wt07fig09.m

一些关于小波的去噪算法

%CAPTION
fprintf('\n');
disp('Figure 7.9')
disp('The left graph is a linear spline Battle-Lemarie scaling')
disp('function. The corresponding linear spline wavelet is on the right.')

close all;
N = 1024;
M = 20*16;
omega = ((1:N)/N -.5) * 2 * M;
omega(N/2) = omega(N/2+1)/100;
cos2 = cos(omega./2).^2;
sin2 = 1-cos2;

hatphi = 4.*sqrt(3).*sin2./((omega).^2 .* sqrt(1+2*cos2));
supp = find(hatphi > max(hatphi/900));

j=5;
n = 1024*16;
J = log2(n);
p = 1;
k = 2^(j-1);
phi = MakeWavelet(J-j,k,'Battle',p,'Mother',n).*2^(j/2);
x = (abs(phi)>1.e-6);
x=double(x);
length = x*x';
m = find(phi == max(phi));
def = (-2^(j-1)-length/2 :-2^(j-1)+length /2) ./2^j;

figure(1);clf
subplot(222)
plot(def,-phi(round(m-length/2):round(m+length/2)));
axis([-4 4 -1.2 2]);

[def,phi] = NormedIFFT(hatphi,2*M);
supp = find(abs(phi) > max(abs(phi)) ./1000);

subplot(221)
plot(def(supp),real(phi(supp)));
axis([-4 4 -0.3 1.5]);

% Written by Maureen Clerc and Jerome Kalifa, 1997
% [e-mail], [e-mail]

%Revision History
% 10/1/05        AM        logical vector x is converted to a double
    
 
 
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