5 ms·

This seems pretty useless in an age with super cheap 8k cameras and novice ability to do a delta-recorded image.

by aeternum 1y ago

Havoc 1y ago
What do you mean by delta-recorded image?
- bob1029 1y ago
  The fixed resolution of an image sensor can be augmented by capturing multiple frames over time. https://www.ipol.im/pub/art/2023/460/ https://www.ipol.im/pub/art/2023/460/
  - zamadatix 1y ago
    Super resolution is a thing but I think they mean to just take the differences and track based on the motions in that data directly. Any deltas which appear to move in a certain way are likely to be aircraft, especially if the same deltas show up on a 2nd camera, even if they aren't clear enough to directly identify. Basically the motion vector estimation step of video encode but tuned really tight and ignoring motions that don't look like aircraft motions. I'm not sure this is really all that perfect/foolproof though, especially with 8k visible light cameras. For one, clouds can be quite the problem (even at non-visible wavelengths). Atmospheric turbulence can also be annoying and the air can be plain hazy depending on the day - both limit detection accuracy at a given range. When night comes the detection ability is greatly hampered even with additional wavelengths (and IR has lower resolution anyways). It worked well enough in a weekend project many years back to use computer vision (the craze at the time) and compare to an ADS-B make by using a 4k 1 FPS image feed in a weekend project to mess with computer vision a decade back. I definitely see it as a valid addition to a detection system... but I would stop short of writing a "Military Dumbfounded at This One Simple Trick" article about it.
- redtexture 1y ago
  Delta encoding. https://en.wikipedia.org/wiki/Delta_encoding https://en.wikipedia.org/wiki/Delta_encoding
denkmoon 1y ago
If it were all that simple would you not expect at least one of China, Taiwan, Iran, Israel, Ukraine, Russia to deploy such a technology? To me this recently popular idea that you can just point a load of cameras at the sky to beat stealth is disproved by the lack of such installations. These are fairly motivated actors.
- cyberax 1y ago
  > To me this recently popular idea that you can just point a load of cameras at the sky to beat stealth is disproved by the lack of such installations. Russia has a 10x advantage over Ukraine in aviation, yet it only uses it to lob guided bombs from safely beyond the Russian border. The anti-air defense far outmatches the stealth of Russian airplanes. They are not the stealthiest, sure. But there are reasons to think that NATO planes are not going to fare much better.
the__alchemist 1y ago
Could you clarify this?
nine_k 1y ago
Numbers don't add up. If you take a 8K camera with a standard 50 mm lens, its angular resolution is about 20" / pixel. A 50 mm lens has a FOV of about 40°. It covers a cone of about 0.38 strad. A full hemisphere has 2·pi = 6.28 strad, so we need at least 16.5 such cones to cover the whole area; actually we need likely 20-25 because of imperfect geometry and some safety margins at intersections. We can, of course, mount fewer and scan. If we take a plane like A320 (larger than a typical fighter jet), and remove it 25 km from us, its angular size would be about about 5', or 300". Our A320 would be 15 pixels wide, assuming very good optics, and very clear skies. This is not much to determine what craft is approaching us. At the cruise speed of 800 km/h, or 220 m/s, the plane will reach us in 122 s, or less than 2 minutes. Not a lot of warning. A fighter jet making 500 m/s would be there in 50 s. This is, of course, without any clouds. Even very light clouds or haze would conceal the aircraft at 25 km. To say nothing of the night time. We could of course take in IR camera, but I don't remember 8K IR cameras being cheap, or even available. A stealth aircraft like B-2 does a lot to make its thermal signature very faint, including the exhaust.
- aeternum 1y ago
  Most camera sensors already detect in the IR range, you just need to remove the filter. I've done it, works great and pretty fun to convert some old webcams, robot vacuums lidar scanners look especially cool. Blurry video is fine when using techniques like this: https://www.youtube.com/watch?v=m-b51C82-UE https://www.youtube.com/watch?v=m-b51C82-UE Clouds also don't save you (unless you have two thick layers to fly through) because this technique is even easier with satellites. Stealth effectively no longer exists for most nation-state level tech. The B-2 is a very cool plane but is unfortunately obsolete. Still great for when you want to put on more of a show than an attack.
  - nine_k 1y ago
    Does a consumer-grade 8K camera sensor detect a 20°C difference in a few pixels? Cameras have to aggressively fight against thermal noise. Visible light is much more energetic than IR; detecting a faint IR signal with a sensor which is about as hot as the object it's looking at is hard. You need to cool the sensor down; old military aircraft even carried a tank of liquid nitrogen for that. I mean, yes, you can take a low-noise sensor, add cooling, add a telescope lens so that you'd see the shape more readily, put a bunch of these telescopes on a rotating platform to scan the sky, etc. This is doable, but the thread started with an idea that it's doable with consumer-grade ("cheap") tech. I doubt that. While at it, even if we assume that stealth does not exist for fast and heavy aircraft, it seems to effectively exist for slow, lighter-weight drones. Ukrainian drones, built from ultralight aircraft like Aeroprakt A-20, somehow penetrate 700 miles into Russian territory to burn refineries. With a cruise speed of 70 mph (sic), it should take them 10 hours to fly this distance. Were they detected efficiently, that would be enough time to scramble an interceptor a hundred times. Apparently this does not happen.
deleted 1y ago
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deleted 1y ago
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This seems pretty useless in an age with super cheap 8k cameras and novice ability to do a delta-recorded image.

Havoc 1y ago

What do you mean by delta-recorded image?

bob1029 1y ago
The fixed resolution of an image sensor can be augmented by capturing multiple frames over time. https://www.ipol.im/pub/art/2023/460/ https://www.ipol.im/pub/art/2023/460/
- zamadatix 1y ago
  Super resolution is a thing but I think they mean to just take the differences and track based on the motions in that data directly. Any deltas which appear to move in a certain way are likely to be aircraft, especially if the same deltas show up on a 2nd camera, even if they aren't clear enough to directly identify. Basically the motion vector estimation step of video encode but tuned really tight and ignoring motions that don't look like aircraft motions. I'm not sure this is really all that perfect/foolproof though, especially with 8k visible light cameras. For one, clouds can be quite the problem (even at non-visible wavelengths). Atmospheric turbulence can also be annoying and the air can be plain hazy depending on the day - both limit detection accuracy at a given range. When night comes the detection ability is greatly hampered even with additional wavelengths (and IR has lower resolution anyways). It worked well enough in a weekend project many years back to use computer vision (the craze at the time) and compare to an ADS-B make by using a 4k 1 FPS image feed in a weekend project to mess with computer vision a decade back. I definitely see it as a valid addition to a detection system... but I would stop short of writing a "Military Dumbfounded at This One Simple Trick" article about it.
redtexture 1y ago
Delta encoding. https://en.wikipedia.org/wiki/Delta_encoding https://en.wikipedia.org/wiki/Delta_encoding

denkmoon 1y ago

If it were all that simple would you not expect at least one of China, Taiwan, Iran, Israel, Ukraine, Russia to deploy such a technology? To me this recently popular idea that you can just point a load of cameras at the sky to beat stealth is disproved by the lack of such installations. These are fairly motivated actors.

cyberax 1y ago
> To me this recently popular idea that you can just point a load of cameras at the sky to beat stealth is disproved by the lack of such installations. Russia has a 10x advantage over Ukraine in aviation, yet it only uses it to lob guided bombs from safely beyond the Russian border. The anti-air defense far outmatches the stealth of Russian airplanes. They are not the stealthiest, sure. But there are reasons to think that NATO planes are not going to fare much better.

the__alchemist 1y ago

Could you clarify this?

nine_k 1y ago

Numbers don't add up. If you take a 8K camera with a standard 50 mm lens, its angular resolution is about 20" / pixel. A 50 mm lens has a FOV of about 40°. It covers a cone of about 0.38 strad. A full hemisphere has 2·pi = 6.28 strad, so we need at least 16.5 such cones to cover the whole area; actually we need likely 20-25 because of imperfect geometry and some safety margins at intersections. We can, of course, mount fewer and scan. If we take a plane like A320 (larger than a typical fighter jet), and remove it 25 km from us, its angular size would be about about 5', or 300". Our A320 would be 15 pixels wide, assuming very good optics, and very clear skies. This is not much to determine what craft is approaching us. At the cruise speed of 800 km/h, or 220 m/s, the plane will reach us in 122 s, or less than 2 minutes. Not a lot of warning. A fighter jet making 500 m/s would be there in 50 s. This is, of course, without any clouds. Even very light clouds or haze would conceal the aircraft at 25 km. To say nothing of the night time. We could of course take in IR camera, but I don't remember 8K IR cameras being cheap, or even available. A stealth aircraft like B-2 does a lot to make its thermal signature very faint, including the exhaust.

aeternum 1y ago
Most camera sensors already detect in the IR range, you just need to remove the filter. I've done it, works great and pretty fun to convert some old webcams, robot vacuums lidar scanners look especially cool. Blurry video is fine when using techniques like this: https://www.youtube.com/watch?v=m-b51C82-UE https://www.youtube.com/watch?v=m-b51C82-UE Clouds also don't save you (unless you have two thick layers to fly through) because this technique is even easier with satellites. Stealth effectively no longer exists for most nation-state level tech. The B-2 is a very cool plane but is unfortunately obsolete. Still great for when you want to put on more of a show than an attack.
- nine_k 1y ago
  Does a consumer-grade 8K camera sensor detect a 20°C difference in a few pixels? Cameras have to aggressively fight against thermal noise. Visible light is much more energetic than IR; detecting a faint IR signal with a sensor which is about as hot as the object it's looking at is hard. You need to cool the sensor down; old military aircraft even carried a tank of liquid nitrogen for that. I mean, yes, you can take a low-noise sensor, add cooling, add a telescope lens so that you'd see the shape more readily, put a bunch of these telescopes on a rotating platform to scan the sky, etc. This is doable, but the thread started with an idea that it's doable with consumer-grade ("cheap") tech. I doubt that. While at it, even if we assume that stealth does not exist for fast and heavy aircraft, it seems to effectively exist for slow, lighter-weight drones. Ukrainian drones, built from ultralight aircraft like Aeroprakt A-20, somehow penetrate 700 miles into Russian territory to burn refineries. With a cruise speed of 70 mph (sic), it should take them 10 hours to fly this distance. Were they detected efficiently, that would be enough time to scramble an interceptor a hundred times. Apparently this does not happen.

deleted 1y ago

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deleted 1y ago

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