An Edge-Guided Image Interpolation Algorithm via Directional Filtering and Data Fusion
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function A=esintp(I)
%%%%%process A%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[n,m]=size(I);
n=2*n;m=2*m;
A=zeros(n,m);
A(1:2:n,1:2:m)=I;
Ax=A;Ay=A;
f=[-1/16 9/16 9/16 -1/16];
for i=4:2:n-4
for j=4:2:m-4
x=[A(i-3,j-3) A(i-1,j-1) A(i+1,j+1) A(i+3,j+3)];
y=[A(i+3,j-3) A(i+1,j-1) A(i-1,j+1) A(i-3,j+3)];
Ax(i,j)=sum(x.*f);
Ay(i,j)=sum(f.*y);
end
end
for i=4:2:n-4
for j=4:2:m-4
zx=[Ax(i-2,j-2) Ax(i-1,j-1) Ax(i,j) Ax(i+1,j+1) Ax(i+2,j+2)];
zy=[Ay(i+2,j-2) Ay(i+1,j-1) Ay(i,j) Ay(i-1,j+1) Ay(i-2,j+2)];
x=[A(i-1,j-1) A(i+1,j+1) A(i+1,j-1) A(i-1,j+1)];
mx=mean(x);
px=sum((x-mx).^2)/3+0.1;
pzx=sum((zx-mx).^2)/4+0.1;
pzy=sum((zy-mx).^2)/4+0.1;
pv1=pzx-px;pv1=max(0.01,pv1);
pv2=pzy-px;pv2=max(0.01,pv2);
R=[pv1 0;0 pv2];
y=[Ax(i,j) Ay(i,j)]';
H=[1;1];
A(i,j)=mx+px*H'*(H*px*H'+R)^(-1)*(y-H*mx);
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Ax=A;Ay=A;
f=[-1/16 0 9/16 1 9/16 0 -1/16];
Ax=conv2(Ax,f);
Ax=Ax(:,4:m+3);
Ay=conv2(Ay,f');
Ay=Ay(4:n+3,:);
c=1.5;
h=[-1 5 5 -1];h=h/sum(h);
for i=5:2:n-5
for j=4:2:m-4
y=[Ax(i-2,j) A(i-1,j) A(i+1,j) Ax(i+2,j)];
my=sum(h.*y);
x=[Ax(i,j-2) Ax(i,j-1) Ax(i,j) Ax(i,j+1) Ax(i,j+2)];
vx=cov(x)+0.1;
vy=c*cov([y my])+0.1;
A(i,j)=(Ax(i,j)*vy+my*vx)/(vx+vy);
end
end
for i=4:2:n-4
for j=5:2:m-5
x=[Ay(i,j-2) A(i,j-1) A(i,j+1) Ay(i,j+2)];
mx=sum(h.*x);
y=[Ay(i-2,j) Ay(i-1,j) Ay(i,j) Ay(i+1,j) Ay(i+2,j)];
vx=c*cov([x mx])+0.1;
vy=cov(y)+0.1;
A(i,j)=(mx*vy+Ay(i,j)*vx)/(vx+vy);
end
end
return;
can anyone explain this code???
2 Comments
Answers (2)
Image Analyst
on 7 Jun 2014
I bet the author could, but probably doesn't want to, or else he or she would have done so by adding comments. I'm not even going to attempt it.
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