How to set up Raspberry Pi Buster and Intel NCS2 and OpenVINO with OpenCV trackers - opencv

Question

Is there a definitive set of instructions to implement OpenCV trackers with OpenVINO and the now-obsolete NCS2 on a RPi 4b - Buster?
My understanding that the last OpenVINO to support the NCS2 was v2020.3.
I attempted to cross-compile using:
https://github.com/opencv/opencv/wiki/Intel-OpenVINO-backend#raspbian-buster
After installing opencv/opencv-contrib 4.5.5 from source:
$ python3
Python 3.7.3 (default, Oct 31 2022, 14:04:00)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> cv2.__version__
'4.5.5'
>>> tracker = cv2.TrackerCSRT_create()
>>>
However, in a test.py script I have:
...
import cv2
net = cv2.dnn.readNetFromCaffe(_weights, _model)
net.setPreferableTarget(cv2.dnn.DNN_TARGET_MYRIAD)
...
detections = net.forward()
I get the error relating to DNN_TARGET_MYRIAD:
cv2.error: OpenCV(4.5.5) /home/pi/opencv/modules/dnn/src/dnn.cpp:1414: error: (-215:Assertion failed) preferableBackend != DNN_BACKEND_OPENCV || preferableTarget == DNN_TARGET_CPU || preferableTarget == DNN_TARGET_OPENCL || preferableTarget == DNN_TARGET_OPENCL_FP16 in function 'setUpNet'
I then used this to install OpenVINO:
https://docs.openvino.ai/latest/openvino_docs_install_guides_installing_openvino_raspbian.html
but using this version of OpenVINO (as the last to support the NCS2):
https://storage.openvinotoolkit.org/repositories/openvino/packages/2020.3/l_openvino_toolkit_runtime...
I exported the paths to the new post cross-compiled opencv_install directory:
$ export PYTHONPATH=/home/pi/Desktop/opencv_install/lib/python2.7/dist-packages/:$PYTHONPATH
$ export PYTHONPATH=/home/pi/Desktop/opencv_install/lib/python3.7/site-packages/:$PYTHONPATH
$ export LD_LIBRARY_PATH=/home/pi/Desktop/opencv_install/lib/:$LD_LIBRARY_PATH
I set up the NCS2 with no errors :
$ sudo usermod -a -G users "$(whoami)"
$ sh /opt/intel/openvino_2020.3/install_dependencies/install_NCS_udev_rules.sh
then:
$ source /opt/intel/openvino_2020.3/bin/setupvars.sh
and then checked:
$ python3
Python 3.7.3 (default, Oct 31 2022, 14:04:00)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> cv2.__version__
'4.3.0-openvino-2020.3.0'
>>> tracker = cv2.TrackerCSRT_create()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: module 'cv2' has no attribute 'TrackerCSRT_create'
>>>
If I open a new terminal and $ source /opt/intel/openvino_2020.3/bin/setupvars.sh
then run a test.py script:
...
import cv2
net = cv2.dnn.readNetFromCaffe(_weights, _model)
net.setPreferableTarget(cv2.dnn.DNN_TARGET_MYRIAD)
...
detections = net.forward()
...
I get a segmentation fault error.
So far I have not edited any of the setup scripts.
Thanks for any help! I'd like to put this NCS2 to work.

Answer 1

Generally, if you are able to run some OpenVINO demo with NCS2 after following this installation guide, then you should be able to use that OpenCV functionality (ensured that you had installed the correct OpenCV).
It's recommended to use the recent OpenVINO and OpenCV version.
As indicated in this OpenVINO System Requirements, the current recommended OpenCV version is 4.5.