How do you know that all those products pouring off the assembly line are within tolerance, completely assembled and ready for shipment? Even if the line is built for remarkable consistency, there still may be a need to compile statistics for trends or to predict when a machine or tool may be wearing.
Machine vision is proving to be a valuable tool for increasing competitiveness. Not your father’s vision systems, though, but rather the new breed of personal computer-based systems and powerful sensors that are easier to use and less expensive.
Mark Sippel，Omron Electronics（www.omron.com/oei），Schaummurg，Schaumburg，Ill。考虑机器视觉市场，包括两个主要部分 - 所应用的特定设备或原始设备制造商（OEM）段和一般- 为机器视觉（GPMV）段。“GPMV市场段可能是最难以满足的，并且通常需要最大的灵活性和功能，”他补充道。
Determining whether an application specific product for a line of OEM machines or general-purpose equipment can be adapted for various uses on a manufacturing line is one thing. But what types of actual products are available?
Steve Geraghty, director at Coreco Imaging’s ipd division (www.goipd.com), a Billerica, Mass.-based machine vision vendor, defines four types of vision products: pixel sensors, vision sensors, smart cameras and vision appliances.
Geraghty says that pixel sensors, sometimes called pixel counters, offer slightly more sophisticated capabilities than traditional photoelectric sensors. Pixel sensors provide high-speed inspections in such basic, low-cost applications as presence/absence and controlled template matching.
他继续使用视觉传感器，包括机器视觉系统的组件，包括传感器（摄像机），数字转换器，处理器，软件，接口，光学（镜头）以及有时照明，进入紧凑的包装中。由于它们是可编程的，这些产品可以用于各种应用中，包括需要多于简单的“通道”或“失败”的应用程序，以及需要更高的编程灵活性。
Smart cameras, he adds, are similar in construction and concept to vision sensors, the main difference being in the programming. Instead of selecting from a comprehensive, and sometime complex, set of operations, users are generally required to develop applications based on library components provided by the manufacturer.
Finally, vision appliances contain hardware similar to that of vision sensors or smart cameras but are designed for specific inspection tasks, such as optical gauging or label inspection. Each vision appliance incorporates software that is customized to the unique requirements of a particular application.
选择提示
Geraghty points out several important features to look for in choosing a vision system:
l易用性以确保正确应用。确保将使用机器视觉产品的所有人员有机会走过演示，并对编程的数量和程度感到舒服。
l以太网与其他厂房自动化的连接，以及信息系统和商业计划。
l Industrially hardened housing to withstand demanding plant floor environments.
l Input/Output capabilities so that the vision system can make decisions and control accordingly what happens when parts or products are accepted or rejected.
l历史/归档能力使用户能够查看从视觉系统累计的数据，确定任何持续的制造问题的原因，并相应地调整它们以最有效的方式提高质量。
l自动补偿照明和控制变化，以及镜头和透视失真，提供更大的检查可靠性。
Omron’s Sipple points out a common problem encountered by vision integrators. “When it comes to solving a vision application, many users have learned that choosing and setting up the correct lighting is a large part of the vision application’s solution.”
