OpenCV was designed for computational efficiency and with a strong focus on real-time applications.
VLFeat open source library implements popular computer vision algorithms specializing in image understanding and local features extraction and matching.
BoofCV is an open source Java library for real-time computer vision and robotics applications.
Visualization Toolkit (VTK) is an open-source, freely available software system for 3D computer graphics, modeling, image processing, volume rendering, scientific visualization, and information visualization.
Insight Segmentation and Registration Toolkit (ITK) is an open-source, cross-platform system that provides developers with an extensive suite of software tools for image analysis.
FSL is a comprehensive library of analysis tools for FMRI, MRI and DTI brain imaging data.
Statistical Parametric Mapping refers to the construction and assessment of spatially extended statistical processes used to test hypotheses about functional imaging data.
GIMIAS is a workflow-oriented environment for solving advanced biomedical image computing and individualized simulation problems, which is extensible through the development of problem-specific plug-ins.
3D Slicer is a free and open source software package for image analysis and scientific visualization.
MIA provides a combination of command line tools, plug-ins, and libraries that make it possible run image processing tasks interactively in a command shell and prototype by using the according shell scripting language.