Interface

Machine Vision Camera Interface

pyramidimaging

Machine vision cameras are used in a variety of applications, including semiconductors, electronics, biotechnology, assembly, and manufacturing industries. The best camera system for the task at hand is crucial to achieving the best image quality. Digital cameras are available with a variety of interface options that are often dependent on an application’s requirements. Some formats, such as the USB varieties, can greatly simplify the setup process by supplying video output and power via a single interface. Other formats may require an additional power supply but provide advantages such as higher data transfer rates, which affects the camera’s framerate, or support for a greater number of simultaneous devices. The following table compares the different digital camera interfaces: 

Digital Interface Data Transfer Rate Max Cable Length # Devices Connector Capture Board 
USB 3.1 5Gb/s 3m (recommended) up to 127 USB 3.1 Micro B/USB-C Optional 
GigE (PoE) 1000 Mb/s 100m Unlimited RJ45 / Cat5e or 6 Not Required 
5 GigE (PoE) 5Gb/s 100m Unlimited RJ45 / Cat5e or 6 Not Required 
10 GigE (PoE) 10Gb/s 100m Unlimited Cat7 or Optical Cabling Not Required 
CoaXPress up to 12.5Gb/s >100m at 3.125Gb/s Unlimited RG59 / RG6 / RG11 Optional 
Camera Link® up to 6.8Gb/s 10m 1 26pin Required 
USB 3.1 Gen 1 is a popular interface due to its ubiquity among computers. It is high speed and convenient; maximum attainable speed depends upon the number of USB peripheral components, as the transfer rate of the bus is fixed at 5 Gb/s. Gigabit Ethernet (GigE) and 10Gigabit Ethernet (10GigE) are other popular interfaces. CoaXPress and Camera Link® are dedicated machine vision interfaces typically used in such applications. In addition to the cameras, systems using these interfaces require frame grabbers. These are specialized adapter cards to receive image data and assemble it into usable images. 

Please note that the choice of interface depends on your specific application needs, including factors like bandwidth, cable length, power delivery, system cost, and ease of integration.

  • FireWire (IEEE1394b): This interface, which is declining in use, has a bandwidth of 80 MB/s and a cable length of 4.5 m. It has low CPU usage and excellent support for multiple cameras. 
  • Gigabit Ethernet (GigE): Widely used GigE has a bandwidth of 125 MB/s and a cable length of 100 m. It has medium CPU usage and good support for multiple cameras.
  • USB 3.1: This increasingly used interface has a bandwidth of 400 MB/s and a cable length of 3 m. It has low CPU usage and excellent support for multiple cameras.
  • Camera Link: Camera Link was Launched in 2000 by Automated Imaging Association (AIA). CameraLink has been upgraded progressively, and now has an HS version, to support higher data speeds, with some versions requiring two cables for transmission.
  • CoaXPress (CXP): Launched in 2008, CXP interfaces use 75ohm coaxial cables and support data transfer speeds of up to 6.25Gbit/s per channel, with the ability to use multiple channels to support even faster data transfer rates.

Published by pyramidimaging

Dr. Rex Lee is a high tech industry veteran and serial entrepreneur with over 45 years of experience in company startups, R&D, manufacturing operations, sales and marketing. Rex has been the owner of 5 high technology companies, holds two patents, published over 50 articles and been an Electrical Engineering Professor at two large universities. He has a Bachelor’s degree in Physics, a Master’s degree in Biophysics and a Ph.D. in Engineering Science. He is currently the founder CEO/President of Pyramid Imaging, LLC. Dr.Lee was a member of the Board of Directors AIA, Automated Imaging Association, part of A3 group that consists of RIA, Robotics Industry Association, and MCMA, Motion Control and Motors Association.

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