The technology works by sending out a low-power infrared laser beam, which sweeps over an object or scene. Some light gets reflected back, though most is scattered in different directions. A detector measures how long it takes one particle of light, a photon, to return to the camera and is then able to calculate the distance from the system to the object. The technique can resolve millimeter-size bumps and changes in depth from hundreds of meters away.
The new camera takes advantage of superconducting nanowires, materials with almost no electrical resistance that have to be cooled to extremely low temperatures. These superconductors are very sensitive and can tell when just a single photon has hit them.
Although other approaches can have exceptional depth resolution, the ability of the new system to image objects like items of clothing that do not easily reflect laser pulses makes it useful in a wider variety of field situations.