Dark field, front light illumination

In dark field, front light illumination, reflected light is not collected by the optics. In this way, only scattered light is captured, enhancing the non-planar features of the surface as brighter characteristics on a dark background (the dark field - see Fig. 11 and 13.a - 13.b ).

Again, this effect is commonly reproduced by means of low angle ringlights (Fig. 12).

Front dark field illumination scheme.
Front dark field illumination scheme.
Low angle ringlight geometry.
Low angle ringlight geometry.
Engraved sample with front dark field illumination (ringlight).
Engraved sample with front dark field illumination (ringlight).
Metal coin with front dark field illumination (ringlight).
Image of a metal coin (featuring embossed parts) with front dark field illumination (ringlight).
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