Advanced Imaging


Advanced Imaging Magazine

Updated: July 8th, 2008 05:26 PM CDT

Processing is Progressing

Matrox Odyssey ECL supports Camera Link acquisistion and features x4 PLIe implementation.
The X64-CL GigE Series digital frame grabber board from Dalsa Coreco.
Vision Components SBC4018 features 16 Mbytes of on-board SDRAM image/data memory.
American ELTEC's PC-EYE/ASYNC frame grabber.
National Instruments' PCI-8254R image-acquisition board enables access to 29 digital I/O lines for synchronizing vision components.

By George Kotelly
Contributing Editor

In the past, developers of ultra-high-speed vision systems have mostly used image-processing and frame-grabber boards to analyze images acquired from industrial cameras. In general, image-processing boards function as frame-grabbers but with on-board logic that can analyze images. These processing boards come in many flavors, from multi-purpose x-86-based computers to special Field Programmable Gate Array (FPGA)-based devices.

As PC processors continue to boost speed and memory at decreasing costs, engineers are investigating their use instead of dedicated image-processing boards. As tempting as this option appears, it is often limited by the PCI (Peripheral Component Interconnect) bus speed of 133 Mbytes of data per second.

However, the recent introduction of faster PCI Express technology has diminished the transfer bottleneck between camera and host CPU. Most new image-processing boards are now used in one of two ways to help process multiple images: to work in parallel or to preprocess images.

Several communications interface standards also have contributed greatly to the surging implementation success of integrating digital cameras and image-processing boards into machine-vision systems, including Camera Link, IEEE 1394 (FireWire), GigE (Gigabit Ethernet) Vision, and PCI Express.

Interface Standards

Under the direction of the Automated Imaging Association (AIA, www.machinevi, Camera Link and GigE Vision are connectivity standards for interfacing digital cameras and frame grabbers. Camera Link specifications define data transmission, camera control, and asynchronous serial communications, all on a single cable. As a result, only two connections (power and Camera Link) via a single MDR-26 pin connector are needed. Benefits include: easy product interchange, simple interface, small and inexpensive cables, image data to 28 bits, and data rates to 2.3 Gbytes/sec. Similarly, GigE Vision is delivering data rates to 1 Gbit/sec over Ethernet networks.

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