Post by imperfectgolfer on Jan 22, 2013 13:06:22 GMT -5
See this BM-forum thread started by cwdlaw223 on the Trackman 9 newsletter
www.brianmanzella.com/golfing-discussions/18021-trackman-newsletter-9-a.html
He stated-: "I'm sure the fun bunch had all of this stuff covered before their research a thon. Well, I'm sure the research a thon II will be better.
You need more than just a camera and the Internet to make these calculations!!! Next up, an iPhone from spare parts at RadioShack and more claims of face rotation rates without any numerical values.
The rotation rate affecting gear effect is an interesting concept.
Incredible machine!"
cwdlaw223 has got it wrong yet again.
This TM 9 newsletter is obviously a reaction to the KM research-a-thon project, and they are trying to pre-empt KM's still unreported findings.
Most amazingly, TM now admits that they need to verify the accuracy of their reported data, and what do you think that they use as the "gold standard" device for accurate measurements?
Answer-: A high speed video camera, like the Phantom camera.
This newsletter shows that cwdlaw223's claim that a high speed camera cannot make accurate measurements is totally wrong. In that article, they show that a high speed camera can give very accurate clubface angle readings, and then one merely has to make a correction for face bulge if there is an off-center strike. For example, they show that a "correction" for a 10.9mm off-center toe strike will require one to correct a face angle reading of -0.3 degrees to 1.9 degrees, and this "correction" can be made automatically as shown in the photo-diagram because the mounted camera system (which can be computer-integrated into the TM system) is automatically aware of the degree of off-center strike. In other words, they are using a high speed camera to determine the accuracy of their TM readings and that means that a high speed camera is making accurate face angle measurements (despite endless objections from cwdlaw223 where he wrongly claimed that this is not possible).
They also mention that they can show accuracy by comparing two TM machines side-by-side. That's obviously not true - because that only demonstrates measurement consistency, but it doesn't prove that the consistent measurements are accurate. TM even foolishly states that the accuracy of TM measurements can be verified by elite golfers, and the TM newsletter states-: "Verifying the consistency of the data can be analyzed when shots are hit by an elite level player". That's not possible because no elite payer can consistently generate path/face angle measuremements within 1 degree-of-consistency from swing-to-swing.
What the TM newsletter doesn't explain is how the TM can get a 1.9 degrees face angle reading if it doesn't know the degree of off-center strike in "real life" use. How is that possible?
Then consider the measurement of path.
The TM newsletter states-: "Also, consider the differences between using the center of gravity of the club head versus a point on the club face when reporting the Club Path value. In the above example, the ultrahigh speed video returns a Club Path of +1.0 degrees. TrackMan returns a value of +1.3 degrees. Both of these values represent the movement of the center of gravity at impact. If the movement at a point on the club face was mistakenly chosen as the point of reference for the ultra-high speed video analysis, a Club Path value of -1.8 degrees would have been returned. Comparing -1.8 degrees versus +1.3 degrees would have lead to a completely different conclusion about the perceived accuracy of the TrackMan measurement(s)".
I don't understand how TM can really measure the COG path when in the newsletter, TM states-: "It is very important to note that both Club Path and Attack Angle are defined relative to the center of gravity of the club head. This point of measurement is based on the simple fact that the golf ball’s movement is a reaction to the club head’s mass at the collision. TrackMan measures the movement of the geometric center of the club head and not directly the center of gravity of the club head. However, the difference between the location of the geometric center of a club head and the center of gravity is typically very small (less than 6mm)."
TM also openly admits that measurement of path can be affected by many factors because they measure clubhead reflections eg. variable clubhead designs, variable swings, and various ball positions relative to the radar. TM had to introduce new software to TM III to make their path measurements more robust. That means that path measurements in previous versions of TM could not have been robust.
By contrast, a correctly mounted high speed camera system can obviously measure the path correctly - because one can place a marker at the COG of the clubhead.
Finally, TM now admits that there is 3rd variable that needs to be considered - clubface closing during the impact interval. The effect of this variable is unknown and even TM admits that they need to research this issue further.
www.brianmanzella.com/golfing-discussions/18021-trackman-newsletter-9-a.html
He stated-: "I'm sure the fun bunch had all of this stuff covered before their research a thon. Well, I'm sure the research a thon II will be better.
You need more than just a camera and the Internet to make these calculations!!! Next up, an iPhone from spare parts at RadioShack and more claims of face rotation rates without any numerical values.
The rotation rate affecting gear effect is an interesting concept.
Incredible machine!"
cwdlaw223 has got it wrong yet again.
This TM 9 newsletter is obviously a reaction to the KM research-a-thon project, and they are trying to pre-empt KM's still unreported findings.
Most amazingly, TM now admits that they need to verify the accuracy of their reported data, and what do you think that they use as the "gold standard" device for accurate measurements?
Answer-: A high speed video camera, like the Phantom camera.
This newsletter shows that cwdlaw223's claim that a high speed camera cannot make accurate measurements is totally wrong. In that article, they show that a high speed camera can give very accurate clubface angle readings, and then one merely has to make a correction for face bulge if there is an off-center strike. For example, they show that a "correction" for a 10.9mm off-center toe strike will require one to correct a face angle reading of -0.3 degrees to 1.9 degrees, and this "correction" can be made automatically as shown in the photo-diagram because the mounted camera system (which can be computer-integrated into the TM system) is automatically aware of the degree of off-center strike. In other words, they are using a high speed camera to determine the accuracy of their TM readings and that means that a high speed camera is making accurate face angle measurements (despite endless objections from cwdlaw223 where he wrongly claimed that this is not possible).
They also mention that they can show accuracy by comparing two TM machines side-by-side. That's obviously not true - because that only demonstrates measurement consistency, but it doesn't prove that the consistent measurements are accurate. TM even foolishly states that the accuracy of TM measurements can be verified by elite golfers, and the TM newsletter states-: "Verifying the consistency of the data can be analyzed when shots are hit by an elite level player". That's not possible because no elite payer can consistently generate path/face angle measuremements within 1 degree-of-consistency from swing-to-swing.
What the TM newsletter doesn't explain is how the TM can get a 1.9 degrees face angle reading if it doesn't know the degree of off-center strike in "real life" use. How is that possible?
Then consider the measurement of path.
The TM newsletter states-: "Also, consider the differences between using the center of gravity of the club head versus a point on the club face when reporting the Club Path value. In the above example, the ultrahigh speed video returns a Club Path of +1.0 degrees. TrackMan returns a value of +1.3 degrees. Both of these values represent the movement of the center of gravity at impact. If the movement at a point on the club face was mistakenly chosen as the point of reference for the ultra-high speed video analysis, a Club Path value of -1.8 degrees would have been returned. Comparing -1.8 degrees versus +1.3 degrees would have lead to a completely different conclusion about the perceived accuracy of the TrackMan measurement(s)".
I don't understand how TM can really measure the COG path when in the newsletter, TM states-: "It is very important to note that both Club Path and Attack Angle are defined relative to the center of gravity of the club head. This point of measurement is based on the simple fact that the golf ball’s movement is a reaction to the club head’s mass at the collision. TrackMan measures the movement of the geometric center of the club head and not directly the center of gravity of the club head. However, the difference between the location of the geometric center of a club head and the center of gravity is typically very small (less than 6mm)."
TM also openly admits that measurement of path can be affected by many factors because they measure clubhead reflections eg. variable clubhead designs, variable swings, and various ball positions relative to the radar. TM had to introduce new software to TM III to make their path measurements more robust. That means that path measurements in previous versions of TM could not have been robust.
By contrast, a correctly mounted high speed camera system can obviously measure the path correctly - because one can place a marker at the COG of the clubhead.
Finally, TM now admits that there is 3rd variable that needs to be considered - clubface closing during the impact interval. The effect of this variable is unknown and even TM admits that they need to research this issue further.