3D Time-of-flight distance measurement with custom - Universität ...
3D Time-of-flight distance measurement with custom - Universität ...
3D Time-of-flight distance measurement with custom - Universität ...
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INTRODUCTION 3<br />
light source<br />
observer<br />
lens<br />
lens<br />
beam splitter<br />
rotating<br />
cogwheel<br />
lens<br />
lens<br />
plane<br />
mirror<br />
Figure 1.2 Fizeau’s experimental setup used to determine the speed <strong>of</strong> light<br />
in 1849.<br />
Today, the speed <strong>of</strong> light (c=λ⋅ν) can be determined much more precisely, for<br />
example by the simultaneous <strong>measurement</strong> <strong>of</strong> frequency ν and wavelength λ <strong>of</strong> a<br />
stabilized helium-neon-laser or by the frequency <strong>measurement</strong> <strong>of</strong> an<br />
electromagnetic wave in a cavity resonator [BRK]. Since 1983 the speed <strong>of</strong> light<br />
has been fixed by definition to c=2.99792458⋅10 8 m/s. With this precise knowledge<br />
<strong>of</strong> the velocity <strong>of</strong> light, it is thus possible to modify Galilei’s or Fizeau’s experiments<br />
and to measure <strong>distance</strong>s. This can be done “simply” by measuring the elapsed<br />
time during which light travels from a transmitter to the target to be measured and<br />
back to the receiver, as illustrated in Figure 1.3. In practice, the active light source<br />
and the receiver are located very close to each other. This facilitates a compact<br />
setup and avoids shadowing effects.
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