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 breakthrough computational imaging algorithm to 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 with laser light and then creates an image from the reflected light.
The reflected light is received within a time frame that depends upon the distance. This ensures that photons that are received beyond a specific time duration can be discarded, thus producing noise-free photographs.
To overcome pollution and environmental distortions, the researchers used an infrared laser with a wavelength of 1550 nanometers, a repetition rate of 100 kilohertz and power of 120 milliwatts. Using such an infrared laser makes the system safe for the eyes and also makes it easy to filter out solar photons that 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 of this long-distance imaging technique include target recognition and identification from a distance, airborne surveillance and remote sensing.
Moreover, the entire setup is highly portable and is similar to a shoe box in size. Therefore, you can 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.
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