Prakt. Met. Sonderband 46 (2014) 375 
;ed on risk 
Fig. 3: Profile analysis to measure the depth of corrosion; 
enabled by InfiniteFocus based on the Focus-Variation technology 
Conventional computations such as the calculation of the average depth are not as 
meaningful as the numerical verification of a voids” depth. Values as average data are less 
representative since they do not comprise any information about the deepest degradation 
depth. Focus-Variation, thus InfiniteFocus is suitable to deal with complex corroded 
1E MICRO surfaces. One of its most distinctive features is the ability to gain numerical information 
with registered true color information. 
n meets all 
ion of up to 4. THE TECHNOLOGY OF FOCUS-VARIATION 
itionally, the 
istered color The operating principle of Focus-Variation, developed by Alicona, combines the small 
D data file. depth of field of an optical system with vertical scanning to provide topographical and color 
information from the variation of focus. Depending on the topography of a surface the 
information from the variation of focus is analyzed in relation to the distance to the optics. 
Using conventional optical measurement techniques a high vertical resolution can only be 
reached with a small vertical scanning range whereas the use of InfiniteFocus yields a 
high vertical resolution over the entire scanning range, allowing a dynamic of 1:500000. 
Additionally. a quality measure is determined for each measurement point. [2] 
2d corrosion, 
sion. Pitting 
rest. Metallic 
m alloys are 
acks can be 
e.g. erosion 
deepest void 
Fig. 4: Optical 3D surface measurement system InfiniteFocus 
based on the Focus-Variation principle