GigE vision
GigE Vision[1] is an interface standard introduced in 2006 for high-performance industrial cameras. It provides a framework for transmitting high-speed video and related control data over Ethernet networks. The standard was initiated by a group of 12 companies and the committee has since grown to include more than 50 members.[2] The 12 founding members are: Adimec, Atmel, Basler AG, CyberOptics, DALSA, JAI A/S, JAI PULNiX, Matrox, National Instruments, Photonfocus, Pleora Technologies and Stemmer Imaging. The Automated Imaging Association (AIA)[3] oversees the ongoing development and administration of the standard. GigE Vision is a registered trademark of the AIA.
GigE Vision is based on the Internet Protocol standard. The standard is trying to unify protocols currently used in machine vision industrial cameras and let 3rd party organizations develop compatible software and hardware. The GigE Vision standard is - by a few definitions (for example, the ITU-T) - an open standard. However, it is available only by signing a non-disclosure agreement, so it is considered by many European countries to be a closed standard. It is available under license to any organization for a nominal fee.[4][5] Additionally, membership in the AIA is open to all organizations,[6] and thus there can be wide representation on committees. One consequence of the license is that it is not possible to write open source software using the GigE Vision specification, as it could reveal the details of the standard, which is why most image acquisition SDKs for GigE Vision are closed source. There is currently at least two different free software projects trying to implement the GigE Vision protocol by reverse engineering.[7] [8]
Features of the GigE Vision standard:
- Fast data transfer rates - up to 1000Mbit/s (based on 1000BASE-T). However, as the standard does not preclude the usage of 10 Gigabit Ethernet, devices capable of operating at that rate will begin appearing on the market in 2012.
- Data transfer length up to 100m (some producers claim even 150m). The use of switches, repeaters or fiber optic converters can increase the length. The performance of each implementation of the GigE Vision standard varies with the quality of the compliant equipment used. Some implementations will achieve very low latency, even in the presence of switches and repeaters, while others will not.
- Based on established standard allowing networking with other Ethernet devices and computers.
- Delivers a standardized environment for the delivery of new-generation, networked video applications based on switched client/server Ethernet architectures.
GigE Vision has four main elements:
- GigE Vision Control Protocol(GVCP). 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(GVSP). Runs on the UDP protocol. Covers the definition of data types and the ways images can be transferred via GigE;
- GigE Device Discovery Mechanism. Provides mechanisms to obtain IP addresses;
- An XML description file based on a schema defined by the European Machine Vision Association's GenICam standard. A datasheet that allows access to camera controls and image stream.[9]
