IC Imaging Control is an image acquisition SDK that works with any video source compiling to Microsoft's WDM specification. As an ActiveX and C++ Class Library, IC Imaging Control allows programmers to create image acquisition applications with only a few lines of code. Free trial version available for download.

Links to many different image processing algorithms

ImLib3D is an open source C++ library for 3D (volumetric) image processing. It comes with an optional viewer that features multiplanar views, animations, vector field views and 3D (OpenGL) multiplanar.

LEADTOOLS Raster Imaging Engine forms the basis for most of the imaging technology found in LEAD Toolkits, encompassing file import/export, image acquisition, image processing, display, and database connectivity.

List of software libraries and toolkits for image processing.