Optical design and evaluation of a three-dimensional imaging and ranging system based on time-correlated single-photon counting

The design and operation of a noncontact surface profilometry system based on the time-correlated single-photon-counting technique are described. This system has a robust optomechanical design and uses an eye-safe laser that makes it particularly suitable for operation in an uncontrolled industrial environment. The sensitivity of the photon-counting technique permits its use on a variety of target materials, and its mode of operation does not require the continual presence of an operator. The system described has been optimized for a 1–25-m standoff, has a distance repeatability of <30 µm, and has a transverse spatial resolution of ∼60 µm at a 2-m standoff and ∼400 µm at a 13-m standoff.