BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI - Universitatea ...

Bul. Inst. Polit. Iaşi, t. LVI (LX), f. 2, 2010 101
moving average is 5 and in this case the first few elements of yf are
calculated as follows:
yf(1) = y(1)
yf(2) = (y(1) + y(2) + y(3))/3
yf(3) = (y(1) + y(2) + y(3) + y(4) + y(5))/5
yf(4) = (y(2) + y(3) + y(4) + y(5) + y(6))/5 and so on.
The diagram of the whole acquired data filtered for a span equal with
3 is shown in Fig. 4.
d [mm]
0.02
0.01
0
-0.01
-0.02
0 50 100 150
l [mm]
Fig. 4 – The filtered values for a span equal with 3.
It is noted that the chart is much more precise and accurate
assessment can be made on the actual shape of the part to be measured.
The filtration effect is observed more clearly if the graph is made for
filtered and the unfiltered data only for first portion of the controlled
piece. In Fig. 5 is represented by the dotted line unfiltered data and
filtered data with continuous line for a span equal with 3 and in Fig.6 for
a span equal with 5.