clear all; 
load wbarb; 
I = ind2gray(X,map);imshow(I); 
I1 = imadjust(I,stretchlim(I),[0,1]);figure;imshow(I1); 
[N,M] = size(I); 

h = [0.125,0.375,0.375,0.125]; 
g = [0.5,-0.5]; 
delta = [1,0,0]; 

J = 3; 

a(1:N,1:M,1,1:J+1) = 0; 
dx(1:N,1:M,1,1:J+1) = 0; 
dy(1:N,1:M,1,1:J+1) = 0; 
d(1:N,1:M,1,1:J+1) = 0; 

a(:,:,1,1) = conv2(h,h,I,'same'); 
dx(:,:,1,1) = conv2(delta,g,I,'same'); 
dy(:,:,1,1) = conv2(g,delta,I,'same'); 

x = dx(:,:,1,1); 
y = dy(:,:,1,1); 
d(:,:,1,1) = sqrt(x.^2+y.^2); 
I1 = imadjust(d(:,:,1,1),stretchlim(d(:,:,1,1)),[0 1]);figure;imshow(I1); 

lh = length(h); 
lg = length(g); 

for j = 1:J+1 
lhj = 2^j*(lh-1)+1; 
lgj = 2^j*(lg-1)+1; 
hj(1:lhj)=0; 
gj(1:lgj)=0; 
for n = 1:lh 
hj(2^j*(n-1)+1)=h(n); 
end 

for n = 1:lg 
gj(2^j*(n-1)+1)=g(n); 
end 

a(:,:,1,j+1) = conv2(hj,hj,a(:,:,1,j),'same'); 
dx(:,:,1,j+1) = conv2(delta,gj,a(:,:,1,j),'same'); 
dy(:,:,1,j+1) = conv2(gj,delta,a(:,:,1,j),'same'); 

x = dx(:,:,1,j+1); 
y = dy(:,:,1,j+1); 
dj(:,:,1,j+1) = sqrt(x.^2+y.^2); 

I1 = imadjust(dj(:,:,1,j+1),stretchlim(dj(:,:,1,j+1)),[0 1]);figure;imshow(I1); 
end