How to find the nearest object to a reference point in binary image?
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Dear all,
I have a binary image that contains two objects(Object_A, Object_B) very close to each other as shown below. I want to find which object is closer to a reference point in order to be selected (Object_B in this example).
I was thinking to find the distance of the centroid of each object to the reference point (in this example the centroid of the reference point X = 360, Y = 330), but this will not work because in few cases the centroid of the far object could be closer to the reference point as I tried to explain in the figure below.
Is there any way to find the closest object to a reference point?
Any help and suggestion will be appreciated.
Meshoo
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Accepted Answer
Image Analyst
on 16 Nov 2014
It's trivial. Just use bwboundaries to get the list of (x,y) coordinates of the boundary and then put in a for loop, calculating the distance using the Pythagorean Theorem to get the boundary that is the closest. In the for loop, you can vectorize it and use min().
boundaries = bwboundaries(binaryImage);
overallMinDistance = inf;
for b = 1 : length(boundaries)
thisBoundaryX = boundaries{b}(:, 1);
thisBoundaryY = boundaries{b}(:, 2);
distances = sqrt((thisBoundaryX - refx).^2 + (thisBoundaryY - refy).^2);
[minDistance, indexOfMin] = min(distances);
if minDistance < overallMinDistance
% This boundary is the closer one.
.............you finish the rest - it's easy.
end
2 Comments
Image Analyst
on 16 Nov 2014
No - this is as easy as it gets. Let me see your code. It should be really trivial so you probably just made a simple mistake.
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