Watching a "Western" on television, you may have noticed that sometimes the wheels on a fast stagecoach appear to be rotating backward. Explain how aliasing causes this effect.
The reason we see the wheel "go backwards" is due to the fact that the image we see on the screen is not a continuous motion, but rather a series of sampled still images.
A movie camera samples the continuous motion of an object at a rate of 24 still images per second.
Let's assume that the wheel is also turning at a rate of 24 revolutions per seconds.
In this case, all the still images will ...
This solution explains how aliasing causes this effect.