New LiDAR can 'see' faces from hundreds of meters away

At a distance of 325 meters, the human eye may only be able to distinguish between a person's head and body, making it difficult to discern any other differences. But a research team including Heriot Watt University in the UK and Massachusetts Institute of Technology in the US has developed a new type of LiDAR scanner that can perform detailed analysis of a person's face from such a distance and create a 3D model of the face. This LiDAR can even capture ridges and indentations as small as 1 millimeter.

The relevant paper was published in the latest issue of the journal Optics. The team has designed a single photon time-of-flight lidar system. The system emits laser pulses, which reflect back to the device after colliding with objects. Lidar can determine the shape of an object by measuring the time required for each pulse to travel back and forth. The system is capable of obtaining high-resolution 3D images of objects or scenes up to a distance of 1 kilometer. Even in harsh environments or when objects are obscured by leaves or camouflage nets, it can achieve precise imaging, greatly improving security monitoring and remote sensing capabilities.

In order to achieve improved resolution, the team carefully calibrated and adjusted different components, such as the tiny parts inside the device used to guide laser pulses. In order to enable the device to distinguish individual photons, the team used a light detection sensor based on extremely fine superconducting wires, which is not commonly used in LiDAR. In addition, it is necessary to filter out sunlight that may enter the detector and reduce image quality. Tests have shown that the system captured a 3D image of a team member's face under 45 meter and 325 meter daylight conditions, distinguishing features as small as 1 millimeter and increasing depth resolution by approximately 10 times compared to their previous records. On a smaller scale, they captured images of Lego figurines from 32 meters away.

In another test, they filmed a communication tower 1 kilometer away. The excellent depth resolution of this system means that it is particularly suitable for imaging objects in cluttered backgrounds, which is a challenge for digital cameras. The team said that creating a detailed 3D map of the surrounding environment is also crucial for autonomous vehicle and even some robots.

Source: laserfair