Filling gaps in the edge of an object



I am trying to get some measurements on this object in the picture shown below but the edges in the photo are not clear and hence not recognized when I choose Process-Make binary

This is how it looks like as a binary photo and you can see the edge that’s missing

The settings I use when I analyse particles are

This is how the final processed photo look like , which shows a count of 62 which I don’t want. I only want measurement of whole object

Filling holes doesn’t work in this case as the edges are missing!

Any help is very much appreciated



You could use a convex hull, for example.

  • Create a selection from your binary mask
  • Edit > Selection > Convex Hull

For more advanced use cases, the 3D Suite offers Plugins > 3D > 3D Convex Hull.


The convex hull will invent an edge that does not exist. I think you’d better capture less saturated images so the faint boundaries can be detected.