scholarly journals Rapid High-Resolution Mosaic Acquisition for Photoacoustic Remote Sensing

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1027 ◽  
Author(s):  
Saad Abbasi ◽  
Kevan Bell ◽  
Parsin Haji Reza
Keyword(s):  
High Resolution ◽  
Photoacoustic Imaging ◽  
Image Resolution ◽  
Large Field ◽  
Reflection Mode ◽  
Step Size ◽  
Fiber Networks ◽  
Optical Scanning ◽  
Rapid Acquisition ◽  
Stage Scanning

Mechanical stages are routinely used to scan large expanses of biological specimens in photoacoustic imaging. This is primarily due to the limited field of view (FOV) provided by optical scanning. However, stage scanning becomes impractical at higher scanning speeds, or potentially unfeasible with heavier samples. Also, the slow scan-rate of the stages makes high resolution scanning a time-consuming process. Some clinical applications such as microsurgery require submicron resolution in a reflection-mode configuration necessitating a method that can acquire large field of views with a small raster scanning step size. In this study, we describe a method that combines mechanical stages with optical scanning for the rapid acquisition of high-resolution large FOVs. Optical scanning is used to acquire small frames in a two-dimensional grid formed by the mechanical stages. These frames are captured with specific overlap for effective image registration. Using a step size of 200 nm, we demonstrate mosaics of carbon fiber networks with FOVs of 0.8 × 0.8 mm2 captured in under 70 s with 1.2 µm image resolution. Larger mosaics yielding an imaging area of 3 × 3 mm2 are also shown. The method is validated by imaging a 1 × 1 mm2 section of unstained histopathological human tissue.

A portable, optical scanning microsystem for large field of view, high resolution imaging of biological specimens

2018 ◽  
Vol 279 ◽  
pp. 367-375 ◽  
Author(s):  
Georgia Korompili ◽  
Georgios Kanakaris ◽  
Christos Ampatis ◽  
Nikos Chronis
Keyword(s):  
High Resolution ◽  
Field Of View ◽  
Large Field ◽  
High Resolution Imaging ◽  
Optical Scanning ◽  
Resolution Imaging

High-Resolution, Reflection Mode Tomographic Imaging Part I: Principles and Methods

1989 ◽  
Vol 11 (1) ◽  
pp. 1-21
Author(s):  
A. Herment ◽  
J.P. Guglielmi ◽  
P. Péronneau ◽  
Ph. Dumée
Keyword(s):  
High Resolution ◽  
Image Reconstruction ◽  
Computation Time ◽  
Tomographic Imaging ◽  
Image Resolution ◽  
Square Root ◽  
Two Dimensional ◽  
Reflection Mode ◽  
Reconstruction Process ◽  
General Method

A general method for improving image resolution is derived and applied to ultrasound signals; it combines the principles of both reflection mode tomography and deconvolution. The different possibilities of applying these principles allow two types of approaches to be defined, depending upon whether image reconstruction is achieved on radiofrequency or detected signals. A thorough description of three methods that are of particular interest due to their lower computation costs is presented, and their results quantified. They permit a gain in resolution of the order of ten with respect to two-dimensional deconvolution of images, as well as an improvement of the S/N ratio, which is related to the square root of the number of projections used in the reconstruction process, and a decrease of about four in computation time.

scholarly journals Blood flow synchronization in renal microcirculation - a high-resolution imaging study.

2021 ◽  
Author(s):  
Dmitry D Postnov ◽  
Donald Marsh ◽  
Will Cupples ◽  
Niels-Henrik Holstein-Rathlou ◽  
Olga Sosnovtseva
Keyword(s):  
Blood Flow ◽  
Angiotensin Ii ◽  
High Resolution ◽  
Blood Vessels ◽  
Image Resolution ◽  
Laser Speckle ◽  
Field Of View ◽  
Large Field ◽  
Kidney Cortex ◽  
Vasoactive Agents

Aims: internephron signalling and interaction are fundamental for kidney function. Earlier studies have shown that nephrons signal to each other over short distances and adjust their activity accordingly. Micropuncture experiments revealed synchronous clusters of 2-3 nephrons formed from such interactions, while imaging and modelling results suggested the possibility of larger clusters. Such clusters are expected to play an important role in renal autoregulation, but their presence has not been confirmed and their size has not been estimated. In this study, we present methodology for high resolution renal blood flow imaging and apply it to estimate frequency and phase angle differences in kidney blood vessels under normal conditions and after administration of the vasoactive agents angiotensin II and acetylcholine. Methods and results: to resolve signals from separate arterioles in a sufficiently large field of view, we developed a method for renal laser speckle contrast imaging. Our setup provides imaging of blood flow in the kidney cortex with a limit of image resolution at 0.8 micrometres per pixel and the imaging frequency of 160Hz. We used the method to record from ~1.5x1.5 mm2 sections of the renal surface in anaesthetised Sprague-Dawley rats in unstimulated conditions and during IV infusion of the vasoconstrictor angiotensin II or the vasodilator acetylcholine. In each section, we resolved and segmented 94.8+-15.66 individual arterioles and venules, and analyzed blood flow using wavelet spectral analysis to identify clusters of synchronized blood vessels. Conclusions: we observed spatial and temporal evolution of blood vessel clusters of various sizes, including the formation of large (>90 vessels) long-lived clusters (>10 periods) locked at the frequency of the tubular glomerular feedback (TGF) mechanism. The analysis showed that synchronization patterns and thus the co-operative dynamics of nephrons change significantly when either of the vasoactive agents is administered. On average, synchronization was stronger (larger clusters, longer duration) with angiotensin II administration than in the unstimulated state or with acetyl choline. While it weakens with distance, increased synchronization duration spanned the whole field of view, and likely, beyond it. Neighbouring vessels tend to demonstrate in-phase synchronization, especially in the vasoconstricted condition, which is expected to cause locally increased pressure variation. Our results confirm both the presence of the local synchronization in the renal microcirculatory blood flow and the fact that it changes depending on the condition of the vascular network and the blood pressure, which might have further implications for the role of such synchronization in pathologies development.

scholarly journals A Portable, Optical Scanning System for Large Field of View, High Resolution Imaging of Biological Specimens

Proceedings ◽  
2017 ◽  
Vol 1 (4) ◽  
pp. 548
Author(s):  
Georgia Korompili ◽  
Georgios Kanakaris ◽  
Christos Ampatis ◽  
Nikos Chronis
Keyword(s):  
High Resolution ◽  
Field Of View ◽  
Large Field ◽  
Scanning System ◽  
High Resolution Imaging ◽  
Optical Scanning ◽  
Resolution Imaging ◽  
Optical Scanning System

Towards 1-Ångstrom-resolution STEM

1993 ◽  
Vol 51 ◽  
pp. 996-997
Author(s):  
H.S. von Harrach ◽  
D.E. Jesson ◽  
S.J. Pennycook
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Phase Contrast ◽  
Spherical Aberration ◽  
A Priori ◽  
Dark Field ◽  
Image Resolution ◽  
Objective Lens ◽  
Annular Dark Field ◽  
First Results

Phase contrast TEM has been the leading technique for high resolution imaging of materials for many years, whilst STEM has been the principal method for high-resolution microanalysis. However, it was demonstrated many years ago that low angle dark-field STEM imaging is a priori capable of almost 50% higher point resolution than coherent bright-field imaging (i.e. phase contrast TEM or STEM). This advantage was not exploited until Pennycook developed the high-angle annular dark-field (ADF) technique which can provide an incoherent image showing both high image resolution and atomic number contrast.This paper describes the design and first results of a 300kV field-emission STEM (VG Microscopes HB603U) which has improved ADF STEM image resolution towards the 1 angstrom target. The instrument uses a cold field-emission gun, generating a 300 kV beam of up to 1 μA from an 11-stage accelerator. The beam is focussed on to the specimen by two condensers and a condenser-objective lens with a spherical aberration coefficient of 1.0 mm.

High-Resolution Large-Field-of-View Ultrasound Breast Imager

2014 ◽  
Author(s):  
Patrick LaRiviere
Keyword(s):  
High Resolution ◽  
Field Of View ◽  
Large Field

scholarly journals Application of Airy beam light sheet microscopy to examine early neurodevelopmental structures in 3D hiPSC-derived human cortical spheroids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dwaipayan Adhya ◽  
George Chennell ◽  
James A. Crowe ◽  
Eva P. Valencia-Alarcón ◽  
James Seyforth ◽  
...  
Keyword(s):  
High Resolution ◽  
Human Brain ◽  
Light Sheet ◽  
Autism Spectrum ◽  
Model Systems ◽  
Large Field ◽  
Autism Spectrum Conditions ◽  
Patient Specific ◽  
Airy Beam

Abstract Background The inability to observe relevant biological processes in vivo significantly restricts human neurodevelopmental research. Advances in appropriate in vitro model systems, including patient-specific human brain organoids and human cortical spheroids (hCSs), offer a pragmatic solution to this issue. In particular, hCSs are an accessible method for generating homogenous organoids of dorsal telencephalic fate, which recapitulate key aspects of human corticogenesis, including the formation of neural rosettes—in vitro correlates of the neural tube. These neurogenic niches give rise to neural progenitors that subsequently differentiate into neurons. Studies differentiating induced pluripotent stem cells (hiPSCs) in 2D have linked atypical formation of neural rosettes with neurodevelopmental disorders such as autism spectrum conditions. Thus far, however, conventional methods of tissue preparation in this field limit the ability to image these structures in three-dimensions within intact hCS or other 3D preparations. To overcome this limitation, we have sought to optimise a methodological approach to process hCSs to maximise the utility of a novel Airy-beam light sheet microscope (ALSM) to acquire high resolution volumetric images of internal structures within hCS representative of early developmental time points. Results Conventional approaches to imaging hCS by confocal microscopy were limited in their ability to image effectively into intact spheroids. Conversely, volumetric acquisition by ALSM offered superior imaging through intact, non-clarified, in vitro tissues, in both speed and resolution when compared to conventional confocal imaging systems. Furthermore, optimised immunohistochemistry and optical clearing of hCSs afforded improved imaging at depth. This permitted visualization of the morphology of the inner lumen of neural rosettes. Conclusion We present an optimized methodology that takes advantage of an ALSM system that can rapidly image intact 3D brain organoids at high resolution while retaining a large field of view. This imaging modality can be applied to both non-cleared and cleared in vitro human brain spheroids derived from hiPSCs for precise examination of their internal 3D structures. This process represents a rapid, highly efficient method to examine and quantify in 3D the formation of key structures required for the coordination of neurodevelopmental processes in both health and disease states. We posit that this approach would facilitate investigation of human neurodevelopmental processes in vitro.

New LWD Image Improvement Method to Mitigate Interpretation Risks

2021 ◽  
Author(s):  
Tianhua Zhang ◽  
Shiduo Yang ◽  
Chandramani Shrivastava ◽  
Adrian A ◽  
Nadege Bize-Forest
Keyword(s):  
High Resolution ◽  
Real Time ◽  
Best Practice ◽  
Synthetic Data ◽  
Image Resolution ◽  
Drilling Process ◽  
Drilling Tool ◽  
Stick Slip ◽  
Geological Interpretation ◽  
Wellbore Temperature

Abstract With the advancement of LWD (Logging While Drilling) hardware and acquisition, the imaging technology becomes not only an indispensable part of the drilling tool string, but also the image resolution increases to map layers and heterogeneity features down to less than 5mm scale. This shortens the geological interpretation turn-around time from wireline logging time (hours to days after drilling) to semi-real time (drilling time or hours after drilling). At the same time, drilling motion is complex. The depth tracking is on the surface referenced to the surface block movement. The imaging sensor located downhole can be thousands of feet away from the surface. Mechanical torque and drag, wellbore friction, wellbore temperature and weight on bit can make the downhole sensor movement motion not synchronized with surface pipe depth. This will cause time- depth conversion step generate image artifacts that either stop real-time interpretation of geological features or mis-interpret features on high resolution images. In this paper, we present several LWD images featuring distortion mechanism during the drilling process using synthetic data. We investigated how heave, depth reset and downhole sensor stick/slip caused image distortions. We provide solutions based on downhole sensor pseudo velocity computation to minimize the image distortion. The best practice in using Savitsky-Golay filter are presented in the discussion sections. Finally, some high-resolution LWD images distorted with drilling-related artifacts and processed ones are shown to demonstrate the importance of image post-processing. With the proper processed images, we can minimize interpretation risks and make drilling decisions with more confidence.

Solid-state VCSEL beam scanner with ultra-large field of view and high resolution

2021 ◽  
Author(s):  
Ruixiao Li ◽  
Zeuku Ho ◽  
Xiaodong Gu ◽  
Satoshi Shinada ◽  
Fumio Koyama
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Field Of View ◽  
Large Field

The Best of Both Worlds: 3D X-ray Microscopy with Ultra-high Resolution and a Large Field of View

2011 ◽  
Author(s):  
W. Li ◽  
J. Gelb ◽  
Y. Yang ◽  
Y. Guan ◽  
W. Wu ◽  
...  
Keyword(s):  
High Resolution ◽  
Field Of View ◽  
Large Field ◽  
X Ray
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