Chinese researchers have developed a new Lidar (Light detection and ranging) based camera that can snap photographs of subjects from 45 kilometers away. This is not the first instance of attempts at long-distance photography, but environmental disturbances like pollution hinder capturing subjects beyond a distance.
Zheng-Ping Li and his colleagues from the University of Science and Technology of China have successfully captured subjects from 45 kilometers (28 miles) away in an environment covered with a dense smog.
How Does The Lidar Camera Work?
The Lidar-based system combines single-photon detectors with a breakthroughcomputational imaging algorithmto create super-high-resolution images by joining the sparsest of data points.
The camera was set up on the 20th floor of a building situated in Chongming Island in Shanghai, and the subjects were captured 45 kilometers away at Pudong Civil Aviation Building across the river.
The Lidar system deployed in the camera illuminates the subject withlaser lightand then creates an image from the reflected light.
The reflected light is receivedwithin a time framethat depends upon the distance. This ensures that photons that are received beyond a specific time duration can be discarded, thus producingnoise-free photographs.
To overcome pollution and environmental distortions, the researchers used aninfrared laserwith a wavelength of 1550 nanometers, a repetition rate of 100 kilohertz and power of 120 milliwatts. Using such an infrared laser makes the systemsafe for the eyesand also makes it easy tofilter out solar photonsthat would be destructive for the detector.
According to Zheng-Ping and his colleagues,“Our results open a new venue for high-resolution, fast, low-power 3D optical imaging over ultralong ranges.”
Applications
Applications of this long-distance imaging technique includetarget recognitionand identification from a distance,airborne surveillanceandremote sensing.
Moreover, the entire setup ishighly portableand is similar to a shoe box in size. Therefore, you may carry it anywhere and use it for capturing photographs from up to 45 kilometers away.
However, China is infamous for its surveillance activities. Therefore, this breakthrough in technology could also be used for hi-tech surveillance purposes.
