ifm Vision Assistant 3D camera O3X1xx
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Explanation of the unambiguity of the measuring range
To measure objects, the device emits a modulated light signal and detects the light reflected on the
objects . The distance of the objects is determined by means of the time of flight of the emitted and the
reflected light .
While the modulation frequency is not changed by the reflection, the phases of the emitted and the
detected light are shifted according to the distance of the reflected point . Phase shifts that are a multiple
of the wavelength cannot be differentiated . Thereby, distances that are longer than half the wavelength
cannot be measured without ambiguity . In case of a modulation frequency of 30 MHz, half the wavelength
is 5 m .
t/ns
D/m
0
33
66
99
0
1
2
3
4
5
6
7
∆φ
∆φ
Example
The following figure shows two captures of the same scene with different distance settings .
1: Maximum visible distance under 5 m [1 frequency]: The colours repeat themselves for distant objects
2: Maximum visible distance up to 30 m [2 frequencies]: Colours can be clearly assigned to different
distances