Only two machine vision product groups grew in 2002 (relative to 2001) in unit volume or dollar amount, according to statistics published by the Automated Imaging Assn. (http://www.machinevisiononline.org). Those are off-line metrology and smart cameras. Only smart camera sales grew significantly in terms of dollar amounts, chalking up a whopping 42% increase in sales.
Just what is a smart camera? There is no precise definition, but comparisons to "dumb" cameras are illustrative. Dumb cameras simply capture an image, convert the image to a format (often proprietary) suitable for data transmission, and send the image to an image processor.
The image processor (usually a PC) frame grabber converts the image to a common digital data format so that it can be stored in memory. The image can then be used as an input to a control and data acquisition system.
A smart camera not only captures an image, it also contains a frame grabber and internal memory. Images captured by a smart camera can be transmitted via industry-standard digital data interfaces such as Ethernet, FireWire (IEEE-1394), and CameraLink digital video.
Smart cameras are often equipped with local diagnostics to detect problems and transmit information about malfunctions via their digital interface. Many smart cameras have internal logic that can be user-programmed to make real-time control decisions. Some smart cameras can be linked in peer-to-peer networks to create a field-based control system.
Smart cameras have much in common with smart field devices such as instruments and sensors used in distributed control systems. Both smart field devices and smart cameras provide a number of advantages to machine builders.
Trade associations predict strong growth for smart cameras, and machine vision vendors confirm this trend. "We sold 15,000 smart cameras from 1996, when the company was established, through 2001," says Endre Toth, director of business development for Vision Components (www.vision-comp.com). "In 2002 alone, we sold 10,000 smart cameras."
Just why are machine builders buying so many smart cameras? One reason is to simplify implementation. Smart cameras are much easier to install and start up than their dumb cousins. There are just two cables to connect: one for power and one for digital communication. The digital communication cable uses a standard interface, rather than the proprietary interfaces common to most dumb cameras.
Camera vendors are aware that ease of use is a huge issue with machine vision systems, so they also provide software that allows their smart cameras to be programmed via fill-in-the-blanks graphical interfaces.
To further ease programming, at least one vendor allows users to program smart cameras via a web browser. Coreco Imaging's ipd division (www.goipd.com) supplies its vision products with a web server and an Ethernet port. Users program these smart cameras via a web browser.
"Because the web server software is resident in the vision appliance, the user interface is delivered via a web browser," says Steve Geraghty, director of ipd. "This means that users don't have to deal with software installation and programming as with most smart cameras."
To further simplify implementation, many vision solutions are designed for a particular, sometime unique, machine vision application.
Another way to simplify implementation is for a vendor to tightly link smart cameras with application software. National Instruments (www.ni.com) provides this linkage by supplying both cameras and software specifically designed for real-time machine vision applications.
"We couple our LabView Real Time technology with our vision hardware to provide our customers with reliable and deterministic software and hardware for mission-critical applications," reports Jason Mulliner, NI's machine vision product manager. "Our customers can create ruggedized machine vision systems because the hardware has no moving parts, no vents, and extended operating temperatures."
Other vendors that are seeing strong growth in smart cameras are DVT (www.dvtsensors.com) and Cognex (www.cognex.com). "Key technologies driving the growth of smart cameras are electronics, networking, and software," says George Blackwell, Cognex director of product marketing. "Advances in processor speed and power allow for more robust vision software and algorithms. Manwhile, cost-per-node reductions and proliferation on factory floors has propelled Ethernet to the forefront of industrial networking and smart camera interfaces."
The final key component to rapid acceptance of smart cameras is software. Instead of low-level programming with C++ or VisualBasic, most smart cameras now provide users with menu-driven development environments.
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