To improve the reliability and sensitivity of an optical inspection system, the optical design of the sub-systems and components should be well-matched to both the inspection requirements and the optical properties of the product of interest. This is done by configuring the lighting, optics and geometry to match the relevant properties of the product to be inspected. Easy? The devil is in the details.

The basic steps to perform on-line optical product inspection and/or control are: first, point a light source at a part; second, sense the part with a photosensor(s) and/or imaging digital camera; and third, then send the detected light signal to a processor (digital or analog) to determine the pass/fail or other operations. Matching the optical properties to the design usually simplifies and speeds the signal and/or image processing as well as improving the reliability and sensitivity.