(picks up the chalk)
I believe fervently that, in the 2D image space, this rotation to grad is useful:
- $M = M$: (no rotation)
- $a = 0, 90, 180, 270, 360$ degrees, or $\left[ 0 , 360 \right]$ degress
-
N = 2dcfft(M);
The elements arecos
andsin
, recall that?
-
O = e^-ia(M);
Element by element component rotation, ok?
-
P = 2dicfft(O);
Image reformation.
-
(offers chalk, no takers)
Note for $a = 0$, or $360$ degrees, $P = M$ to computational accuracy. So, WTF happens in between? Well, it's all about pencil sketches and modellingmodeling for art classes. I do that. And in the studio, I hold still, shut TF up, and think about the brain dynamics.
In between:
At $a = 90$, $O = \left| \nabla \left( M \right) \right|$. The other angles are left as an exercise for the interested reader!
Cheers from Dana at Replikon Dot Net Mathcad 6.0 Plus!
(chalk returned)