scholarly journals Non-labeled lensless micro-endoscopic approach for cellular imaging through highly scattering media

2018 ◽  
Vol 38 (1) ◽  
Author(s):  
Omer Wagner ◽  
Aditya Pandya ◽  
Yoav Chemla ◽  
Hadar Pinhas ◽  
Irina Schelkanova ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Imaging Techniques ◽  
Post Processing ◽  
Scattering Medium ◽  
Scattering Media ◽  
Noise Levels ◽  
Signal To Noise ◽  
Blood Capillaries ◽  
In Vitro Investigation ◽  
Highly Scattering Medium

We describe an imaging approach based on an optical setup made up of a miniature, lensless, minimally invasive endoscope scanning a sample and matching post processing techniques that enable enhanced imaging capabilities. The two main scopes of this article are that this approach enables imaging beyond highly scattering medium and increases the resolution and signal to noise levels reaching single cell imaging. Our approach has more advantages over ordinary endoscope setups and other imaging techniques. It is not mechanically limited by a lens, the stable but flexible fiber can acquire images over long time periods (unlike current imaging methods such as OCT etc.), and the imaging can be obtained at a certain working distance above the surface, without interference to the imaged object. Fast overlapping scans enlarge the region of interest, enhance signal to noise levels and can also accommodate post-processing, super-resolution algorithms. Here we present that due to the setup properties, the overlapping scans also lead to dramatic enhancement of non-scattered signal to scattered noise. This enables imaging through highly scattering medium. We discuss results obtained from in vitro investigation of weak signals of ARPE cells, rat retina, and scattered signals from polydimethylsiloxane (PDMS) microchannels filled with hemoglobin and covered by intralipids consequently mimicking blood capillaries and the epidermis of human skin. The development of minimally invasive procedures and methodologies for imaging through scattering medium such as tissues can vastly enhance biomedical diagnostic capabilities for imaging internal organs. We thereby propose that our method may be used for such tasks in vivo.

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 Holistic description of new deep sea megafauna (Cephalopoda: Cirrata) using a minimally invasive approach

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Alexander Ziegler ◽  
Christina Sagorny
Keyword(s):  
Minimally Invasive ◽  
Dna Barcoding ◽  
Deep Sea ◽  
Imaging Techniques ◽  
Structural Complexity ◽  
Micro Computed Tomography ◽  
Invasive Approach ◽  
Non Invasive ◽  
Additional Support ◽  
Holistic Description

Abstract Background In zoology, species descriptions conventionally rely on invasive morphological techniques, frequently leading to damage of the specimens and thus only a partial understanding of their structural complexity. More recently, non-destructive imaging techniques have successfully been used to describe smaller fauna, but this approach has so far not been applied to identify or describe larger animal species. Here, we present a combination of entirely non-invasive as well as minimally invasive methods that permit taxonomic descriptions of large zoological specimens in a more comprehensive manner. Results Using the single available representative of an allegedly novel species of deep-sea cephalopod (Mollusca: Cephalopoda), digital photography, standardized external measurements, high-field magnetic resonance imaging, micro-computed tomography, and DNA barcoding were combined to gather all morphological and molecular characters relevant for a full species description. The results show that this specimen belongs to the cirrate octopod (Octopoda: Cirrata) genus Grimpoteuthis Robson, 1932. Based on the number of suckers, position of web nodules, cirrus length, presence of a radula, and various shell characters, the specimen is designated as the holotype of a new species of dumbo octopus, G. imperator sp. nov. The digital nature of the acquired data permits a seamless online deposition of raw as well as derived morphological and molecular datasets in publicly accessible repositories. Conclusions Using high-resolution, non-invasive imaging systems intended for the analysis of larger biological objects, all external as well as internal morphological character states relevant for the identification of a new megafaunal species were obtained. Potentially harmful effects on this unique deep-sea cephalopod specimen were avoided by scanning the fixed animal without admixture of a contrast agent. Additional support for the taxonomic placement of the new dumbo octopus species was obtained through DNA barcoding, further underlining the importance of combining morphological and molecular datasets for a holistic description of zoological specimens.

Does Motion Perception Follow Weber's Law?

Perception ◽  
1995 ◽  
Vol 24 (4) ◽  
pp. 363-372 ◽  
Author(s):  
Johannes M Zanker
Keyword(s):  
Motion Perception ◽  
Stimulus Intensity ◽  
Signal To Noise Ratio ◽  
Weber’S Law ◽  
Noise Levels ◽  
Signal To Noise ◽  
Weber's Law ◽  
The Absolute ◽  
Noise Ratio ◽  
Random Dot Patterns

The subjective strength of a percept often depends on the stimulus intensity in a nonlinear way. Such coding is often reflected by the observation that the just-noticeable difference between two stimulus intensities (JND) is proportional to the absolute stimulus intensity. This behaviour, which is usually referred to as Weber's Law, can be interpreted as a compressive nonlinearity extending the operating range of a sensory system. When the noise superimposed on a motion stimulus is increased along a logarithmic scale (in order to provide linear steps in subjective difference) in motion-coherency measurements, observers often report that the subjective differences between the various noise levels increase together with the absolute level. This observation could indicate a deviation from Weber's Law for variation of motion strength as obtained by changing the signal-to-noise ratio in random-dot kinematograms. Thus JNDs were measured for the superposition of uncorrelated random-dot patterns on static random-dot patterns and three types of motion stimuli realised as random-dot kinematograms, namely large-field and object ‘Fourier’ motion (all or a group of dots move coherently), ‘drift-balanced’ motion (a travelling region of static dots), and paradoxical ‘theta’ motion (the dots on the surface of an object move in opposite direction to the object itself). For all classes of stimuli, the JNDs when expressed as differences in signal-to-noise ratio turned out to increase with the signal-to-noise ratio, whereas the JNDs given as percentage of superimposed noise appear to be similar for all tested noise levels. Thus motion perception is in accordance with Weber's Law when the signal-to-noise ratio is regarded as stimulus intensity, which in turn appears to be coded in a nonlinear fashion. In general the Weber fractions are very large, indicating a poor differential sensitivity in signal-to-noise measurements.

An overview of structured illumination microscopy: recent advances and perspectives

2021 ◽  
Author(s):  
Krishnendu Samanta ◽  
Joby Joseph
Keyword(s):  
Spatial Frequency ◽  
Basic Principle ◽  
Imaging Techniques ◽  
Resolution Enhancement ◽  
Super Resolution ◽  
Diffraction Limit ◽  
Structured Illumination ◽  
Post Processing ◽  
Structured Illumination Microscopy ◽  
Near Future

Abstract Structured illumination microscopy (SIM) is one of the most significant widefield super-resolution optical imaging techniques. The conventional SIM utilizes a sinusoidal structured pattern to excite the fluorescent sample; which eventually down-modulates higher spatial frequency sample information within the diffraction-limited passband of the microscopy system and provides around two-fold resolution enhancement over diffraction limit after suitable computational post-processing. Here we provide an overview of the basic principle, image reconstruction, technical development of the SIM technique. Nonetheless, in order to push the SIM resolution further towards the extreme nanoscale dimensions, several different approaches are launched apart from the conventional SIM. Among the various SIM methods, some of the important techniques e.g. TIRF, non-linear, plasmonic, speckle SIM etc. are discussed elaborately. Moreover, we highlight different implementations of SIM in various other imaging modalities to enhance their imaging performances with augmented capabilities. Finally, some future outlooks are mentioned which might develop fruitfully and pave the way for new discoveries in near future.

Coherent imaging of objects through thin-layer highly scattering medium based on optical encryption

2021 ◽  
pp. 127558
Author(s):  
Xing Bai ◽  
LuoZhi Zhang ◽  
Jinxi Li ◽  
Zhan Yu ◽  
Zhongzhuo Yang ◽  
...  
Keyword(s):  
Thin Layer ◽  
Scattering Medium ◽  
Coherent Imaging ◽  
Optical Encryption ◽  
Highly Scattering Medium

Minimally Invasive Palliative Tumor Therapy Guided by Imaging Techniques: The UCLA Experience

1994 ◽  
Vol 12 (2) ◽  
pp. 65-73 ◽  
Author(s):  
DAN J. CASTRO ◽  
ROMAINE E. SAXTON ◽  
JACQUES SOUDANT ◽  
THOMAS CALCATERRA ◽  
ROBERT LUFKIN ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Imaging Techniques ◽  
Tumor Therapy

scholarly journals Ultrasonic Propagation in Highly Attenuating Insulation Materials

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2285
Author(s):  
David A. Hutchins ◽  
Richard L. Watson ◽  
Lee A.J. Davis ◽  
Lolu Akanji ◽  
Duncan R. Billson ◽  
...  
Keyword(s):  
Pulse Compression ◽  
Steel Pipe ◽  
Frequency Range ◽  
Noise Levels ◽  
Signal To Noise ◽  
Ultrasonic Signals ◽  
Insulation Materials ◽  
Viscoelastic Effects ◽  
Ultrasonic Propagation ◽  
Cladded Steel

Experiments have been performed to demonstrate that ultrasound in the 100–400 kHz frequency range can be used to propagate signals through various types of industrial insulation. This is despite the fact that they are highly attenuating to ultrasonic signals due to scattering and viscoelastic effects. The experiments used a combination of piezocomposite transducers and pulse compression processing. This combination allowed signal-to-noise levels to be enhanced so that signals reflected from the surface of an insulated and cladded steel pipe could be obtained.

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