Pros and cons of high-speed machine vision interfaces

When deciding on which machine vision interface would be best for an application, it's important to assess the application's unique needs and consider ease of deployment, cable length, low life-cycle cost and customer ecosystem.
By AIA May 27, 2018

Image courtesy: Bob Vavra, CFE MediaFor high-speed machine vision imaging applications, finding the right camera interface is a critical part of achieving the desired imaging performance for an application. But with so many different interfaces and performance considerations, it can be difficult to find the right one. The most common camera interfaces for high-speed applications include USB 3.2, Thunderbolt3, CoaXpress 2.0, 10 Gigabit Ethernet, and CameraLink HS. Each of these camera interfaces differs in performance and potential applications.

Performance considerations for high-speed camera interfaces

When deciding on which machine vision interface would be best for an application, it’s important to take a holistic view of the vision and imaging performance attributes that are needed and prioritize based on what will have the greatest impact on the application.

While it’s important to assess the application’s unique needs, there are a few performance attributes of camera interfaces to assess regardless of the application. These would include throughput, ease of deployment, cable length, low life-cycle cost and customer ecosystem. 

Pros and cons of high-speed machine vision interfaces

Each high-speed camera interface has several pros and cons in relation to the above performance considerations:

  • USB 3.2: this camera interface is twice as fast as USB 3.1 with a 20 Gigabit/second transfer speed, but short cable lengths and high costs limit their adoption.
  • Thunderbolt3: these interfaces allow for extremely high transfer speeds of 40 Gigabit/second and allows for daisy-chained hosts, but short cable length of 0.5 meters for passive copper cables is an important drawback for some applications.
  • CoaXpress 2.0: this camera interface allows for 4K60 video over a single cable with triggering rates over 500 kHz, but still requires a frame grabber and becomes expensive for purpose-built multi-core assemblies.
  • 10 Gigabit Ethernet: with long cable lengths and reliable transfer, these camera interfaces are perfect for a range of industrial applications, but low throughput limits their ability in many high-speed applications.
  • CameraLink HS: these camera interfaces feature error correction for reliability and come with many cable options, but they still require frame grabbers and their speed drops as the cable length increases.

Finding the right camera interface in high-speed vision and imaging applications is one of the most important parts of achieving the desired system performance. The camera interfaces listed above are the ones best suited for high-speed applications, although each has various pros and cons.

This article originally appeared on the AIA website. The AIA is a part of the Association for Advancing Automation (A3). A3 is a CFE Media content partner. Edited by Chris Vavra, production editor, Control Engineeringcvavra@cfemedia.com.

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