scanning

why excel, i wonder. you can do formulae and lots and lots more in Access. You could collect that data that way also or, you can do this in Word by inserting the image in the header in a blank document. that makes a 'watermark' out of the image, which fills the entire page. It looks grayish but prints black. then you can make bookmarks at all the spots for the user to fill in data. the bookmarks could correspond to database record fields.
this would be a pretty awful way probably. why don't you post more exactly what task you need to accomplish. i bet others will many ideas.;
I don't know how to do what you want in Excel...i have always been disappointed in form filling software but you could look into a product that handles forms.
this form changing a lot? why not recreate it?

You have to have OCR software; such as OmniPage Pro, which recognizes and scans text into a document.

As the previous answer stated; this software is generally not very reliable. Generally these products only scan into a word processor; I am not aware of one that scans into spreadsheet software.