Difficult-to-inspect parts need custom vision system

A discussion with Rick Ross of Ross Inspection Systems

VSD:How does RIS use machine vision?

Ross: Ross Inspection Systems [RIS] is a supplier of machine-vision systems for inspection and measurement. Most of our systems are custom-built, combining off-the-shelf components, including lights, PCs, and frame grabbers, with original software. Typically our customers are manufacturers with harder-to-inspect parts, for which an off-the-shelf solution from other companies will not suffice. We work with companies in several different industries, including pharmaceutical, packaging, electronics, and semiconductors.

VSD:How is RIS using these components? How is each component more or less important for applications you serve?

Ross: The vision components industry now has a large selection of OEM peripherals that can meet a majority of inspection requirements. Frames grabbers, PCs, and cameras are pretty much a commodity today. However, for the more difficult inspections, involving complex geometries or nonfixtured parts, the available software is deficient. Therefore, on our typical system, all of the components are OEM, except for the software and some of the lighting. This is true regardless of which industry we are working for since every industry has some difficult inspections and some easier inspections.

VSD:What market changes are driving the implementation of new technologies that you choose for these applications?

Ross: Over the past few years, much of the marketplace has raised its inspection standards toward zero tolerance. The pharmaceutical industry has faced pressure from the FDA. In industries such as auto parts, perfect part quality has become necessary to allow flawless automation of assemblies and subassemblies. Many parts industries are also very competitive, and buyers obviously discriminate between their suppliers, based on the quality of the parts they receive.

Finer resolution defects, more complicated assemblies, higher speeds, color inspection, and nonvisible light inspection have been some of the tougher requirements that we are now facing. These involve higher-speed cameras, nonvisible light sensing, more cameras, multicamera acquisition boards, and windowed acquisition.

VSD:What are users demanding from you in the design of such systems?

Ross: High quality and low cost. Everybody wants the most for the least, especially in today's world. Seriously, though, 100% inspection is the number-one demand. Because of the pressures they are facing, customers want to find every possible defect on all of their parts. Customers also want flexibility—they generally want the ability to tune their inspection parameters on-the-fly through the inspection system's GUI.

Remote support is another request that we have seen a lot of lately. In response, our algorithms can now be tuned via e-mail.

VSD:Is there a list of RIS-qualified vendors and integrators? Do you qualify, design, build, or RFP all imaging systems that you sell?

Ross: We do not have a list of RIS-qualified vendors. We approach every job differently and choose the components that fit best for that job. We both design and build all of our imaging systems but never RFP complete systems.

VSD:Have you considered using a "system" supplier that has already integrated frame grabbers, CPUs, and networking into a single "vision solution" system instead of off-the-shelf components?

Ross: We have considered using "system" suppliers, but find generally that packaged systems are not capable enough or flexible enough to meet most of our customers' demands. We find that these canned systems work only under perfect conditions—regularly shaped objects, fixtured parts, slower speeds, where 100% inspection is not a requirement. Also, such systems limit our ability to do future system upgrades for our customers.

At Abbott Laboratories (Ashland, OH, USA), a Ross Inspection Systems custom machine-vision system detects defects and performs measurements on baby nipples.

Stereo systems serve as a good comparison to inspection systems. For some people, an off-the-shelf mini system is sufficient. However, the critical customer wants to build his system by components, selecting the best of each component, and only the components that suit him. Most of our customers are critical customers.

VSD:Do you see a trend in real-time operating systems for imaging?

Ross: The only part of the system that must be "real time" is the acquisition. By using asynchronous reset cameras and triggering the acquisition directly from the production line's PLC or a dedicated part-in-place sensor, modern acquisition boards can achieve real-time image capture. Once the image is captured, the inspection is time-limited, sometimes severely so, but it does not usually require real-time response.

VSD:How do you think so-called "switched-fabric" technology such as PCI Express or other serial buses such as FireWire and USB 2.0 affect systems design?

Ross: Because essentially all of our systems require real-time response to acquisition events, we always use a direct point-to-point connection between the camera and a dedicated image-storage area on an acquisition card. Though some of the switched-fabric and other serial buses can obtain impressive data-transfer speeds, the indeterminant signal latency inherent in their designs obliviates our ability to use them. With the larger-pixel-count, higher-frame-rate cameras that we use more and more today, we often need higher-bandwidth capabilities than the standard PCI bus can obtain, but in these situations we find the AGP slot versions of our standard PCI acquisition cards give us the bandwidth we need while still preserving the necessary real-time acquisition and providing a familiar product.

VSD:How do you envision the future of imaging in the industries you serve? What kinds of new applications do you expect to emerge, and how will OEM components have to change to meet those applications?

Ross: We see the marketplace continuing its trend of requiring more detailed inspection for lower cost. Government agencies have promised to continue to strengthen their standards, while parts suppliers are facing increasing competition from abroad.

Also, we expect automated inspection to be more fully integrated into the six-sigma process, rather than just serve to check parts that are completed. More advanced automation projects will include in-process inspection that gives feedback to controls allowing the manufacturing process to be self-correcting.

RICK ROSS is president of Ross Inspection Systems (Nanuet, NY, USA; www.rossinspection.com), which he founded in 1984 as Ross Microsystems. He has a B.S. in electrical engineering from City College of New York, an M.S. in electrical engineering from New York University, and an M.B.A. from St. John's University. Editor in chief Conard Holton talked to him about trends in specialized inspection and measurement.