Posted by Kevin Matthews on March 17, 2001 at 13:58:14:In Reply to: THANKS GUYS! Re: Artlantis Anti-aliasing Options posted by Bob Sprague on March 16, 2001 at 16:28:12:
a real photo is not anti-aliased...
Well... I'm not sure I'd put it quite that way, Bob. Certainly a real photo doesn't usually need to be put through a discrete anti-aliasing processing step to get smooth images.
But why not? Consider a typical digital camera, which is much like a conventional film camera, except the image is received at the "film plane" by some kind of chip-like device which collects a pixel-by-pixel sampling of the optical image.
Due to the millions and millions of photons streaming through the camera in a normal exposure, each pixel in the camera's sensor will typically receive many photons. If a series of pixels happens to correspond to the region of a sharp edge in the scene, then each pixel will get a mixture of photons from across its tiny cell of the picture. The effect of this multi-sampling aross the image is just like anti-aliasing. In fact, synthetic multi-sampling aross the image is one of the best ways to achieve anti-alising in computer graphics.
So, you could say a real photograph doesn't get anti-aliased, because it doesn't need to. But I'd prefer to say that real photographs are naturally anti-aliased, and thus, I see synthetic anti-aliasing in rendering software as a natural part of making a realistic simulation.
cheers,
K