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.