How to make a 2-d binary shape a little more round?

Hi All,

I'm new to image processing, and hope you can help: I managed to generate a binary mask indicating the location of roundish shapes in an image. The problem is that sometimes the mask is not very round and I want make it a little rounder, i.e., smooth the irregularities a bit, but not loose the original shape. Can anyone suggest a way to do that?

Thanks, Rachel

Answer 1

[Jan]

You can try IMDILATE(IMERODE(Image)):

img    = imread('text.png');
radius = 1;
imga   = imdilate(img, strel('disk', radius));
imgb   = imerode(img, strel('disk', radius));

A bigger radius removes more details.

[Sean de Wolski]

The above is the same as a morphological closing, imclose.

[Eli]

thanks, I'll try that!

Answer 2

[Wolfgang Schwanghart]

You could also use a median filter to remove small objects and irregular boundaries. In a BW image, the median image would act like a majority filter.

http://www.mathworks.com/help/toolbox/images/ref/medfilt2.html