Calibration targets reduce unwanted reflections

MAY 19, 2009--Unwanted reflections from the surface of a calibration target cause problems in many optical calibration configurations. A method to reduce unwanted reflections is to use a calibration target with a white scattering surface. Due to light scattering caused by the surface roughness, no direct reflections occur. As an alternative to costly substrates such as ceramic substrates, a cost-effective method for the manufacture of the scattering surface has been developed. Cost reduction is primarily achieved by applying a white surface on standard glass substrates. The scattering surface show a uniform light distribution (quasi Lambertian scatter shape). The combination of a high-end patterning process for metal layers and the quality of the white surface produce an optical calibration target with good edge acuity and high pitch accuracy. Typical applications are 2-D calibration, reference marking of large objects, and photogrammetry.
IMT Masken und Teilungen
Greifensee, Switzerland
www.imtag.ch

For related information, visit the Lighting & Optics topic center.

-- Posted by Carrie Meadows, Vision Systems Design, www.vision-systems.com

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PRESS RELEASE

Reflexion free optical calibration targets
Unwanted reflections from the surface of a calibration target cause problems in many optical calibra-tion configurations. The specular reflexion of the illumination light source causes a strong distortion in light intensity measurements. Vision systems have difficulty coping with this effect.

An efficient method to reduce the unwanted reflections is to use a calibration target with a white scattering surface. Due to the light scattering caused by the surface roughness, no direct reflections occur.

As an alternative to the hitherto used costly substrates used for this purpose (e.g. ceramic sub-strates), a novel, cost-effective method for the manufacture of the scattering surface has been de-veloped by IMT. The costs reduction is primarily achieved by applying the white surface on standard glass substrates.
The scattering surface show a uniform light distribution (quasi Lambertian scatter shape)

The combination of IMT's high-end patterning process for metal layers in combination with the quality of the white surface enable maintaining the quality and accuracy required for a high-end optical calibration target, e.g. good edge acuity and high pitch accuracy at a very competitive price.

Typical applications are 2D calibration, reference marking of large objects and photogrammetry.

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