Reference Manual
Chapter
1
Ruler E
Overview
1.2.1
Range Resolution
When measuring heights, the resolution depends on which algorithm that is used when
detecting the laser line. For example the
HorMaxThr
method returns the location of the
line with 1/2 pixel resolution, while the Hi3D method has a resolution of 1/16
th
of a pixel.
Besides the measurement method, the actual measurement accuracy in millimeters
depends on the distance between the Ruler and the object. The further away the object,
the lower the accuracy.
This is because the object is viewed from a perspective, and therefore a pixel at the bot-
tom of the image shows a larger area of the object than pixels at the top of the image.
Therefore, one way of increasing the accuracy in the measurements is to move the Ruler
closer to the objects to measure.
Figure 1.5 – The laser line seen from a perspective, on the sensor, and the resulting
profile
Millimeters
Viewed from
the Ruler
(world)
Millimeters
Columns
Rows
Sensor image
Range
(mm)
Resulting
Profile
Width
(mm)
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