Find the circle for the image using imfindcircles

Hello,

I have an image for which i need to determine the outer circle and then find the centre for the outer circle.I am using the function

imfindcircles()

I have the following code to do this :

img2 = imread('Image.bmp'); imshow(img2);

% Find all the circles with radius >= 15 and radius <= 30
          [centers, radii, metric] = imfindcircles(img2,[15 416]);

            % Retain the five strongest circles according to metric values
            centersStrong5 = centers(1:1,:);
            radiiStrong5 = radii(1:1);
            metricStrong5 = metric(1:1);
             % Draw the circle perimeter for the five strongest circles
            viscircles(centersStrong5, radiiStrong5,'EdgeColor','b');

but when i run this code i am getting the following error.

Error in Cap_Test (line 16)
          centersStrong5 = centers(1:1,:);

Please let me know the reason for this and how to solve this.

I am attaching the image here for which I need to find the centre.

The radius for this is around 416.

Looking forward to hear from you.

Thanks Pankaja

[Ashish Uthama]

The image attachment did not make it through, could you try again?