OpenCV Imports Failing with NumPy 2.0

Problem Statement

When attempting to import OpenCV (cv2) or related libraries like imutils in Python, you may encounter compatibility errors with NumPy 2.0:

AttributeError: _ARRAY_API not found
ImportError: numpy.core.multiarray failed to import

This occurs because:

1. OpenCV and its dependencies were built using NumPy 1.x
2. NumPy 2.0 contains breaking changes for compiled extensions
3. The mismatch occurs even if you're not directly using NumPy, as it's a core dependency for computer vision libraries

Common error trigger points:

import imutils  # Fails because it imports cv2
import cv2      # Direct import fails

Solution: Downgrade to NumPy 1.x

The most reliable solution is to downgrade NumPy to the latest 1.x version that maintains compatibility with pre-built computer vision packages.

Step-by-Step Fix

1. Uninstall your current NumPy version:

   pip uninstall numpy

2. Install a compatible NumPy version:

   pip install "numpy<2.0"  # Installs latest 1.x version

   or

   pip install numpy==1.26.4  # Specific stable version

3. Verify successful installation:

   import numpy
   print(numpy.__version__)  # Should show 1.x

4. Confirm OpenCV imports work:

   import cv2
   print(cv2.__version__)

PyCharm-Specific Notes

If using PyCharm:

1. Ensure you're modifying the correct virtual environment:

   • Open File > Settings > Project: [Name] > Python Interpreter
   • Select your project's virtual environment

2. Apply the NumPy downgrade within Pycharm's terminal:

   # Use the terminal pane at bottom
   pip uninstall numpy
   pip install "numpy<2.0"

3. Restart the PyCharm Python interpreter after changes

For Docker Users

In your Dockerfile:

# Replace numpy installation command
RUN pip uninstall -y numpy && \
    pip install "numpy<2.0"

Alternative Approach: Upgrade Dependencies

If you must use NumPy 2.0, update all dependencies to their latest versions:

pip install --upgrade numpy pandas pyarrow opencv-python imutils

WARNING

This solution is less reliable:

• OpenCV Python wheels may not yet support NumPy 2.0 (as of July 2024)
• Dependency conflicts may occur if other packages require older NumPy versions

Explanation: Why Does This Happen?

1. ABI Incompatibility: NuGet Py 2.0 changed internal C APIs that compiled extensions like OpenCV rely on
2. Dependency Chains: Imutils → OpenCV → NumPy creates hidden dependency
3. Binary Compatibility: Pre-built wheels only work with the specific NumPy version they were compiled against

Best Practice

Keep NumPy pinned to a specific version in requirements.txt for production systems:

numpy~=1.26.4  # Pinned to last stable 1.x
opencv-python==4.9.0.80
imutils==0.5.4

Verifying the Fix

Confirm your environment configuration with:

pip show numpy opencv-python

Check that:

• NumPy version starts with 1.
• OpenCV version matches recent stable build