Dear Kees;

Check out the following reference:
Sedarat et al, Am J Physiol Heart Circ Physiol 2000 279: H202-H209

It might be helpful to answer all your specific questions.

Regards, Franklin

Franklin Sedarat
Cardiovascular Lab (BCRICWH)
BC Children's and Women's Hospital
Vancouver, BC, Canada

On Wed, 28 Feb 2001 17:48:18 +0100 [log in to unmask] wrote:

> Thanks for those suggestions.
>
> But before trying to track down all those pieces of software to run our
> data through, what is the basis of quantification? More specifically,
> what statistical (or other) math is used to come to a number that
> describes just how well 2 images colocalize? I have tried a bit using
> e.g. correlation coeeficient of paired pixel intensities, or covariance,
> or Pearsons regression coeeficient, and roughly get numbers that give
> what you expect. But how significant are those values (without putting a
> full month into trying to calculate that)? For example, I noted that if
> I make 2 images of the same channel, one noisy and the other nice and
> smooth by averaging, I get correlation coefficients that are worse than
> in the case that I take 2 times that smooth image, one of which is
> rotated by 90 degrees (which clearly is a wrong result).
>
> Regards, Kees
>
> --
>
> Kees Jalink Ph.D.
> The Netherlands Cancer Institute, dept. of Cell Biology H1
> Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
> 020-5121933 (tel office)/ ...1947 (tel lab) / ...1944 (fax) /
> [log in to unmask] (email)
> at home: Paulus Potterlaan 5, 2102CC Heemstede
> 0235-476047 / [log in to unmask]