OpenCV : an open source computer vision and machine learning software library
JavaCV : Java interface to OpenCV and more
OpenCVDotNet : .NET Framework Wrapper for Intel's OpenCV Package
VXL : the Vision-something-Libraries, a collection of C++ libraries designed for computer vision research and implementation
IVT : the Integrating Vision Toolkit, a stand-alone easy-to-use, platform-independent open source C++ computer vision library with an object-oriented architecture
ccv : C-based/Cached/Core Computer Vision Library, a Modern Computer Vision Library
VIGRA : Vision with Generic Algorithms, Generic Programming for Computer Vision, an image processing and analysis library that puts its main emphasis on customizable algorithms and data structures
BoofCV : an open source Java library for real-time computer vision and robotics applications
Darwin : a framework for machine learning and computer vision research and development
RAVL : Recognition And Vision Library, a base C++ class library together with a range of computer vision, pattern recognition, audio and supporting tools
SIFT : Scale Invariant Feature Transform
SURF : Speeded Up Robust Features
LBP : Local Binary Patterns
HOG : Histograms of Oriented Gradients
DAISY : a Fast Local Descriptor for Dense Matching
BRIEF : Binary Robust Independent Elementary Features
VLFeat : Vision Lab Features Library
FST : Feature Selection Toolbox, a standalone widely applicable C++ library for feature selection
LibPaBOD : a LIBrary for PArt-Based Object Detection in C++
OLT Toolkit : INRIA Object Detection and Localization Toolkit
bgslibrary : a Background Subtraction Library