opencv

name	opencv
description	OpenCV computer vision library. Use for image processing.

OpenCV

OpenCV is the fundamental library for Image Processing. v5.0 (2025) modernizes deep learning support and licensing.

When to Use

• Image Manipulation: Resizing, cropping, color space conversion (BGR -> RGB).
• Classic CV: Edge detection (Canny), Feature matching (SIFT/ORB).
• Video I/O: Reading/Writing webcams or video files.

Core Concepts

BGR

OpenCV reads images as Blue-Green-Red (not RGB) by default. History quirks.

cv::Mat

The core matrix structure (in C++). In Python, it's just a NumPy array.

DNN Module

Running darknet/onnx models directly in OpenCV (lightweight inference).

Best Practices (2025)

Do:

• Use it for Preprocessing: cv2.resize() is highly optimized.
• Use headless: pip install opencv-python-headless for server deployments (smaller, no GUI deps).

Don't:

• Don't implement Deep Learning training: Use PyTorch. Use OpenCV only for inference/preprocessing.

References

• OpenCV Documentation