How to import OpenCV in Python3?

Alex123 · 22 Dec 2020, 06:20

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 · 24 Dec 2020, 18:22

Hi @Alex123 ,

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

https://gitlab.com/voxl-public/other/voxl-opencv-3-4-6/-/blob/master/examples/april-tag-detect/april-tag-detect.cpp

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 · 29 Dec 2020, 06:23

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 · 7 Jan 2021, 12:43

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 · 29 Dec 2020, 10:29

@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 · 31 Dec 2020, 12:17

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

Chad Sweet · 31 Dec 2020, 17:02

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

Alex123 · 7 Jan 2021, 12:43

@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 · 8 Jan 2021, 18:15

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

Alex123 · 14 Jan 2021, 06:52

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

tom · 15 Jan 2021, 19:57

@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?