Open Source Solid Modeling CAD
BRL-CAD is a powerful cross-platform constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing for rendering & geometric analyses, network distributed framebuffer support, image & signal-processing tools.
A powerful C++ class library for image manipulation
ImageStone is a powerful C++ class library for image manipulation. Its features include load, save, display, transformation, and nearly 100 special image effects. It can be used cross platform (includes Windows, Linux, Mac), and especially under windows it can be used as a DIB wrapper class.
TiffIO is a plugin to enable TIFF images from any Qt app. The plugin is a wrapper to libtiff 3.9.4 : It enables any Qt3 or Qt4 based application to load and save any QImage to and from most TIFF formats combinations supported by libtiff.