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Illumination

Illuminate features & make defects visible

Direct incident light

This simple lighting technique can be used with non-reflective materials that scatter light strongly due to their matt, porous, fibrous, non-glossy surface. Any type of surface-emitting lighting can be used for direct incident light. Ideally, a ring light is chosen for smaller fields of illumination, which can be arranged around the lens.
Ein Schattenwurf durch absolut senkrechte Beleuchtung wird somit weitestgehend vermieden. Aber auch Halogenstrahler und große Fluoreszenzbeleuchtungen können eingesetzt werden.

Advantages of direct incident light for Machine Vision

  • Direct incident lighting is cost effective and does not require complex design.
  • Ideal for lighting large areas. Several luminaires can be combined simultaneously.
  • Direct light is usually bright due to a direct emitting surface with a small aperture angle of the luminaire and strong back reflection.
Caution: Smooth, reflective surfaces can easily cause unwanted reflections, which can move around the entire component with the slightest change in position and angle!

Avoidance of disturbing reflections when using direct incident light

  • The principle of vertical illumination from above often creates unwanted reflections on the surface of the component. By tilting the illumination slightly, total reflection can be avoided. If the component has a spatial depth, shadows are possible with slightly tilted illumination.
  • The use of polarised light and a polarisation filter on the lens can possibly suppress interfering reflections. However, much light is suppressed in this way.

Direct front light

Front light reflection on matt metal finish, perpendicular illuminated

Light tilted by 10 degrees

Direct incident light on matt metal surface, but tilted by 10 degrees

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