Machine Vision Seeing in Color

With its latest machine vision systems, Omron has tapped into the growing need for fast color inspections in 2D and 3D

Joseph Ogando, Senior Editor -- Design News, August 28, 2008

Machine vision systems in general are starting to see the world a lot more clearly of late. "Applications have become a lot more demanding," says Paul Kellett, director of research for the Automated Imaging Association. "What you're starting to see more of, and this won't come as a surprise to anyone, is a trend toward higher speeds, higher resolution and greater use of color."  Kellett also sees an upswing in the use of 3D vision systems, which grew by 5 percent last year to make up 14 percent of application-specific vision system sales.

Omron Electronics taps into all of these trends with enhancements to its high-end vision systems to improve speed and color performance. Among those enhancements is a groundbreaking 3-D system that the company has not yet started to sell in North America – but will soon.

With its latest FZ2 systems, Omron has introduced True Color Vision sensors that can capture over 16.77 million colors. Tom Kahn, manager of the company's vision and RFID products, says the data volume associated with the color capabilities is more than 65,500 times greater than the volume associated with previous black-and-white image processing. "This vision sensor approaches the color-processing capabilities of the human eye," Kahn says.

Omron has upped the ante on speed as well. Its previous standard camera offered an input of 30 fps, or 33.3 ms. But a new 300,000-pixel camera bumps up that speed to 80 fps or 12.5 ms. For its high-definition 2-million-pixel cameras, which are just one of many camera options available on the FZ2, the capture speed is 30 fps, or 33.3 ms. "That's about twice as fast as earlier two-million-pixel cameras," Kahn says. Other architectural changes include the addition of an expanded memory buffer for each camera, which allows for continuous image capture while the system's main memory crunches measurement data.

The FZ2 system offers nine different types of smart cameras and a variety of related components. And a single controller can handle up to four cameras, allowing users to mix and match black-and-white and color cameras as needed for a given inspection job.

And soon those inspections will take place in 3D. Omron has developed its first vision-based 3D measurement system, one capable of making real-time hole, gap and defect inspections as well as handling part selection tasks on moving assembly lines. "Obviously, it was developed for automotive applications," says Kahn, though other assembly operation involving parts with complex shapes would be a natural fit too.

Kahn believes the vision-based system could replace some of the lasers now used for these applications. "The vision systems have a greater range and field of view than the lasers, so you can locate them further from the line," says Kahn. The trade-off for that location flexibility is accuracy. "Laser systems tend to work within the micron range," he says. "Our new vision system won't be that accurate, though it will be well within the range of automotive body panel tolerances."