Lighting

[Morini]

The topic of adding additional lights to help with reads keep coming up, with users posting pictures of all types of spotlights. As I understand it, they won't help at all as the Skytrak illuminates with IR strobe. Yes, a large number of users insist that it helps get reads. Can we get the official word on this?

[Lombo]

I know that it's not supposed to do anything, but I have more accurate reads when I have even lighting on in my sim room, rather than having a single light in the hitting area. It's not that it helps with the no reads, they are about the same, it's that I seem to get more accurate numbers with the even lighting. Without even lighting, the numbers seem to be a bit lower on average. I've actually tested this, hit 10 shots with and without lights and it always seems to be a bit lower distance measurements without the even lighting. There might be other reasons for this with my setup, but I've done a lot to simply and eliminate reflective the backgrounds including painting all walls black.

[Morini]

Any chance that you actually make slightly better contact when you see the ball better due to better lighting? The way the technology works, and I simply can't see any benefit to additional light.

[jefe]

If lighting wasn't a bigger issue, then outdoors use in direct sunlight wouldn't be an issue... Right?

[GungHoGolf]

If lighting wasn't a bigger issue, then outdoors use in direct sunlight wouldn't be an issue... Right?

Direct sun is an issue because it "blinds" the IR flash and cameras with too much IR light and glare. SkyTrak's cameras and IR flash do a good job of illuminating a white ball against a black background (that's what the photos look like) even in a completely dark room. Too much direct sun can make the background too bright, plus add glare, which can confuse the algorithms trying to identify the ball and pick it out of the background.

[Morini]

The way skytrak freezes the ball is to block visible light and then capture the ball with a very brief flash of IR illumination. It is a bit like the old 1960s photos of bullets frozen in flight. Those did not use a high speed camera, but instead left the shutter open and captured the bullet with a very brief flash. Back in the day mechanical shutters were the only option, and they were simply not responsive enough, unlike flashes that could fire within microseconds of being electronically triggered.


Skytrak works in a similar way. It needs illumination only at the exact time the strobes fire. These are very precisely timed, with the second strobe 4.14 milliseconds after the first. There is simply no way that continuous external visible light can help. Even if it got through the IR passthrough filter, it would just serve to create a blurred ball image, as it is continuous, not coordinated with the strobe. Simply no way that light can help capture better images.

Yet there are dozens of people who feel that they get more accurate reads with external lighting. What gives?

[GungHoGolf]

Yet there are dozens of people who feel that they get more accurate reads with external lighting. What gives?

Confirmation bias perhaps. Someone should do a controlled study with a very consistent ball striker (that rules me out lol).

[Morini]

I am leaning that way ... but the most credible anecdotes have been that it helps for putting and lofted wedges. I don't know how putting works, but suspect that is totally different method, so maybe continuous light actually helps.

With regards to lofted shots, they are very difficult to time. As mentioned, the time between strobes is fixed (4.14 ms), and if second strobe fires too early, ball is not yet in horizontal view of second camera. If too late above vertical field of view of second camera. Just speculating, I am wondering if external light interferes with laser curtain and alters timing of strobe firing (earlier) for the better. I simply don't know what else.

I would love some official word on this, as the number of users who believe that light helps is growing, and no doubt some of them are overdoing it resulting in more no-reads.

[3on3putt]

Maybe better lighting in the room leads to better ball striking, and better ball striking equates to numbers that we all feel are "right." I use a small desk lamp with a bendable arm next to my skytrak to put some light on the ball. Helps my ballstriking because without it, it's a bit dark on the mat with just the light from the projector being the only other light in the room. I dunno, it's an interesting debate.

[GungHoGolf]

Good point (as usual from you), 3on3putt

[jpotas]

Has anyone ever tried a tinted film that would reduce glare when using outside?

I tend to agree with 3on3putt regarding better lighting equating to better ball striking. When I try hitting with very dim lighting it feels unnatural and I am sure it changes my swing (feels slower).

[GungHoGolf]

Has anyone ever tried a tinted film that would reduce glare when using outside?

I tend to agree with 3on3putt regarding better lighting equating to better ball striking. When I try hitting with very dim lighting it feels unnatural and I am sure it changes my swing (feels slower).

Tinted film wouldn't be a good idea, but several folks have had success with cardboard shades placed over the top of the unit - like a golf ball box or other small cardboard box shade, when in direct sun.

[wbond]

Could the extra light be masking something in their environment that is causing a mis/no read?

[Morini]

3putts theory is excellent and I have speculated about it in the past. Just not sure. Here is a quote from Ron's facebook group by Tim Huser. He did a little bit of testing, and here is what he wrote (keep in mind that this was for lofted wedge):

I’ll do some more testing but this was very conclusive. I’m an engineer, and couldn’t let it go. Lights down, no reads, none. Light up a bit, no Mis-reads. Dozens of shots, back and forth. I’ll make a video soon.

Again, not sure what to make of all this.

[pcascio]

This is certainly an illuminating conversation. All lights include a infrared component, so the more you light the tee area, the more you risk overexposure. However, the high shutter speeds and high flash intensity far outweigh ambient lighting in almost all cases. The one thing to keep in mind however is that the cameras need to see and interpret a low contrast subject. Increasing contrast by occasionally re-marking the balls with a black sharpie will probably do more to improve accuracy than anything else.

[GungHoGolf]

Agree with everything you said, but don't sharpie balls if you're hitting into an impact screen unless you want sharpie ink on the screen.

[Morini]

I think it is a bit more than overexposure. As I mention above, skytrak does not use a high speed camera in the traditional sense. It uses the strobe to freeze the ball, not a fast shutter. So if for example, we disabled the strobe and shined a fairly powerful continuous IR light on the ball area the captured images would not show a frozen ball but rather a ghost like streak of the balls trajectory. Since most visible light contains IR, if we replaced the IR source with visible light, the same thing (albeit weaker ghost image). If we enable the strobe again, we'd see the ghost streak still, and then also the frozen ball. The point here is that external light cannot possible help capture better images (as many think) because the continuous light is not timed with the strobe. Not to put anyone of the spot, but it would be great if somebody from skytrak can break radio silence on this issue.

[Morini]

As mentioned, lots of anecdotes that light help, but few experiments with data and controls. Tim's is pretty clear, and he is making a video demonstration. In his case, it was a wedge. As mentioned, the only way I can see light having a difference (for better or for worse) is that it could interfere with the reflected laser curtain light. This could change the waveform of this reflected light, which in turn would alter strobe timing.