from Hacker News

Locating Stealth Fighters with Cheap Cameras Without Using AI or Radar [video]

by jryb on 4/10/25, 12:40 PM with 56 comments

  • by iamleppert on 4/10/25, 4:13 PM

    He doesn't mention how he calibrates the camera extrinsics or intrinsics. This isn't new, it's basic structure from motion. He is going to be amazed when he "discovers" photogrammetry and bundle adjustment next.

    I checked out the code and there is no consideration for camera parameters it seems. It's a neat demo but impractical given the need for precise camera calibration over distance. Long baseline stereo has problems unless you can figure out how to keep the cameras aligned within fractions of a mm over great distances.

  • by freefaler on 4/10/25, 3:17 PM

    At night in Ukraine they use microphone arrays to track the drones:

    https://www.twz.com/land/thousands-of-networked-microphones-...

  • by djoldman on 4/10/25, 1:58 PM

    * Locating moving objects that could be anything that can move at a speed, with Cheap Cameras Without Using AI or Radar

  • by eloisius on 4/10/25, 3:42 PM

    He didn’t go into detail on how the cameras are calibrated by I wonder if he’s using stars to do that or what. Standard SfM would struggle with such featureless images and wide baseline.

  • by mikewarot on 4/11/25, 2:10 PM

    Is anyone else here interested in actually trying this? I live near a fairly active small airport in Lansing, Illinois, and in the flight paths of everything going to/from Midway and Ohare, so combining this with ADSB might make for some interesting sources of calibration data, and a way to debug this algorithm.

    I think a neighborhood of Raspberry Pi based cameras networked together could prove quite effective. I wonder if all the installed Ring door cameras could do this in a national security emergency.

    I further wonder if it's being done to the US (with the current installed camera base) by China or others.

  • by sigmoid10 on 4/10/25, 2:19 PM

    * as long as it's a bright sunny day

    Good look doing that at night or when it's cloudy.

  • by pj_mukh on 4/10/25, 3:24 PM

    Super cool! Though cloud cover disabling your detection technique may make this infeasible for anything but low-altitude drones.

    One small nit: Calling Ray-tracing "Not AI" is like calling Matrix Math "Not AI". It's definitely a core component of a lot Machine Perception (i.e. AI) tasks.

    I'm guessing OP meant "Without using any costly CNN or Transformer inferencing", which is actually a clever achievement.

  • by maxglute on 4/11/25, 7:06 AM

    If you spam a dense enough network of connected sensors you can detect anything.

  • by netsharc on 4/10/25, 3:13 PM

    > This technique can also be used to detect drones from many kilometers away

    Sudden spike of git pulls from Ukraine for the repo...