How can I use imfindcircles function to tell me when there isn't any circle in the image?

I am working on a eye blink detection project. I use the vision.CascadeObjectDetector function to find my eyes, and then I use imfindcircles function to find my pupils. Already I can determinate when my eyes are open (there is a viscircles). How can I use the imfindcircles function to determinate when mi eyes are closed, I mean, when there is a circle, or when there isn't.?

Answer 1

[Jayanti]

Hi Eduardo,

To determine if eyes are closed you can check whether “imfindcircles” function detects any circles. If no circles are detected, it might indicate that the eyes are closed.

If it detects circles, centers will be a non-empty array else it will be an empty array.

[centers, radii] = imfindcircles(eyeRegion, [rMin rMax]);
if isempty(centers)
    disp('Eyes are likely closed');
else
    disp('Eyes are open');
    viscircles(centers, radii, 'EdgeColor', 'b');
end