What the code means

Can any one let me know what are the benefits of this code and what it's components mean?

[Image Analyst]

Don't the comments do that? Do you know who the author is, so you can ask them?

[dpb]

The comments don't seem to align well with the actual code, IA.

The example use syntax doesn't match the footprint (or even name) of the function code...would seem one would have to dig a little dipper to really understand what it does...