Machine Vision 201 - The Marketplace
If a vision system seems right for you and you've begun to research your options, you've likely found a confusing marketplace. This article will attempt to summarize what goes into a system and what exists out there for manufacturers. Consider it a roadmap to the marketplace. An attempt is made not to advocate one technology or provider over another, but to show how they all fit together.
A Basic System:
Lights + Camera + Lens + Cables + Computer + Software >>> External Devices
Lights + Smart Camera (Camera and Computer Combination) + Lens + Software >>> External Devices
External devices can be anything that takes output from the system. Examples might include an SPC package, a PLC or a device which removes the defective part from the production line.
There are a wide variety of camera manufacturers offering almost every type of camera imaginable. Across the industry, manufacturers typically classify their products by how the data comes out from the camera (the IO mechanism).
Because camera and computer are combined, the camera manufacturer takes care of communication between the camera and computer and data from the sensor can get directly to the processor.
In GigE vision the camera sends its data out on an Ethernet cable.
CameraLink - FireWire (IEEE 1394):
A cabling system developed specifically for demanding machine vision applications. Originally released by Apple, FireWire is another option for machine vision systems. Some camera manufacturers provide more than just cameras - bundling a lens, cables and sometimes software with their products.
The lens frequently gets overlooked until it's not quite right and the expensive camera can't focus on the part properly. If you've decided to build the system internally, make sure you have detailed discussions with your lens supplier to get the appropriate lens for your application.
These often get bundled with a camera, but be sure you know what's going to be on the other end of each cable you buy. These are a small component of the system but it's important to get them right. Do you have a spare PCIe slot if you're going to need it? Can you source the card you need?
Sometimes this comes with the camera (a smart camera) but often you'll need to source this is as well. There are some solutions designed for vision applications or you can take a more general purpose computer and install the software you'd like.
Again a peripheral, but a crucial one. You have a lot of options here (back light, ring light, CDI). Talk to a manufacturer and make sure you're getting what you need.
Unless you want to re-invent the wheel in processing raw video data, software is a must. Sometimes this choice is linked to the camera or computer you may have chosen, sometimes you have flexibility here on whose platform you use. Keep in mind, this software is general purpose. It has functions like edge detection, thresholding and geometric pattern match from which you can write a program to inspect your specific product. Some software is built for a more limited use case and works on more of an "out of the box" basis, but no software package will immediately understand your part without some programming. Sometimes packages are sold with a claim that no programming is involved. This typically means you will not write code by hand, but the software will certainly need many inputs from you before it knows what to inspect. Think of building a website with commercial software. There is no programming, but it will certainly be a demanding project getting the software to translate your thoughts into html and css.
Those who program and install systems in this industry are typically called machine vision integrators. Their role in the market is to serve as a general contractor for vision systems. They source the proper components for the job and then build the turn-key vision system you need. Integrators also often serve as distributers as well, and frequently are willing to offer hardware for a job even if you don't need specific integration help. There are many integrators out there to choose from and we would encourage you to solicit bids from a few parties before making any decision.