Conflicting OpenCV Version in Jetson Nano Orin

Issue Overview

Users of the Nvidia Jetson Orin Nano Dev board are experiencing a version conflict with OpenCV when attempting to use it in their applications. Specifically, when executing Python commands to check the OpenCV version, different versions are reported depending on whether python or python3 is used:

• Running python3 -c "import cv2; print(cv2.__version__)" returns version 4.2.0.
• Running python -c "import cv2; print(cv2.__version__)" returns version 4.5.4.

This issue arises during the setup phase while configuring the development environment, particularly for users working with SDK 5.1.3 and Python version 3.8.10 on the Jetson Nano Orin.

The inconsistency in OpenCV versions can lead to compatibility problems, as different functionalities and features may be available in one version but not the other. This can significantly impact user experience and application functionality, leading to confusion and potential errors during development.

Possible Causes

• Multiple OpenCV Installations: The presence of different OpenCV versions installed for different Python environments (e.g., Python 2.x vs Python 3.x) can lead to conflicts.

• Environment Variables Misconfiguration: Incorrectly set environment variables like LD_LIBRARY_PATH and PYTHONPATH may not point to the intended OpenCV installation.

• Incomplete Installation: If the installation of OpenCV was not completed successfully or if there were issues during the installation process, it could result in incomplete or conflicting libraries.

• User Errors: Misconfigurations or mistakes made by the user while setting up the environment may lead to unexpected behavior.

Troubleshooting Steps, Solutions & Fixes

1. Check Current OpenCV Installations:

   • Use the following command to check where OpenCV is installed:

     python3 -c "import cv2; print(cv2.__file__)"
     python -c "import cv2; print(cv2.__file__)"
     

   • This will help identify which installation is being accessed by each Python interpreter.

2. Modify Environment Variables:

   • Ensure that your .bashrc file has the correct paths for both LD_LIBRARY_PATH and PYTHONPATH. Update them if necessary:

     echo 'export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH' >> ~/.bashrc
     echo 'export PYTHONPATH=/usr/local/lib/python3.8/site-packages/:$PYTHONPATH' >> ~/.bashrc
     source ~/.bashrc
     

3. Clean Existing OpenCV Installations:

   • If you suspect multiple installations are causing conflicts, consider removing existing installations before reinstalling:

     sudo apt-get remove --purge python-opencv python3-opencv
     

4. Install a Specific Version of OpenCV:

   • To ensure a clean installation of a specific version of OpenCV (e.g., 4.6.0), use the provided script from GitHub:

     wget https://raw.githubusercontent.com/AastaNV/JEP/master/script/install_opencv4.6.0_Jetson.sh
     chmod +x install_opencv4.6.0_Jetson.sh
     ./install_opencv4.6.0_Jetson.sh
     

   • This script includes an option to remove previously installed versions, ensuring a clean environment.

5. Verify Installation:

   • After installation, verify that both Python interpreters report the same OpenCV version:

     python3 -c "import cv2; print(cv2.__version__)"
     python -c "import cv2; print(cv2.__version__)"
     

6. Documentation and Updates:

   • Check for any relevant documentation on Nvidia’s developer forums or GitHub repositories for updates or patches related to OpenCV on Jetson devices.

7. Best Practices:

   • Regularly update your development environment and libraries to avoid compatibility issues.
   • Document any changes made to your environment for future reference.

By following these steps, users should be able to resolve the conflicting OpenCV version issue on their Nvidia Jetson Orin Nano Dev board effectively.