Board gives vision-based inspection a speed boost

An image-acquisition board from National Instruments can speed the performance of vision-based inspection systems commonly used in making semiconductors, optoelectronics, telecommunication devices and automotive components. Known as the PXI-1409, the board is designed for use with high-resolution analog cameras whose output is digitized for megapixel performance and double-speed scan rates.

National Instruments engineers said the key advantage is the board's use of the increasingly popular PXI (CompactPCI extension for instrumentation) standard, which lets it quickly pass data to digital I/O boards or motion cards. To accomplish that, its local bus allows devices to communicate with each other without borrowing bandwidth from the host PCI bus.

"You can send high-bandwidth information across the local bus between adjacent modules and take up zero of the PCI bandwidth," said Eric Starkloff, PXI and instrument control platform manager for National Instruments. "That way, you free up the full bandwidth for streaming large images, and you don't degrade the performance of your PC."

The local bus, also known as a real-time systems integration (RTSI) bus, is embedded in the PXI backplane and uses no external cabling. It incorporates built-in switching, enabling the vision system to route signals to and from the bus instantly through software. It is available for chaining two, three, four or five boards together. During operation of the vision system, the backplane handles all of the RTSI functions.

"The ability to have an image-acquisition card talk directly to a motion card or other device and not have an Intel processor intervene is very powerful," said Jason Mulliner, National Instruments' imaging-products manager. Since it's built directly into the backplane, "devices can plug in and automatically use it."

The PXI configuration is also a key enabler for the PXI-1409's compatibility with faster, double-speed progressive-scan cameras, which operate at up to 60fps.

The data-acquisition board also includes four video inputs to connect multiple cameras, as well as hardware calibration to ensure consistent and repeatable image acquisition.

National Instruments said that the PXI-1409 and its updated driver software enable engineers and scientists to easily change the type of camera used in their applications. They reportedly can replace a low-cost, lower-resolution camera with a higher-resolution model with only a few software changes. The company said that the use of such high-resolution cameras is becoming critical in some vision applications, such as inspection of wire bonds on electronics modules and submicron measurements of optoelectronic devices. "The bottom line is that this board enables inspection of more parts per second, even at higher resolutions," Mulliner said. The PXI-1409 is priced at $1,395.

? Charles J. Murray

EE Times