Speckle noise reduction in high speed polarization sensitive spectral domain optical coherence tomography.

Erich Götzinger,Rainer A Leitgeb,Christoph K Hitzenberger,Michael Pircher,Tilman Schmoll,Harald Sattmann,Bernhard Baumann

doi:10.1364/oe.19.014568

Erich Götzinger, Rainer A Leitgeb + Show 5 more

Open Access

https://doi.org/10.1364/oe.19.014568

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Journal: Optics Express	Publication Date: Jul 14, 2011
Citations: 67	License type: cc-by

Affiliation: Medical University of Vienna

Abstract

We present a high speed polarization sensitive spectral domain optical coherence tomography system based on polarization maintaining fibers and two high speed CMOS line scan cameras capable of retinal imaging with up to 128 k A-lines/s. This high imaging speed strongly reduces motion artifacts and therefore averaging of several B-scans is possible, which strongly reduces speckle noise and improves image quality. We present several methods for averaging retardation and optic axis orientation, the best one providing a 5 fold noise reduction. Furthermore, a novel scheme of calculating images of degree of polarization uniformity is presented. We quantitatively compare the noise reduction depending on the number of averaged frames and discuss the limits of frame numbers that can usefully be averaged.

Highlights

Optical coherence tomography (OCT) has developed into a very useful technique for imaging of transparent and scattering tissue [1, 2], and can be regarded as a standard tool in retinal diagnostics [3]
We demonstrate a related method for generation of high quality speckle reduced Polarization sensitive (PS)-OCT images
We have presented an improved Spectral domain (SD) PS-OCT system capable of retinal imaging with up to 128 k A-lines/s

Summary

Introduction

Optical coherence tomography (OCT) has developed into a very useful technique for imaging of transparent and scattering tissue [1, 2], and can be regarded as a standard tool in retinal diagnostics [3]. PM fiber based PS-OCT allows to maintain one of the main advantages of previous bulk-optics PS-OCT [17], i.e. the use of only a single input polarization state to simultaneously acquire reflectivity, retardation, optic axis orientation, and Stokes vector. We record images at a scanning speed of 70-128 kAlines/s, up to more than 6 times faster than with our previous systems for retinal imaging. The speckle pattern of each B-scan changes slightly and after averaging one can obtain speckle reduced PS-OCT images of intensity, retardation, and optic axis orientation.

Methods

Signal Processing

In Vivo Imaging

Discussion