scholarly journals Transmissive Single-Pixel Microscopic Imaging through Scattering Media

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2721
Author(s):  
Huaxia Deng ◽  
Guan Wang ◽  
Qiang Li ◽  
Qianzhen Sun ◽  
Mengchao Ma ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Medical Imaging ◽  
Medical Diagnosis ◽  
Alternative Solution ◽  
Optical Systems ◽  
Scattering Media ◽  
Microscopic Imaging ◽  
Non Invasive ◽  
Strong Scattering ◽  
Single Pixel

Microscopic imaging is of great significance for medical diagnosis. However, due to the strong scattering and absorption of tissue, the implementation of non-invasive microscopic imaging is very difficult. Traditional single-pixel microscopes, based on reflective optical systems, provide an alternative solution for scattering media imaging. Here, the single-pixel microscope with transmissive liquid crystal modulation is proposed. The microscopic ability of the proposed microscope is calibrated. The multi-spectral microscopic imaging of the object is demonstrated. The transmissive imaging of the object behind the scattering media is analyzed. The proposed prototype of the transmissive single-pixel microscope is expected to be applied in microscopic imaging through scattering media and medical imaging.

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.

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.

Optical systems for non-invasive cardiovascular biosensing

2005 ◽  
Author(s):  
R. Erts ◽  
J. SpigulisSr. ◽  
M. Ozols
Keyword(s):  
Optical Systems ◽  
Non Invasive

scholarly journals A Review of Non-Invasive Optical Systems for Continuous Blood Glucose Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6820
Author(s):  
Bushra Alsunaidi ◽  
Murad Althobaiti ◽  
Mahbubunnabi Tamal ◽  
Waleed Albaker ◽  
Ibraheem Al-Naib
Keyword(s):  
Blood Glucose ◽  
Glucose Monitoring ◽  
Daily Basis ◽  
Glucose Sensing ◽  
Blood Glucose Monitoring ◽  
Optical Systems ◽  
Glucose Levels ◽  
Non Invasive ◽  
Blood Glucose Levels ◽  
Continuous Blood Glucose Monitoring

The prevalence of diabetes is increasing globally. More than 690 million cases of diabetes are expected worldwide by 2045. Continuous blood glucose monitoring is essential to control the disease and avoid long-term complications. Diabetics suffer on a daily basis with the traditional glucose monitors currently in use, which are invasive, painful, and cost-intensive. Therefore, the demand for non-invasive, painless, economical, and reliable approaches to monitor glucose levels is increasing. Since the last decades, many glucose sensing technologies have been developed. Researchers and scientists have been working on the enhancement of these technologies to achieve better results. This paper provides an updated review of some of the pioneering non-invasive optical techniques for monitoring blood glucose levels that have been proposed in the last six years, including a summary of state-of-the-art error analysis and validation techniques.

Medical Imaging of the Airway

2019 ◽  
Author(s):  
Gilbert S Tang
Keyword(s):  
Foreign Body ◽  
Medical Imaging ◽  
Mediastinal Mass ◽  
Imaging Techniques ◽  
Traumatic Injury ◽  
Spine Injury ◽  
Non Invasive ◽  
Faraday’S Law ◽  
Magnetic Resonance Imaging Mri ◽  
Abnormal Anatomy

Non-invasive imaging techniques such as ultrasonography, x-ray, computerized tomography (CT) and magnetic resonance imaging (MRI) provide details about airway anatomy that complement the physical examination. They are of particular value in patients with traumatic injury, malignancy, abscess, foreign body or mass in the airway that displace, distort, disrupt, encroach or compress airway structures in ways that may not be readily apparent otherwise. Many anesthesiologists do not receive formal training in interpreting medical imaging, and a thorough discussion of this subject is beyond the scope of this review. Interpreting the subtleties of normal and abnormal anatomy require years of experience and best left to expert radiologists. The goal here is to introduce the imaging techniques available and examples of clinical applications in airway evaluation of interest to the anesthesiologist. This review contains 12 figures, 2 tables, and 37 references. Keywords: piezoelectric effect, photoelectric interaction, Faraday’s law, pneumothorax, cervical spine injury, LeFort fracture, foreign body, airway infection, mediastinal mass

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
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