Multi-exposure speckle imaging through an optical fiber bundle

Logan Parker; Qingwei Fang; Andrew Dunn; James W. Tunnell

doi:10.1117/12.3003394

12 March 2024 Multi-exposure speckle imaging through an optical fiber bundle

Logan Parker, Qingwei Fang, Andrew Dunn, James W. Tunnell

Proceedings Volume 12856, Biomedical Applications of Light Scattering XIV; 1285604 (2024) https://doi.org/10.1117/12.3003394
Event: SPIE BiOS, 2024, San Francisco, California, United States

Abstract

Multi-Exposure Speckle Imaging (MESI) utilizes laser speckle for visualizing flow and quantifying flow changes. Using a coherent laser source to illuminate the sample, the reflected speckle pattern is captured at various exposure times, enabling the estimation of flow dynamics. Free space MESI setups have a fixed imaging geometry limiting the flexibility in certain applications such as handheld, bandage integrated, or endoscopic systems. This study explores the use of an optical imaging fiber bundle to capture the reflected speckle pattern. A bundle containing 18,000 individual 7.6μm fibers was incorporated into a MESI optical setup with two paths: a conventional free space configuration and a fiber bundle configuration. MESI images were acquired of tissue simulating phantoms (microfluidic channel of 300μm; flow rates of 1-100 μL/min), in-vivo mouse cortical flow, and stroke response (ROI selection from capillaries and vessels). The inverse correlation time (ICT) of the speckle autocorrelation function is determined by fitting a physics-based speckle model to the contrast of the captured images. For both microfluidic and in-vivo experiments, ICT measurements from the fiber path were linearly related to ICT measurements from the free space path with Pearson correlation coefficient of 0.993-1.00 and 0.952-0.988 for the microfluidic and in-vivo data, respectively. There is a strong positive correlation in both experiments showing the feasibility of detecting differences in flow speeds using MESI through a fiber bundle. Integrating an optical fiber bundle into the MESI system increases the flexibility of the technique for use in other applications.

Conference Presentation

Citation Download Citation

Logan Parker, Qingwei Fang, Andrew Dunn, and James W. Tunnell "Multi-exposure speckle imaging through an optical fiber bundle", Proc. SPIE 12856, Biomedical Applications of Light Scattering XIV, 1285604 (12 March 2024); https://doi.org/10.1117/12.3003394

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