ifft to the coefficients.
%coef=ifft(reshape(coef,M,N*W))*sqrt(M);
coef=ifft(coef)*sqrt(M);
% Set up the small matrices
coef=reshape(coef,M,N,R,W);
if p==1
for rw=0:R-1
for w=0:W-1
for s=0:d-1
for l=0:q-1
for u=0:q-1
C(u+1+rw*q,l+1+w*q,:,s+1)=coef((1:c)+l*c,mod(u+s*q+l,N)+1,rw+1,w+1);
end;
end;
end;
end;
end;
else
% Rational oversampling
for rw=0:R-1
for w=0:W-1
for s=0:d-1
for l=0:q-1
for u=0:q-1
C(u+1+rw*q,l+1+w*q,:,s+1)=coef((1:c)+l*c,mod(u+s*q-l*h_a,N)+1,rw+1,w+1);
end;
end;
end;
end;
end;
end;
% FFT them
if d>1
C=fft(C,[],4);
end;
% Multiply them
for r=0:c-1
for s=0:d-1
CM=reshape(C(:,:,r+1,s+1),q*R,q*W);
GM=reshape(gf(:,r+s*c+1),p,q*R);
ff(:,:,r+1,s+1)=GM*CM;
end;
end;
% Inverse FFT
if d>1
ff=ifft(ff,[],4);
end;
% Place the result
if p==1
for s=0:d-1
for w=0:W-1
for l=0:q-1
f((1:c)+mod(s*M+l*a,L),w+1)=reshape(ff(1,l+1+w*q,:,s+1),c,1);
end;
end;
end;
else
% Rational oversampling
for w=0:W-1
for s=0:d-1
for l=0:q-1
for k=0:p-1
f((1:c)+mod(k*M+s*p*M-l*h_a*a,L),w+1)=reshape(ff(k+1,l+1+w*q,:,s+1),c,1);
end;
end;
end;
end;
end;