|Optical Engineering: Sensing
Norman N. Axelrod
enhances the optical signal before the light reaches an electronic camera
or photodetector, before signal processing and before control decisions.
It exploits optical variations arising from changes in materials,
structure and processing to enhance signal-to-noise or optical contrast.
It eliminates background images & produces signals from critical
features only. This improves reliability and simplifies software & hardware. |
Optical techniques can enhance a signal and obscure background
A defect runs from top to bottom in this semiconductor wafer (above
but it is much clearer with better optics (above
Differences in geometry were used to
eliminate interfering light reflected
from the cylindrical surface of a
plastic filament (above left).
Differences in spectral properties between the extruding material and defect
were then used to increase contrast and S/N. (above right).
Optical and illumination
design enabled a medical manufacturer to reliably & accurately gauge coating thickness on a critical
Beer bottles with damaged threads are
difficult to open. Here, a tiny chip is barely visible among many
reflections with normal optics and lighting (below left), but
improved optical and illumination design clearly shows the chip.
Additional information and illustrated
examples of Smart OpticsSM methodology are available in an article "Smart Machine Vision", Quality Magazine, Feb. 2011
For overview see "Detect Defects Optically" in Quality, May 2006, pp 42-44.
"Vision Provides Reliability by Design: Smart Optics Improves Machine Vision Systems ...", Photonics Spectra, March 1997, pp 116-122 by A. M. Ballangrud and N. N. Axelrod.
Articles can be obtained on line or by request:
e-mail or by writing to
445 East 86th Street
New York, NY 10028