This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Light scattered in tissue usually ceases to be a useful source of information. But what if, instead of forcing it to travel along a single path, we allowed it to wander a little differently each time?
Scientists from ICTER tested this seemingly risky idea and showed that a series of measurements that differ from one another can produce a clearer image than a single frame. The new method was developed by scientists from the International Center for Translational Eye Research (ICTER), part of the Institute of Physical Chemistry of the Polish Academy of Sciences. The team combined a mathematical model, computer simulations and experiments using optical coherence tomography (OCT).
The researchers wanted to determine whether controlled changes in the way light is scattered could reduce speckle noise and make images less sensitive to selected optical aberrations. The findings are described in the article "Reducing spatial coherence via dynamic scattering media enables aberration and speckle suppression in optical imaging" published in Scientific Reports. The study's first author is Klaudia Nowacka-Pieszak, MSc Eng.
She worked with Piotr Kasprzycki, Ph.D.; Patricio Espinoza Guevara, MSc; Karol Karnowski, Ph.D.; and Dawid Borycki, Ph.D., DSc. Light traveling through tissue encounters cell membranes, fibers, blood vessels and boundaries between structures with different optical properties. Some rays change direction, while the phase of the light wave is disrupted.
As a result, the image may lose sharpness, become distorted or be covered by a grainy texture. This texture is known as speckle noise. It arises when waves scattered by different parts of a sample overlap.
In some places they reinforce one another, while in others they cancel one another out. The resulting image contains a random pattern of bright and dark spots that can obscure fine structures. Speckle is not ordinary electronic noise; it arises from the properties of the light being used (in this case, coherent laser light).
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