Views: 87 Author: Site Editor Publish Time: 2020-04-01 Origin: Site
Enabling autonomous cars with reliable vision has always been a difficult problem in technological development. Today, developers can create a monitoring system by combining various sensors. The key to the system is diversity and redundancy of the sensors. Overlapping sensors can verify the accuracy of objects detected by the vehicle.
Three of the most important sensors for autonomous vehicles are cameras, radars and lidars, which work together to provide the vehicle with a complete view of the surroundings and help it detect the speed, distance, and the three-dimensional shape of nearby objects.
From photos to videos, cameras are the most accurate way to visualize the world, and it's especially important for autonomous cars.
Autonomous cars rely on cameras placed on each side of the vehicle to stitch together to form a view of the environment. Some cameras have a wider field of view, which is up to 120 degrees. Other cameras focus on a narrower angle of view to provide a wider field of view.
Some cars even have installed the fish-eye lens, which can provide a panoramic view of the car with the help of an ultra-wide lens, so that the driver can get a panoramic view to better understand the environment behind the vehicle.
Although it can provide an accurate view, the camera has its limitations. Although they can identify the details of the surroundings, they cannot calculate the distance between the object and the vehicle. Therefore, they cannot accurately know their locations. In addition, camera-based sensors have difficulty detecting objects in conditions of low visibility, such as in fog, rain and so on.
Radars can complement the camera's function in conditions of low visibility, such as driving at night, and radars can help autonomous vehicles improve the capabilities of detection.
Radar works by radio waves in pulses and it is traditionally used to detect ships, aircraft, and so on. Once these waves hit the object, they will return to the sensor and provide data about the object's speed and position.
Like cameras on vehicles, radars are usually placed around the car to detect objects at various angles. They can determine the speed and distance of objects, but they cannot distinguish between different types of vehicles.
Although the data provided by radars and cameras is sufficient for autonomous driving at lower-level, they still cannot handle all the driving problems.
Cameras and radars are common sensors, which are mostly used for advanced assistance in driving and parking. With the monitoring systems, they can also achieve lower levels of autonomous driving.
However, if you want to achieve the autonomous driving completely, the lidar is indispensable.
Lidar is used to measure the distance. With a pulsed laser, it enables a car to have a 3D view of surroundings. It can provide the shape and depth of cars and pedestrians, as well as the geographic environment of the road.
What is more, there are other sensors that are widely used in the autonomous vehicles, such as the tire pressure monitor system, which can be used to monitor the tire pressure to keep the safety of driving.
