Chapter
3
Reference Manual
Ruler E
Configuring the Ruler
Figure 3.4 – The difference between horizontal threshold and horizontal maximum
Intensity
Maximum value
Threshold
Sensor row
Mean value of
the threshold
Mean value of the
maximum position
3.6.1
Horizontal Threshold (HorThr)
This algorithm is used when high speed is needed. If a smaller sensor region is used up to
10000 profiles can be acquired per second.
The threshold algorithm uses one or two fixed thresholds. Using one threshold gives ½-
pixel range resolution, using two gives ¼-pixel resolution. Using two thresholds typically
increase the execution time of the algorithm with a factor close to two.
Median and/or Morphology filters can also be used in this algorithm. The Median filter
calculates a median value on the binary image data of 3 columns (actual column and its
left-right neighbors) before the range algorithm is applied. The morphology filter is used for
reducing noise in the sensor image before the laser line is detected. If both filters are
used, the morphology filter is applied before the median filter.
Input parameters
Start row
The first sensor row to acquire data from. 0 – 511. Default value
0.
Number of rows
The number of rows to acquire algorithm data from. 16 – 512.
Default value 128.
Exposure time
The time that the sensor is exposed to light (microseconds)
Threshold 1
First (low) threshold level. 0 – 255.
Threshold 2
Second (high) threshold level. 0 – 255.
Number of thresh-
olds
Number of thresholds to use.
1 = One threshold is used, Threshold 1.
2 = Two thresholds are used, Threshold 1 and Threshold 2.
Median
States if the Median filter should be applied on the data or not.
0 = filter disabled
1 = filter enabled
Morphology
Morphology filter on sensor image enabled or not.
0 = filter disabled
1 = expand mode
2 = shrink mode
Morphology size
Filter size 3 – 5 rows.
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