More camera interfaces for machine vision exist today than since the very beginning of machine vision. Since January, two new interface standards have been introduced: the serial Camera Link HS and CoaXPress. Now a third, called USB3 Vision, is under development, targeted for release in 2012.
At first glance, it might seem that the more camera interface standards, the merrier. In March, the Japan Industrial Imaging Association (JIIA) finalized coax cable-based CoaXPress. At the Automate 2011 show in Chicago that month, a pre-release form of the "next-generation" high-speed Camera Link HS standard was unveiled.
Measuring just 29mm x 29mm x 30mm, Point Grey's FL3-U3 "SuperSpeed" USB 3.0 camera
is designed for machine and computer vision applications.
The Automated Imaging Association (AIA) expects to release Camera Link HS, which will not be backward compatible with Camera Link, in November this year. There's also the serial GigE Vision interface, which makes it easier to take advantage of Ethernet's ubiquity and build point-to-multipoint vision networks, plus the original, parallel Camera Link.
Aside from these three, soon to be five, machine vision-specific choices, some engineers designing industrial vision systems use interfaces based on general-purpose protocols originating in consumer PCs. USB, now in its "SuperSpeed" version of USB 3.0, is one contender, as are FireWire and even plain vanilla Gigabit Ethernet. Now the count is up to six standards, and it will reach eight some time next year.
Some engineers prefer these direct camera connections that don't need a frame grabber. With their open standard cables and other components, hooking up USB or Gigabit Ethernet cameras is generally easier than with some of the machine vision-specific interfaces. Some vendors also support these standards so they can control the software, drivers, and protocols in their cameras. This makes it easier to add new features quickly and integrate cameras based on different interfaces without changing code.