Reference Manual Chapter 3
Ranger E/D
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Mounting Rangers and Lightings
Figure 3.8 – Correct alignment between camera and object motion. Camera’s y-direction
should be parallel with the direction of transportation.
3.5 Light sources for Color and Gray Measurements
Different light sources have different spectral properties – that is, different composition of
wavelengths. This section lists some typical light sources, some of which are commonly
used for line-scan gray and color imaging applications.
A measure often used for spectral content of a light source is color temperature. A high
color temperature (4-6000) indicates a “cold” bluish light and a low color temperature (2-
3000) a “warm” yellow-reddish light. Color temperature is measured in the Kelvin scale
(K).
3.5.1 Incandescent lamps
Incandescent lamps are not often used in line-scan machine vision applications. This is
since they commonly use low frequency AC drive current, which causes oscillations in the
light.
They are warm with a typical color temperature of ~2700 K.
3.5.2 Halogen lamps
Halogen lamps are common in machine vision applications, and are often coupled to a
fiber-optic extension so that shapes such as a line or ring can be generated. In the optical
path a filter can be placed to alter the color temperature of the lamp.
Halogen lamps typically have a color temperature of ~3000 K, which means that the
illumination has a fairly red appearance.
In a ColorRanger application using halogen illumination it is expected that the blue and
green balance needs to be adjusted to be much larger than the red channel due to the
strong red content. To shift the color temperature of the lamp it is also possible to insert
additional filters in the light source. Filters for photography called cooling color tempera-
ture filters in the series 80A/B are recommended for this.
Transportation
Camera
Camera
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