On Tue, Jan 31, 2017 at 02:28:43PM +0100, Maria Joao Almeida wrote:
> Just to make sure that I am not making a mistake: if my sample has an
> isotropic surface, Kx and Ky corresponding to the maximum of the PSDF
> (horizontal and vertical, respectivelly I guess) are necessarily
> broadly the same, and in that sense shouldn't the respective K on the
> radial PSDF be the same as Kx and Ky?
Well, no. Or not necessarily. You have to keep in mind that all the
one-dimensional functions are some kinds of projection.
For instance consider the 2D PSDF shown in psdf2d.png (you can use
Spectral synthesis to create an image with such PSDF).
For this you get W₁(Kx) and Wr(K) as in psdf-rpsdf.png. Wr(K) is
obviously close to a δ-function because the 2D PSDF is a thin ring. But
W₁(Kx) is a broad function because it is the distribution of Kx. And the
x-projections of the spatial frequencies contained in the image range
from zero to the maximum frequency. The maximum frequency (outer ring
diameter) is of course clearly visible on both curves.
Regards,
Yeti
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