How does LiDAR work?
In the dark of night, a self-driving car can still clearly see a person walking ahead. The secret is a technology called LiDAR.
Measuring distance with light
LiDAR means measuring distance with light. It's like a bat listening for echoes, but it uses laser pulses instead of sound.
STEP 1/3
Send a laser flash
Step one: the device sends out a very short laser flash that your eyes can't see. The flash flies out, hits an object and bounces back.
STEP 2/3
Time the trip there and back
Step two: the device times how long it takes, from sending to receiving. Light is so fast that going 15 meters and back takes only one ten-millionth of a second.
STEP 3/3
Work out the distance
Step three: work out the distance. Multiply the time by the speed of light, then divide by two, because the light went there and came back.
Millions of dots
The device does this hundreds of thousands of times per second, in every direction. Each measurement is one dot. Together they make a 3D map called a point cloud.
AI AT WORK
AI reads the point cloud
Then AI reads those dots to tell what is a person, what is a car, and how far away they are. That's how the car knows when to brake.
AROUND YOU
LiDAR is all around you
LiDAR is also in robot vacuums, mapping drones and the Pro iPhones.
This article is based on the video How does LiDAR work? from the Mark học AI channel. Watch the video (in Vietnamese) to see the animations.