Calibration of Lateral Scanning in Optical Coherence Tomography Devices
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ICAL INSTRUMENTS FOR ECOLOGY, MEDICINE, AND BIOLOGY
Calibration of Lateral Scanning in Optical Coherence Tomography Devices S. Yu. Ksenofontova,*, A. A. Moiseeva, V. A. Matkivskya, P. A. Shilyagina, T. V. Vasilenkovaa, V. M. Gelikonova, and G. V. Gelikonova a Institute
of Applied Physics of the Russian Academy of Sciences, Federal Research Center, Nizhny Novgorod, 603950 Russia *e-mail: [email protected]
Received February 26, 2020; revised March 2, 2020; accepted March 3, 2020
Abstract—Methods for determining the dependence of the lateral-scan coordinate on the A-scan number from tomographic images of test samples are investigated and techniques for compensating for horizontal distortions of tomographic images caused by uneven speed of the probing-beam displacement are proposed. An opal-glass Ronchi ruling and an inclined flat surface of the volume-scattering plate were used as test samples. DOI: 10.1134/S0020441220040296
INTRODUCTION The methods described in this paper were used for the development and technological support of optical coherence tomography (OCT) devices [1]. In particular, we consider the use of OCT technologies for visualizing the internal structure of the external biological tissues of a living organism in real time. Probing of the studied sample with low-power broadband low-coherence optical radiation in the near-IR range is used in OCT systems for visualizing such structures. Radiation with a central wavelength of ~1.3 μm is used most often to study external biological tissues. Analysis of inverse scattering together with OCT technologies makes it possible to obtain the distribution of scatterers within a studied sample and, hence, the information on the internal structure of the studied biological tissue. The structure of tissues, such as mucous membranes or skin, can be visualized using OCT methods to a depth of 1.5–2.0 mm. The longitudinal resolution for various modifications of the OCT systems is determined by the characteristics of probing radiation and varies from a few to two dozen micrometers. There are two main types of OCT systems: confocal and full-field [1]. In full-field systems, the entire studied tissue sample is simultaneously irradiated during probing. Full-field OCT systems are the fastest, since they do not contain mechanical drives and actuators. A basic drawback of full-field OCT systems consists in their fundamental sensitivity to multiplescattering signals, which generate numerous coherent noises and artifacts and reduce the effective dynamic
range of the method. This is one of the main reasons for the limited practical application of such OCT systems. Time-domain, spectral-domain, and swept-source OCT methods lack this drawback [1]. Such devices can be considered as confocal OCT systems, since they use a focused narrow probing beam. During OCT scanning, it mechanically moves over the surface of a tissue along one or two coordinate axes. A number of methods are used in OCT for lateral scanning [2–15]. The most common method is the angular scanning of the beam with
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