Application-Specific Machine Vision: Optimized to the Max
by Winn Hardin, Contributing Editor - AIA Posted 06/11/2012Machine vision has been called an enabling technology because it helps users to perform some “other” task, from building microchips to assembling cars. Another reason is that customers probably will never hop in the car and go down to the “machine vision” store to pick up the latest smart camera.
It is the power and flexibility of machine vision that make it a helpful tool for most – if not all –industries, from petroleum refining (e.g., pipe inspection) to grading pomegranates. But this doesn’t mean machine vision cannot be a standard product designed for a very specific job.
Wrap machine vision technology in the right hardware and software choices and optimize the connectivity, image processing techniques, and housing to a specific task, and you have an application-specific machine vision (ASMV) system. Should Wal-Mart ever open a machine vision department, ASMV systems would line the shelves.
Like turnkey systems, ASMV systems are designed to do a specific task. However, unlike turnkey systems, ASMV systems rarely use the latest Dell personal computer to power their image processing tasks.
All ASMV systems are highly optimized, even to the point of specialized housings, enclosures, and computational platforms. Barcode readers, automated food portioning, traffic monitoring, and high-speed package-sorting systems are all examples of ASMV systems. And while expertise is important to develop both turnkey and ASMV systems, the best ASMV systems are often the result of decades of experience in specialized applications, resulting in systems that become industry standards, rather than just another enabling techno gadget.
Expertise Rules in 3D Measurement
Let’s say you need a 3D inspection system for a lumber processing plant. Ask five machine vision integrators about the relative importance of already designing a similar system, and you’ll probably get five different answers. Some will say previous experience is critical. Others will say any integrator who is deeply immersed in machine vision technology and computational approaches can solve virtually any system.
Ask buyers of ASMV systems if experience is critical, however, and the vote is weighted heavily toward “Yes!”
LMI Technologies Inc. (British Columbia, Canada) has specialized in ASMV 3D machine vision technology for lumber, road, rubber, and related industries for more than 30 years. LMI was recently acquired by AUGUSTA Technologie AG to expand the parent holding company’s expertise in 3D vision.
“Our major focus for the past two years has been our Gocator family of flexible, all-in-one 3D smart sensors based on laser line triangulation,” explains Kevin Brown, Director of Sales for LMI Technologies. “We’re trying to show the world that 3D sensor technology is no longer hard to use. The whole notion that you have to be a software programmer to get data out of 3D sensors is no longer correct.”
The Gocator is a 3D sensor system that includes sensor, illumination, I/O, networking, software, and processing capabilities in a single IP67-rated industrial housing made for difficult, if not hazardous, environments. The product family is broken down into two categories: the 2000 Family with smaller sensor arrays and lower frame rates for factory automation applications, and the high-power 2300 Family with high resolution and high frame rates for electronics inspection.
“We’ve taken our 30 years of laser scanning knowledge and simplified the most complicated aspects of 3D sensing, such as exposure control and being able network small to large systems of sensors together to handle complex surfaces with different reflectivites, for example,” says LMI’s Brown.
According to Brown, the company’s past experience as the “go to” shop for the most complicated 3D sensing applications – such as optimizing the process of turning trees into boards of specific grades, sizes, and shapes – prepared LMI for creating a true ASMV system for 3D sensing.
“A lot of 3D laser line sensing comes down to dynamic exposure and having the right laser class for the job, and that’s mostly dictated by controlling the camera and timing of the systems,” adds Brown. “We look at exposure control as everything because, depending on the material surface, exposure is the difference between success and failure.”
Brown attributes Gocator’s success to a range of products in the family that can handle everything from very large objects to semiconductor structures measured in microns. The devices are designed out of the box to work with almost any trigger – from external trigger to encoder or free-running operation. Gocator is also programmed through a Web-based front end with sliders and pull-down menus to relieve the need of the programmer to understand the underlying machine vision algorithms and simplify parameter setting. For the serious programmer, the system also comes with a full software development kit (SDK) that gives an experienced programmer full access to Gocator’s individual functionality.
But even with this much optimization, LMI still spends considerable time using the company’s knowledge of 3D laser line triangulation, algorithms, and different material surfaces to help the customer choose among the 11 different Gocator models.
“Gocator is allowing us to move into new industries because, historically, our business was based on sensors developed for very specific applications, like lumber, molten metals, tires, road scanning, electronics, and automotive body and white inspection. “The chances that our sensors would be used in other industries were slim. Now, we have a generic family of products that is truly opening up our sales channels.”
Laser Sharp Focus on Machine Code Scanning
Barcode and data matrix autoID solutions represent another large volume market for ASMV systems. VITRONIC Machine Vision Ltd. (Louisville, Kentucky) broke into the autoID market developing a system for international carrier UPS in the 1990s. Since then, the company has continued to optimize its autoID and sorting systems. The flagship autoID product, VICAMssi2, is now in its seventh generation, including more than 500 units installed during the last year.
“Because we’re not as large as some general-purpose machine vision companies, we try to focus our R&D on specific applications, such as autoID, inspection and traffic,” explains Jay Stone, Vice President of Sales and Marketing at VITRONIC Machine Vision Ltd. “Our traffic technology solutions are experiencing significant growth globally.”
The UPS experience was a great start to designing ASMV systems, Stone says, because the company insisted that the system be high tech, but easy to use out of the box. But even with an ASMV product, Stone says that VITRONIC’s differentiators include understanding of different customer back-end systems and a willingness to integrate or guide the customer on how to integrate the autoID system into their warehouse management system, while helping the customer to identify their specific system requirements.
To make it easier to install and connect to different customer operations, VICAM is designed to work with all major I/O connections used in warehouse management, including RS232, Gigabit Ethernet, fiber, etc. VITRONIC also developed its own “decoder” software, which is the part of the software algorithm that “reads” one or two dimensional machine readable codes, and optical character recognition (OCR) string. All of these solutions have transferred to the company’s latest compact autoID systems, the VICAMsnap!.
“Many competitors license a decoder from a third party provider,” adds Stone. “But we’ve been developing our decoder for more than 10 years and it is extremely mature. By controlling how the decoder works, we can optimize exposure control and improve our read rates while reducing false positives compared to competing solutions. By having control of your decoder and the way it integrates into your solution, it allows you to provide greater flexibility to your customers and reduce overall system costs. Today, you see a number of autoID companies trying to get away from licensing their decoders so they can optimize performance, too.”
Customers who choose ASMV solutions can expect to pay less over the course of the system’s deployment, adds Stone, especially when it comes to installation, troubleshooting, and other soft costs like vendor and program management.
“Most companies that buy ASMV systems don’t want to manage numerous vendors for a single integrated solution,” concludes Stone. “Our customers want to work with one source to better manage their project and to keep overall project costs down. And it’s not just about the labor costs. If you choose one vendor for software, another for hardware, and a third to integrate the system, you can expect to pay much more for the solution than to choose a vendor who can provide a turnkey solution.”
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