3.6.7.1
Particle filter
The particle filter blanks small, irrelevant reflection pulses in dusty environments and
in rain or snow which are caused by dust particles, raindrops, snowflakes or the like. In
doing so, successive scans are continuously evaluated in order to detect static objects.
!
Figure 11: Without the particle filter: Violation
of the contour due to dust particles in the
vicinity of the object.
"
Figure 12: Using the particle filter: The
response to dust particles in the field is
delayed by one scan. Particles can thereby be
blanked.
3.6.7.2
Median filter
This filter is suitable for excluding individual outliers from the calculation of an average
value.
The values included in the calculation are defined using a 1 x 3 matrix :
3 measured values,consisting of the distance values of a point and its two adjacent
points in the scan, are sorted by size.
The measured value in the middle of this sequence is output as the distance value,
along with its remission value.
The calculation and output of the media values are done statically.
By activating the media filter, 3 distance values within a scan can be reduced to one
output value, which reduces the number of output values to 1/3 compared to the
unfiltered scan.
Table 5: Example: Median for scan 1 and 2
Angle (distance values in mm)
Scan
1
2
3
4
5
6
7
8
...
1
850
852
851
849
850
850
851
850
...
Scan 1 output value
850 |
851
| 852
849 |
850
| 850
...
2
849
850
850
853
852
852
850
851
...
Scan 2 output value
849 |
850
| 850
852 |
852
| 852
...
...
...
...
...
...
...
...
...
...
...
3.6.7.3
Average filter
The sliding average filter smooths the distance value. It does this by calculating the
arithmetic mean from several scans of the same point. The number of scans can be
configured (maximum 4 scans).
Table 6: Example: Average filter over 5 scans
Angle (distance values in mm)
Scan
1
2
3
4
5
6
7
8
9
…
1
0
0 1100 1100 1150 1150 1380 1380
0
…
3
PRODUCT DESCRIPTION
18
O P E R A T I N G I N S T R U C T I O N S | TiM4xx
8026151//2020-11-15 | SICK
Subject to change without notice
