Monday, January 27, 2014

USB3 Vision: A force not to be reckoned with



The birth of modern vision industry happened during the 90s computer boom . With personal computer becoming cheaper and faster during that era, running machine vision algorithm no longer requires expensive investment in hardware development such as DSP and FPGA. Back then machine vision related companies were mushrooming in every corner of the developed world.

The digital evolution of industrial camera is fuelled by the ever growing appetite for higher resolution and faster frame rate. The machine vision industry looks towards digital interface when traditional analogue standards can no longer coped with the increasing demand.

During that period, with no single standard digital format, interoperability was near impossible. In October 2000, the very first digital standard known as Camera Link was introduced. It was, and still is, an expensive technology, but semiconductor equipment makers embraced it quickly as the need for quality inspection technologies exceed the cost it incurred. Unnoticeable by some, the Camera Link standard has actually fired off the first servo in the race for dominance in the digital age of modern machine vision .

Within a year after the induction of Camera Link, Pointgrey and AVT pioneered the firewire standard (1394A) developing range of successful low cost digital format cameras for the industry. The salient of this new technological front are AVT’s Dolphin series and Pointgrey’s Firefly series. Almost immediately, these cameras enter the industry like a welcoming storm from a long drought, shaking up the mainstream and low end machine market. Applications that require higher resolution and yet at a lower speed now have an alternative solution, Firewire instead of Camera Link. With the success of Firewire, industry innovators are now in two camps. With one camp tirelessly looking into high end dedicated imaging interfaces (deriving today HS-link and Coaxpress standard), predicting that this is the future industry needs.  While the other believes that there should be a low cost solution and ploughs ahead with commercial standards.

In 2006, the GigE Vision standard was inaugurated; it provided a much larger bandwidth and at the same time eliminated the limitation of cabling distance of firewire technology. Among the early adopters of this technology was Basler. The Basler Pilot series with Kodak sensor together with their Scout series with Sony sensor was first introduced in 2006. The impact of GigE Vision became apparent when Basler launches her Ace product near the end of 2009. Its success lies not only in her indigenous design but also the strategic alliances with major industry partners such as National Instruments and Cognex .

Today, USB3 Vision emerged as the new mainstream digital standard. Unlike its predecessors (GigE Vision and Firewire), USB3 Vision is more than a replacement technology for the earlier mainstream market. It has the great potential to penetrate into the untouchable high end area scan market that had been continuously dominated by Camera Link technology for the last 10 years.


Camera Link Base interfaces with a bandwidth of 255Mbyte/sec makes up the major demand for area scan Camera Link market. USB3 Vision with its 400Mbyte/sec bandwidth provides a competitive alternative to Camera Link Base. There is one major drawback in earlier technology such as GigE or Firewire, CPU loading for camera acquisition gets significant with increasing amount of data steamed to PC. USB3 is different from such earlier consumer technology, thanks to the use of DMA (Direct Memory Access), CPU loading becomes negligible.

Camera Link Base
Firewire
GigE Vision
USB3 Vision
Bandwidth
255MB/s
80MB/s
100MB/s
400MB/s
CPU Loading
Low
High
High
low
Triggering Concurrency on multiple cameras
High
Low*
Low
Low

Most OEM equipment makers are now keeping a keen eye on this technology and are seeking for the perfect moment to adopt the change. In 2 to 3 years time, the proliferation of USB 3.0 hardware on PC will become prevalence and in tandem, development in the consumers industry is working towards an overwhelming bandwidth of 10GB/s with USB 3.5. Already a Taiwanese chip maker, ASMedia, has planned to release her first USB 3.5 host controller by 2014. There are definitely plenty of rooms for improvement in the USB vision technology. A whole new world will emerge for machine vision as the evolution of USB technology in the consumer industry continues to advance. It is indeed an exciting time for the future of the industry.