With backlighting or transmitted light illumination, the object is located between the light source and the camera. The camera sees the object as a shadow. This type of illumination therefore produces excellent contrasts and is well suited for surveying tasks. Example of a backlight (source: Vision Doctor) A distinction is made between diffuse backlighting, directional […]
Similar to diffuse incident light, diffuse background lighting is achieved by using large-area light panels or surface lighting. The light source is covered with semi-transparent plastic or glass panels. In conjunction with stabilized DC lighting, these are suitable for surveying tasks. Example of diffuse backlighting (source: Vision Doctor) Büchner offers a large selection of backlights […]
One problem with diffuse backlighting is the occurrence of side light. For high-precision measurements, even better results can be achieved by using a telecentric backlight. As with the telecentric lens, this form of illumination has a parallel beam path. This is achieved by a collimator lens between the light source and the light panel.
As with polarized incident light, polarization filters can also be used for backlighting. This can improve the contrast of transparent parts and even make surface tensions visible. For this purpose, a polarization filter is applied to the light plate and a second polarization filter is placed in front of the camera. Depending on the angle […]
