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Post by imperfectgolfer on Dec 14, 2012 0:00:12 GMT -5
cwdlaw223 wrote-: "Why is video more practical (not for teaching obviously) when it can't see anything behind the face actually in contact with the ball?"
The Phantom video can see the Cface at the point of first contact with the ball, and that really presents the major CF angle reading of interest. If there is an effect on ball flight due to distortion of the Cface under the ball is not presently known, and we can presume (for the time being) that it is not a significant factor. Certainly, a radar device could never determine that fact. Secondly, the video can determine the Cf angle on both sides of the ball during maximal compression and it seems reasonable to presume that the CF angle under the ball is identical (in the absence of significant trampolining of the Cf under the ball).
Jeff.
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Post by cwdlaw223 on Dec 14, 2012 0:06:29 GMT -5
I have no problem with a first touch reading, however, the machines don't give that reading. What's the face angle number(s) going to be from Jeffy from first touch through max compression? More than one face angle reading during that time period. Hopefully there won't be any round numbers.
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Post by imperfectgolfer on Dec 14, 2012 0:12:16 GMT -5
cwdlaw223,
You asked-: "What's the face angle number(s) going to be from Jeffy from first touch through max compression?"
I don't know yet - but it is going to be interesting to see how much the Cf angle changes between the time of first contact and maximal compression, and whether it varies i) between different golfers and ii) between centered versus off-centered strikes.
Jeff.
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Post by tapiosantala on Dec 14, 2012 0:46:44 GMT -5
Tapio wrote-: " I have said before that STOP THAT BULLSHIT and don't put words to my mouth.
I have never said by any word that the calculation is wrong. So shut up
Wher do this kind of idiots born..." I previously/repeatedly warned Tapio that I would not tolerate this type of ad hominem attack post in this NGI forum. I have contacted Rand Smith (Administrator) and I have requested that he ban Tapio from this forum. Jeff. Thank you Jeff. I think it's just guys like CW you need to this forum more than me. Guys who are lying to your face and putting words to your mouth using their imagination to create meanings to someones words that never has been there. Guys who are not even clever enough to say "I'm sorry and it was total mistake to say that" Yep...they keeps the forum alive when it takes 10 pages to explain even most simple things I just can't stand two things. Total stupidity and lying. When those are put together and they are even against me, I tell what I think and it can be personal as it is to the person who acts like that. And there is not many like that but they are easy to find as they use to be active. I also very well understand you want to ban me and just wait the good reason for that. This is your forum and like in Manzella's case, the official truth has to be supported. Same will be in my own forum at acegolf when it opens at january. The difference is that things there are based on real 3D data and not to 2D face on videos which has been leading people to wrong direction for decades now.
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Post by tapiosantala on Dec 14, 2012 1:00:01 GMT -5
Tapio wrote-: " I have said before that STOP THAT BULLSHIT and don't put words to my mouth.
I have never said by any word that the calculation is wrong. So shut up
Wher do this kind of idiots born..." I previously/repeatedly warned Tapio that I would not tolerate this type of ad hominem attack post in this NGI forum. I have contacted Rand Smith (Administrator) and I have requested that he ban Tapio from this forum. Jeff. Jeff - If I mistated Tapio's position I would request that he not be banned. I viewed his post #71 as claiming that every time the machine gave "wrong numbers" he was challenging the toe/heel hit explanation. He specifically stated the machine was giving "wrong numbers." (I'm not offended by his post BTW). If the machines are giving wrong numbers then there must be something wrong with their calculations and he knows the correct numbers or calculations. And totally wrong again...
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Post by cwdlaw223 on Dec 14, 2012 7:39:12 GMT -5
Tapio -
I take you at your word when you say the machine gives wrong numbers. That's exactly what you stated in post 71 and I was not lying. If the machine gives wrong numbers then the calculations have to be wrong because the face angle number (which is what we're talking about) is calculated. By implication, you state the calculations are wrong when you claim the machine gives wrong numbers.
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Post by gmbtempe on Dec 14, 2012 9:28:02 GMT -5
How do you have both units directly behind the ball on the target line at the same time? Not sure how both units can test the exact same shot. Yea, problematic, wonder if either device can be elevated slightly without affecting the results.
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Post by tomdavis76 on Dec 14, 2012 11:50:45 GMT -5
cwdlaw223, You wrote-: " Even if the face angle is different from video, who is going to take a shot with a phantom camera, get the line drawing program out, measure the video and then get a number 10-15 minutes later for one shot? It's impractical." I agree that the Phantom camera is not practical for teaching. However, it is very practical for determining the Cface angle at impact when comparing it to a radar device (like TM and Flightscope) to determine whether those radar devices give accurate Cface readings for centered shots. The issue of CF distortion under the ball during the impact interval may be another issue that needs further study. However, I eagerly await the preliminary results from the research-a-thon, which seemed to be well executed. Jeff. That's not true. Kelvin teaches with it. Using an on-screen protractor gives very accurate face angle and path readings. I measured one of Denny's face angles using ProAnalyst, taking into account the influence of bulge on face angle from the deviation of the contact point from center impact (which we calculate for each shot), and got -2.7 degrees. Kelvin got -2.8 right off of the screen. Trackman got -1.7, a good match for Trackman. To repeat what I have already posted, Trackman states that face angle is reported at max compression, so that's what we use for comparative purposes.
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Post by cwdlaw223 on Dec 14, 2012 13:25:00 GMT -5
One guy teacing with a phantom doesn't make it practical. Even if you exclude the extreme cost ($50,000-$150,000 - I wonder if Kelvin's is new or used?), it takes time to view the video and draw on the screen and then move the camera around from top down view to face on view. I presume he doesn't just hold the camera when taking video and has to stabilize the camera for accurate recording.
Not sure that a 2D camera is "very" accurate for 3D path especially if the camera is positioned for a top down view.
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Post by mchepp on Dec 14, 2012 14:00:10 GMT -5
I don't think a phantom is necessary for teaching purposes. The 300fps from a Casio is more than enough information to help students improve. The difference between 300fps and 10,000fps (or more) in terms of information for helping a golfer get better is not clear to me. I have watched Kelvin's videos of swings using the Phantom and have not learned more than I could have watching a swing at 300fps.
I do think a Phantom is necessary for the purposes that Jeff and Kelvin used it for, club and ball interaction. I am very excited to see how Kelvin uses his knowledge to help us everyday golfers get better. I want to believe it is more than just proving Trackman wrong, because for me that is nice to know, but I am not clear how it is going to make me a better player.
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Post by tomdavis76 on Dec 14, 2012 16:47:38 GMT -5
One guy teacing with a phantom doesn't make it practical. Even if you exclude the extreme cost ($50,000-$150,000 - I wonder if Kelvin's is new or used?), it takes time to view the video and draw on the screen and then move the camera around from top down view to face on view. I presume he doesn't just hold the camera when taking video and has to stabilize the camera for accurate recording. Not sure that a 2D camera is "very" accurate for 3D path especially if the camera is positioned for a top down view. It takes no longer than a Casio at 300fps to process impact and it is mounted on a bracket. You'd have to reset for a face-on view. Takes a few minutes. Two synced cameras would be better, but there isn't much vertical movement during the millisecond or two we are looking at.
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Post by imperfectgolfer on Dec 14, 2012 23:08:06 GMT -5
Jeffy,
When do you anticipate that we will be getting some results/conclusions from the research-a-thon?
Jeff.
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Post by tomdavis76 on Dec 14, 2012 23:16:38 GMT -5
Jeffy, When do you anticipate that we will be getting some results/conclusions from the research-a-thon? Jeff. It is a massive amount of data to process, and I actually have to do some real work over the next week. I already sent preliminary conclusions to Trackman last Sunday morning: So far, we have tested 17 players ranging from a senior lady player with an average driver clubhead speed of 69 mph and average carry distance of 110 yards, to several long drive players with average clubhead speed reaching 136 mph and average carry distance of 328 yards.
When looking at the overhead view of impact, we see that players with moderate swing speeds (~90 mph), near center contact, and near zero path and clubface angle at impact generate Trackman path and face angle readings reasonably consistent with what is observed in the contemporaneous Phantom video shot at 24,000 frames per second. As the player's contact diverges from center and/or the path and face angle diverge from zero, the Trackman calculations and the Phantom observations diverge, and this divergence seems to be exacerbated by high clubhead speeds. The observed divergences can be quite large and even involve directional changes (e.g., a face angle Trackman reading of 2 degrees closed but an observed face angle of 4 degrees open). This leads us to conclude that the algorithms used to calculate path and face angle operate reliably only in a relatively narrow band of impact conditions.
Based on the data processed so far, I have no reason to expect that those preliminary observations won't be confirmed.
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Post by imperfectgolfer on Dec 15, 2012 0:10:15 GMT -5
Jeffy,
I can imagine that there is a massive amount of data that needs to be perused. I appreciate the effort that you and KM have made, and this may be a landmark research undertaking.
Jeff.
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Post by gmbtempe on Dec 15, 2012 16:10:02 GMT -5
I told Kelvin during the testing I could imagine this might take some time, I know it would for me because there is certain to be lots of scrutiny over the results.
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