Convex Hull BG for ImageJ
This is a plugin for ImageJ (or Fiji if you wish) that evens out background illumniation in brightfield microscopy images.
Compared to the wellknown Rolling Ball algorithm which is implemented in ImageJ in Process -> Subtract Background…
- it does not decrease contrast as much as RB
- it is much, much faster
but also
- it cannot handle a decrease in intensity followed by in increase when scanning in any direction over the image; it only handle increases, followed by decreases, or only decreases. In other words, a local decrease in intensity cannot be handled. These cases are handled by RB very well. In brightfield microscopy most cases of uneven illumination are vignetting and lightfall to one side of the image (or a combination thereof).
This plugin shows itself as "Convex Hull BG" in the Plugins/Process menu of ImageJ.
This algorithm makes use of code in
QuickHull3d by Richard van Nieuwenhoven, see https://github.com/Quickhull3d/quickhull3d JSI by aled, see https://github.com/aled/jsi
These dependencies are taken care of by maven.