yes the discrete sampling only seemed to be important when sigma became very small, and in resampling you do not get sigma smaller that 1/2. I don't think it is worth the effort.NicolasRobidoux wrote:@Anthony: If I understand correctly, what you are talking about is "exact area filtering".

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Yes, I know I'm simplifying, and not quite dealing with the precise question. But my opinion is that this direction (exact area methods) is a back back back back burner.

It isn't even used a lot with convolve kernel generation! Though the kernel generator for 1-D Gaussian does make some effort. It takes 3 'samples' of the function to generate the discrete value for the kernel. Comments say this was 'how photoshop did it'. Still it causes major headaches and worries when I was creating Named Kernels. It is not done for 2-d Gaussian, DoG or the closely related LoG kernels.