Filtering and special effects, Related topics – Adept AdeptSight User Guide User Manual
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Strobe
Strobe lighting is required when the speed of moving objects exceeds one pixel every 17 mil-
liseconds. Strobes cast harsh shadows, but can be diffused (see above).
Filtering and Special Effects
In many cases, specific lighting problems can be solved by placing an optical filter on the cam-
era lens. The three most common filters used for black and white cameras are polarizing
filters, color filters, and infrared filters.
Polarizing Filters
Reflected light is highly polarized (the light waves have a predominant orientation about the
wave axis). A polarizing filter can be adjusted so that light waves with a predominant orien-
tation are filtered. If reflected glare from an object is a problem, a polarizing filter may be able
to minimize the problem. A polarizing filter reduces the overall scene brightness so more
intense lighting sources are needed with this type of filter. By adjusting the orientation of
polarizing filters on both the light source and lens, you can significantly reduce ambient light
and reduce shiny reflections.
Color Filters
Color filters allow you to reduce or eliminate different colors of light that reach the camera.
Color filters may enable the system to ignore irrelevant object features that are a given color,
or ignore non-significant differences in an object that develop due to differences in the colors
of the feature. Color filtration is difficult and should be attempted only when other avenues
have been exhausted.
Infrared Filters
CCD cameras usually have a relatively high sensitivity to infrared light. Warm or hot objects
emit infrared light (which is invisible to the human eye). If you suspect your camera data
may be inaccurate due to infrared emissions, try placing an infrared filter over the lens.
Related Topics
Filtering and Special Effects
AdeptSight User's Guide, Version 3.2.x, Updated: 8/23/2012
Page 645