> Image data is all positive.
>
> So the FT of an image has a large DC component.
>
> But, are there other characteristic properties of an all-positive
> function? Similar, for example to the 'real-is-even' etc?
No, other than the general conjugate-symmetry that applies whenever you
transform real data. The reason is that you can take *any* real array
and make it all positive by adding a sufficiently large constant to
every element of the array, and adding such a constant only affects the
DC element.
Cordially,
Steven G. Johnson
Reply by Chris Bore●October 11, 20052005-10-11
Image data is all positive.
So the FT of an image has a large DC component.
But, are there other characteristic properties of an all-positive
function? Similar, for example to the 'real-is-even' etc?
Chris
===========================
Chris Bore
BORES Signal Processing
www.bores.com