how to save all value of centoid of many object from one image ?

i have a code,

 a=imread('cen.png'); contain 2 object
bw=im2bw(a);
labeledimage=bwlabel(bw,4);
object=regionprops(labeledimage);
count=size(objek,1);
centroid = zeros(2,2);
 for i=1:count
    centroid(i) = object(i).Centroid;
end

i try to get the centroid of each object, and save the all value of centoid object. But i get the error :

In an assignment A(I) = B, the number of elements in B and I must be the same.

Error in cek (line 8) centroid(i) = objek(i).Centroid;

i try to fix this error,but i don't find the way to fix this error. please help me.. thanks

Answer 1

[Sven]

The centroid is not a scalar value. It has two components (X coordinate, Y coordinate), so you cannot assign it to a scalar variable. Your code will work if you change this line:

centroid(i) = object(i).Centroid;

To this line:

centroid(i,:) = object(i).Centroid;

However you can also clean up the code chunk quite a bit and simply do:

a = imread('cen.png'); contains N objects
bw = im2bw(a);
stats = struct2table(regionprops(bw));
centroid = stats.Centroid; % Will be an N-by-2 array where N is the # of objects

Did this answer the question for you?

Thanks, Sven.

[ElizabethR]

hai sven, thanks for replay my question. i will try it, but what the meaning of struct2table ?

[Sven]

It's just that tables are a little easier to use (in my opinion) than the regular output of regionprops() which is a struct. You could also do the following for the same result:

stats = regionprops(bw);
centroid = cat(1,stats.Centroid);

[Image Analyst]

Or

allCentroids = [stats.Centroid];
xCentroids = allCentroid(1:2:end);
yCentroids = allCentroid(2:2:end);