So in the class I've learned that Aliasing refers to the jagged edges resultant from the discrete nature of computer graphics way of representation.

Also, I know that Anti-aliasing refers to a technic (mainly of blurring) to remove (our camouiflage) aliasing.

But I was presented a question about "A picture flickering in a game room when the user moves" and the answer was given as being an aliasing problem.

I did not get the relation between flickering and aliasing. Can someone clarify it to me?


1 Answer 1


Flickering can be a form of temporal aliasing. It's a similar phenomenon to spatial aliasing such as jaggies, but it occurs in time instead of space.

For instance, a common cause of image flickering in graphics is when the camera or geometry is in motion, and geometric features fluctuate in pixel size as they move. For example, imagine a railing with thin vertical bars. Depending where a bar appears relative to the pixel grid, it might get rendered as 2 pixels wide, only 1 pixel wide, or it might not appear at all. And in motion, it may rapidly fluctuate between these states, creating a visually objectionable flicker.

Another common cause of image flickering is specular surfaces with a bumpy normal map and a high specular power. The specular highlights can flicker in motion, due to their alignment with pixels changing from frame to frame.

Antialiasing strategies that address only spatial aliasing will often produce an image that looks good in a static screenshot, but turns into a flickery mess as soon as things start moving. This is one reason why temporal antialiasing has become popular in games in recent years.

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    $\begingroup$ Very good answer, especially for the pointing to the Wikipedia arcticle that I could not reach in google searches. $\endgroup$ Oct 27, 2016 at 20:34
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    $\begingroup$ I would add that aliasing is a general phenomenon that can be found in contexts other than (screen) "spatial aliasing" or "temporal aliasing": en.wikipedia.org/wiki/Aliasing $\endgroup$
    – wip
    Oct 28, 2016 at 6:27

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