[WM]: DFT - Magnitude Manipulation

["Nathan Jones" <iamfrank@bigpond.net.au>]

Hey guys,

I'm working with someone who's getting me to do their Matlab programming = for them.

He's getting me to load an image in Matlab, perform DFT on it, then = modify the magnitude.  I've tried a few approaches, then
finally settled = on just adding a multiplication factor that I apply to the DFT matrix.

The problem I'm getting is, if I multiply out the whole matrix by the = factor, I get what I would expect, i.e. if I multiply it all
by 0.5, I = get an image where everything is dull.
Now, if I try to modify just a particular cell, or a row, it doesn't = work.  If I read back the matrix after I've modified it with
either = approach, they appear the same.  

Once I convert it back to an image and display it though, the one where = the I modified the single cell or row has no visual
difference at all.  = If I then reconvert that once again back into a DFT, the changes are = basically gone.

Any ideas what this would mean?  If you don't quite understand what I = mean, which parts don't make sense.  If there is a flaw in
my logic, = please let me know too ;)

Cheers,
Nathan


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