Chromatic confocal imaging (1, 2) is a non-contact single-point distance measuring technique that benefits from all the advantages offered by confocal imaging such as eliminating the out-of-focus ambient light originated from points on the object other than the one being imaged. Additionally, in contrast to conventional confocal microscopy, chromatic confocal imaging eliminates the need for a vertical scanning mechanism by use of chromatic coding. In a chromatic confocal probe, the objective lens of a confocal microscope is replaced by a dispersive lens and a spectrometer is placed behind the confocal pinhole. The wavelength at which the intensity output of the spectrometer peaks can be related to the height of the object at that point. Although due to chromatic coding no vertical scanning is required, but chromatic confocal imaging is a single-point measuring technique and lateral scanning of the probe across the surface of the object is still necessary.
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