My unit got a couple sets of combination image intensifying/thermal goggles back in 2008 to try out (long before the AN/PSQ-42s were even in development). The thing that stuck out most to me was how much everyone disliked them without really being able to articulate why.
There was also a rumor that if you turned your head fast enough with them on they’d cause you to vomit and pass out, which is almost certainly not true but boy did we believe it.
We used the PVS-7 monocular devices in the Contingency Response Groups. While it wasn’t anything I’d want to live in, it works ok enough to drive a HMMWV at night safely
These new ones would be wild, I’ll see if I can get a demo this year somewhere.
Basically it said infrared goggles use digital processing, so there's at least one frame of lag for every image, which can cause those issues. Image intensifying googles are totally analog so there's no lag to avoid that issue.
> so there's at least one frame of lag for every image
Well, 24 fps vs 120 fps would technically matter, to the point where at a high enough frame rate you could not possibly tell the difference; I suspect it's more like 48 fps (if it's a constant 48 fps) than 120 *
> There was also a rumor that if you turned your head fast enough with them on they’d cause you to vomit and pass out, which is almost certainly not true but boy did we believe it.
Sounds like (slightly exaggerated) VR sickness symptoms, e.g. when there's too much latency between head movement and vision updates. Some people are more sensitive to this than others.
Perhaps it has to do with the optical center being offset? I don't have one to test it out, but if it works like it says online, the optical center would move from somewhere in the middle of your eye to somewhere in the middle of the device, which would cause changes in parallax, and therefore mismatch in movement between the inner ear and what is inferred from the eyes. Maybe that's what causes the discomfort.
So an IIT doesn’t really have a “refresh rate”, but the thermal component does.
I don’t get any motion sickness with Gen3 IIT’s even moving fast, but with digital systems there’s a latency in refresh rate that becomes very disorienting.
The thermal part of the combined system is digital - in the units I’ve looked at, the image from the thermal is “projected” into the IIT’s lens. So while the image from the IIT alone is lag free, the thermal overlay does have lag and can mess you up a bit.
Depends where you are! ITAR/etc means the markets fucking confusing.
In the US it’s possible to get really nice L3Harris Gen3 tubes, whereas in Europe you are more likely to find Photonis Echo or similar - which are really nice.
There’s the older school green phosphor tubes, and more modern white phosphor tubes - the WP ones are better in terms of contrast, and IMO easier on the eyes.
The set I have the most time on uses Gen3 WP Photonis Echo tubes, and is really nice, but I’m told it doesn’t hold up great compared to the ones available in the US.
There’s some Chinese tubes on the market now that are supposedly rather good, but I’ve not played with those.
You will find Veritasium's video on night vision goggles [1] very interesting. He explains well how they work, and the pros and cons of each implementation and generation.
In particular you can see just how much better (in terms of quality / resolution, not latency) the thermal vision is. Absolutely not surprising that they're trying to merge the two solutions to get the best of both worlds - fast updates from amplified visual, higher fidelity / resolution / range from the thermal channel.
I always hated the biocular NVGs when I was in, but that was back when the conversation was between PVS-14s and PVS-7s. Hopefully the dual tube design helps with the nausea I had trying to drive with PVS-7s in Grafenwöhr back in the day.
I’m stuck with PVS-7s and 14s. The nerd part of me is amazed looking at the stars with them, but the soldier part of me is frustrated having to move with them. I can’t imagine having I^2 and thermal imaging in a single NOD.
Readit News
These new ones would be wild, I’ll see if I can get a demo this year somewhere.
Basically it said infrared goggles use digital processing, so there's at least one frame of lag for every image, which can cause those issues. Image intensifying googles are totally analog so there's no lag to avoid that issue.
Well, 24 fps vs 120 fps would technically matter, to the point where at a high enough frame rate you could not possibly tell the difference; I suspect it's more like 48 fps (if it's a constant 48 fps) than 120 *
Sounds like (slightly exaggerated) VR sickness symptoms, e.g. when there's too much latency between head movement and vision updates. Some people are more sensitive to this than others.
Deleted Comment
I don’t get any motion sickness with Gen3 IIT’s even moving fast, but with digital systems there’s a latency in refresh rate that becomes very disorienting.
The thermal part of the combined system is digital - in the units I’ve looked at, the image from the thermal is “projected” into the IIT’s lens. So while the image from the IIT alone is lag free, the thermal overlay does have lag and can mess you up a bit.
The give-and-take relationship between this technology and video games is ... something.
I can’t understate how fucking awesome the technology is, even the stuff available in civilian market.
In the US it’s possible to get really nice L3Harris Gen3 tubes, whereas in Europe you are more likely to find Photonis Echo or similar - which are really nice.
There’s the older school green phosphor tubes, and more modern white phosphor tubes - the WP ones are better in terms of contrast, and IMO easier on the eyes.
The set I have the most time on uses Gen3 WP Photonis Echo tubes, and is really nice, but I’m told it doesn’t hold up great compared to the ones available in the US.
There’s some Chinese tubes on the market now that are supposedly rather good, but I’ve not played with those.
[1]https://www.youtube.com/watch?v=UAeJHAFjwPM&t
Deleted Comment