1 January 2002
Eye on Machine Vision
By Evan Lubofsky
Lower-cost systems attract manufacturers’ attention
Widespread adoption of quality standards such as ISO 9000 and increased pressures for "cost down" automation have combined to drive machine vision technologies to the forefront of manufacturers’ purchase plans.
In the past five years, machine vision sales revenue has doubled worldwide, while the total number of units sold has more than quadrupled. This shows that the use of machine vision technologies is increasing, while the typical price of a system is rapidly falling.
As recently as five years ago, machine vision products hit an unwilling and wary customer base. Most manufacturing engineers had no hands-on experience with machine vision products but were aware of the technology. The general feeling was that systems were potentially useful but expensive, complicated, lacking in sophistication, and difficult to implement.
At that time, there was a strong machine vision market with many thousands of vision systems installed worldwide. But most of them went to cash-rich, high-technology companies—typically operating in the electronics and semiconductor industries.
Programming often took a capable software engineer weeks, and the cost to develop a working system could be considerable and cost-effective only if there was sufficient demand for a large number of systems that could run the same software.
Today, there are many machine vision systems able to fulfill a wide range of inspection tasks requiring different configurations. Generally, they fall into three categories: frame grabbers, PC-based vision systems, and machine vision sensors.
Frame grabbers allow programmers to configure highly specialized applications, with very few limits on the level of complexity they wish to include. Development may be long and complicated, so it is usually limited to applications with many repeat systems.
PC-based vision systems are easier for configuring even sophisticated applications, often for one-off tasks, where a reasonable amount of time and money is available for development.
Machine vision sensors allow for configuring quick, cost-effective systems. This is the largest growth area in the vision market and where the majority of vision developers target their products.
Today, there is a growing trend toward using machine vision sensors, which in many cases are compact and affordable enough to go throughout the factory. By using vision sensors at key process points, users find defects earlier in the manufacturing process and can quickly identify equipment problems.
The most advanced vision sensors available today offer built-in Ethernet communications, which enable users to distribute vision throughout the process and to also link two or more sensors in a fully manageable, scalable vision area network, where data can be exchanged among sensors and managed by a host.
A network of vision systems can also be easily uplinked to plant and enterprise networks, allowing any workstation in a factory with TCP/IP capability to remotely view vision results, images, statistical data, and other information.
In many ways, the uptake of machine vision compares with the use of computers. In the 1980s, computers were large and expensive, with complicated operating systems. Only experienced users would toil at the keyboard. Now, with PCs’ evolution, prices have dramatically fallen, and PC-based machine vision has become widespread.
As machine vision becomes even more affordable, more compact, and easier to use, you will likely find many small, discrete camera stations along a production line instead of a single system inspecting only at the end of the line.IC
About the Author
Evan Lubofsky is a senior writer for Cognex Corp. in Natick, Mass.
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