image analysis

[Enrique Castro]

William Sun wrote:
> 
> Hello all,
> 
> I wish to quantitate my northern signals on autorad film.  What is the best
> and cheapest way?  Can I just scan the film with a conventional flatbed
> scanner and analyze the image with ImageQuant?  Is this accurate enough?
> Thanks for any advice.

	You can bet not. There are two separate problems in scanning films for
quantitation:
a) The film response is logarithmic and with reduced dynamic range (100
at most)
b) The scanning is highly non-linear too given an image where the
intensity is NOT proportional to film darkening.

Without proper calibration (difficult) this method don't give you a
better answer than your eye: this band is faint, this other is darker,
but no precise quantitation. And you eyes are 'default', 'standard',
equipment.  

Enrique Castro

--