I do not know

Histogram-based background subtractor for ImageJ.

The implemented algorithm is based on the assumption that, compared to the background region, object (foreground) regions are small. The plugin builds local histograms and assumes the most occuring intensity to be part of the background.

The purpose of this plugin is to register—in other words, to align or to match—two images, one of them being called the source image and the other the target image.