Ensuring the safe movement of self-guided vehicles is extremely important for their launching into operation. Especially in light of the recent deaths involving an unmanned auto Uber. The greatest danger any vehicle presents in conditions of insufficient illumination and visibility, in particular in a fog. And recently, researchers from the Massachusetts Institute of Technology developed a method that makes it possible for lidars (the basic elements for orientation in space) to "see" with a strong fog.
At its core, any lidar is an instrument that emits a laser beam and, based on its reflection, receives data about the surrounding objects. With a huge number of advantages, the lidar has a significant drawback: clean air does not interfere with its operation, but nothing can be seen through a dense fog device. A group of scientists led by Ramesh Raskar came up with a method that allows lidars to receive a signal reflected from objects even in a very dense fog.
Distribution of photons as a function of fog density
This is as follows: the laser emits pulses into the fog area, and next to the receiving device is a special camera consisting of single-photon detectors. They fix the time of the return of each photon. Each fixed "frame" contains information about the time of photon acquisition. Then the computer program builds a diagram in which each column describes the number of registered photons and builds on this basis the data on the location of the objects.
Reception of signals from fog and from objects located in it
In a series of experiments, scientists tested their method in conditions of artificially created fog. It turned out that at a time when the line of sight is 37 centimeters, a modified lidar catches objects at a distance of 57 centimeters. At the moment, the experiments continue, and the authors will continue to improve the technology. In particular, the main problem now is that the lidar can only record static objects.
The article is based on materials .
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