Vision Processing using Jevois Camera

Hello everyone, we have been working on the jevois camera for some time now. We are trying to use jevois inventor to detect color off reflecting tape. But we don’t really know how to work with the jevois inventor properly. I want to ask if any of you guys know how to work with jevois inventor to detect color off reflecting tape or if you guys have another software to detect color off reflecting tape. (We use windows)

I’m not sure I understand the question, but here goes.

First, Jevois inventor doesn’t actually do any processing. I.e. it cannot detect the color of the reflecting tape. Jevois Inventor allows you to see the output of the camera.

That output can be any image, and in OpenCV, most of the processes involved create a new image from an old on.

So, the most common way to see whether or not your OpenCV code, running as part of the script on the Jevois camera, can call the inRange function, which will produce a binary image, and you can send that as the output of the camera. That way, you can see which pixels were detected, and you can tell whether you are actually picking up the correct pixels that represent the tape.

Before you do that, you have to set the values of your color filter itself, and for that, I highly recommend the use of Grip. If you haven’t downloaded it yet, do so. It’s free and awesome. Google FRC Grip to find it.

Finally, one step that might be going wrong in any of this might be setting the sensitivity of the camera. To use the fairly standard light ring+ color filter method of detecting tape targets, you have to change the sensitivity of the camera. Dial it way down so that the only pixels that show up are lights and reflectors. You’ll end up with a mostly black screen where the tape targets are green, assuming a green LED ring. (Green seems to work best, though other colors can be used.) Setting the sensitivity can be a bit tricky, and frankly isn’t well documented, but there are threads in here (search for jevois) that discuss it. However, there are some errors in those threads, too. (I know, because I posted some of those errors when I was learning Jevois durning the 2019 build season.) The tech support is pretty good if you go their technical forum.

I don’t have my jevois code handy, but if you are still having difficulty and are interested, reply here and I will post some more details on how to make those steps happen.

You’ll want the LED ring for sure. Night and day difference.
Follow this guide (mostly) to get set up: https://docs.google.com/document/d/1duM0ncfjExYepVAZtkhaMqqkwEJHyFDX487YP9TIzzA/edit?usp=sharing
It’s a little outdated, but basically anything that requires the Arduino terminal can be done using the Inventor now. There’s a section in there detailing what different filters in GRIP do; you can implement these yourself in OpenCV on the Jevois if you want.