SkyTrak Reproducible Misreads Making TGC 2019 Society Tours Unplayable?

[hankydysplasia]

Let me start by saying I have a lot of fun with the SkyTrak - using it daily since Christmas. I enjoy playing with family or the kids. However, I having a hard time believing it can be functional for competitive play.

I know about GungHoGolf's tips. The unit is 0 degrees level in both axes. It is on a flat surface off the mat. My ball is placed appropriately from the laser with drivers back and wedges up. I have a new ball every couple rounds with the logo facing the sensor. Alignment works great and is accurate. I have TGC settings optimized with straight putt, no boosts. When I hit shots in or out of doors, I know where the ball is going within a 5 yard radius in distance and direction 90% of the time. I trust the device on the other 10%. I don't know my swing speed, but my driver ball speed is up to 165 on a good drive. I have a natural draw, and my misses are big hooks or weak push blocks that go shorter. My peak IRL handicap was about a +3 in 2005.

The reproducible problem is with my mid irons. I first noticed it on the Torrey Pines tournament, the 8th hole my 7 iron went 235 yards and they informed me from data on the Discord that it was a misread on the backspin. Unfortunately, at Pebble Beach this week, this happened more 7 irons than not as 3 of the 4 par 3's were 7i distance for me. (FWIW, the 7i is a newish club and clean.) Here is #17 in the first round, which was the epitome of 7i for me that was about 5 feet from intended target:

BS

HA

LA

SA

SS

BS

CA

127.1

1.1

17.5

-3.3

-370

6418

173.48

Here are all the other "correct" 7i's from the round.

128.2

3.9

18.5

-4.9

-581

6781

170.10

128.8

1.3

17.3

-5.7

-627

6288

176.41

129.5

1.3

16.7

-5.7

-626

6278

178.00

Here are a the 7i's that misread.

Hole PAR	1 4	2 5	3 4	4 4	5 3	6 5	7 3	8 4	9 4	10 4	11 4	12 3	13 4	14 5	15 4	16 4	17 3	18 5	72
ROUND 1	4	3	5	4	7	6	3	4	4	3	3	3	4	4	3	4	2	6	72

#3 - second shot from "heavy rough". Out of bounds, cost 2 shots.

131.8

4.9

17.3

7.4

616

4743

195.87

#5 - Shoots of to the right down the cliff, cost at least 2 shots (quad bogey)

131.2

4.3

17.5

-2.5

-216

4962

193.59

#12 - Long slice leaving 40 years back to the hole, saved par.

132.3

1.2

16.0

24.6

1586

3465

207.14

Again, the ball came of the clubhead the same as the "correct" shot. The ball flight is one that I have never once seen of my club in real life and I never have hit that club ~200 yards carry. This is a round where I had 5 birdies and an eagle and was hitting extremely consistently. I shot even par with 5 balls (3 from misreads, 2 due to taking an aggressive line) that had to be rehit. I'm confident that the ball flight was not how the ball was struck in each of these cases.

The second round these were my 7i's:
#12 - Deja vu from round 1. Same spot. Not as lucky and got bogey.

130.3

1.2

16.1

7.4

567

4368

195.18

#17 - Birdied first round, put same swing second round and went 30 yards past.

135.8

0.0

16.1

2.5

218

4995

202.01

And here are 2 driver misreads for good measure
Baseline "normal" drive -

162.5

1.9

11.9

-1.6

-89

3193

270.88

#6 - went into the water with 314y carry - cost 2 shots

176.9

4.9

12.8

3.1

112

2080

314.04

#9 - went 340y in game in fairway on flat but I didn't capitalize on it.

182.1

0.0

11.4

1.6

81

2915

311.51

It is not physically possible for me to hit the ball that hard.

All-in-all, with Guest (probably rightfully) shutting off rewinds, I don't really have the ability to be competitive. Assuming I don't make a single birdie with those swings, it's 9 shots, or the difference between T19 and 4th. At least 8 misreads in 2 rounds. I know it's just internet points, but part of the fun is competing and instead I finish a round frustrated.

The SkyTrak seems to be reading too much ball speed and not enough spin. It also seems to be converting backspin to sidespin. The users that reviewed the shot data on discord suggested that this was a known high speed swing data problem. I'm looking for any recommendations or options. Since this is reproducible, I would think that it could be fixed.

[3on3putt]

Are you using an updated version of skytrak? I know there was an update not too long ago that addressed the high ball speed issue.

What's behind you? Anything shiny or white that the camera can see?

What you're experiencing is the exception, not the rule. To say that it's not accurate enough for competitive play discounts the experience of so many others who have no issues whatsoever. I've had mine for about a year now and have no problems with it at all. It's incredibly accurate to real life. For whatever reason, some people have different experiences. But your experience is certainly not universal.

[hankydysplasia]

Are you using an updated version of skytrak?

3.4.2
firmware 1.7

What's behind you? Anything shiny or white that the camera can see?

Mostly plywood, a table with keyboard. Nothing white.

What you're experiencing is the exception, not the rule. To say that it's not accurate enough for competitive play discounts the experience of so many others who have no issues whatsoever. I've had mine for about a year now and have no problems with it at all. It's incredibly accurate to real life. For whatever reason, some people have different experiences. But your experience is certainly not universal.

Thanks a lot for your input. I’m only speaking for me, and then hearing on discord that what I am experiencing is a known issue. I’m not denying some people are not experiencing problems. I’ve posted tons of data here to help get it solved and show I’m not just blowing smoke, that there actually is a problem. I appreciate your troubleshooting questions.

[mcnugget]

I started getting more low spin miss reads too. It was a big pain at Torrey for me as well since those shots often went off a cliff. I did have better luck this week at pebble after I cleaned my clubs and started using a new ball. I have been playing so much inside both my clubs and balls were just a bit "slick" even though they were not dirty. My biggest issue has been miss reads on the horizontal launch angle and short chips but I think there isn't much to do about that.

[hankydysplasia]

I did have better luck this week at pebble after I cleaned my clubs and started using a new ball. I have been playing so much inside both my clubs and balls were just a bit "slick" even though they were not dirty. My biggest issue has been miss reads on the horizontal launch angle and short chips but I think there isn't much to do about that.

I'll give it a shot on cleaning it again.

I totally agree about horizontal launch and chips - that's much much harder to prove with the swing data though. I can't play it wide open for a flop. There's no consistency in if it will decide to shoot it way off to the right (I'm RH) or go straight. I notice this in bunkers when I'm trying to simulate how I would actually hit it. Chipping is the area I'm most concerned will be off when I get back out on the real course - there's the mat vs grass factor too. I've got a new indoors chip swing that has been very effective on shots 6-12 yards. I keep a lob wedge pretty closed and do a hybrid chip/putt swing. No misreads with the chip patch turned on in settings. We'll see how it translates.

[Morini]

If you watch the TXG review, you will have seen something similar. I think that some flier spins come from poor mat, and maybe technique (say 4500 rpm). This does happen, and might be ruled in or out by hitting off a short tee and comparing the average spin.

But not the 2000 RPM range spin for 7 iron. I have mentioned this a couple of times. I think it is caused by rotation symmetry on the ball where the skytrak gets confused.

Imagine that the ball marking was "+" sign. The system could not tell a 1/4 rotation from a 1/2 from a 3/4 from a full. I am totally guessing here, but I think it may be using a simplistic ball speed function for disambiguity. If a ball spun 3/4 turn, the image engine is unsure if it was 1/4 or say 3/4, so maybe it uses ball speed to decide, and goes with 1/4, which gives flier flight, and overshoots green.

I may be way off here, but it definitely seems to happen a lot with those swinging around tour speed or higher. Hopefully something that can be fixed in software.

In the meanwhile, I'd try different balls, and also to have different parts of the ball face the skytrak to see if it makes any difference. And as mentioned, hit some off a short tee to rule out mat.

[hankydysplasia]

Imagine that the ball marking was "+" sign. The system could not tell a 1/4 rotation from a 1/2 from a 3/4 from a full. I am totally guessing here, but I think it may be using a simplistic ball speed function for disambiguity. If a ball spun 3/4 turn, the image engine is unsure if it was 1/4 or say 3/4, so maybe it uses ball speed to decide, and goes with 1/4, which gives flier flight, and overshoots green.

I may be way off here, but it definitely seems to happen a lot with those swinging around tour speed or higher. Hopefully something that can be fixed in software.

In the meanwhile, I'd try different balls, and also to have different parts of the ball face the skytrak to see if it makes any difference. And as mentioned, hit some off a short tee to rule out mat.

I think you're on to something!
I don't think it's the mat because of the disproportional problem I have on my 7i.

I think its possibly a rotational symmetry issue.
"Correct" read RPM Average: 6441
Misread RPM Average: 4767 = 74%
Outlier super flyer average: 3465 = 53%

They're looking to be almost exactly 3/4 or 1/2 the rotation.

That leads to my next question. I point the ball name at the SkyTrak. That is not a "+" sign, it is an asymmetric word (Titleist or Snell). Is the ball making 4+ full rotations and being read as 3? If it's not making a full rotation, how would this problem be happening?

[JacobM21]

I have the same issue. For the life of me can't get anything over 3000 rpm with my irons. I see guys stop the ball on a dime on the green, but I've never been able to do that with the skytrak. I do it in real life, but the skytrak won't do it. Ordered a fiberbuilt mat in hopes it helps with the issue

[hankydysplasia]

If you watch the TXG review, you will have seen something similar.

I just watched the video. It actually was the 7i for them too! He says his club is about 185 and he was hitting it 205. That's almost exactly my findings except 175 and 195. For TXG, they had a smaller (n) than I presented, but his spin rates were 6000 average on GCQuad with 3012 and 4399 for the misreads which were almost exactly 50% or 75% of the problem.

For the life of me can't get anything over 3000 rpm with my irons. I see guys stop the ball on a dime on the green, but I've never been able to do that with the skytrak. I do it in real life, but the skytrak won't do it. Ordered a fiberbuilt mat in hopes it helps with the issue

Some of the reaction on the greens is all software. 8i and below don't really go forward for me on normal greens, but I get 3-7y of roll in TGC 2019. I can't zip back a gap or sand wedge and I have to watch it on the course. I read that fiberbuilt Launch Angle is about 4 degrees higher and 1000rpm less for mid irons. Truestrike was 3 and 700. (Source at 10:03) I would love to see a side-by-side comparison of Fiberbuilt, TrueStrike, Divot Action, CCE, etc. and real turf for differences.

[Morini]

Maybe I oversimplified with the + sign, but I am fairly sure it is something along those lines. Maybe you should look at how spin axis plays in. As you have noticed, it is off by predictable factor. And it happens a lot for people with tour like 7 irons speed.

I would definitely experiment with different balls and the direction it faces. There are so many unknowns about the Skytrak. I will read patent again for clues. I am fairly sure it would read a ball without logo. Maybe it gets messed up about dimple patterns. Not sure.

With regards to mat, my son averages 6900 with 7 iron, 112 mph ball speed off my DIY DA. It spins very close to fairway. But swing plays in too of course. As I am sure you know, TGC2019 green firmness ranges from PGA Tour to concrete, so spinning back is a challenge.

[Morini]

Oh, and the time between strobes is 4.14 milliseconds, so 7000 rpm is roughly a half turn. A ball spinning with 14,000 RPM will read as zero spin. So a full spin 7 iron is 1/2 turn, the 3500 is roughly 1/4 turn.

[hankydysplasia]

I have continued to gather data on this.
My read error rate in tournament rounds is 16 errors and 43 successful (16/59), 27% of all 7 irons. My read error rate for 6 irons is 7/38 or 18%. Read errors on other clubs are much less frequent.

I continue to take every measure I can to ensure this stops, but it continues. My clubs are clean, new ball is pointed logo at SkyTrak. This continues to be a large frustration for me.
I would love to work with SkyTrak_Seth or anyone who can help overcome this issue in a future release.

[Morini]

Is it still a near perfect ratio of full spin? If so it's proof that it is not just simple random misread at play.

There has also been reports that others have had the reverse problem, players with slower swing speeds have had their driver spin rates in the 8000s.

As I mentioned, i think that Skytrak takes some shortcuts when calculating spin, and for certain trajectories and spins, it gets it off by 75, 66 or 50%. No idea, but figured it was ball markings. But why only around 120 ball speeds for medium trajectories? What would be different than other speeds and trajectories? I am going to guess that at these spin rates, speeds and trajectories, there is minimal overlap of ball markings between images.

[hankydysplasia]

Yes, it’s very odd.

Here’s some more interesting info.
The ball speed for misreads is almost always higher. Average is 5mph more and the standard deviations no overlap at all. Max correct - 129.7 Ave 126. Min error - 129.9 Ave 131.7. I did all these “errors” based on the spin numbers that are way off and I just discovered the balls speed. I highly suspect this is a misread as well as my ball speed numbers with correct spin rates have little variance.
Also, the side spin numbers and spin axis are all over the map. No rhyme or reason. My favorite was an axis of -31.1 with a backspin of 1890.
Launch angle is relatively consistent.

[Morini]

Interesting.

We don't know whether there is a cause and effect or mere correlation.

For example:

• Does the excess speed cause the spin error?
• Or does the spin error cause the excess speed.
• Or are both errors caused by something else?

Based on your belief that your ball speeds are consistent, likely not the first one.

While you mention that the launch angle is consistent, what is it for shots with misreads?

Things to try:
Hit shots around this speed with a different club and trajectory (say 4 iron with a bit of speed taken off).
Hit your 7 iron but reduce speed until misreads don't appear.

Observations about zero speed overlap is very interesting. Very likely you are onto something, but the devil's advocate would say that you swung differently and ball speed went up and spin down. In any case, it is like there is a blind spot in the system, either in the actual images ... which is not fixable. Or in the image engine end.

Maybe it really is a blind spot of sorts. A very narrow window of speed and (and maybe trajectory) where it is not possible to get two clean images of the ball. At 130 mph, the ball moves almost exactly 3 inches between images, which is roughly the spacing between the cameras. I also know that there is some directionality to the strobe (it's part of the patent). Who knows.

Maybe you could try to avoid the 128 to 130 ball speed window for a bit. Maybe choke down an inch or so and keep ball speed max below 128.. Just to see what happens to your misread percentage.