How to remove the for loop in this code?

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Shreyas Kamath
Shreyas Kamath il 26 Mag 2016
Commentato: Shreyas Kamath il 15 Giu 2016
Hi, I am working on a code related to matching score calculation which is provided below:
ref_points=size(tpol,1); %number of rows=number of referenence image points
in_points=size(ipol,1); %number of rows=number of input image points
radsize=7*ones(ref_points,1);
angsize=11* ones(ref_points,1);
radlow=-radsize./2;radhigh=radsize./2;anglow=-angsize./2;anghigh=angsize./2;
epsillon=10;
mscore=0;
for i=1:ref_points
for j=1:in_points
rdiff=tpol(i,1)-ipol(j,1);
ediff=tpol(i,2)-ipol(j,2);
thetadiff=tpol(i,3)-ipol(j,3);
if ((radlow(i) < rdiff) && (rdiff < radhigh(i)) && (anglow(i) < ediff) && ...
(ediff < anghigh(i)) && (abs(thetadiff) < epsillon) && ...
(tpol(i,4)==ipol(j,4)))
mscore=mscore+1;
tpol(i,4)=3; %Change type
end
end
end
end
I am interested to reduce the for loop as it takes high computation time. It would be very helpful if anyone could guide me through this. Thanks in advance.

Risposte (1)

Andrei Bobrov
Andrei Bobrov il 26 Mag 2016
Modificato: Andrei Bobrov il 26 Mag 2016
r = [-3.5 3.5];
a = [-5.5 5.5];
ep = 10;
ti = bsxfun(@minus,tpol,permute(ipol,[3 2 1]));
p = all([bsxfun(@gt,ti(:,1:2,:),[r(1),a(1)]) & bsxfun(@lt,ti(:,1:2,:),[r(2),a(2)]),...
ti(:,3,:) < ep, ti(:,4,:) == 0],2);
mscore = nnz(p);
tpol(any(p,3),4) = 4;
  4 Commenti
Shreyas Kamath
Shreyas Kamath il 26 Mag 2016
The first mat file has equal number of ipol and tpol data (same values)as both are same image to be matched. Whereas the second mat file has different data i.e. two different images are being matched.
Shreyas Kamath
Shreyas Kamath il 15 Giu 2016
I was trying to figure out the problem, it seems that
(tpol(i,4)==ipol(j,4)))
provides a different value when compared to
ti(:,4,:) == 0
The logic is correct. But the answer do not match. The rest of the "if conditions" work and provide the same answer. It would be helpful if you could help me solve this.

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