4 Design and function
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CD40131 Version 1
3DPIXA
4.7
Illumination
Textures in the images are an important pre-condition for the passive stereo approach. To
make the structures of the surface visible in the image, the interaction of the surface
properties and illumination is crucial.
Illumination types
For each object surface there is an optimal illumination setting to minimize the specular
reflections and to maximize the visibility of the structures of the surface.
Optimal illumination will ensure that the visible structures in the left and in the right image look
almost identical. Thus pattern matching can be performed reliably and accurately.
The following table shows different illumination types and examples of use. For information on
the illustrated illumination devices refer to the Corona II manual.
More details can be found on our partner portal at http://www.chromasens.de/user
(Downloads > Whitepapers > Application Overview).
Illumination type
Properties
Examples of use
Bright-field illumination
The reflecting portion of
the incoming light goes
directly into the camera.
Bright image
Good visibility of most
structures
Diffuse bright field:
Plastic parts
Brushed aluminum
Flat surfaces
Dark-field illumination
The bigger portion of the
incoming light is
reflected away from the
camera.
Mainly the light scattered
by the structure of the
surface goes into the
camera.
The brightness of the
camera image highly
depends on the structure
of the surface.
Diffuse reflecting materials:
Leather
Wood
Food
Paper
Raw steel
Rubber
