Here is a list of all topics with brief descriptions:

[detail level 1234]

▼Camera Calibration and 3D Reconstruction
Fisheye camera model
▼Core functionality
Basic structures
Operations on arrays
Asynchronous API
XML/YAML Persistence
Clustering
▼Utility and system functions and macros
Logging facilities
SSE utilities
NEON utilities
VSX utilities
Softfloat support
Utility functions for OpenCV samples
OpenGL interoperability
Intel IPP Asynchronous C/C++ Converters
Optimization Algorithms
DirectX interoperability
Eigen support
OpenCL support
Intel VA-API/OpenCL (CL-VA) interoperability
▼Hardware Acceleration Layer
Functions
Interface
▼Universal intrinsics
Private implementation helpers
Low-level API for external libraries / plugins
▼Parallel Processing
Parallel backends API
▼CUDA-accelerated Computer Vision
▼Core part
Initialization and Information
Data Structures
▼2D Features Framework
Feature Detection and Description
Descriptor Matchers
Drawing Function of Keypoints and Matches
Object Categorization
▼Hardware Acceleration Layer
Interface
Clustering and Search in Multi-Dimensional Spaces
▼Image file reading and writing
Flags used for image file reading and writing
iOS glue
MacOS(OSX) glue
▼Image Processing
Image Filtering
Geometric Image Transformations
Miscellaneous Image Transformations
Drawing Functions
Color Space Conversions
ColorMaps in OpenCV
Planar Subdivision
Histograms
Structural Analysis and Shape Descriptors
Motion Analysis and Object Tracking
Feature Detection
Object Detection
Image Segmentation
▼Hardware Acceleration Layer
Functions
Interface
▼Object Detection
Cascade Classifier for Object Detection
HOG (Histogram of Oriented Gradients) descriptor and object detector
Barcode detection and decoding
QRCode detection and encoding
DNN-based face detection and recognition
Common functions and classes
ArUco markers and boards detection for robust camera pose estimation
▼Video Analysis
Motion Analysis
Object Tracking
▼Video I/O	Read and write video or images sequence with OpenCV
Flags for video I/O
Additional flags for video I/O API backends
Hardware-accelerated video decoding and encoding
C API for video I/O
iOS glue for video I/O
WinRT glue for video I/O
Query I/O API backends registry
Core_c
Imgproc_c
Tracking_detail