Is there a possibility that there appears a maxima in the fourier space (in the absolute value of the transform) of a purely periodic structure. I was of the impression that purely periodic structures could not have a local maxima at frequencies lower than the fundamental frequency of the structure
The image shown above has hexagonal symmetry and is supposed to be hexagonally symmetric. It's fourier transform is shown in the image below
The white spots shown below are the fundamental frequencies of the periodicity of the structure. But, we also see other spots (pink) at frequencies lower than the fundamental frequency (white spots). Why do these frequencies occur? Or are they simply maxima/minimas?
Any and all help is appreciated.
P.S. the sampling matrix of the image file(first image) for sure will not see pure periodicity since the sampling lattice is square in shape while the image periodicity is hexagonal.