Unable to get opencv 4.5.1 to work with jetpack 4.5

Robotics & Edge Computing Jetson & Embedded Systems Jetson Xavier NX
1

I followed the instructions given here:

I used cmake 3.10.2 with python 3.6.9 and a virtual environment that I named cv

Everything went as described in the instructions. But when start python in the cv virtual env and I import cv2 this is what I get:

(cv) xxxx@xxxx:~$ python
Python 3.6.9 (default, Jan 26 2021, 15:33:00)
[GCC 8.4.0] on linux
Type “help”, “copyright”, “credits” or “license” for more information.
>>> import cv2
Traceback (most recent call last):
File “<stdin>”, line 1, in
ImportError: /home/alan/cv2.so: undefined symbol: _ZTIN2cv3dnn14dnn4_v202011175LayerE

I have no idea what the problem is. I bought this jetson to run opencv on it. But I cannot. Can anyone help me to understand why it is not working and to get it working?

3
  1. check the built opencv is able to be imported well at system env not virtual env.
  2. if YES, make sure the proper .so is there
    /usr/local/lib/python3.6/site-packages/cv2.*.so
4

Thank you for your reply, MtHiker. I get the same error,

ImportError: ./cv2.so: undefined symbol: _ZTIN2cv3dnn14dnn4_v202011175LayerE

when the virtualenv is active or inactive.

Any suggestions?

5

hi Futznabble:
when you flash your Xavier with sdkmanager, you can select install OpenCV together that version is guaranteed from NV, other verision is NOT tested.

6

@Futznabble

The post you referenced says that at the step 4.
The prompt of your logs “(cv) xxxx@xxxx:~$” says the vurtualenv is activated and running.

To activate it when you want,
xxxx@xxxx:~$ workon cv
Then the prompt should starts with (cv).
To deactivate it,
(cv) xxxx@xxxx:~$ deactivate