With the help of various code snippets from this forum, I have managed to create a working metaball simulaton.  I used a threshhold to get a clean border between the metaballs and the background.

Now, I would like to draw just the outlines of the metaballs. I tried using a min. and max. treshholds to achieve this, and allthough the result (shown below) does show something aking to an outline, it's still not quite what I am looking for. Especially the thicker parts of the line is what I want to get rid of.

As far as I understand it, the above image doesn't actually contain any lines, but just neighbouring white pixels which give the impression of a line.

I am thinking that it should be possible to find coordinates on  these "outlines" and use them to create a bézier curve, wich would then creat a clean, continuously thick line around the metaballs. The problem: I have no idea how to start doing this.

Is this actually possible?

Am I overthinking this using metaballs and there is in fact a better solution?

Does this have something to do with blob-detection?

I'm not trying to create moving metaballs. I just want to draw the metaballs once and then create the clean outlines. So performance isn't an issue for once.

If anybody has any pointers, I'd be thankful.