Tutorial: What is the GigE Vision standard?
GigE Vision is a camera interface standard developed using the Gigabit Ethernet communication protocol. Here's what it can do to improve your application. See photos, links.
By Control Engineering Staff
The NI PXIe-8234 dual-port gigabit Ethernet controller transfers images at full gigabit Ethernet bandwidth through both ports simultaneously.
GigE Vision is a camera interface standard developed using the Gigabit Ethernet communication protocol.
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.
Articles in the May 2009 Control Engineering North American print edition supplement:
“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"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.
Version 1.1 arrives
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. The NI 8234 module provides support for GigE Vision, transfer speeds up to 1000 Mb/s on each of two gigabit Ethernet ports, and support for
According to NI, engineers and scientists can add GigE modules to a PXI Express system to use more GigE Vision cameras with the NI 8234. As a result, they can stream images from multiple GigE Vision cameras simultaneously to a PXI platform. Visit the National Instruments website for more on this and other vision products .
JAI in April announced the release of two new high performance 16-megapixel cameras equipped with standard GigE Vision digital interfaces.
In April 2009, JAI announced the release of two new high performance 16-megapixel cameras equipped with standard GigE Vision digital interfaces. The new models join the Camera Link versions introduced in December as part of the “Advanced” series of the company’s multi-tiered C3 Camera Suite.
Like the previous models, the new GigE Vision cameras incorporate the Kodak KAI-16000 dual-tap progressive scan CCD to deliver full 4872 x 3248 pixel resolution at 3 frames per second. The AM-1600GE provides monochrome output, while the AB-1600GE produces raw Bayer color output for host-based interpolation. Both models feature user-selectable 8-bit, 10-bit, or 12-bit output.
A series of pre-processing functions are built into the camera to achieve high image quality while offloading these tasks from the user’s host PC.he cameras are compatible with any GigE Vision/GenICam-compliant application development tools, and are also supported by JAI’s own comprehensive camera control tool and SDK package.
See the Machine Vision supplement in the Control Engineering May 2009 issue for an article on how motion and vision combine to detect flaws in plastic film using another NI PXI board.
Also see the Machine Vision supplement in the Control Engineering May 2009 issue for an article on how machine vision system integrator CI Vision used the GigE Vision camera interface standard, a Matrox 4Sight X industrial PC, and its own CIVCore software to prevent operators from bypassing an image-based quality control system.
– By Renee Robbins , senior editor
Control Engineering News Desk
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