10 votes

Why is spherical harmonics used in low frequency graphics data instead of a spherical Fourier transform?

Spherical harmonics really are the "spherical Fourier transform" you're looking for. The kind of hack you mention in comments, of doing a 2D Fourier transform on a lat-long projection, suffers from ...
Dan Hulme's user avatar
  • 6,810
4 votes

Image rotation using FFT

Yes, it is possible. Remember that a shift in space is equivalent to a linear-phase multiplication in frequency. A rotation can be accomplished by a shearing operation in one direction followed by a ...
Stan Reeves's user avatar
1 vote

How to calculate spatial frequency of an image just in one direction?

You can take a 1D Fourier transform of a row of pixels from the image; it will give you the horizontal frequencies present in that row. You could sample one row out of the image, or else average all ...
Nathan Reed's user avatar

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