# User talk:TheLarry/Notebook/Larrys Notebook/2009/11/12

### From OpenWetWare

Steve Koch 00:20, 13 November 2009 (EST): Yeah, I think you can just use gaussians for the point spread functions of single emitters. Then, you'd need to randmoly pick where the photons go in each frame, based on that probability density function (unless you want to just have fixed pixel intensities). You should be able to calculate the point spread function from the NA of the objective and magnification relative to the CCD, though, I've never done that. As far as convolution, that was if you wanted to model the MT as a rectangle emitting light, and see how it fuzzed out on the CCD. You'd convolute the rectangle shape with a 2-D gaussian (or whatever point spread function).

TheLarry 11:01, 13 November 2009 (EST): I am confused by the "randomly pick where the photons go in each frame." I thought i would randomly choose where the fluorescence labels where on the microtubule and then smear them. Also the fixed pixel intensities i don't understand what you mean by that. Oh yeah and i don't know how to calculate the point spread function from the NA, magnication or whatever. But i might be able to figure that out from some place.