Droplet images behaving strangely with particle analyser

Hi there!

I’m trying to use the particle analyser function to define the edges and shapes of droplets in an image. The problem I’m having is that the particle analyser seems to only detect the droplets which are joined to other droplets at the edge of the image.

Here is an image after thresholding, some of the droplets have misaligned edges and therefore do no form complete circles, however many of them do.

When I use the particle analyser (size: 100-infinity, circularity: 0-1), it does not detect droplets that are intersected by the edge of the image (as expected) and only seems to detect droplets connected to the edge of the image. This can be seen here:

To note, when I use the “fill holes” function to clean up the noise inside each droplet, all of the central droplets (that are not detected by the “analyse particles” function) are filled away.

If anyone could lend some insight into why the functions are behaving like this, it would be much appreciated.


Welcome to the Forum!

Would you be able to post the original dataset? As well as the steps you take to threshold… then I can see what I can do to help.

eta :slight_smile:

@DTaylor Just thinking a bit more about this… if your droplets are not closed completely - then you will get that disappearance issue you are seeing with ‘fill holes’. You should look into some of the morphological operators, such as erode, dilate, open, close to try to remedy that issue. Once your droplets are sufficiently ‘sealed’ - ‘fill holes’ will work just fine.

Hope this helps a bit in the meantime…

eta :slight_smile: