Acousto-optic imaging is a hybrid imaging technique that exploits the interaction between light and sound to image optical contrast at depth in optically turbid media with the high spatial resolution of ultrasound. Quantitative measurement of optical properties using this technique is confounded by multiple parameters that influence the detected acousto-optic signal. In this article, we describe the origin of the acousto-optic response and review techniques that have been proposed to relate this response to the optical properties of turbid media. We present an overview of two acousto-optic sensing approaches. In the first, we demonstrate that the local transport mean free path within turbid media can be obtained by varying the pressure of the ultrasound field and processing the resulting acousto-optic signals. In the second, we demonstrate that the acousto-optic response elicited by a high-intensity ultrasound field during thermal therapy can be used to monitor the onset of lesion formation, ascertain lesion volume, and provide real-time control of exposure duration.
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http://dx.doi.org/10.1007/s10439-011-0425-z | DOI Listing |
Considering the obvious application value in the field of minimally invasive and non-destructive clinical healthcare, we explore the challenge of wide-field imaging and recognition through cascaded complex scattering media, a topic that has been less researched, by realizing wide-field imaging and pathological screening through multimode fibers (MMF) and turbid media. To address the challenge of extracting features from chaotic and globally correlated speckles formed by transmitting images through cascaded complex scattering media, we establish a deep learning approach based on SMixerNet. By efficiently using the parameter-free matrix transposition, SMixerNet achieves a broad receptive field with less inductive bias through concise multi-layer perceptron (MLP).
View Article and Find Full Text PDFAdverse weather conditions present a primary challenge for ground-based LiDAR imaging systems in outdoor applications. The use of polarization has been proposed as an effective filtering mechanism. However, the number of potential situations is large, complex and difficult to parameterize with accuracy.
View Article and Find Full Text PDFAchieving high-fidelity image transmission through turbid media is a significant challenge facing both the AI and photonic/optical communities. While this capability holds promise for a variety of applications, including data transfer, neural endoscopy, and multi-mode optical fiber-based imaging, conventional deep learning methods struggle to capture the nuances of light propagation, leading to weak generalization and limited reconstruction performance. To address this limitation, we investigated the non-locality present in the reconstructed images and discovered that conventional deep learning methods rely on specific features extracted from the training dataset rather than meticulously reconstructing each pixel.
View Article and Find Full Text PDFAnalyst
November 2024
Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Spatially offset Raman spectroscopy (SORS) is a transformative method for probing subsurface chemical compositions in turbid media. This systematic study of Monte Carlo simulations provides closed-form characterizations of key SORS parameters, such as the distribution of spatial origins of collected Raman photons and optimal SORS geometry to selectively interrogate a subsurface region of interest. These results are unified across an extensive range of material properties by multiplying spatial dimensions by the medium's effective attenuation coefficient, which can be calculated when the absorption and reduced scattering coefficients are known from the literature or experimentation.
View Article and Find Full Text PDFBiomed Opt Express
August 2024
Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Straße 3/5, 91052 Erlangen, Germany.
The previous research proves that the random laser emission reflects not only the scattering properties but also the absorption properties. The random laser is therefore considered a potential tool for optical properties sensing. Although the qualitative sensing using the random laser is extensively investigated, a quantitative measurement of optical properties is still rare.
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