GigE Vision and beyond

The GigE Vision standard for the transfer of image data from a camera to a host computer was developed in 2006, following CameraLink as the second data transfer standard produced specifically for the machine vision industry. The standard is based on Gigabit Ethernet technology and offers users a number of key benefits:

• Data transmission at rates up to 110 Mb/sec over distances up to 100m, using standard Ethernet cables and components. 

• Compatibility and interchangeability of GigE Vision cameras from any manufacturer.

• The network structure means that frame grabbers are not required .

Managed by the AIA trade association (www.visiononline.org) the GigE Vision standard has been adopted globally, with most major industrial vision hardware and software vendors having developed products that are GigE Vision-compliant. Since its launch it has proven to be particularly popular in factory installations where the use of Ethernet cabling and components is common practice, and because of the long distances over which images can be transmitted without repeaters. However, with the increasing availability of ever higher resolution CMOS image sensors and ever faster inspection speeds, the amount of data needing to be transferred has increased significantly and this has led to the need for higher speed data interfaces. 

“The vision industry has reacted to this need with the development of further vision standards – notably CameraLink HS, CoaXPress and most recently, USB3 Vision,” said Allan Anderson, chairman at the UK Industrial Vision Association (UKIVA).  “While these all offer higher data transmission rates than GigE Vision, none can transfer images over similar distances without the use of special cables and/or repeaters. 

“For applications where the higher data transfer rates are essential, then one of the alternatives must be used, with whatever associated complexity of cabling. Nevertheless, GigE Vision continues to dominate the market, with a survey conducted in 2018 by one UKIVA member indicating that GigE Vision still accounted for over 40% of the machine vision systems used. According to Mordor Intelligence, the GigE camera market was worth $0.81 billion in 2017.” 

The GigE Vision standard has evolved since its original launch. GigE Vision 2.0, released in 2011, improved the real-time synchronisation of multi-camera systems by utilising the IEEE 1588 Precision Time Protocol to allow each camera on the network to be simultaneously triggered.  

Version 2.1, announced in 2018 now features multi-part transmission. This allows the sending of more complex data structures used in 3D imaging or any application which would benefit from a 3 coordinate data structure. The continuing popularity of the GigE Vision standard is undoubtedly related both to the distances over which data can be transmitted and the ease of integration using industry standard components. It therefore comes as no surprise that increasing the data transmission rate within this framework in order to accommodate greater data volumes is a continuing goal. 

Different approaches have been applied to boost standard GigE Vision capabilities, ranging from link aggregation to proprietary software solutions. Nevertheless developing more wide-ranging Ethernet solutions is a preferable approach. The networking stack used is divided into a number of different layers. The ‘Ethernet’ layer is unaware of the protocols and connections of the layers either above or below it which means the technology is future proofed. The latest development is the use of NBASE-T to allow users to get the benefit of significantly increased data throughput without the expense and difficulty of replacing existing Ethernet cabling. Fully compatible with GigE Vision, NBASE-T is an extension to the IEEE 802.3 Ethernet standard and increases data transmission using industry standard CAT 5e cable to speeds of 2.5 and 5 Gb/s for 2.5BASE-T and 5BASE-T respectively and to 10 Gb/s using CAT 6A cable for 10BASE-T. 5BASE-T exceeds the data transfer speeds of both USB 3.1 (Gen1) and USB 3.0, while 10BASE-T also exceeds rates for CameraLink (Full/80-bit) and CoaXPress (single lane CXP-6). They all maintain the original GigE Vision data transmission distances of up to 100 metres. A number of 5BASE-T and 10BASE-T cameras are now available from UKIVA members, to take advantage of these improved data transfer rates.

Stemmer Imaging has supplied and supported a wide range of GigE Vision cameras since the standard was introduced. Mark Williamson, managing director at Stemmer Imaging UK,  has seen no decline in their popularity. He said: “We are particularly excited by a new range of 5BASE-T cameras that combine the higher inherent data transfer rates with in-built proprietary technology utilising sophisticated pixel analysis and processing to deliver an overall bandwidth of 985 MB/sec. That is over double the speed of USB3 and approaching the speeds of 10BASE-T, but it requires only standard Cat5e cables that operate up to 100m cable lengths. They are also significantly physically smaller and consume less power than 10 GigE Vision cameras, allowing deployment in a wider range of factory applications.”