How to remove the for loop in this code?

2016 5 26
1 个回答
更新时间：2016 6 15
2 次查看（30 天）

0 个投票

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.

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回答（1 个）

Andrei Bobrov
Andrei Bobrov 2016-5-26
编辑：Andrei Bobrov 2016-5-26

0 个投票

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 个评论
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Shreyas Kamath
Shreyas Kamath 2016-5-26
I tried this code, but it gives an error when I execute the line with variable p. It says too many input arguments. Am I missing something here? Thank you.
Andrei Bobrov
Andrei Bobrov 2016-5-26
编辑：Andrei Bobrov 2016-5-26
Attach your data (tpol, ipol).
Corrected.
Shreyas Kamath
Shreyas Kamath 2016-5-26
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 2016-6-15
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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