2IS with spinner wheels
07-05-07, 01:25 AM
#31
Pole Position
Join Date: Feb 2007
Location: Nevada
Posts: 360
Likes: 0
Received 0 Likes
on
0 Posts
Cool Video...not spinners though...its an effect commonly known as Temporal Aliasing or the Wagon Wheel Effect. In short it has to do with frame rate and frequency.
Longer Version: Motion-picture cameras conventionally film at 24 frames per second; however, the wheels of a vehicle are not likely to be turning at 24 revolutions per second, which would be extremely fast. However, suppose each wheel has twelve spokes and rotates at only two revolutions per second. Filmed at 24 frames per second, the spokes in each frame will appear in exactly the same position. Hence, the wheel will be perceived to be stationary. In fact, each photographically captured spoke in any one position will be a different actual spoke in each successive frame, but since the spokes are close to identical in shape and color, no difference will be perceived.
If the wheel rotates a little more slowly than two revolutions per second, the position of the spokes is seen to fall a little further behind in each successive frame and therefore the wheel will seem to be turning backwards.
Longer Version: Motion-picture cameras conventionally film at 24 frames per second; however, the wheels of a vehicle are not likely to be turning at 24 revolutions per second, which would be extremely fast. However, suppose each wheel has twelve spokes and rotates at only two revolutions per second. Filmed at 24 frames per second, the spokes in each frame will appear in exactly the same position. Hence, the wheel will be perceived to be stationary. In fact, each photographically captured spoke in any one position will be a different actual spoke in each successive frame, but since the spokes are close to identical in shape and color, no difference will be perceived.
If the wheel rotates a little more slowly than two revolutions per second, the position of the spokes is seen to fall a little further behind in each successive frame and therefore the wheel will seem to be turning backwards.
07-05-07, 07:34 PM
#33
First 2IS with Nitrous?
5hp per sticker = 30+hp over stock
Thread
Thread Starter
Forum
Replies
Last Post
