How to import OpenCV in Python3?

[Alex123]

I've installed Python3 on the voxl core-board. I've also installed OpenCV-3.4.6 using https://gitlab.com/voxl-public/other/voxl-opencv-3-4-6
But I'm unable to access OpenCV in Python3.
I'm getting an error like this.

/ # python3
Python 3.6.9 (default, Dec 19 2020, 12:09:26)
[GCC 4.9.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>import cv2
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'cv2'

How to import OpenCV in Python3?

Any suggestions would be greatly appreciated!
Thanks!

[modaltb]

Hi @Alex123 ,

The opencv-3-4-6 project above isn't a python3 package installation rather for c++, for example:

examples/april-tag-detect/april-tag-detect.cpp · master · voxl / VOXL SDK / Third Party / voxl-opencv · GitLab

This project describes how to build OpenCV for ModalAI's VOXL platform and provides a simple example.

GitLab (gitlab.com)

Are you requirements Python3.6.9 and OpenCV 3.X? (let me know specifics if possible).

If so, do you requirements allow you to run your program in a Docker container on VOXL?

Thanks!

[Alex123]

Yes, I have to run my program using Python3.6.9 and OpenCV 4.X.
And it wouldn't allow running a program on Docker container on VOXL.

[Chad Sweet]

The easiest path is to use an Ubuntu Docker container on VOXL. https://docs.modalai.com/docker-on-voxl/

Otherwise you will have to build the python bindings for OpenCV. We have never tried this, but it looks well documented here: https://docs.opencv.org/master/da/d49/tutorial_py_bindings_basics.html

[Alex123]

@Chad-Sweet
If I'll use an Ubuntu Docker container on VOXL, can you provide documentation or steps using which I can build OpenCV4.x on Python 3.6.9?

Or a pre-build file of OpenCV4.x for Python3.6.9?

Thanks!

[Alex123]

How can I use OpenCV4.x with Python3.6.9 using Ubuntu Docker container on VOXL?

[Chad Sweet]

You can use apt to install, follow any normal Ubuntu instructions

[Alex123]

@Chad-Sweet
I'm using the Ubuntu Docker container on VOXL.
OpenCV4 in Python3 is working.

But I'm facing issues while mounting sdcard on it.
I'm referring to this link.

I'm using the below command to mount sdcard.
docker run -v /mnt/sdcard:/root/yoctohome/:rw -w /root/ roskinetic-xenial:opencv

How can I mount a sdcard on the Ubuntu Docker container on VOXL?

[tom]

@Alex123 You should be able to mount the sdcard directory using the following param
docker run -v /sdcard:/sdcard

[Alex123]

@tom
I've tried docker run -v /sdcard:/sdcard, but not working. It's not showing sdcard directory.

[tom]

@Alex123 here is the exact command I tested with on a VOXL.

docker run -it --rm --privileged --net=host --name roskinetic -v /home/root:/root/yoctohome/:rw -v /sdcard:/sdcard -w /root/ roskinetic-xenial:v1.0 /bin/bash

Can you try this?