MATLAB: I want to count the number of metric elements in if statement using ‘sum’, but it shown all the content of elements, not the number. I’m new.. pls help..

Question

here the code

stats = regionprops(L,'Area','Centroid', 'BoundingBox');
threshold = 0.88;
for k = 1:length(B)
boundary = B{k};
delta_sq = diff(boundary).^2;
perimeter = sum(sqrt(sum(delta_sq,2)));
area = stats(k).Area;
metric = 4*pi*area/perimeter^2;
metric_string = sprintf('%2.2f',metric);
if metric >= threshold 
  centroid = stats(k).Centroid;
  plot(centroid(1),centroid(2),'ko');
  as = sum(metric);
end  
end

Answer 1

Way too clumsy. Try something like this (untested):

stats = regionprops(L,'Area','Centroid', 'Perimeter');
allAreas = [stats.Area];
allPerimeters = [stats.Perimeter];
circularities = (4*pi*allAreas) ./ allPerimeters.^2; % Inverted compared to how I use it.
threshold = 0.88;
roundObjects = circularities > threshold;
as = sum(circularities(roundObjects));