I am wanting to create a robot that can pick up trash. I am planning on taking a picture of the trash, using an ai i've trained to detect the trash, using opencv to find the contour of the trash, and then lining the contour up with a pointcloud generated by LiDAR to determine where the object is in space and its dimensions. However, I know that LiDAR can't accurately see glass or plastic. Is there a way to sense transparent objects with LiDAR? If there isn't any reasonable way to, are there any other sensors that can sense glass? I am aware of ultrasonic, but I'm under the impression that it won't be able to create a point cloud accurate for what i'd be needing, if at all. I also am aware of infrared, but I was under the impression that some plastics are transparent to infrared. I also don't know if it can generate a point cloud for what I need. I found some things about 3d scanning, which said to spray paint it before scanning, but that wouldn't work in this situation. Also, I'm not experienced with robotics, so if this won't work at all, please tell me :).


1 Answer 1


This question is interesting. Look at this video of Doug using AI and a kinect sensor to locate objects and generate the transforms that locate the objects in the space around the camera(robot).



The range that the kinect works at may not be suitable for your uses and it may struggle with transparent things as well, but this should get you thinking. Intel makes a similar sensor that may have more suitable functional ranges.

Regarding your question if this will work...everything is impossible until someone tries. If your true goal is just to pick up trash, put on some gloves and start picking up trash. If this is a way to learn about technology and robotics, it's a fantastic idea and you'll learn more than you thought possible. It's a pretty significant idea and will involve significant effort to get something working. In my mind a robot that can pick up paper but misses the bottles is still a great robot. I'm not sure you should lose sleep over the misses, focus on the gets.

Apologies for not answering the question about getting lidar to see glass. If you're really set on this, take a look at thermal imagers. Glass is opaque (and reflective) in the range that thermal imagers work at. There may be something there but the reflectiveness likely creates new issues.

Also look at stereo cameras. They can locate objects and give you distance, but expensive.

  • $\begingroup$ Do you have any recommendations for stereo cameras? I looked up a few popular ones, like intel realsense, And it looks like it might also have a problem with glass. $\endgroup$
    – eop3
    Sep 23, 2023 at 15:02
  • $\begingroup$ You'll have to make sure that when you say "glass" you're thinking the same thing as they are. A camera based system will not tolerate measuring a glass window. That doesn't mean it wouldn't see a glass bottle, or shards of broken glass. The video link I posted shows the Kinect identifying and locating a clear plastic bottle. People can struggle to see glass windows but we have no issue with seeing glass bottles. All camera based systems will be the same. Last note, Intel says the realsense are stereo cameras, but I had the understanding that there was one sensor for distance and one RGB. $\endgroup$
    – billy
    Sep 23, 2023 at 17:52
  • $\begingroup$ I went and looked at Intel page, they are now almost all true stereo, with only a few models that use IR and RGB. $\endgroup$
    – billy
    Sep 23, 2023 at 18:03
  • $\begingroup$ Okay, thanks! Stereo sounds promising and I’ll do some more research into it. $\endgroup$
    – eop3
    Sep 23, 2023 at 20:41

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