Category: Interface

Machine vision camera interface information

Interface

Machine Vision Camera Interface

pyramidimagingLeave a comment

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.
Camera Link · CoaXPress · Range Extenders

Extending your Vision – How Range Extenders are adding value to High Speed Machine Vision Applications

pyramidimagingLeave a comment

Over the last 18 years, options for acquiring and analyzing images has increased dramatically.  Today’s choices include Camera Link, CoaXpress, Camera Link HS, USB (2 and 3), GigE Vision, 10 GigE and the newer Thunderbolt I/O.  However, limits exist for all these technologies with regards to cable length and bandwidth.  These limits create challenges for even the most experienced machine vision application engineer.

Camera Link and CoaXPress are highly recommended for high speed events.  Camera Link (now at version 2.0) is still a go to standard, with a maximum distance of 10 meters and a payload throughput of 850 MB/s it was built for real time, high bandwidth communication.  Buyers of Camera Link have plenty of options when it comes to the cameras, as well as all the connected devices that use the Camera Link standard (as of the last posting, 84 manufacturers have licensed Camera Link products).   The newer, CoaXpress standard was introduced by the Japan Industrial Imaging Association in 2009 and in cooperation with other interested parties maintain the standards.  CoaXpress offers users up to 6250 Mb/s of data transfer at 40 meters and 1250 MB at 130 meters which is more robust, although there are less than 10 manufacturers of CoaXPress cameras, supported devices such as Frame Grabbers and cables are well represented in the industry.

With the limits on distance and bandwidth, Camera Link and CoaXPress posed design challenges as the cameras had to be closer to the objects being captured and recorded.  Technology introduced in 2016 allows extending the range and maintains the high quality, high speed imaging for which standards are known.

Leading the way in these technologies, Kaya Instruments based in Israel has introduced extenders for both Camera Link and CoaXPress.  Constructed of two converters, one on the camera side and one on the Camera Link/CoaXPress frame grabber side, these devices provide bidirectional communication over fiber.  The camera link extender offers 10.3125 Gbps equal to Camera Link Full/80 bit (Deca) over a single fiber cable. The CoaXPress extender introduced in 2017, increases the standard CoaXPress transmission distances yet maintains the low jitter, low latency and high resolution CoaXPress delivers.  The extender enables video, control signals and power over CoaXPress (PoCXP) transmission for full control of data stream and camera handling. The CoaXPress range extender can provide a downlink of up to 6.25Gbps and uplink at 20.83Mbps.  Other options from Kaya Instruments include; CoaXPress over Coax, Single Link CoaXPress. Additionally, acquisition systems for both Camera Link and CoaXPress provide the extended distances and increases data transfer rates using interface boards with the extender.  Starting at around $1,500 these devices will expand Camera Link and CoaXPress capabilities making these standards a solid go to solution for high speed, high bandwidth, extended distance applications.

Other manufacturers are also recognizing the need to extend the range of Camera Link and CoaXPress.  Manufacturers Phrontier Technologies, SkyBlue, and Vivid Engineering are just a few who have solutions available.

So, don’t let the limit of the standard hold you back, these relatively low-cost devices can Extend your Vision.  If you are facing a challenging vision project, give us a call or email us at sales@pyramidimaging.com.  With 20 years of experience in machine vision, we have most likely already solved your challenge.  Machine vision is touching every industry and solving real world problems, can’t wait to see where you all take it next.