代写assignment-激光传感器的简介和讨论。激光传感器主要用于发射电磁波的光脉冲。近红外光谱波长为800-950nm，紫外光谱波长为1500 nm (Yenkanchi, 2016)。当汽车运动时，物体之间的距离由飞行时间信息来计算，飞行时间信息负责计算接收脉冲与发射脉冲之间的差值。这些类型的传感器能够检测多个对象。然而，这些传感器也有一些缺点，比如它们对悬挂的天气很敏感，而且对灰尘也很敏感。如果镜头被灰尘覆盖，它们就不能很好地反射目标。然而，一些重要的功能，如消除事故，减少碰撞和自动停车是很少的例子。
The most significant laser based sensors are the Laser Scanner and Light Detection and Ranging (LIDAR). The Laser sensors are those that work on the technology that mainly emits the light impulse of the electromagnetic waves. The wavelength of the electromagnetic spectrum near infra red is 800-950nm and in the ultra violet, the wavelength is 1500 nm (Yenkanchi, 2016). When the car is moving, the distance between the object is calculated by the time-of-flight information, which is responsible for taking the difference between the received pulses and emission. These types of sensors have the ability to detect multiple objects. However, there are some drawbacks of these sensors, such as they are sensitive towards the hanging weather and are also dirt sensitive. They poorly reflect the target if the lenses are covered by the dirt. However, some important functions like eliminating accidents, collision mitigation and automatic parking are few examples.
For the appropriate road safety and guidance, it is very significant that acquisition of all the objects on and around the road should be clear for this purpose good lighting conditions are very important (Petit et al., 2015). The weather should be clear and day lighting is required.
The sensors for the driverless cars can be classified in two different types, Active sensors and Passive sensors. This classification is done on the basis of their capability and physical phenomenon they are able to measure by actively probing the environment or by passively perceiving the environment (Yenkanchi, 2016). Active sensors are mainly those which send the radiations for detecting an object around the vehicle and it also eliminates the noise of emissions. However, the passive sensors are those perceiving the information that is based on the illumination of the environment. Passive sensors are considered to be less expensive in the way of their mechanism. Some of the examples of the active sensors are radar based sensors, laser based sensors and ultrasonic based sensors. One significant example of the passive sensor is camera. Since the autonomous automated cars are the next evolution of the transportation and will increase the safety, driving experience and traffic efficiency (Petit et al., 2015). A completely automated vehicle will significantly rely on the sensor reading for the long term (planning) and short term (related to safety) driving decisions.
Under the poor lighting conditions, Laser sensors are unable to provide the precise information about the geometry information of the objects on the road. Although, some forecasts state that driverless cars are going to dominate the roads by 2040, still the completely autonomous cars seem to be the distant reality due to many technological factors. The Laser Imaging Detection and Ranging (LIDAR) are required to process more than 1 million points per second in 3D form for detecting objects and pedestrians on the road. The pedestrian detection system can be achieved through the infusion of the various sensors and by combining the data of the various sensors that include time-of-flight cameras, laser sensors, stereoscopic machine vision and normal cameras that can be significantly useful for solving the problem of object and pedestrian detection (Navarro et al., 2016).