When it comes to LIDAR, we often see descriptions such as “64 lines”, “128 lines”, “300 lines equivalent”, etc. What is the “number of lines”? Is the more lines the better for LiDAR?
Today, let’s talk about this topic.
For 360° rotating and one-dimensional rotating mirror architectures, there are several sets of laser transceiver modules and several lines in the vertical direction, which are called the number of lines.
In this case, the number of lines is equivalent to the number of lasers inside the lidar.
In layman’s terms, the higher the line count, the more lasers there are, and the more powerful the LIDAR’s overall performance. Let’s visually compare the point cloud effect of different line count LIDARs, it is easy to understand.
16 lines / 128 lines / 64 lines simulation point cloud effect schematic
Obviously, when the number of LIDAR lines is higher, the more detail the object can be captured, i.e., the higher the resolution. As shown in the figure above, the point cloud map created by the 128-line LiDAR is significantly sharper and has a much higher resolution than the lower line count LiDAR.
Although the higher the number of lines, the better the results. However, if 128 laser transceiver modules are stacked vertically inside a lidar, it will lead to a very large lidar size and extremely high cost, making it impossible to achieve mass production.
Can you imagine driving a car with a “big flower pot” lidar on the road?
Of course, this is not going to happen.
The current cutting-edge chip-based technology in the LIDAR industry has made it possible to integrate 128 laser transceiver modules into a few centimeter-sized chips. In this way, a “true 128-line” LIDAR can be made very small and easily integrated into the body.
So what are the benefits of a 128-line LiDAR?
The more lines you have, the better you can see.
A 128-line LiDAR scan pattern looks neat and clear, and remains uniformly high resolution across the board. Whether it’s cars, pedestrians, tires, cone buckets, or other easily missed details, LIDAR captures them all accurately and completely, ensuring that the driving system makes the most accurate decisions to avoid danger.
The higher the number of lines, the safer it is.
Not only that, but the higher the number of lasers, the higher the safety redundancy that can be provided. Because 128 lasers work independently, even a very small probability of failure of one of them will have little impact on the overall sensing capability of the LIDAR.
To summarize: in 360° rotating and 1D rotating mirror architectures, the number of LIDAR lines is equal to the number of lasers, and indeed the more the merrier.
In addition, in 2D scanning architectures, you will also see the concept of “equivalent xx lines”. The “equivalent” number of lines, in fact, is to use a small number of lasers, through high-speed two-dimensional scanning to achieve a similar high number of lines of scanning effect, in fact, there are not so many internal “lines”. The industry has not yet formed a strict definition of the “equivalent” line count, so we will not discuss it.
With the continuous iterative development of LIDAR chip technology, the future high line count and high performance LIDAR will become more and more compact, and the cost will continue to decrease, becoming the “standard” for more smart cars.
