Coins

Some of the Euro coins have been scanned using a Xyris 4000 (confocal laser). The color corresponds to the height of the surface.

The 1 Euro coin:

Contrary to some sources Crete is still on the map of the 1 Euro coin as the following image shows:

The 10 Cent coin:

The surface roughness of the 10 cent coin was measured in the area indicated by the red rectangle below. With a Gaussian filter and a cut-off wavelength of 2.5 mm the roughness Ra is between 0.65 and 0.70 µm.

5 Cent coin

And a detailed view of the globe:

5 Pence Coin

This 5 pence coin was scanned using a Xyris 3000 (triangulation laser). It shows some of the limitations of triangulation lasers, particularly the 'shadows' to the left of the coin. The data set has 201 x 201 points over an area of 20 x 20 mm.

Below, the image of another 5 pence coin, this time scanned using the con-focal laser. The fine detail in the queen's crown shows the superior resolution of the con-focal laser over the triangulation laser. The con-focal laser is not affected by 'shadows'.