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GigE Vision Meets Important Data Path Needs
Automated Imaging Association (Ann Arbor, Mich.)
The Challenge
While many interface standards are available to use in machine vision, there was still a large gap that frustrated many manufacturers, system builders and users. The industry wanted a commercial, high bandwidth, scalable solution that isn't limited in cabling length, is affordable and is true plug and play.
USB 2.0 is affordable and is certainly scaleable (up to 127 devices), but it offers a lower bandwidth and is limited in cable lengths. 1394b or FireWire™ has bandwidth a bit higher than USB 2.0 and is scalable (up to 63 devices), but is still limited in cable lengths. Camera Link® offers the highest bandwidth in industry today, but is limited in cable distance. You also pay a bit more for this high resolution.
The Solution
GigE Vision™ is a new camera interface standard developed using the Gigabit Ethernet communication protocol. It represented over 2 years of work by individuals from 12 companies serving the machine vision industry. The Automated Imaging Association (AIA) oversees the ongoing development and administration of the standard.
GigE Vision™ is the first standard to allow for fast image transfer using low cost standard cables over very long lengths. With GigE Vision™, hardware and software from different vendors can interoperate seamlessly over standard Ethernet connections. The GigE Vision™ standard has four elements:
- The GigE Device Discovery Mechanism, which defines how cameras and other compliant devices obtain IP addresses
- The GigE Vision™ Control Protocol (GVCP), which runs on top of Universal Datagram Protocol (UDP) IPv4. It defines how to control and configure compliant devices such as cameras, specifies stream channels and provides mechanisms for cameras to send image and control data to host computers.
- The GigE Vision™ Stream Protocol (GVSP), which defines data types and describes how images are transmitted over GigE.
- An XML description file based on the emerging GenICam™ standard, which provides the equivalent of a computer-readable datasheet to allow access to camera controls and image stream
GigE Vision™ offers many benefits including:
