[Spm] image comparison and subtraction

[Iain McNab]

Dear All,

Could someone please recommend to me the best (and simplest) way of doing the 
following:

(1) Comparing two images (that have drift between them) to find the best 
possible overlap (I'm guessing a correlation program of some sort).
(2) Then trimming both images so they show the same area.
(3) Subtracting the resulting images from one another.

I know I can do this "visually" in photoshop etc., but I'm hoping there is a 
more precise solution on offer. At present I have the images as both bitmaps, 
and also in RHK's native format, *.SM4.

All help will be most gratefully received, thank you for your time.

Best regards.... Iain McNab

URL:	http://www.utoronto.ca/jpolanyi
URL:    http://www.phys.ncl.ac.uk/research/atomic/irm/mcnabgroup.htm
**********************************************************************
Iain R. McNab
Department of Chemistry
University of Toronto
80 St. George Street
Toronto, Ontario, M5S 3H6
Canada

Tel. No.: (416) 978-3625
Fax No.:  (416) 978-7580
E-mail:   imcnab at chem.utoronto.ca
**********************************************************************