How far, you ask? Just about 45 km away.
First, a phone that has a camera that can zoom up to 50x — enough for you to see the spots on the moon. Now, this. Looks like China does not want to put on the brakes when it comes to developing their cameras.
This super camera takes advantage of single photodetectors combined with 3D computational imaging. The technique is based on laser ranging and detection, a technology that illuminates its subjects using laser light and then proceeds to create an image using reflected light.
The big advantage of this kind of active imaging is that the photons reflected from the subject return to the detector within a specific time window that depends on the distance. So any photons that arrive outside this window can be ignored.
This “gating” dramatically reduces the noise created by unwanted photons from elsewhere in the environment. And it allows lidar systems to be highly sensitive and distance specific.
To make the new system even better in urban environments, Zheng-Ping and co use an infrared laser with a wavelength of 1550 nanometers, a repetition rate of 100 kilohertz, and a modest power of 120 milliwatts. This wavelength makes the system eye-safe and allows the team to filter out solar photons that would otherwise overwhelm the detector.
(Image Credit: Technology Review)