A novel method of rapid three-dimensional optical metrology that is based on triangulation of a configration of color-coded light stripes is presented. The method exploits polychromatic illumination and a combined diffractive–refractive element, so the incident light is focused upon a stripe that is axially dispersed, greatly increasing the depth-measuring range without any decrease in the axial or the lateral resolution. The discrimination of each color stripe is further improved by spectral coding and decoding techniques. An 18-fold increase in the depth of focus was experimentally obtained while diffraction-limited light stripes were completely maintained.
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