OpenCV is OSS maintained by Willow Garage. Intel provides the Intel Performance Primitives which implement basic filtering up through haar, segementation, optical flow.
Machine vision usually refers to the domain of industrial inspection where the scene contents are highly controlled, and computer vision usually refers to harder problems where someone is walking around a real environment with bad lighting and awkward perspectives.
OpenCV originated at Intel and was based on Intel's IPL.
Some researchers prefer the term 'machine vision' as more general, referring to the entire field of artificial vision problems, not necessarily involving a 'computer' in common terms (i.e. FPGA-based or analog electronics).
Examples include Intel's OpenCV and the CVPR conference.
(I actually thought that it was weird that they called themselves "machine vision" rather than computer vision in the title.)