We demonstrate a fiber-optic-based parallel optical coherence tomography (OCT) using spectrally encoded extended illumination with a common-path handheld probe, where the flexibility and robustness of the system are significantly improved, which is critical in the clinical environment. To the best of our knowledge, we present the first parallel OCT based on fiber optics including a fiber coupler with a sensitivity of 94 dB, which is comparable to that of point-scanning OCT. We also investigated the effect of the phase stability of the fiber-based interferometry on the parallel OCT system by comparing the common-path OCT with two-arm OCT. Using the homemade common-path handheld probe based on a Mirau interferometer, the phase stability was 32 times better than that of the two-arm OCT. The axial resolution of the common-path OCT was measured as 5.1±0.3  μm. To demonstrate the in vivo imaging performance of the fiber-optic-based parallel OCT, human skin was imaged.

Automatic measurement of an object shape is very important in solid modeling, machine vision, industrial inspection, and medical diagnostics, etc. We propose an optical sensor, which comprises a telecentric projector with a sinusoidal grating and a linear CCD camera. We use the FTP (Fourier transform profilometry) method to make a measurement on three-dimensional object. In the FTP method, a grating pattern projected onto the object surface is modulated by the height distribution of the object. The deformed fringe pattern is Fourier transformed and processed in the spatial frequency domain as well as in the space signal domain to demodulate the object shape from the main frequency component in the Fourier spectra. This optical sensor provides a rapid and non-invasive three-dimensional image acquisition. The repeatability is better than 5 µm within the 3σ limits.