
Gauss2D Fit: 'cor' parameter

mailfert
I'm using the Gauss2D function to fit data contained in an image.
In this function, we have the possibility to access to a 'cor' parameter, which corresponds to a cross-correlation parameter.
What does it represent exactly. I can't find this formula on the litterature.
The second question is maybe a lack of knowledge but if in my image I've got something like a PSF that looks like an ellipse. If I want to fit this PSF with a function that could reveal the fact that the ellipse could be rotated compared to the axes, how could I do?
Thanks for your help.
Sébastien
http://en.wikipedia.org/wiki/Multivariate_normal_distribution
But note that Igor fits a function that is not normalized as a probability distribution (that is, the total integral is not equal to 1.0).
I assume that you mean that the projection of the PSF onto the XY plane has an elliptical outline, and the distribution of Z values is Gaussian. The ellipse at an angle is what the cor fit coefficient is for. If you are looking for a fitting function that uses the angle with the X axis as a fit parameter, you will need to find the formula and create a user-defined fitting function.
John Weeks
WaveMetrics, Inc.
support@wavemetrics.com
July 22, 2011 at 09:07 am - Permalink
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