OpenCV means Open Source Computer Vision Library. It is a collection of C functions and a few C++ classes that implement many popular Image Processing and Computer Vision algorithms.
This book is:
OpenCV provides cross-platform middle-to-high level API that includes about 300 C functions and a few C++ classes. Also there are constantly improving Python bindings to OpenCV, see interfaces/swig/python and samples/python. OpenCV has no strict dependencies on external libraries, though it can use some (such as libjpeg, ffmpeg, GTK+ etc.) when it is possible.
OpenCV is free for both non-commercial and commercial use (see the license for details).
OpenCV provides transparent interface to Intel® Integrated Performance Primitives (IPP). That is, it loads automatically IPP libraries optimized for specific processor at runtime, if they are available. More information about IPP can be retrieved at http://www.intel.com/software/products/ipp/index.htm
The list of authors and major contributors can be found in the file THANKS.
See the ChangeLog.
Go http://www.sourceforge.net/projects/opencvlibrary. If it does not work, type "OpenCV" in Google (http://www.google.com).
You may also look at the PDF manual, but do not trust it much - it is pretty out of date, especially, the reference part.