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The following peak evaluation methods (algorithms) are available:
8.1. Evaluation method
8.1.1. Center of Gravity (Cog)
The Cog evaluation method calculates the peak’s center of gravity, whose×-coordinate is the sought crude
result. The peak has to be separated from the “sink” for the purpose of center of gravity analysis, which neces-
sitates calculation of the so-called sink height.
background level
sink height
measured value
Sink height is the mean value of all pixel intensities and is thus somewhat higher than the background level.
All pixels to the left and to the right of the maximum, whose intensity is greater than the sink height, are used
in order to calculate the center of gravity. With 16-bit resolution, the measured values are highly precise thanks
to this evaluation method.
8.1.2. Edge Evaluation
In this evaluation method, the peak's edges are evaluated. The advantage of this evaluation method is the fact
that the peak’s asymmetrical crests, caused for example by speckle effects resulting from a sheet metal panel,
are excluded from the evaluation.
measured value
With edge evaluation as well, the measured values achieve highly precise 13-bit resolution.
