Dome lighting
The best diffuse incident light is obtained with dome lighting. They provide homogeneous light from all directions and are therefore often referred to as “cloudy day illumination”. They are ideal for shiny and/or uneven test surfaces, as scratches and unevenness are softly illuminated. Surfaces appear quite homogeneous and therefore structureless.
It is important to keep the working distance as short as possible in order to illuminate as diffusely as possible. The hole through which the camera looks is a disadvantage. In the case of reflective test objects, the hole can then be recognized as a dark spot. If coaxial lighting of the same brightness is installed above the hole, this spot is also “illuminated away”.
Related types of lighting to dome lighting are tunnel lighting and coaxial incident lighting.
Principle sketch of dome lighting (source: Vision Doctor).
Büchner Lichtsysteme offers dome lighting in various diameters.
