scholarly journals Non-invasive imaging through strongly scattering media based on speckle pattern estimation and deconvolution

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Zhouping Wang ◽  
Xin Jin ◽  
Qionghai Dai
Keyword(s):  
Speckle Pattern ◽  
Scattering Media ◽  
Non Invasive

scholarly journals Locating and Imaging through Scattering Medium in a Large Depth

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 90
Author(s):  
Shuo Zhu ◽  
Enlai Guo ◽  
Qianying Cui ◽  
Lianfa Bai ◽  
Jing Han ◽  
...  
Keyword(s):  
Phase Space ◽  
Signal To Noise Ratio ◽  
Speckle Pattern ◽  
Heuristic Method ◽  
Scattering Medium ◽  
Scattering Media ◽  
Signal To Noise ◽  
Practical Applications ◽  
Large Depth ◽  
Strong Scattering

Scattering medium brings great difficulties to locate and reconstruct objects especially when the objects are distributed in different positions. In this paper, a novel physics and learning-heuristic method is presented to locate and image the object through a strong scattering medium. A novel physics-informed framework, named DINet, is constructed to predict the depth and the image of the hidden object from the captured speckle pattern. With the phase-space constraint and the efficient network structure, the proposed method enables to locate the object with a depth mean error less than 0.05 mm, and image the object with an average peak signal-to-noise ratio (PSNR) above 24 dB, ranging from 350 mm to 1150 mm. The constructed DINet firstly solves the problem of quantitative locating and imaging via a single speckle pattern in a large depth. Comparing with the traditional methods, it paves the way to the practical applications requiring multi-physics through scattering media.

scholarly journals A Robust Method for Adjustment of Laser Speckle Contrast Imaging during Transcranial Mouse Brain Visualization

Photonics ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 80 ◽  
Author(s):  
Vyacheslav Kalchenko ◽  
Anton Sdobnov ◽  
Igor Meglinski ◽  
Yuri Kuznetsov ◽  
Guillaume Molodij ◽  
...  
Keyword(s):  
Biological Tissues ◽  
Laser Speckle ◽  
Robust Method ◽  
Scattering Media ◽  
Contrast Imaging ◽  
Speckle Contrast ◽  
Non Invasive ◽  
Sagittal Sinus ◽  
Brain Vasculature

Laser speckle imaging (LSI) is a well-known and useful approach for the non-invasive visualization of flows and microcirculation localized in turbid scattering media, including biological tissues (such as brain vasculature, skin capillaries etc.). Despite an extensive use of LSI for brain imaging, the LSI technique has several critical limitations. One of them is associated with inability to resolve a functionality of vessels. This limitation also leads to the systematic error in the quantitative interpretation of values of speckle contrast obtained for different vessel types, such as sagittal sinus, arteries, and veins. Here, utilizing a combined use of LSI and fluorescent intravital microscopy (FIM), we present a simple and robust method to overcome the limitations mentioned above for the LSI approach. The proposed technique provides more relevant, abundant, and valuable information regarding perfusion rate ration between different types of vessels that makes this method highly useful for in vivo brain surgical operations.

scholarly journals Non-invasive optical focusing inside strongly scattering media with linear fluorescence

2020 ◽  
Vol 116 (24) ◽  
pp. 241104
Author(s):  
Dayan Li ◽  
Sujit Kumar Sahoo ◽  
Huy Quoc Lam ◽  
Dong Wang ◽  
Cuong Dang
Keyword(s):  
Scattering Media ◽  
Non Invasive ◽  
Optical Focusing

scholarly journals Guidelines for obtaining an absolute blood flow index with laser speckle contrast imaging

2021 ◽  
Author(s):  
Smrithi Sunil ◽  
Sharvari Zilpelwar ◽  
David A Boas ◽  
Dmitry D Postnov
Keyword(s):  
Blood Flow ◽  
Speckle Pattern ◽  
Quantitative Measure ◽  
Laser Speckle ◽  
Flow Index ◽  
Scattering Media ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Speckle Contrast ◽  
Blood Flow Index

Laser speckle contrast imaging (LSCI) is a technique broadly applied in research and clinical settings for full-field characterization of tissue perfusion. It is based on the analysis of speckle pattern contrast, which can be theoretically related to the decorrelation time - a quantitative measure of dynamics. A direct contrast to decorrelation time conversion, however, requires prior knowledge of specific parameters of the optical system and scattering media and thus is often impractical. For this reason, and because of the nature of some of the most common applications, LSCI is historically used to measure relative blood flow change. Over time, the belief that the absolute blood flow index measured with LSCI is not a reliable metric and thus should not be used has become more widespread. This belief has resulted from the use of LSCI to compare perfusion in different animal models and to obtain longitudinal blood flow index observations without proper consideration given to the stability of the measurement. Here, we aim to clarify the issues that give rise to variability in the repeatability of the quantitative blood flow index and to present guidelines on how to make robust absolute blood flow index measurements with conventional single-exposure LSCI. We also explain how to calibrate contrast to compare measurements from different systems and show examples of applications that are enabled by high repeatability.

Scalable non-invasive imaging through dynamic scattering media at low photon flux

2021 ◽  
Vol 144 ◽  
pp. 106641
Author(s):  
Yiwei Sun ◽  
Xiaoyan Wu ◽  
Yuanyi Zheng ◽  
Jianping Fan ◽  
Guihua Zeng
Keyword(s):  
Photon Flux ◽  
Scattering Media ◽  
Non Invasive ◽  
Dynamic Scattering

scholarly journals In-Depth Analysis of Egg-Tempera Paint Layers by Multiphoton Excitation Fluorescence Microscopy

2020 ◽  
Vol 12 (9) ◽  
pp. 3831
Author(s):  
Alice Dal Fovo ◽  
Mikel Sanz ◽  
Mohamed Oujja ◽  
Raffaella Fontana ◽  
Sara Mattana ◽  
...  
Keyword(s):  
Fiber Optics ◽  
Nonlinear Optical ◽  
Near Infrared ◽  
Three Dimensional ◽  
Optical Systems ◽  
Scattering Media ◽  
Invasive Approach ◽  
Non Invasive ◽  
Egg Tempera ◽  
Depth Analysis

The non-invasive depth-resolved imaging of pictorial layers in paintings by means of linear optical techniques represents a challenge in the field of Cultural Heritage (CH). The presence of opaque and/or highly-scattering materials may obstruct the penetration of the radiation probe, thus impeding the visualization of the stratigraphy of paintings. Nonlinear Optical Microscopy (NLOM), which makes use of tightly-focused femtosecond pulsed lasers as illumination sources, is an emerging technique for the analysis of painted objects enabling micrometric three-dimensional (3D) resolution with good penetration capability in semi-transparent materials. In this work, we evaluated the potential of NLOM, specifically in the modality of Multi-Photon Excitation Fluorescence (MPEF), to probe the stratigraphy of egg-tempera mock-up paintings. A multi-analytical non-invasive approach, involving ultraviolet-visible-near infrared (UV-Vis-NIR) Fiber Optics Reflectance Spectroscopy, Vis-NIR photoluminescence, and Laser Induced Fluorescence, yielded key-information for the characterization of the constituting materials and for the interpretation of the nonlinear results. Furthermore, the use of three nonlinear optical systems allowed evaluation of the response of the analyzed paints to different excitation wavelengths and photon doses, which proved useful for the definition of the most suitable measurement conditions. The micrometric thickness of the paint layers, which was not measurable by means of Optical Coherence Tomography (OCT), was instead assessed by MPEF, thus demonstrating the effectiveness of this nonlinear modality in probing highly-scattering media, while ensuring the minimal photochemical disturbance to the examined materials.

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