Cognex’s vision for vision technology
January 11, 2011 - MMH Editorial
I received a press release from Cognex before the holidays announcing a new overhead image-based bar code reader for postal, logistics and retail applications.
Vision-based or camera-imaging systems are something we don’t write about often at Modern, in part because they have seemed to have limited adoption. Manufacturers use them for quality inspection. Big box retailers and parcel carriers use them for bar code reading in high speed, high throughput handling applications, like quickly scanning hundreds of bar codes in a parcel operation. I also interviewed a wine and spirits distributor last year that was using a vision system to verify the contents of cartons of liquor before they left the distribution center. If there was a dispute when that carton was opened at the customer’s location, the distributor had a record of what left the DC.
In some respects, that’s still the state of adoption today, Jorge Schuster, Cognex’s director of ID sales for the Americas, told me. In part, that’s because camera-based image systems are expensive. “If you look at the full spectrum of bar code applications, laser scanners are affordable and do a pretty good job at the low end of things,” he said. “At the high end, large camera systems run tens of thousands of dollars for a six-sided reader system for a high speed parcel application. No one has really created an affordable image-based reader for the medium range of the solution spectrum, so like the bottom end, it has been dominated by lasers.”
Schuster defined a medium range application as a 36-inch wide conveyor moving at 500 feet per minute with an affordable fixed reader designed to just read the top or side of a carton.
That’s the niche that Cognex is aiming for with its new reader. “We’ve developed a proprietary chip that allows images to be processed very quickly, at a speed of about 1,000 frames per second,” Schuster said. “In the past, a laser-based bar code reader would struggle in that environment, so people overbought an imaged system to get something that would work. Our system is price competitive with laser scanning, and is easier to install than a typical vision system, which often needs a specialist for installation.”
Why does someone need an image-based system? A laser-based bar code scanner does one thing: it reads a bar code. With an image-based system you not only read the bar code, you can also capture the image of that bar code for later use. If you start getting no reads, you can go back to the stored images to see if there’s a problem with the bar codes themselves. For instance, is a printer on the fritz, or are your associates loading the bar code improperly on the conveyor? Lettering on a label or a carton can be read by an OCR system. And, like the liquor distributor, that store image can be used for loss prevention.
“Vision is still used by parcel, postal and big box retailers,” Schuster said. “If you’re getting packages and labels from all over the world, well, that’s when a laser-based system starts to have trouble. Companies that have not been able to justify an expensive camera-based system may not have to do that any more.”
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