Machine vision’s GigE Vision standard

GigE Vision is a camera interface standard developed using the Gigabit Ethernet communication protocol. In industrial machine vision applications, GigE Vision allows fast image transfer using low cost standard cables over very long lengths. It also allows hardware and software from different vendors to interoperate easily.

06/01/2009







A number of products already support the standard. National Instruments offers a high-performance dual gigabit Ethernet interface for PXI Express, while JAI has released two high performance 16-megapixel cameras equipped with standard GigE Vision digital interfaces.

GigE Vision is a camera interface standard developed using the Gigabit Ethernet communication protocol. In industrial machine vision applications, GigE Vision allows fast image transfer using low cost standard cables over very long lengths. It also allows hardware and software from different vendors to interoperate easily.

The Automated Imaging Association (AIA) oversees the ongoing development and administration of the standard. GigE Vision has been developed by a group of about 50 companies, including: Adimec, Atmel, Basler AG, CyberOptics, DALSA, JAI A/S, JAI PULNiX, Matrox, National Instruments, Photonfocus, Pleora Technologies, and Stemmer Imaging. Based on the Gigabit Ethernet standard, which uses standard Ethernet category cabling, GigE Vision is trying to unify protocols currently used in machine vision industrial cameras and let third-party organizations develop compatible software and hardware.

“Since the standard’s adoption in 2006, GigE Vision cameras increased six-fold in units sold and over five-fold in sales revenue. This... leaves little doubt of the growing importance of GigE Vision,” said Paul Kellett, AIA’s director of market analysis. GigE Vision should not be confused with devices that only say they are “GigE,” he adds. While a GigE device may use Ethernet connectivity, those without the “GigE Vision” logo do not use the GigE Vision communication protocol and will not plug-and-play with GigE Vision compliant devices.

Features of the GigE Vision standard include fast data transfer rates—up to 1,000Mbit/s (based on 1000BASE-T)—and data transfer length up to 100 m (some producers claim even 150 m). This exceeds the maximum length of firewire, USB and Cameralink, a serial communication protocol for machine vision applications also administered by the Automated Imaging Association. The use of switches or repeaters increases the length and, while the cabling is simpler, a separate cable is required to supply power to the camera.

GigE Vision has four main elements:

  • GigE Vision control protocol, which runs on the UDP protocol. The standard defines how to control and configure devices. Specifies stream channels and the mechanisms of sending image and configuration data between cameras and computers;

  • GigE Vision stream protocol, which covers the definition of data types and the ways images can be transferred via GigE;

  • GigE device discovery mechanism, which provides a means to obtain IP addresses; and

  • An XML description file based on the GenICam standard. This datasheet allows access to camera controls and image stream.

Last month the GigE Vision standard committee released Version 1.1 of the standard, and announced new features. Additionally, the standard– which was originally released only in English – is now also available in Japanese. Eric Carey, chair of the GigE Vision standard committee notes, “This is the first revision of the specification since it was introduced. While not introducing new camera features itself, the subtle changes allow developers and camera manufacturers to better control internal processes thus allowing for more full-feature camera options.”

The committee intends for the interface to follow the growth of Ethernet bandwidth, and it is already preparing for incorporation of 10GigE as it becomes the mainstream protocol, says Carey.

Among the many changes, clarifications, and improved documentation are several new features including new pixel formats and Bayer format support; improved error handling; support for multiple versions of the GenICam schema and GenAPI; and new commands allowing action commands to be sent to multiple devices simultaneously as well as managing the execution time.

A number of products already exist supporting the standard. For example, in June 2008 National Instruments announced its first high-performance dual gigabit Ethernet interface for PXI Express. In April 2009, JAI released two new 16-megapixel cameras with GigE Vision digital interfaces as standard. The cameras are compatible with any GigE Vision/GenICam-compliant application development tools, and are also supported by JAI’s own camera control tool and SDK package.

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Author Information

Renee Robbins is senior editor for Control Engineering. Reach her at renee.robbins@reedbusiness.com .