SOLVED: IMX500 AI Camera Qt Viewer Issue on Raspberry Pi 5
The Problem
I was developing a computer vision application using the Sony IMX500 AI camera module with my Raspberry Pi 5. The application is designed to classify Lincoln pennies (obverse/reverse sides, dates, and mint marks) using a custom-trained MobileNetV2 model.
When running my Python script, the application would initialize and begin loading the network firmware to the IMX500, but then fail with this Qt-related error:
System Details
Raspberry Pi 5 Model B Rev 1.0
Debian GNU/Linux 12 (bookworm)
Python 3.11.2
OpenCV 4.11.0
Picamera2 0.3.25 with IMX500 support
Root Cause
The issue was that I was using a Python virtual environment (ai_venv) that couldn't properly access the system's Qt libraries and plugins. System information showed that my virtual environment couldn't access these system packages.Solution
I created a new virtual environment with system-site-packages access:The --system-site-packages flag was the key, as it allows the virtual environment to access system-installed packages like PyQt5.
Possible Alternative Solutions
If you prefer to keep your existing virtual environment, you can also:
Set environment variables in your script before importing GUI packages:Ensure all system dependencies are installed:
For applications requiring GUI components like camera viewers on Raspberry Pi, it's important to either:
/ Create virtual environments with the --system-site-packages flag,
/ Explicitly set environment variables to locate system Qt plugins or,
/ Ensure proper installation of all GUI library dependencies.
Hope this helps anyone facing similar issues with OpenCV, picamera2, or other GUI-dependent libraries on Raspberry Pi!
The Problem
I was developing a computer vision application using the Sony IMX500 AI camera module with my Raspberry Pi 5. The application is designed to classify Lincoln pennies (obverse/reverse sides, dates, and mint marks) using a custom-trained MobileNetV2 model.
When running my Python script, the application would initialize and begin loading the network firmware to the IMX500, but then fail with this Qt-related error:
QObject::moveToThread: Current thread (0x7fff5c00a810) is not the object's thread (0x7fff5c240490).
Cannot move to target thread (0x7fff5c00a810)
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "/home/nickharing/penny_ai/ai_venv/lib/python3.11/site-packages/cv2/qt/plugins"
This application failed to start because no Qt platform plugin could be initialized.
System Details
Raspberry Pi 5 Model B Rev 1.0
Debian GNU/Linux 12 (bookworm)
Python 3.11.2
OpenCV 4.11.0
Picamera2 0.3.25 with IMX500 support
Root Cause
The issue was that I was using a Python virtual environment (ai_venv) that couldn't properly access the system's Qt libraries and plugins. System information showed that my virtual environment couldn't access these system packages.
Code:
PyQt5 was installed, but only at the system level (/usr/lib/python3/dist-packages)The Qt XCB plugin was available in the system (/usr/lib/aarch64-linux-gnu/qt5/plugins/platforms/libqxcb.so)I created a new virtual environment with system-site-packages access:
Code:
bash# Create a new environment with system packagespython -m venv penny_env_new --system-site-packages# Activate the new environmentsource penny_env_new/bin/activate# Install required packagespip install picamera2 opencv-pythonPossible Alternative Solutions
If you prefer to keep your existing virtual environment, you can also:
Set environment variables in your script before importing GUI packages:
Code:
pythonimport osos.environ["QT_QPA_PLATFORM_PLUGIN_PATH"] = "/usr/lib/aarch64-linux-gnu/qt5/plugins"# Then import other librariesCode:
bashsudo apt-get install -y python3-pyqt5 libqt5gui5 libxcb-xinerama0For applications requiring GUI components like camera viewers on Raspberry Pi, it's important to either:
/ Create virtual environments with the --system-site-packages flag,
/ Explicitly set environment variables to locate system Qt plugins or,
/ Ensure proper installation of all GUI library dependencies.
Hope this helps anyone facing similar issues with OpenCV, picamera2, or other GUI-dependent libraries on Raspberry Pi!
Statistics: Posted by SCII — Sun Apr 13, 2025 1:56 am