floating type input to FFT

["Meghan Canning" <mkcanning(at)hotmail.com>]

Hi there,

I have been using the FFT function, and have just realized that the output
spectra generated is wrong.  More specifically, I read in an image, and
depending on whether I pass it straight through the function, or scale
it/convert to float (using FLOAT), the output changes.  As far as I can
tell, it's fine when I just pass in image data (integer gray values).  When
I convert to floating type first, the magnitude and PSD result in a very
unusual symmetry.

Any ideas?

Meghan