Installation of higher version of opencv

Autonomous Machines Jetson & Embedded Systems Jetson Nano
#1

Hi,

I want to run my custom object detector of darknet on jetson nano but iam facing the following error while i run my code for detection.

“”""
nvidia-jetson-sndk@nvidiajetsonsndk-desktop:~/Downloads/yolov3_darknet_python$ python3 yolov3_darknet.py --image station3.jpg
Weight Number: 40500
Traceback (most recent call last):
File “yolov3_darknet.py”, line 41, in
net = cv.dnn.readNetFromDarknet(modelConfiguration, modelWeights)
AttributeError: module ‘cv2’ has no attribute ‘dnn’
“”""

Any help would be appreciated.

#2

Hi,

You can install it by building it from the source.
Here is a script of OpenCV4.0 for your reference:
https://github.com/AastaNV/JEP/blob/master/script/install_opencv4.0.0_Nano.sh

Thanks.

#3

I installed opencv 4 but it is still taking opencv 3.2.0 could you help me to overcome this? please find the attachment.

Screenshot from 2019-05-15 16-37-49.png
Screenshot from 2019-05-15 16-37-49.png1920×1080 281 KB

#4

Hi,

If the default opencv is not removed, you will need to update your Makefile to the correct header/lib.
Thanks.

#5

Hi,

On the nano, I removed opencv-3.2.0 using:

sudo sudo apt-get purge *libopencv*

I confirmed removal with find and:

import cv2
Traceback (most recent call last):
File “”, line 1, in
ModuleNotFoundError: No module named ‘cv2’

Then ran the script posted by AastaLLL (#2):

install_opencv4.0.0_Nano.sh

After running install_opencv4.0.0_Nano.sh there was confirmation of install:
…
Setting up libopencv-videostab3.2:arm64 (3.2.0+dfsg-4ubuntu0.1) …
Setting up libopencv-contrib3.2:arm64 (3.2.0+dfsg-4ubuntu0.1) …
Setting up python3-opencv (3.2.0+dfsg-4ubuntu0.1) …
Setting up python-opencv (3.2.0+dfsg-4ubuntu0.1) …
Processing triggers for libc-bin (2.27-3ubuntu1) …
** Install opencv-4.0.0 successfully
** Bye :)
nvidia@nvidia-desktop:~$ python3
Python 3.6.8 (default, Jan 14 2019, 11:02:34)
[GCC 8.0.1 20180414 (experimental) [trunk revision 259383]] on linux
Type “help”, “copyright”, “credits” or “license” for more information.

import cv2
cv2.version
‘3.2.0’

It appears opencv-3.2.0 was installed, not opencv-4.0.0:

AastaLLL (#4) suggests:
“If the default opencv is not removed, you will need to update your Makefile to the correct header/lib.”

Apologies in advance if pedestrian for this forum:

  • What Makefile is AastaLLL referring to?
  • How do I find the correct header/lib and change Makefile accordingly?
    • #6

    Hi,

    Sorry about that there is a bug inside the install_opencv4.0.0_Nano.sh:

    sudo apt-get install -y python-opencv python3-opencv

    The command will install the package from apt which is v3.3.
    This is no needed since the script already build the version 4.0.

    I have removed the line from the install_opencv4.0.0_Nano.sh.

    After building OpenCV from source, the python package is located at {folder}/opencv-4.0.0/release/python_loader.
    Please update the library path like this:

    export PYTHONPATH=$PYTHONPATH:/path/to/your/folder/opencv-4.0.0/release/python_loader/

    Thanks.