Gaussian filtering with dynamic sigma..

hallo, I need use the Gaussian filter to smooth the images according to an Algorithm from a paper. it says: "smoothing the image with an 11-pixel Gaussian filter with a standard deviation of 11 pixels". it means I think, the sigma should be dynamically changed with Pixels covered by the filter. can someone help me how to achieve it? thank you in advance. Qu Z.

[Rik]

That interpretation sounds really different from what is usually meant by smoothing. How I read this, is that they had a normal Gaussian filter with an SD of 11 pixels, but that is only 11 by 11 pixels large, which seems a bit small given the the SD.