Sources and detectors: general information
Non-contact measurement - Optical methods (part 1)

The light source may be natural (daylighting), but is often artificial. In the past, incandescent lamps were widely used. In many cases, they are now preferred to light-emitting diodes (LEDs) and laser diodes, due to their size, cost and low power consumption. Laser tubes are reserved for complex, high-end systems requiring either high optical power or high metrological quality of the light beams emitted. On the other hand, they take up much more space.

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