Difference between revisions of "Measure Rev Rate"

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Rev Rate requires a video.
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{{Howto}}
  
Tape from PAP to above fingers.  
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Calculating Rev Rate requires a video.
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Place Tape from PAP to above fingers.
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*Make sure the tape is contrasting in color to the ball. This will allow you to easily see the rotations.
 
Film a few throws
 
Film a few throws
  
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On a frame-by-frame player (Quicktime) count the number of times the tape revolves over 10 frames.  
 
On a frame-by-frame player (Quicktime) count the number of times the tape revolves over 10 frames.  
 
Be as exact as possible with this calculation.  
 
Be as exact as possible with this calculation.  
1/4 rotation over 10 frames is equivalent to 45 RPM, so a minor mistake in reading the video can be large
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To minimize error, throw more than one shot, and average your results.
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The higher the video quality, and the higher the frame rate, the more exact results you can obtain.
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*1/4 rotation over 10 frames is equivalent to 45 RPM, so a minor mistake in reading the video can be large
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*To minimize error, throw more than one shot, and average your results.
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*The higher the video quality, and the higher the frame rate, the more exact results you can obtain.
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A short duration such as 10 frames is best, as this allows you to remove many effects of the lane such as friction.
 
A short duration such as 10 frames is best, as this allows you to remove many effects of the lane such as friction.
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You will end up with
 
You will end up with
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At this point, it's simply conversion factors from high school science class:
 
At this point, it's simply conversion factors from high school science class:
 
* I am using 30FPS, as most video cameras in the US will use this *
 
* I am using 30FPS, as most video cameras in the US will use this *
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(x Revs / 10 frames} x (30 Frames / Second) = (revs / Second)  
 
(x Revs / 10 frames} x (30 Frames / Second) = (revs / Second)  
 
(Revs / Second) (60 Seconds / 1 Minute)
 
(Revs / Second) (60 Seconds / 1 Minute)
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Multiply X Revs by 3, (or multiply by 30 and divide by 10)
 
Multiply X Revs by 3, (or multiply by 30 and divide by 10)
 
The Multiply your result by 60.  It's pretty simple!
 
The Multiply your result by 60.  It's pretty simple!
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For example:
 
For example:
 
If the ball Completes 2 FULL rotations only over 10 frames
 
If the ball Completes 2 FULL rotations only over 10 frames
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2/10 * 30/1 * 60/1 = 360RPM
 
2/10 * 30/1 * 60/1 = 360RPM
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==Video==
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Video Courtesy of JustinWi<br />
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{{#ev:youtube|pkcvF_M1SaU|640}}
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[[Category: Bowler Measurements]]

Latest revision as of 13:56, 15 February 2013