Speckle noise attenuation in optical coherence tomography by compounding images acquired at different positions of the sample

• Published in: Optics communications 2007-01, Vol.269 (1), p.247-251
• Main Authors: Popescu, Dan P., Hewko, Mark D., Sowa, Michael G.
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Fundamental areas of phenomenology (including applications); Imaging and optical processing; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Interferometers; Optical instruments, equipment and techniques; Optics; Physics; Speckle and moire patterns
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2006.07.063

This study demonstrates a simple method for attenuating the speckle noise generated by coherent multiple-scattered photons in optical-coherence tomography images. The method could be included among the space-diversity techniques used for speckle reduction. It relies on displacing the sample along a weakly focused beam in the sample arm of the interferometer, acquiring a coherent image for each sample position and adding the individual images to form a compounded image. It is proven that the compounded image displays a reduction in the speckle noise generated by multiple scattered photons and an enhancement in the intensity signal caused by single-backscattered photons. To evaluate its potential biomedical applications, the method is used to investigate in vitro a caries lesion affecting the enamel layer of a wisdom tooth. Because of the uncorrelated nature of the speckle noise the compounded image provides a better mapping of the lesion compared to a single (coherent) image.