Jetson nano OpenCV cuda::getCudaEnabledDeviceCount() return 0

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

Hi
I have build OpenCV with WITH_CUDA=ON based on

With some changes as below successfully:

  1. commented out the line
    sudo apt-get dist-upgrade -y --autoremove
    as it upgraded JetPack 4.4.0 to 4.4.1 which resulted the e-con system camera does not work.
  2. added:
    -D WITH_QT=ON
    as I am using Qt Creator for coding and debugging.

But the line below return 0 during my test
int count = cuda::getCudaEnabledDeviceCount();

No CUDA enabled device is available, why?
How to fix it?
Thanks

2

Your application may be running the old version of opencv.
Use:

std::cout << cv::getBuildInformation() << std::endl;

for checking what the running version of opencv supports.

3

Thank you for your help.
Yes. you are right.
The newly build OpenCV does not overwrite the previous OpenCV installation.
The newly build OpenCV installed at /usr/local/