USB 3.0 is the next generation of (camera) interfaces, and it is already off to a strong start. An interface serves as the junction between two systems, such as a smartphone and electrical socket, or between camera and PC. Currently, USB is the most common interface for the mass market. To make this consumer-oriented interface functional and stable enough for use in industrial settings, a coalition of different camera makers came together to develop an industrial standard for the USB 3.0 interface. The result: the USB3 Vision standard, published in January 2013. Using this standard, hardware and accessories can be tested for USB3 Vision compliance. Any components earning this certification are guaranteed to work together smoothly and stably and to meet the industry’s stringent specifications.
USB 3.0 and its Competitors
Of course, USB 3.0 isn't the only camera interface on the market. Other popular interfaces include GigE (Gigabit Ethernet), Camera Link, FireWire and USB 2.0. Each of these interfaces has pros and cons and a different ideal use scenario. GigE, for example, works well with long cables, while Camera Link is a good option when very large volumes of bandwidth are required.
FireWire and USB 2.0 are older technologies with significant technical limitations; as the number of components compatible with the technology begins to dwindle they can no longer be recommended without reservation. In its time, FireWire offered impressive plug and play and real-time compatibility, but there are already now fewer affordable components for FireWire, and the trend is likely to continue. Replacing defective components is expected to become more expensive and difficult. FireWire will in fact likely disappear from the market in the medium term. USB 2.0 devices are very cheap and universally available, but the interface itself has already been surpassed by its successor USB 3.0. More on that later in this discussion.
Depending on the requirements of your application, you can also generally choose between Camera Link, GigE or USB 3.0 to achieve the best combination of properties to deliver image data quickly, securely and reliably from camera to PC.
USB 3.0 combines the positive features of several different interfaces. It offers a volume of bandwidth to close the gap between GigE and Camera Link. Beyond this, there is plug-and-play compatibility, low CPU load and the reliable USB3 Vision industrial standard. Beyond this, USB 3.0 offers highly reliable data transfer between host and device and integrated (buffer) memory for top stability in industrial applications.
USB 3.0 vs. GigE
USB 3.0 is a relatively new camera interface, and has not yet penetrated the machine vision market as deeply as the consumer market. Experience shows that industry usually lags by about five years before a new interface arrives and is accepted on that market. One good example of this: the roll-out of the GigE Vision standard back in 2006. It took a number of years before GigE won over enough users worldwide to gain the necessary critical mass. Today GigE is one of the most important interfaces for Vision technology.
USB 3.0 vs. USB 2.0
As mentioned earlier, we should also offer a comparison of USB 3.0 with its "predecessor" USB 2.0. One of the prime arguments to date in favor of USB 2.0 — the tremendous availability of USB 2.0 components — no longer applies. The latest generation of computer hardware comes with USB 3.0 connections pre-installed.
The availability of USB 3.0 components will continue to increase in coming years.
Another argument for USB 3.0 is the larger bandwidth, which allows cameras to work faster. In addition, recent camera sensors, such as the latest generation of CMOS sensors, require more power than their predecessors. This prevents them from being used with USB 2.0 cameras. The USB 3.0 interface, by contrast, delivers enough power to operate those sensors. The interface is also perfectly equipped to work with the resolution levels produced by the new generation of sensors without cutting speeds.
What does the future hold?
USB 3.0 faces the same issues as every new interface: switching over to a new technology only makes sense if it adds real value. Yet USB 3.0 is clearly progressing quickly, with a market share growing from year to year. The USB3 Vision standard is also expected to take a stronger hold of the market in coming years. This will promote USB 3.0 — together with GigE — to the status of leading interface on the market for industrial machine vision.