The human eye can see well over a wide range of lighting conditions, but a machine vision system is not as capable. You must therefore carefully light the part being inspected so that the machine vision system can clearly 'see' them.
The light must be regulated and constant so that the light changes seen by the machine vision system are due to changes in the parts being inspected and not changes in the light source.
You will want to select lighting that 'amplifies' the elements of the part that you want to inspect and 'attenuates' elements that you don't want to inspect. In the left picture, poor lighting makes it difficult to read the letters on this part. In the right picture, the lighting has been selected to clearly show the lettering.
Images courtesy of NER / RVSI, Inc.
Proper lighting makes inspection faster and more accurate. Poor lighting is a major cause of failure in machine vision inspection systems.
In general, the available or ambient light is poor lighting and will not work. For example, the overhead lights in a factory can burn out, dim or be blocked, and these changes might be interpreted as part failures by the machine vision system.
Selecting the proper lighting requires some knowledge and experience. Our distributors and lighting vendors will be able to do an analysis of the parts you want to inspect and recommend proper lighting.
Teledyne DALSA works with the following lighting vendors:
Advanced Illumination (www.advancedillumination.com)
24 Peavine Drive
Rochester, VT 05767
CCS America (www.ccsamerica.com)
CCS America, Inc.
48 Weston St.
Waltham, MA 02453
Metaphase Technologies (www.metaphase-tech.com)
3580 Progress Drive
Bensalem, PA 19020
ProPhotonix Limited (www.prophotonix.com)
32 Hampshire Road
Salem, NH 03870
Smart Vision Lights (www.smartvisionlights.com)
2359 Holton Road
Muskegon, MI 49445
Dark Field Lighting