CAMERA INTERFACES: USB 3.0 challenges mainstream camera interface standards

The dizzying number of competing camera interface standards might leave many engineers wondering which one, if any, might emerge over the next few years as a clear leader. For Arndt Bake, COO at Basler (Ahrensburg, Germany;www.baslerweb.com), the choice is clear - USB 3.0, and its faster successor USB 3.1, will start to dominate the world of computer vision after 2020.

Bake explains that his company views the camera market in three segments - high end, mainstream and entry level. At present, each of these segments is served by a number of camera interface standards.

USB 2.0 - an interface standard widely used in the computer peripheral market is capable of an effective throughput of 280Mbit/sec, Bake claims, will be superseded by the new "superspeed" USB 3.0 interface which, with its faster 4Gbit/s data rate, will dominate the entry level market and take a substantial share of the mainstream market. Not only that, but

Bake also believes that cameras based on the new "superspeed" USB 3.0 will totally replace those based on the Firewire standard by the year 2020, despite the fact that the latest incarnation of the Firewire specification (IEEE 1394-2008) can theoretically deliver an effective throughput of up to 3.2 Gbits/s - speeds that could potentially mean that the standard would compete directly with USB 3.0. Bake believes, however, that USB will dominate the market, due to its high bandwidth and its cost which will reduce as the number of consumer products that adopt it increases.

At the top end of the mainstream camera market, the dominant computer to camera interface at the present time is Camera Link, which is offered in Base, Medium, Full and Extended Full configurations with data transfer speeds of up to 6.8Gbits/s. However, Bake thinks that, over the long haul, even the Camera Link standard will face stiff competition from USB, since once the newer USB 3.1 standard is adopted, with its data transfer speeds up to 10Gbit/s, many existing Camera Link applications will migrate to this standard.

At the very high-end, Bake admits that one camera interface standard - CoaXPress - has come to dominate, having stolen the thunder from the competing Camera Link HS standard which has failed to gain a foothold. But CoaXPress is a standard that he believes will also eventually come under threat from USB 3.1. At the present time, the CoaXPress interface enables cameras to be connected to frame grabbers at bit rates from 1.25 Gbit/s to 6.25 Gbit/s per cable - up to 25Gbit/s if systems integrators employ frame grabbers and cameras with four cables. At 10Gbit/s, however, USB 3.1 could mean that all but those computer vision systems that demand the very highest speed could find themselves using a USB interface.

To enable its customers to quickly upgrade their camera-based systems from one interface standard to another, Basler has developed a suite of software called Pylon. Based on the GenApi module of the GenICam reference implementation, it offers a single generic programming interface for programming the functionality of any Basler camera with a Windows or Linux PC. No matter what interface technology the cameras are using or what features they are implementing, the application programming interface (API) remains the same, easing the task of the systems integrator.

For its part, Basler appears to have no intentions, at present time at least, to compete in the high end camera market served by CoaXPress. Its position is to continue to serve its customers in the mainstream factory automation, ITS and medical and life sciences fields. To do so, it will consolidate its position supporting the Camera Link and GigE interfaces while looking to the future by developing a suite of USB based cameras.