On Fri, Oct 16, 2015 at 03:18:39PM +0200, Frederik Edler wrote: > What is the reason for the difference?
The reason is that one value is calculated by summing differences from the mean value, whereas the other is calculated by fitting one-dimensional HHCF using an assumed theoretical curve. Why do you expect exactly the same value? The values have to agree mutually and with the true value only if the surface is infinite and corresponds perfrectly to the theoretical HHCF (including no global distortion, row mismatch etc.). Value from HHCF will be typically smaller because roughness with small spatial frequencies (comparable to √image size) contributes less, row mismatch increases the plain σ estimate while having no influence on 1D HHCF, etc. Regards, Yeti ------------------------------------------------------------------------------ _______________________________________________ Gwyddion-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/gwyddion-users
