An improved algorithm of structural image reconstruction with rapid scanning optical delay line for Optical Coherence Tomography

Denis Petrov,Sergey Proskurin,Saif Abdulkareem,Kamal Ghaleb

doi:10.18287/jbpe16.02.020302

Abstract

A new algorithm of structural image reconstruction in Optical Coherence Tomography is described. The modified rapid scanning optical delay (RSOD) line, low numerical aperture, small angle raster scanning with consecutive averaging and multilevel digital filtering have been used to obtain high quality structural images of an onion and the nail bed of a human thumb. The proposed method significantly improves image contrast and allows visualization of small blood capillaries under the nail plate.

Highlights

The signal expression measured by an optical coherence tomography (OCT) system is derived, which reveals the possibility of tissue dispersion compensation by introducing the required amount of dispersion in the reference arm and may be implemented by incorporating the grating- based rapid scanning optical delay (RSOD) lines in the reference arm of OCT
There are several advantages we can get with the modified RSOD: transmission bandwidth sufficiently improved its value fourfold, incident radiation power was decreased to 0.4 mW and it enables to shift carrier frequency to region of several tens of kilohertz what helps to avoid noise increasing at the higher frequencies
Applying low numerical aperture helps to register mainly photons which are reflected from the layered structures and to avoid multiply scattered in the tissues photons

Summary

Introduction

Biological tissues characterized by a high scattering coefficient and on the great depth most part of the light are scattered and only a little part of it escapes object without being scattered, so OCT can be efficient only at small depth at one or two millimeters. Instead optical coherence tomography can provide much better (less than 10 micrometers) resolution, so that it could be used to visualize even tiny biological structures. Light emitted by the source divided by the beam splitter and directed to the reference and the sample arm where the investigated object is located. Light reflects from optical heterogeneities inside sample arm and from mirror inside reference arm and returns back to the beam splitter which directs it to the photodetector. After that the acquired data is processed and displayed as a 2D image of the inner structures of the object under investigation [2]

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