Fill a Circle in an Image

Question

Let's suppose I have something like this (the image resulting from this):

ColorNegate[Rasterize[Graphics[Circle[{100, 100}, 50]]]]

Now, what I want to do is fill the inside of the circle (in the image, not transforming Circle->Disk :) ) with White (the color of the circle).

Ideas?

Binarize@FillingTransform@ ColorNegate[Rasterize[Graphics[Circle[{100, 100}, 50]]]] works for your specific case, though without the binarize the color is different to the edge — dr.blochwave, Commented Sep 25, 2015 at 14:54
Also see here: mathematica.stackexchange.com/questions/7781/… — dr.blochwave, Commented Sep 25, 2015 at 14:58
Oh... Of course it's FillingTransform. I didn't know about the Binarize. Thank you. If you want to create an answer, and explain maybe better the Binarize part, I'll accept it. — mgm, Commented Sep 25, 2015 at 14:59
there you are, hopefully a better explanation of the binarization... — dr.blochwave, Commented Sep 25, 2015 at 15:10

dr.blochwave · Accepted Answer · 2015-09-25 15:07:55Z

7

FillingTransform is what you're after:

img = FillingTransform@ColorNegate[Rasterize[Graphics[Circle[{100, 100}, 50]]]]

But this gives a gray fill because your image wasn't binary to begin with. Easy to fix, e.g. with a subsequent Binarize:

Binarize@img

Alternatively, ColorReplace[] might provide a more general solution.

ColorReplace[img, Gray -> White]

answered Sep 25, 2015 at 15:07

dr.blochwave

8,7983 gold badges42 silver badges76 bronze badges

Add a comment |

Syed · Accepted Answer · 2023-12-11 15:14:53Z

2

Using RegionImage: (Introduced Sept 14, 2017)

RegionImage[Disk[]]

answered Dec 11, 2023 at 15:14

Syed

56.1k5 gold badges37 silver badges88 bronze badges

Add a comment |

2 Answers 2