Convert to monochromatic & Recognize centroid and radii

I have a color image that I want to convert to monochromatic. Also he image contains many broken/slightly deformed circles because it is a cross section of an object. I need to be able to recognize the centroid sand radii of them. I have attached the picture below.

Note: I don't have the image processing toolbox. If it isn't possible to convert to monochrome that isn't a huge deal

Answer 1

[Youssef Khmou]

Micheal, The only contribution i can offer is like this : i think the centroid function is in the Image processing ToolBox, but you can proceed as the following :

Suppose your Image I is RGB ( or HSV) you convert it to grayscale :

 X=(0.2989*I(:,:,1)+0.5870 *I(:,:,2)+0.1140*I(:,:,3));

You make a binary sample by choosing a certain threshold, lets say the mean of the whole sample :

 thresh=mean(X(:));
 [m n]=size(X);
 B=zeros(m,n);
 for x=1:m
   for y=1:n

                 if X(x,y)>thresh
                     G(x,y)=1;
                 end
   end
end

Next you choose a tiny portion, let say a elementary particle from your sample ( in the medium as example ):

 S=G(floor(end/2):10+floor(end/2),floor(end/2):10+floor(end/2));

You try next to count the white pixels, and try to use some geometrical relation to deduce the Radius,

[Michael]

I have been able to acquire a license for the image processing toolbox. Can you give me advice on how to calculate the centroid, the radii and the number of circles?

Thanks