Machine Vision 201
If you are searching for a machine vision solution, you've likely found it to be a confusing marketplace. This page will act as a road map to explain what exists out there, and what goes into building a successful system. An attempt is made not to advocate one technology, or provider over another, but to show how they all fit together.
What is 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.
- Cameras: Across the industry, manufacturers typically classify their products by the data output from the camera (the IO mechanism). There are a wide variety of cameras to choose from, available from different manufacturers, that range in sizes, capabilities and prices.
- Smart Cameras: Smart Cameras combine a camera and computer. The camera manufacturer takes care of the communication between camera and computer, and therefore the data from the sensor is sent directly to the processor.
- GigE Vision: GigE vision cameras send out data via 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 will provide more than just cameras - bundling a lens, cables, and software with their products.
- Lenses: Although, lenses are frequently overlooked, it is important to ensure that the camera is focusing on the part accurately. If you've decided to build the system internally, make sure the appropriate lens has been chosen for the application.
- Cables: Cables are often bundled with the camera, but be sure you know what is going to be on the other end of each cable purchased. These are a small component of the system, but very important to get right. Examples to ask yourself - Is a spare PCIe slot available if the application requires it? Can you source the card needed?
- Computer: Sometimes this is included with the camera (i.e. smart camera), but often this will need to be sourced as well. There are some options available for vision system applications, and others will need to be programmed with the appropriate software.
- Lighting: Again this tends to become a peripheral thought, but should be a crucial decision. There are a lot of options, including back lights, ring lights, CDIs. When discussing with a manufacturing, ensure you are inquiring about the best lighting for a successful application.
Unless you are looking to reinvent the wheel in processing raw video data, software is mandatory. Sometimes this choice is linked to the camera or computer you may have chosen, and sometimes there is platform flexibility. Keep in mind, that certain software is more general and has functions like edge detection, thresholding, and geometric pattern-match from which you can write a program to inspect your specific product. Certain software is built much more limited ranges of function, but no software is capable of understanding the inspection with any programming at all.
Machine Vision System Integrator:
Machine vision system integrators provide testing support and assist in choosing the most appropriate application for the inspection. Their role in the market is to serve as a general contractor for vision systems, choose the right hardware and software, as well as implementing the final solution. Machine vision system integrators source proper components for the job and then build the turn-key vision system you need. There are many integrators to choose from, and we would encourage you to solicit bids from various parties before making a final decision.