Jetson nano has CUDA, cuDNN and OPENCV installed after flashing the sd card.Right? Or are we installing them?
CUDA and cuDNN are preinstalled with JetPack but OpenCV comes without CUDA support by default, and it is necessary to build it yourself if you want CUDA support in OpenCV.
Is it enough to enter the commands at the address you provided?
If you mean the guide to build and install OpenCV with CUDA support, then yes. But the guide is not perfect, it suggests to overwrite system files which may get updated later and overwrite what you have installed by
sudo make install.
Personally, I prefer to use deb files to install software packages. You can download prebuilt deb package with OpenCV with CUDA enabled and install it like this (it was built on Jetson Nano with JetPack 4.5):
wget http://dragon.studio/2021/02/opencv_2021-02-27-1_all.deb && sudo apt remove libopencv opencv-licenses libopencv-python libtbb-dev libopencv-dev && sudo apt install ./opencv_2021-02-27-1_all.deb
The package includes libtbb.so this is why conflicting preinstalled package with libtbb needs to be uninstalled along with other OpenCV related packages.
To build OpenCV with CUDA support yourself or use prebuilt deb, is a matter of personal preference. If you build yourself, I suggest to uninstall conflicting packages before installing your own version of OpenCV (otherwise if you install self-built OpenCV without using deb package by
sudo make install, you end up silently overwriting system files from all packages mentioned in
You can use jtop and check INFO tab to see what have installed: it will show CUDA, cuDNN, OpenCV versions and if CUDA support is enabled in OpenCV.