Sensors might include optical sensors that detect a broken light beam, a proximity switch that detects metal parts, or a shaft encoder that determines the position of a moving stage or handler mechanism. In each case, the sensor sends a trigger signal to the machine-vision system, which then acquires an image and processes it under software control. The PC provides the key to a machine-vision system. Most vision systems require at least a 133-MHz Pentium processor and several open PCI connectors. The faster the processor, the less time the machine-vision system will need to process image information.
Speed is particularly important on high-speed production lines.
In addition to the machine-vision hardware, you'll also need inspection software. Most frame-grabber manufacturers offer some software that you can use with their boards. The manufacturers may offer demo versions of their software so you can make sure a package meets your needs. Often you can use the demo version to perform image-processing tests on your bitmapped test images. If you're a top-notch C programmer, you may want to use basic routines and write and debug your own applications.