Feature-Finding > Find Circles
Finds circles in the Current Image using an algorithm based on searching within the image’s Hough transform. This function can take some time to complete depending on the size of and number of circles in the image.
Sets method for circle finding. Phase Code tends to be faster and more accurate.
- Phase-Code: Uses the phase-code algorithm for circle detection 
- Two-Stage: Uses the two-stage algorithm for circle detection [2,3]
Sets whether circle edges are bright or dark outlines in the image
- Bright: Looks for circles with bright outlines
- Dark: Looks for circles with dark outlines
3. Min. Radius
Minimum radius of circles to be found (Recommended: 10-20)
4. Max. Radius
Maximum radius of circles of the found (Recommended: 20 larger than Min. Radius)
Sets how much contrast needs to be between circles and the background. A higher sensitivity will find more circles, but may increase false positives.
6. Edge Threshold
Another parameter which affects how many circles are found. A lower Edge Threshold finds more circles, but may increase false positives.
 T.J Atherton, D.J. Kerbyson. “Size invariant circle detection.” Image and Vision Computing. Volume 17, Number 11, 1999, pp. 795-803.
 H.K Yuen, .J. Princen, J. Illingworth, and J. Kittler. “Comparative study of Hough transform methods for circle finding.” Image and Vision Computing. Volume 8, Number 1, 1990, pp. 71–77.
 E.R. Davies, Machine Vision: Theory, Algorithms, Practicalities. Chapter 10. 3rd Edition. Morgan Kauffman Publishers, 2005,
Need more help with this?
Chat with an expert now ››