NED
RCDL4K8GE
UME-0111-01
18
2.3 Optical Interface
The amount and wavelengths of light required to capture useful images depend on
the intended use. Factors include the
property, speed, the object’s spectral
characteristics, exposure time, the light source characteristics, the specifications of
the acquisition system and so on.
The exposure amount (exposure time x light amount) is the most important factor
in getting desirable images. Please determine the exposure amount after studying
what is most important to your system.
Keep these guidelines in mind when setting up your light source:
⚫
LED light sources are relatively inexpensive, provide a uniform field and longer
life span compared to other light sources. However, they also require a camera
with excellent sensitivity.
⚫
Halogen light sources generally provide very little blue relative to infrared light
(IR).
⚫
Fiber-optic light distribution systems generally transmit very little blue light
relative to IR.
⚫
Metal halide light sources are very bright but have a shorter life span compared
to other light sources.
Generally speaking, the brighter light sources, shorter life span.
CMOS image sensors are sensitive to infrared (IR). We recommend using daylight
color fluorescent lamps that have low IR emissions. If you use a halogen light source,
to prevent infrared from distorting the images use an IR cutoff filter that does not
transmit IR wavelengths.
