OpenCV

1. Tutorials overview

   Index of OpenCV tutorials across modules.

2. Core functionality and Mat

   The Mat n-dimensional array, basic structures, and operations.

3. Image I/O

   Reading and writing images and image codecs.

4. Image processing

   Filtering, geometric transforms, color conversion, thresholding, and morphology.

5. Feature detection and description

   Keypoints, descriptors, and matching with ORB, SIFT, and others.

6. Camera calibration and 3D

   Camera models, calibration, pose estimation, and stereo.

7. Video analysis and tracking

   Optical flow, background subtraction, and object tracking.

8. Video I/O

   Capturing from cameras and files and writing video.

9. Object detection

   Cascade classifiers, HOG, and QR code detection.

10. Deep neural networks

    Loading and running inference with ONNX, TensorFlow, and other models.

11. High-level GUI

    Windows, trackbars, and mouse events for visualization.

12. OpenCV-Python tutorials

    Using OpenCV from Python with NumPy arrays.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.