count number of circles in image code example

Example 1: detect a circle in an image along with radius and color

[centersBright,radiiBright,metricBright] = imfindcircles(rgb,[20 25], ...
    'ObjectPolarity','bright','Sensitivity',0.92,'EdgeThreshold',0.1);

delete(hBright)
hBright = viscircles(centersBright, radiiBright,'Color','b');

Example 2: detect a circle in an image along with radius and color

[centers,radii] = imfindcircles(rgb,[20 25],'ObjectPolarity','dark', ...
          'Sensitivity',0.95);

delete(h)
viscircles(centers,radii);