PDA

View Full Version : Wheel speed



ZERO25
11-07-2019, 07:14 PM
I have no knowledge how a camera works, but can you determine the wheel speed from a video?

LRtireCHANGER
11-07-2019, 09:41 PM
Without knowing how many frames per second are being displayed, no, you cannot determine wheel speed from video. Have you ever watched a video, and something on the video appeared to rotate in the opposite direction that you expected it to rotate??? This phenomenon occurs due to an incompatibility between the original source video frame rate/second compared to the frame rate/second of the video that u saw. Simply put, the wagon wheels appear to rotate in the wrong direction because the video that you watched was shot at a frames per second rate that was different when compared to the original video. On the origanal video, a wheel might be in the 12 o'clock postion on the first obeserved frame, and on the second frame, the wheel would be in the 3 o'clock postion, and on the 3rd frame, it might be on the 6 o'clock position. These positions would seem to indicate that the wheel was rotating in a certain manner. But if you convert the video to a different format, the wheel might appear to rotate in the opposite direction. This phenomenon is due to a different sampling rate. Hope this helps, it is hard to describe this in text format. If this is unclear to you, message me, and i will try to explain over the phone.

Austin34471
11-07-2019, 10:49 PM
I have no knowledge how a camera works, but can you determine the wheel speed from a video?
I’ve used the iPhone slo mo camera to see the percentage of wheel slip a car had (comparing Hoosier logo rotating on LR tire compared to LF tire over some span of distance) but calculating the actual wheel speed would be above my pay grade.. and not sure what the utility would be anyways.

ZERO25
11-08-2019, 01:25 PM
I’ve used the iPhone slo mo camera to see the percentage of wheel slip a car had (comparing Hoosier logo rotating on LR tire compared to LF tire over some span of distance) but calculating the actual wheel speed would be above my pay grade.. and not sure what the utility would be anyways.

That's the same thing I do. I guess with LR's post, its an optical illusion at times!

Ima math nerd and like solving equations! lol