3D scanning is a tricky business. Whether you're using a USD$50,000 unit or a USD$100 Microsoft Kinect, none will meet all possible scanning requirements. You might require super-fine detail of a small object, or perhaps you're scanning a building, or simply just grabbing a scan of your girlfriend's face for a quick 3D print.
But what happens if you need to 3D scan an object that's over a kilometer away? None of the usual 3D scanning options can do this.
Until now. A team of researchers in the UK and The Netherlands has demonstrated a method of long-range 3D scanning using "a free-running, low noise superconducting nanowire single-photon detector."
The specifications for this experiment are a bit scary:
- One centimeter resolution at a distance of one kilometer
- "Relatively" eye-safe laser scan wavelengths of 1560nm
- Millisecond-level exposure times per pixel
This sounds to us like an incredible tool for spies, armies, explorers, hobbyists or Bigfoot hunters. Where ever you need a rough 3D scan but cannot get close to the subject, this is the technology you need.
The image above shows experimental results of a scan, showing original optical image and corresponding pixel depth image, where the darker pixels are slightly farther away from the scanner. The amazing part? These dudes are 910 meters distant!
One issue we see with this approach is that the 3D image for only a single view of the subject. To truly capture a full 3D image, the subjects would have to cooperatively rotate smoothly in 360 degrees in front of the scanner. This is perhaps unlikely in the usage scenarios we envision. Another approach would be to somehow take the scanner around the subject in a full or partial 360 circle at a fixed radius. That's even more unlikely to happen.
Via Optics Infobase