a question about ISIS "equalizer" module?

[xwc2016]

I am currently working on Mars image processing by using the "equalizer" module of the ISIS software. I don't understand some information in the "Output text file", so I would like to ask for advice, or if you have a detailed description of the content of the file, if you can forward me to learn it.

under the label "Object = OverlapStatistics":

I think that the statistics given here are the deviation of pixel values in the overlapping areas of the two images, is that correct?

Width*Height, Does this refer to the size of the inner rectangle of the polygon of the effective pixels in the overlap area?

Under this label, there are three sub-label pairs here, including "MultivariateStatistics","File1", and "File2".

In which reference can I finder the statistical process of "MultivariateStatistics" in the "equalizer" module？