get properties from matrix - matlab

Question

I have a paired matrix with pixels equal 0 or 255 and when it's 255 it makes disk shape.
I would like to labelize the differents disks and get in a tab for each label : their radius and their central point. How can I do for this last two points?
Below an exemple with a small matrix
Mat=zeros(12,12);
Mat(2,6:7)=255; Mat(3,5)=255; Mat(3,8)=255; Mat(4,5)=255
Mat(4,8)=255; Mat(5,6:7)=255;
Mat(10,10)=255; Mat(11,9)=255; Mat(12,10)=255; Mat(11,11)=255;
CC=bwconncomp(Mat,8);
MatL=labelmatrix(CC);
figure, imagesc(Mat)

Answer 1

you can use regionprops to compute centroid and area, and then use area to compute approximate radius:
% generate matrix
Mat=zeros(12,12);
Mat(2,6:7)=255; Mat(3,5)=255; Mat(3,8)=255; Mat(4,5)=255;
Mat(4,8)=255; Mat(5,6:7)=255;
Mat(10,10)=255; Mat(11,9)=255; Mat(12,10)=255; Mat(11,11)=255;
% convert to binary
MatBin = Mat > 0;
% fill circles
MatFull = imfill(MatBin,4,'holes');
% get centroids and areas
props = regionprops(MatFull,{'Area','Centroid'});
Area = [props(:).Area];
Centroid = reshape([props(:).Centroid],[],2)';
% compute radius
Radius = sqrt(Area ./ pi);
% plotting
imshow(MatFull,[],'InitialMagnification','fit')
hold on
for ii = 1:numel(Radius)
text(Centroid(ii,1),Centroid(ii,2),['r = ' num2str(Radius(ii))],...
'VerticalAlignment','middle','HorizontalAlignment',...
'center','FontSize',12,'Color','b');
end
hold off