![]() ![]() This bouncing would cause the light to take a longer path than it would in a vacuum, where it has no atoms to bounce off. The other wrong explanation is that light goes through the glass, hitting atoms and bouncing off, before eventually making its way through the material. It's basically many lasers on a single chip, and it's what makes it possible to put lidar in a smartphone. These multiple beams of light are due to an array of vertical cavity surface-emitting lasers, or VCSELs. All I know is that instead of one beam of light to measure distance, the iPhone uses a grid of dots emitted from the phone in the near infrared wavelengths (like the light from your infrared TV remote). So how does lidar work on an iPhone? I want to just say "It's magic"-because it seems that way to me. After you have collected thousands of them, these points will merge to form an image shaped like the surface of the object you are scanning.īut using a laser plus a spinning mirror isn't just expensive, it's also too bulky to fit in your phone. Keep doing this and you can get a whole bunch of points. Next, you just need to repeat this with the laser pointing in a slightly different direction, usually by using a spinning mirror. If you know where the laser is pointing, you can get a distance and bearing to give you one point on the surface of an object. In order to get that, you need more data. It isn’t enough to make one of these awesome 3D lidar surface images that shows the shapes of objects. Then it's a simple calculation to get the distance the light traveled.īut that only measures a single distance. When a short pulse is emitted, a computer measures the time it takes to get a signal back to the device. Most versions of lidar use a single laser with a detector. (He couldn't actually get a measurement.) Of course, he didn't have lasers or even a nice stopwatch, but that didn't stop him from trying. Galileo actually attempted something like this with his experiment to determine the speed of light. If you want to get lidar to work, you would need a really quick stopwatch. If you’re measuring a distance of 10 meters (like in the BallDAR example), the flight time would be around 0.000000067 seconds, or 67 nanoseconds. ![]() There is, of course, a practical issue: Light travels really fast. Then you just need the speed of light to calculate the distance. As soon as you see that laser spot on the wall, stop the stopwatch. The light will travel outward, hit the wall, and then reflect back. Just aim your laser at some object, and as soon as you turn on the laser, start a stopwatch. Theoretically, you could create a DIY version of lidar with a flashlight or even a laser pointer. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |