Basic knowledge illumination angle
Law of Reflection
The main task of lighting is to create the best possible contrast difference between the defect feature and the component. The lighting angle and form have a decisive influence on how the inspection and defect features become visible in the image.
The fundamental rule in the arrangement of lighting is the law of reflection:
Angle of incidence = Angle of reflection
Depending on the surface structure, material composition, and shape, the light can be directed from above, angled from one side or both sides, horizontally directed, or directed from underneath onto the test object. The light is reflected, scattered, absorbed, transmitted, or a shadow is cast on the test object and its defect features. In addition to the lighting angle, it is important whether the light strikes the test object directly or diffusely. The same object leads to a completely different result in the camera image depending on the positioning of the light.
Incident light, direct
Incident light, angled
Dark field, tilted
Dark field, horizontal
Back lilght
Coaxial
Dome
Ring light
Oblong
Rectangle
Special shape
