How to detect closed contour objects in an image and store radii and center points?

0
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I have the following picture: enter image description here

I would like to detect the 7 white 'circular' paper-parts (closed contours) in Matlab and store the radii and center points. I have tried the following ways:

  • Feature matching the original image (top-left) with reference image (bottom-right)
  • Filter out the edges (top-right and bottom-left) and fit multiple circles to the data points
  • Detecting circles in original picture (top-left) with Circular Hough

but they did not work. I am a beginner in image processing, could someone please help? Thanks :)

2
matlabimage-processing

2 Answers

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You can play with contour function, by specifying either number of levels or levels directly. If you need contour coordinates, you can use the low level function contourc, whose output format is a little tricky.

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Use blob detection after adaptive binarization. Center and area are readily computed and you can estimate the radius from the area.