CODEWITHSUNDEEP
matlabimage-processingcrop
Powisss
Powisss

Reputation: 1142

How to crop out a detected circle as a square?

I have detected a circle as shown below:

As later I want to detect what speed limit is in the detected sign, how do I crop it out so that I am left with an image like below?

When program finishes it, it shows me where the center is and the radii in terminal.

centers =

  248.4873  170.4811


radii =

   24.5024

I know how to use imcrop but how do I use the values that are returned instead of writing in them myself, as there might be more than 1 circle detected?

Code:

I = imread('p1.tif');
subplot(3,3,1); imshow(I); title('Original Image'); 
%sharpen edges
B = imsharpen(I);
subplot(3,3,2); imshow(B); title('sharpened edges');

%find circles
Img = im2bw(B(:,:,3));
minRad = 20;
maxRad = 90;
[centers, radii] = imfindcircles(Img, [minRad maxRad], ...
                                    'ObjectPolarity','bright','sensitivity',0.87)
imagesc(Img);
viscircles(centers, radii,'Color','green');

Upvotes: 1

Views: 303

Answers (1)

Nirvedh Meshram
Nirvedh Meshram

Reputation: 469

Assuming you have one centre and one radius. This should do it

rect = [centers(1)-radii,centers(2)-radii,2*radii,2*radii]
I2 = imcrop(I,rect)

For multiple circles you can do this process for each of the circle returned in a loop.

Upvotes: 2

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