ATFLIR Technician Jeremy Snow discusses Gimbal, FLIR1, and GoFast

[Mick West]

Source: https://www.youtube.com/watch?v=fsCw3shLWBU


Automated transcript (will have inaccuracies, but useful for searching) https://otter.ai/u/KnPwdXYqkuOb5Brf8usaTfamP2Y?utm_source=copy_url
I've also attached a text file with the transcript.

This is an interview I did a few months ago. It was briefly discussed on Twitter, but I never got around to publishing it here. Of interest mostly to ATFLIR nerds, Jeremy was willing to get into some depth, but ultimately there were no great revelations. Still, useful context, and interested people might find something that helps.

One thing Jeremy mentioned is that the amount of glare might indicate the camera focus was slightly off.

Mick West 13:31
Yeah. I don't think anyone said that, like set the light fairly early on in the discussion, like saying it was like, a sense error. We I think everyone kind of agrees that this, what we're looking at here is a real object. The dispute is really is is this the actual shape of the object? Is it some kind of sausage shaped object? Or is the saucer shape? The shape of the glare? From the from the whatever it is the heat source the engines?

Jeremy Snow 14:00
Yeah, this one's a little odd, because you've seen images of where, yeah, it's been focused in on a jet and you can actually see it pretty clear. So I'm kind of thinking that for one, maybe they're not focused in very well. So there is a focal length in there. And this may not be set, but unfortunately, they did like the Declutter. So you can't see the focus values which would be kind of like on the on the left side

....
Mick West 15:26
So you're saying the gimbal video then might be a little bit out of focus, which might accentuate the, the size of this the glare?

Jeremy Snow 15:37
Yeah,

Mick West 15:38
yeah. If it is a glare?

Jeremy Snow 15:40
Yeah, if it if it is glare

 

[John J.]

Jeremy mentioned the possibility that the ATFLIR might have been deployed without having been calibrated from its on-board black body (approx. 55:44 to 56:32 on the video, 54:40 - 56:03 transcript).

Would omitting calibration result in an equal reduction in sensitivity/ image sharpness across the dynamic range?
I'm wondering if there might be proportionately greater distortion / less optimal imagery for higher temperature "targets" viewed by an uncalibrated ATFLIR.

 

[Domzh]

Jeremy mentioned the possibility that the ATFLIR might have been deployed without having been calibrated from its on-board black body (approx. 55:44 to 56:32 on the video, 54:40 - 56:03 transcript).

is it reasonable though to assume that a fully trained navy pilot wouldnt notice that something is off with the image sharpness in this scenario?

not necessarily when watching the flir1 or gimbal video but Underwood himself, whos using the pod actively?

only situation i could imagine where he wouldnt notice it, is if he used this pod only once and only filmed the alleged tic tac with it but even then pilots before him would have most likely noticed that something is wrong with this specific pod, wouldnt they?

 

[John J.]

only situation i could imagine where he wouldnt notice it, is if he used this pod only once and only filmed the alleged tic tac with it but even then pilots before him would have most likely noticed that something is wrong with this specific pod, wouldnt they?

Only mentioned it because Jeremy Snow raises it as a possibility.
I don't think he's saying there's anything wrong with the pod- but it needs to re-calibrate from its internal black body before each use, if I understood his comments correctly.

is it reasonable though to assume that a fully trained navy pilot wouldnt notice that something is off with the image sharpness

Fully trained airmen make mistakes, just like everyone else.
This cockpit footage is from Iraq, 28 March 2003. Two A-10s attacked friendly armour- from about 2:17 in, you can hear a pilot mention that he sees orange panels (agreed friendly forces air identification panels). From 3:40, one of the pilots has decided that the orange panels are in fact orange rockets on a launcher. His wingman sounds doubtful at first- "Orange rockets?"
Tragically, mistakes happen, and misidentifications are made, even by the best. (I'm glad I don't have their responsibilities).

Edited to add (15:54, 08/08/23),

I'm wondering if there might be proportionately greater distortion / less optimal imagery for higher temperature "targets" viewed by an uncalibrated ATFLIR.

I raised this because I got the impression that Jeremy Snow was not wholly convinced that a rear view of distant jet engines would result in the amount of IR "glare" necessary to explain the imagery seen in the ATFLIR footage.
I've absolutely no idea if it might be correct, partially correct or wholly wrong... hopefully someone with greater knowledge of ATFLIR or similar IR imaging systems can help.

 

[Domzh]

i havent seen anyone using these systems professionally that thought the gimbal thing looked like a jet engine glare.

i myself thing this could have coming from a drone with IR deception / spoofing capabilities.

The navy has various documents talking about decoy drone swarms as being part of NEMESIS (their electronic warfare system of systems SoS).

It would make sense that not many pilots know how something like this would look on FLIR.

If the us navy is developing / utilizing this, then its pretty safe to assume that other adversaries have similar technology and or that the navy is testing it among their own forces without telling everyone about it.

 

[Mendel]

i myself thing this could have coming from a drone with IR deception / spoofing capabilities.

It'd still be glare, though.

 

[Domzh]

It'd still be glare, though.

ah yes of course, it would just explain why so many people used to work with this system said it doesnt look like an airplane / looking inside the engine of one. i would have to find each single one of them but iirc they said even if its glare it doesnt look like anything they have seen. i would assume they have seen a couple of glaring engines viewed from behind and or banking.

 

[AmberRobot]

Jeremy mentioned the possibility that the ATFLIR might have been deployed without having been calibrated from its on-board black body (approx. 55:44 to 56:32 on the video, 54:40 - 56:03 transcript).

Would omitting calibration result in an equal reduction in sensitivity/ image sharpness across the dynamic range?
I'm wondering if there might be proportionately greater distortion / less optimal imagery for higher temperature "targets" viewed by an uncalibrated ATFLIR.

I don't know the details of this optical system nor have any information about its operations; however, I would comment on this in the following way:

The reason for having a "blackbody" on board a system like this is for radiometric calibration. A blackbody has a known radiance for a given temperature. This would allow you to know the absolute responsivity of the system. I can think of two reasons why you would want to calibrate this: 1) you want an absolute calibration of the target radiance, which may tell you the temperature of the target given known or reasonably guessed information about the emissivity. 2) you want to set the exposure settings of the optical system to have a specific output for a known input.

The reason you would want an on-board calibration source, instead of say calibrating it against a ground source occasionally, is that you have a reasonable belief that the calibration of the system either changes on short timescales (like being dependent on environmental conditions such as temperature, pressure or humidity) or needs to be adjusted for specific types of observations.

If the instrument were not calibrated then perhaps the exposure settings would be not be correct for the types of observations you want to do. In this case, one could be overexposing sources that would normally be well exposed. If a bright source were overexposed then the detail in the image would be lost as the detectors saturated. One sees this kind of effect say when you take a photograph of the Moon. If it's well exposed you can't see any stars in the background. If you want to see the stars you overexpose the Moon but then you can't see the surface features on the Moon. And if you have any scattering or stray light in the system that gets enhanced in the image as you've cranked up the exposure of the camera.

 

[Mendel]

In this case, one could be overexposing sources that would normally be well exposed.

I have a feeling that, in a tactical setting, accidental underexposure is the thing to avoid.

 

[jplaza]

I can think of two reasons why you would want to calibrate this: 1) you want an absolute calibration of the target radiance, which may tell you the temperature of the target given known or reasonably guessed information about the emissivity. 2) you want to set the exposure settings of the optical system to have a specific output for a known input.

I can think of a third reason: Non-Uniform Correction (NUC)

Each pixel of the sensor can have its own sensitivity (or even be a dead pixel), so when put in front of a black body, all pixels receive the same amount of radiation, but generate different currents. The NUC corrects pixel by pixel the currents so to have a correct uniform image.

 

[AmberRobot]

I can think of a third reason: Non-Uniform Correction (NUC)

Each pixel of the sensor can have its own sensitivity (or even be a dead pixel), so when put in front of a black body, all pixels receive the same amount of radiation, but generate different currents. The NUC corrects pixel by pixel the currents so to have a correct uniform image.

That is correct, the black body would provide a good flat field. I don't know what kind of sensor they have but from my experience pixel to pixel response variations tend to be on the order of a couple of percent at most. You also get larger scale non-uniformities that arise from things like shadows of dust on the optics and vignetting. These will be larger effects than the pixel-to-pixel stuff.

I apologize for the omission, I was just typing off the top of my head.