Tuesday, February 4, 2014

A new age for digital interaces, Coaxpress and Camera Link HS

Coaxpress and Camera Link HS emerged after the unsuccessful attempt on VISILink. The event unfolds by these two digital interfaces in industrial cameras draw parallels to the iconic video format war in the consumer market. In the 70s we have VHS verse Betamax and in the recent millennium, HD-DVD verses Blue-Ray. If there is anything to learn from history, neither the best nor the cheapest technology will emerge as the victor.

Of the most lucrative and largest volume in the high bandwidth industrial digital camera is the sales of linescan cameras. In linescan applications there is endless request for higher line speed and larger data bandwidth, this poses a challenge to the existing bandwidth of CameraLink standard as sensor technology advanced. The demand for a new high speed digital interface arises.

Dalsa with its linescan solution has precipitated a formidable wall in the industry. Dalsa not only actively seek for available technology but also invested heavily on prototypes. With opportunity arises during the flat panel and LEDs era in the mid 2000s, Dalsa announced its solution to serve the market request, HS-Link together with Piranha HS 12K TDI camera in 2009. Thereafter, they take this development to AIA to adopt it as Camera Link HS.

Coaxpress is originally developed by five companies and anointed by JIIA. With many anxious to jump onto the high speed wagon, Coaxpress is now being supported by many cameras and framegrabber card vendors. Among them, e2v and Active Silicon presented an attractive alternative to Dalsa Camera Link HS 16k linescan solution (ELiiA 16k linescan camera with FireBird framegrabber card). Compared to Dalsa monochromic domination in Camera Link HS, the Coaxpress technology appears to fill with genetic diversity and vibrancy.

From the technological perspective, Coaxpress uses EqcoLogic transceiver while Camera Link HS leverages on 8b/10b Gigabit Ethernet technology. 

Camera Link HS
Camera Link


3.2ns Jitter
12ns Jitter
0 ns Jitter

15m on CX4
Com Channel

Integrated into FPGA

*Today there is an untested alternative from kaya instrument

With bandwidth double of Camera Link HS and superior running distance, at a single glance, CoaXpress looks set to replace Camera Link HS. However, the winner of the consumer video format war has taught us that superior technological and lower price does not guarantee success. Camera Link HS have some very distinctive advantages, Dalsa has been dominating the high end linescan (TDI) market for years, there is already a very well established integrated Dalsa camera and framegrabber solution and by exploiting network technology (8b/10b) there is a possibility of cheaper solution in the near future by third party framegrabber cards.  There is third party framegrabber card vendor pledging support on Camera Link HS under the IAI flag and evidence of any serious challenges against Dalsa linescan domination at this moment is still exiguous.         

The die has been cast and the clash between the two standards in the linescan arena is inevitable. The cameras technology available from either side will act as the hammer whiles the interface standard as the anvil. A new chapter for linescan inspection will be forged with higher line speed and higher sensor resolution. 

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