NOVOTEST T-UD3, Руководство по эксплуатации, Страница: 27 / 53

Operation Manual
Hardness Tester NOVOTEST T-UD3
Page. 27
Figure 2.25 - Setting the permissible error for the intelligent mode
Also, in order to reduce the influence of external factors user can switch on the Kalman filter or
the Median filter in the device settings.
To make the most accurate device measurements, user has to select the proper filter for the
particular case.
Kalman filter
The Kalman filter is a linear filter, which is used to obtain the most correct value. Also, the
Kalman filter can be defined as a filter giving the least mean-square error.
The main idea of the filter is to find the coefficient C that will correct the received value so that it
would minimum differ from the true (correct) value.
Kalman filter is recommended to be used when measuring heterogeneous structure product, where
there are hardness value jumps, which must be taken into account when calculating the common
hardness value of the product. Kalman filter can reduce the influence of external factors on the
measurements, while not distorting hardness value jumps.
Median Filter
The median filter - is a nonlinear filter that is applied to signals which are under the influence of
pulse interference.
The medial filter is recommended for measuring homogeneous products, in which there are no
hardness value jumps. In case, when due to external factors, the probe fixes hardness value jumps, the
filter will correct it to the normal value.
2.3.6.5 SIGNAL
The mode is active for the dynamic probe only and shows the voltage. M - represents the
maximum value that corresponds to the signal (Figure 2.26).
Figure 2.26 - Signal mode