Problem 42616. Detect circles in images

Created by Matthew Eicholtz

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171 Solutions
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Last Solution submitted on Jan 17, 2023

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3 Comments

LY Cao on 18 Sep 2015

PDIST2 is not available here, please fix it

Matthew Eicholtz on 18 Sep 2015

Thanks for bringing this to my attention LY Cao. The test suite has been fixed.

Rafael S.T. Vieira on 10 Jun 2020

Fair warning to the challenger, we need to do some preprocessing for each image. There are black and white, grayscale, and color images within the test case set. I learned a lot from this problem, however...I found it very unsettling that I could not use functions from the image processing toolbox (I had to implement the Circle Hough transform myself).
Imho, the required precision should have been smaller: 5-pixel distance is absurd when one has rubber bands in an image that are not perfect circles. Or, at least, the test cases should allow that we return any number of circles and radii (it is easy to test if the desired circles are within the returned results).

Solution Comments

Solution 773489

2 Comments

2 Comments

Alfonso Nieto-Castanon on 8 Nov 2015

100% precision/recall, but using N so no pat in the back for me

Rafael S.T. Vieira on 10 Jun 2020

I've got precision 100% for most of the test cases. Colored images were the hardest.

Solution 772610

1 Comment

1 Comment

Jan Orwat on 6 Nov 2015

Combination of LY Cao's and mine code. 98.5% precision and recall in total (one circle in test 4 didn't fit in tolerance), without using N. That was fun :)

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Problem 42616. Detect circles in images

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Problem 42616. Detect circles in images

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