LiDAR, you might have heard the term, but you likely don’t know exactly how this important imaging and sensing technology works. That’s why this article entitled lidar for beginners and those who want to learn more is a great starting point.
From an article in Interesting Engineering by Trevor English.
Short for Light Detection And Ranging, this technology utilizes pulsed lasers to accurately and constantly measure distances to a given target or area. LiDAR sensors are essentially light-based measurement and mapping tools that are incredibly useful in a variety of sectors.
But, while that brief introduction may be enough Lidar for beginners, it’s likely too short to really understand exactly what LiDAR is and how it can be used. Let’s take a closer look at everything you need to know about LiDAR technology.
What is LiDAR?
Like I mentioned before, LiDAR is based around a pulsed laser beam. It’s an active and remote sensing technology that is generally used to map out environments and large areas. The way this pulsed laser technology works is essentially on the principle of time of flight.
Engineers know the speed of light, which means that by pulsing a laser and measuring how long it takes the light to get back to where it was shot from, you can determine how far away something is.
For example, the speed of light is 299 792 458 m/s. If we shot out a laser beam and saw that it came back to us in 1 second (or any period of time), then the equation is really simple. All we have to do is multiply the time (1 s) by the speed, 299 792 458 m/s. The seconds cancel out (s from time, 1/s from speed = 0) and we’re left with a distance in meters (299 792 458 m)!
The underlying mathematics to LiDAR may be incredibly simple, but taking this principle from concept into reality is harder than it may seem.
The other aspect to LiDAR is that it not only can tell distance, but it can also determine an object’s optical characteristics, like reflectivity and absorption. This ultimately provides material data about an object in addition to how far away it is – perfect for mapping.
This data is collected then not through time, but rather the characteristics of the reflected beam upon its return.
LiDAR is fairly similar in sensing capabilities to radar and sonar technologies, it’s just far more precise. Radar struggles with plotting exact locations of objects and rather can just tell you a general area and movement. Sonar operates in much the same way.
This sort of precision is okay for the applications in which radar and sonar are used, but in many applications, like mapping environments and autonomous driving, one of LiDARs most promising sectors, a greater level of precision is needed.
LiDAR can map out visually what an object looks like. We can compare this to radar, something many of us might be familiar with from war movies. Rather than a blip on the screen, with LiDAR, we’d see the actual object, say a small boat or submarine, along with details of the object. The data LiDAR provides is known as a point cloud map of the object, and it is developed through thousands of individual laser measurements that are pulsed out of the sensor.
The beginnings of LiDAR and laser ranging date back to the 1960s and 70s, when the terrain was first starting to be digitally mapped and categorized. These first applications for early LiDAR were also able to develop highly accurate elevation and topographical data for different regions.
Early LiDAR devices were big and clunky, but today, LiDAR is getting smaller and more mobile. You might recognize LiDAR sensors as those spinning cylinders on top of self-driving cars. While those are still seemingly “large” the LiDAR sensors of the past were comparatively massive.
All this shrinkage comes at the hand of the miniaturization of electronics components and the improvement of laser diode technology. Artificial intelligence has also helped LiDAR technology as it is used to process the massive amounts of data the sensors collect, inferring a larger amount of detail, and extrapolating out more useful data.
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