en_BA_OM70_multi-spot.docx
53/60
Baumer Electric AG
04.01.2021 14:26/tof V1.2 ANW_81156398
Frauenfeld, Switzerland
6.9
Standard deviation
The standard deviation is a term from the field of statistics or stochastics and is given in σ (sigma). With the
standard deviation it is possible to determine how great the dispersion of values around a mean value is.
Broadly speaking, the standard deviation is the average distance of all measured expressions of a
characteristic from the mean value.
The standard deviation is only useful if you consider measured values which should actually be identical but
which vary. For the sensor, this means that an even surface is observed vertically (or with an activated FLEX
MOUNT). The standard deviation is then a measure for the unevenness of the surface. All measuring points
within the preset field of view are taken into consideration.
Remember
The standard deviation is a measure for the dispersion of the height values of all measured profile
points in mm.
It can only be used on a plane that is either vertical with respect to the sensor or is parallel to the Flex
Mount reference.
The plane must cover the entire field of view in the X direction.
6.9.1
Example
This is a profile of 190 points on an even surface as recorded by the sensor before evaluation (height in mm).
It is a typical line.
The red line represents the mean value, and the green lines each represent 1x standard deviation. The
standard deviation indicates how level the measured line is.
Standard deviation: 0.03 mm
Max-Min = 0.157mm
6.1
6.15
6.2
6.25
6.3
6.35
6.4
6.45
6.5
6.55
6.6
1
7
13
19
25
31
37
43
49
55
61
67
73
79
85
91
97
10
3
10
9
11
5
12
1
12
7
13
3
13
9
14
5
15
1
15
7
16
3
16
9
17
5
18
1
18
7
