Phytec FireWire-CAM-011H, Manual

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FireWire-CAM-011H/-012H
60
©
PHYTEC Messtechnik GmbH 2006 L-680e_1
In this section we briefly describe a few lighting procedures.
•
reflected-light method
The reflected light method is one of the most commonly used lighting
methods.
In this method a light source (e.g. a standard lamp or a special ring
light,
see Figure 456
) is pointed at the object from above.
This lighting technique is used if structures need to be recognizable on
the object, such as print, dirt, color (in this case a color-stable lighting
is recommended) or mounted parts (attendance monitor or position
monitor). There are different variations of this method.
Problems that may occur with this procedure are uneven lighting,
reflection (particularly on shiny surfaces) and shadows.
Figure 46: PHYTEC Ring Light Order No.: VZ-001-x, VZ-002-x
•
Diffuse Lighting
With diffuse lighting no direct light rays hit the viewed object. This
reduces problems with reflections and overexposed areas.
The Ring Light (
Figure 456
) can generate diffuse lighting if a
corresponding filter ring is attached, thereby solving this problem.
For especially critical applications, such as highly reflective surfaces,
special shapes are available that shine the light on the object indirectly
over a dome shaped lighting bell.