GigE Vision - Gigabit Ethernet Cameras for Industrial Applications
Camera interface standards for machine vision cameras have evolved over the last ten years. A decade ago, industrial digital cameras were very difficult to install and integrate into machine vision systems. The difficulty was largely because there were no camera interface standards. System integrators and end users desparately needed something more standardized.
In the late 90's, the AIA formed a camera interface standard based on channel link, a parallel bus designed particularly for laptop computer displays. By defining a standard cable and connector, together with some standardized signal assignments, the Cameralink™ standard was born. Around the same time, IEEE-1394 firewire cameras were conforming to a digital camera interface standard called DCAM, now more commonly known as IIDC. The DCAM (IIDC) camera interface standard went further than Cameralink in that it not only defined a standardized hardware interface but also defined a standardized software control interface making DCAM-compliant firewire cameras truely plug and play. Until recently, these two interfaces have dominated the industrial digital camera market.
However, there is a new interface standard that will soon dominate the industrial camera market. The AIA GigE Vision™ standard for Gigabit Ethernet cameras is now the state of the art interface for high-performance digital cameras for machine vision and industrial applications.
What is Gig-E?
GigE, or Gigabit Ethernet, is a particularly fast version of Ethernet which everyone knows and loves. Every one is familiar with Ethernet because it is the ubiquitous means of connecting a computer to a network. Standard Ethernet has a maximum data rate of 10 megabits per second (Mbps) and Fast Ethernet has a maximum data rate of 100 Mbps, but Gigabit Ethernet is much faster at 1000 Mbps. Standard Ethernet and Fast Ethernet are too slow for streaming uncompressed image data, and way too slow for machine vision cameras. Gigabit Ethernet (GigE), however, with its maximum data rate of 1000 Mbps, or 1 gigabit per second (Gbps) is capable of handling streaming image data and providing reliable transmission of image data from high performance machine vision cameras such as the Gigabit Ethernet cameras from Prosilica Inc. Prosilica's GigE cameras are capable of streaming data at a sustained rate of 125 megabytes per second over their gigabit Ethernet interface.
What is GigE Vision?
The GigE Vision™ standard from the AIA is an interface standard for high-performance machine vision cameras that is widely supported in the industrial imaging industry. GigE (Gigabit Ethernet), on the other hand, is simply the network structure on which GigE Vision is built. The GigE Vision standard includes both a hardware interface standard (Gigabit Ethernet) and standardized means of communicating with, and controlling, a camera. The GigE Vision camera control registers are based on a command structure called GenICam which is administered through the European Machine Vision Association (EMVA). GenICam seeks to establish a common camera control interface so that third party software can communicate with cameras from various manufacturers without customization. GenICam is incorporated as part of the GigE Vision standard, so any truly GigE Vision-compliant camera also complies with GenICam. GigE Vision is analogous to Firewire's DCAM (IIDC) and has great value for reducing system integration costs and for improving ease of use.
