5 ms·

I don’t know how to reconcile that with the video evidence: https://images.app.goo.gl/CtJmayDTwVrz9xwi6 https://images.app.goo.gl/CtJmayDTwVrz9xwi6

pbmonster 2y ago
From the article: > PITCHf/x is a video-based tracking system that is permanently installed in every MLB stadium and has been used since the start of the 2007 season to track every pitch in every MLB game. The system consists of two 60 Hz cameras mounted high above the playing field, with fields of view that cover most of the region between the pitching rubber and home plate > Depending on the specifics of each installation, the pitch is typically tracked in the approximate range y=5-50 ft, resulting in about 20 images per camera for each pitch So the raw data is from two 60 Hz cameras build some time before 2007, each taking 20 pictures of a small, fast moving object tens/hundreds of feet away? The error bars on that raw data must be significant, especially when a "knuckleball wobble amplitude" of just a few inches would already be very effective. If I'd design that PITCHf/x system today, I'd add a handful of 80 GHz radar modules, and cameras on two more axis.
- belter 2y ago
  Anything similar for Basketball?
  - le-mark 2y ago
    I vaguely recall a company with a rfid like ball and player tracking system that was seeing some adoption by colleges. Maybe someone knows more?
    - belter 2y ago
      I know what you are talking about. I think they went bankrupt. I looked at that and I think there are few Chinese copies on Amazon. I am looking into something with higher tracking requirements. Maybe this is the equivalent: https://www.catapult.com/sports/basketball https://www.catapult.com/sports/basketball
- skywhopper 2y ago
  Yeah, based on the description of the system I’m skeptical that the “raw” data is all that good. The author makes some assertions about it, but he’s also working with a vanishingly small sample size. He makes no attempt to compare specific knuckleball pitches with apparent wild behavior to the captured data. He just pulls data from four games of two knuckleball pitchers. Which is weird because the gif above does seem to follow the pattern the author himself mentioned about a very-slow-spin pitch being influenced by wind against the ball’s seams in different ways as it rotates.
- relaxing 2y ago
  Article is from 2012. MLB has since adopted a doppler radar system called TRACKMAN.
  - bradleyankrom 2y ago
    ...which was replaced a few years ago, now using optical tracking from Hawk-Eye.
- aidenn0 2y ago
  The maker of the camera system claims 0.5" precision; TFA calculates a mean 0.3" RMS deviation from an aerodynamic model.
relaxing 2y ago
Good news, the author of this study has addressed that pitch, using higher quality radar data. https://baseball.physics.illinois.edu/DickeyPitch103a.html https://baseball.physics.illinois.edu/DickeyPitch103a.html Verdict: It is indeed nasty stuff.
- knuckleballfan 2y ago
  This is great, thanks!

pbmonster 2y ago

From the article: > PITCHf/x is a video-based tracking system that is permanently installed in every MLB stadium and has been used since the start of the 2007 season to track every pitch in every MLB game. The system consists of two 60 Hz cameras mounted high above the playing field, with fields of view that cover most of the region between the pitching rubber and home plate > Depending on the specifics of each installation, the pitch is typically tracked in the approximate range y=5-50 ft, resulting in about 20 images per camera for each pitch So the raw data is from two 60 Hz cameras build some time before 2007, each taking 20 pictures of a small, fast moving object tens/hundreds of feet away? The error bars on that raw data must be significant, especially when a "knuckleball wobble amplitude" of just a few inches would already be very effective. If I'd design that PITCHf/x system today, I'd add a handful of 80 GHz radar modules, and cameras on two more axis.

belter 2y ago
Anything similar for Basketball?
- le-mark 2y ago
  I vaguely recall a company with a rfid like ball and player tracking system that was seeing some adoption by colleges. Maybe someone knows more?
  - belter 2y ago
    I know what you are talking about. I think they went bankrupt. I looked at that and I think there are few Chinese copies on Amazon. I am looking into something with higher tracking requirements. Maybe this is the equivalent: https://www.catapult.com/sports/basketball https://www.catapult.com/sports/basketball
skywhopper 2y ago
Yeah, based on the description of the system I’m skeptical that the “raw” data is all that good. The author makes some assertions about it, but he’s also working with a vanishingly small sample size. He makes no attempt to compare specific knuckleball pitches with apparent wild behavior to the captured data. He just pulls data from four games of two knuckleball pitchers. Which is weird because the gif above does seem to follow the pattern the author himself mentioned about a very-slow-spin pitch being influenced by wind against the ball’s seams in different ways as it rotates.
relaxing 2y ago
Article is from 2012. MLB has since adopted a doppler radar system called TRACKMAN.
- bradleyankrom 2y ago
  ...which was replaced a few years ago, now using optical tracking from Hawk-Eye.
aidenn0 2y ago
The maker of the camera system claims 0.5" precision; TFA calculates a mean 0.3" RMS deviation from an aerodynamic model.

relaxing 2y ago

Good news, the author of this study has addressed that pitch, using higher quality radar data. https://baseball.physics.illinois.edu/DickeyPitch103a.html https://baseball.physics.illinois.edu/DickeyPitch103a.html Verdict: It is indeed nasty stuff.

knuckleballfan 2y ago
This is great, thanks!