Nimitz ATFLIR Focus Issues

Mick West

Administrator
Staff member


The available Nimitz video is obviously low quality. It's just 240 pixels high, and only uses 214 of them (i.e., it's about 214x214 pixels).

It's also blurry. Not simply the target being out of focus, but the numbers on the screen are blurry. However, this seems to be mostly the result of reduced resolution. If you take the Gimbal video and reduce that to 214 pixels, then the text appears very similar, other than contrast.

2021-06-22_16-37-44.jpg

Now it's frequently suggested that there's a better version of this video, and it's much clearer. Example:

Source: https://twitter.com/MiddleOfMayhem/status/1407474525147582464


The point is, that the object on the screen would be much clearer and hence discernable as a Tic-Tac with small legs.

But is this true? I think the ATFLIR system is actually out of focus because it's set to manual focus, level 8, when it should be set to 9.

A simple measure of blur is the pixel spread. Take a solid black or white edge; how much does it spread out?

Spead from blur should not be confused with the spread from aliasing, which is where what would be a single pixel's worth of color is spread over multiple other pixels. This smooths out lines and edges.

For example, the text and the horizon indicator are not really blurred; they are just aliased due to the low resolution. We can draw a single pixel line in photoshop, pixel perfect, and it looks the same as the horizon line:

2021-06-22_17-13-55.jpg

Notice, though, that the vertical lines have spread much more; this does not seem to be a result of the reduced resolution but rather a limitation of the system, possibly just reduced horizontal resolution. Here's the same thing in GoFast
2021-06-22_17-39-29.jpg
Notice horizontal lines are sharp, and vertical lines are blurry as if they are half the resolution. This is also visible in the text, again in Gimbal:
2021-06-22_17-45-03.jpg
Note the brighter, mostly 2-pixel thick horizontal lines and the darker 4-pixel thick vertical lines. We see this repeated (at a much lower resolution) in Nimitz/Flir1
2021-06-22_17-46-16.jpg

So what we see is that the reduction in resolution in the video is not adding significant blurring to the image beyond what is expected from aliasing. Vertical spread is one pixel. The horizontal spread is two pixels.

So if we are to draw a clean-edged Tic-Tac at this resolution, we would expect that the horizontal edges would remain as clean as the horizontal lines in the horizon indicator, just spreading a single pixel. This is what happens. But the horizontal edges don't look like this in the actual object. They are spread much more than the horizon line is spread.
2021-06-22_17-15-34.jpg

Instead of having the one pixel vertical spread that we see in our clean additions, the "Tic-Tac" object has between four and five pixels vertically. We also notice the top and bottom edges are very uneven - something we don't see at all in the horizon line.

So we can see the text and lines are not significantly different from what would be expected from a simple downscaling, the object is much blurrier vertically (and even more horizontally, but it starts out more blurry anyway). I think that the only way this is possible is if it is out of focus.

The conclusion being that while there was a higher-resolution video, the object must also have been out of focus there. Certainly not "crystal clear."

How is it out of focus? Well, the focus controls are on screen, and focus is set to 8:
2021-06-22_17-55-29.jpg

The A1-F18AC-746-100 Technical Manual says:
Focus is adjusted from 0 (least sensitivity) to 8 (highest sensitivity) for close targets with an adjustment of 9 for far targets. Initially focus is set to 8.
Content from External Source
Since it seems pretty clear this is a far target; perhaps the focus should have been set to 9?
 
Last edited:
Well yeah I don't know how you could argue higher resolution would make the object "crystal clear' when there is an additional 3 pixels of blurred edge on it compared to everything else.

Even if you didn't take the rest of the image into context and just argued that various compressions had blurred it somehow that wouldn't explain why the 2xzoom has about twice as much blur as the 1x, which lines up more with the theory it is already blurred due to focus and the digital zoom is just stretching that edge blur.
 

Attachments

  • zoom.png
    zoom.png
    6.4 KB · Views: 231
Maybe down res Gimbal so the text looks the same and see what it does to the object.
Gave this a try by scaling gimbal to half horizontal and equal vertical res of flir then back to normal horizontal res. Bit rough maybe and gimbal not best match as it's infrared and has sharpening applied but here are the results.

Top examples are flir, bottom is degraded gimbal (both in 2x zoom for object)
 

Attachments

  • blurcomparison.png
    blurcomparison.png
    724.2 KB · Views: 236
Since it seems pretty clear this is a far target
Is this clear? As far as I know the '99.9 RNG' indicates that is has encountered an error while ranging rather than it being far away or out of range.
For example I can get the 99.9RNG displayed at 35nmi in DCS:
1624451328398.png1624451353396.png

Edit, found this:
1624452230972.png
 
Last edited:
Is this clear? As far as I know the '99.9 RNG' indicates that is has encountered an error while ranging rather than it being far away or out of range.
For example I can get the 99.9RNG displayed at 35nmi in DCS:
From the small size of the object on screen. Distant plane seems likely.

Also being out of focus.
 
Is this clear? As far as I know the '99.9 RNG' indicates that is has encountered an error while ranging rather than it being far away or out of range.
For example I can get the 99.9RNG displayed at 35nmi in DCS:
1624451328398.png1624451353396.png
I'd be interested in the steps taken to get the 99.9 displayed.
 
I'd be interested in the steps taken to get the 99.9 displayed.

I didn't do anything, the other plane was actively jamming so the RADAR could only get and AOT. This is the only time the 99.9 RNG is mentioned in the manual which back up when Fravor said on Rogan that it was actively jamming in the footage, however Lemoine says that it means that it's really far away so I don't know if Fravor was right to make that conclusion.
 
I seem to recall there being talk of jamming in relation to one or the other of these videos (they are all kind of blurring into one).
 
assuming its the same tic tac fravor saw, slaight mentioned it had some sort of "heat waves" coming of its surface.

maybe this could add to the fuzzyness?
 
assuming its the same tic tac fravor saw, slaight mentioned it had some sort of "heat waves" coming of its surface.

maybe this could add to the fuzzyness?
Don't think so, heat difference can refract light but it is a minor effect that needs to be exaggerated by distance, so it could warp whatever is behind the object but would barely affect the object itself.

Not really sure what is even meant by heat waves though except... it being hot. Earlier in vid there is infrared footage of it, nothing bizarre except also being blurry.
 
The same focus setting is seen in the IR footage, yet the UFO is not visibly more out of focus like you see in the TV footage, more evidence for the TV UFO being out of focus before digital conversion / compression.

1624496480267.png

Does anyone know anything about focus in infrared? Is it more forgiving than visible light focus?
 
Don't think so, heat difference can refract light but it is a minor effect that needs to be exaggerated by distance, so it could warp whatever is behind the object but would barely affect the object itself.

Not really sure what is even meant by heat waves though except... it being hot. Earlier in vid there is infrared footage of it, nothing bizarre except also being blurry.
well IR shows heat so...
 
well IR shows heat so...
Yes, engines are hot, and the background sky is cold. But describing something with "some sort of heat waves coming off its surface" implies to me something more exciting than it has engines. (I've not heard anyone make this claim though so not sure what they mean)

yet the UFO is not visibly more out of focus like you see in the TV footage
Looks like it has sharpening applied? (darker aura around it). Still looks plenty blurry to me (maybe moreso), but you'd get some glare from the infrared that you wouldn't from TV footage.
 
Back
Top