Monday, August 27, 2012

King of the (camera interface speed) hill

Most of us were happy with FireWire-b and had no need of faster data rates. Then along came GigE and the bits flowed faster. If we needed real speed, like for those occasional linescan projects, there was always CameraLink.

But just as racing drivers always want more, so too do some machine vision people. Many of these are in the high speed web inspection niche, and they were starting to think that good old CameraLink might not be up to the job in a few years. So Dalsa started work on an interface they called “HSLink”.

This showed a lot of promise, but as Mike Miethig of Dalsa discusses in “Vision Market Touts Camera Link HS in Boston, Beyond” (Quality magazine, August 7th, 2012,) it never really gained traction.

Fortunately for the speed freaks though, it did set the scene for CameraLink HS, which promises speeds of up to 2.1Gbytes/sec. Now that number might be hard to grasp, so I’ve put together a little graphic to show just how much faster than the older standards that is.

Now there are some important caveats. CameraLink speeds are complicated because they depend on whether it’s Base, Medium, or Full configuration. CameraLinkHS is much the same: there are three speed flavors, starting at a relatively paltry 300Mbytes/sec. And then, missing from my table, is CoaXpress.

CoaXpress boasts of up to 6.25Gbps, (which I suspect is gigabits rather than bytes,) so it’s not a s fast as CameraLink HS. More importantly, it’s not an AIA standard – it’s supported by the Japan Industrial Imaging Association – so whether it will prosper remains to be seen.

And what does this mean for the regular machine vision user? It means there’s virtually no limit to how fast you can shove those pixels down the pipe. The only question to consider is, how deep are your pockets?


Vincent Rowley said...


Some quick comments.

With its "80-bit" mode, Camera Link can go up to 6.8 Gbps (850 MBps).

You are correct that CoaXPress can go up to 6.25 Gbps. This is per cable (link). I think that some vendors already started deploy some multi-link CoaXPress products.

Perhaps you should also include 10 GigE in your analysis since GigE Vision over 10 GigE is now enabled by at least two vendors.

Some many choices you would say. Well, wait until Thunderbolt checks in :-)

Vincent Rowley

Anonymous said...

March 30, 2011: CoaXPress Standard Gains Endorsement from the AIA and EMVA to Achieve Global Standardization Status