Full-field optical coherence tomography with a complimentary metal-oxide semiconductor digital signal processor camera

Abstract

Full-field optical coherence tomography (OCT) using a complementary metal-oxide semiconductor (CMOS) camera with an integrated a digital signal processor (DSP) is demonstrated. The CMOS-DSP camera employed is typically used in machine vision applications and is based on an array of 1024 × 1024 direct readout pixels that are randomly addressable in space and time. These characteristics enable the camera to be used as a fast full-field detector in carrier-based optical metrology systems. The integrated DSP facilitates basic signal processing including real-time filtering and undersampling. The optical setup used to implement this OCT method is composed of a free-space Michelson interferometer and a superluminescent diode (SLD) light source, with an electromechanical shaker for depth scanning. Unlike classical OCT approaches, however, the setup does not require any electromechanical device for lateral scanning. A 64 × 30 pixel region of interest was imaged at 235 frames/s and sampled in depth, corresponding to a volumetric measurement of 875 × 410 × 150 μm. Measurements carried out on a simple calibration specimen indicated lateral and axial resolutions of 14 and 22 μm, respectively. The presented approach offers an inexpensive and versatile alternative to traditional OCT systems and provides the basis for a functional machine vision system suitable for industrial applications. © 2006 Society of Photo-Optical Instrumentation Engineers.