scholarly journals Signal-to-noise, spatial resolution and information capacity of coherent diffraction imaging

IUCrJ ◽  
2018 ◽  
Vol 5 (6) ◽  
pp. 716-726 ◽  
Author(s):  
Timur E. Gureyev ◽  
Alexander Kozlov ◽  
Yakov I. Nesterets ◽  
David M. Paganin ◽  
Andrew V. Martin ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Electron Density ◽  
Spatial Resolution ◽  
Three Dimensional ◽  
Information Capacity ◽  
Fourth Power ◽  
Imaging Method ◽  
Signal To Noise ◽  
Diffractive Imaging ◽  
Reconstructed Volume

It is shown that the average signal-to-noise ratio (SNR) in the three-dimensional electron-density distribution of a sample reconstructed by coherent diffractive imaging cannot exceed twice the square root of the ratio of the mean total number of scattered photons detected during the scan and the number of spatially resolved voxels in the reconstructed volume. This result leads to an upper bound on Shannon's information capacity of this imaging method by specifying the maximum number of distinguishable density distributions within the reconstructed volume when the radiation dose delivered to the sample and the spatial resolution are both fixed. If the spatially averaged SNR in the reconstructed electron density is fixed instead, the radiation dose is shown to be proportional to the third or fourth power of the spatial resolution, depending on the sampling of the three-dimensional diffraction space and the scattering power of the sample.

X-ray microtomographic imaging and analysis for basic research

2006 ◽  
Vol 21 (2) ◽  
pp. 125-131 ◽  
Author(s):  
J. H. Dunsmuir ◽  
S. Bennett ◽  
L. Fareria ◽  
A. Mingino ◽  
M. Sansone
Keyword(s):  
Spatial Resolution ◽  
Three Dimensional ◽  
Basic Research ◽  
Integrated Approach ◽  
Imaging Method ◽  
Structure Property ◽  
3D Images ◽  
X Ray ◽  
Structure Property Relationships ◽  
Essential Components

For research facilities with access to synchrotron X-ray sources, X-ray absorption microtomography (XMT) has evolved from an experimental imaging method to a specialized, if not yet routine, microscopy for imaging the three-dimensional (3D) distribution of linear attenuation coefficients and, in some cases, elemental concentration with micron spatial resolution. Recent advances in source and detector design have produced conventional X-ray source instruments with comparable spatial resolution but with lower throughput and without element specific imaging. Both classes of instrument produce 3D images for analysis. We discuss an integrated approach for the implementation of analytical XMT to support basic research into the structure-property relationships of a variety of materials. The essential components include instrumentation for collecting quantitative 3D images, a 3D image processing environment to address questions as to the quantity, composition, geometry, and relationships among the features in one or more images, and visualization to provide insight and communicate results. We give examples of image analysis of resolved and unresolved pore spaces of sandstones.

scholarly journals Three-Dimensional Microwave Holographic Imaging Employing Forward-Scattered Waves Only

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Reza K. Amineh ◽  
Maryam Ravan ◽  
Justin McCombe ◽  
Natalia K. Nikolova
Keyword(s):  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Imaging Method ◽  
Two Dimensional ◽  
Signal To Noise ◽  
High Loss ◽  
Holographic Imaging ◽  
Multiple Receivers ◽  
Satisfactory Performance ◽  
Resolution Limits

We propose a three-dimensional microwave holographic imaging method based on the forward-scattered waves only. In the proposed method, one transmitter and multiple receivers perform together a two-dimensional scan on two planar apertures on opposite sides of the inspected domain. The ability to achieve three-dimensional imaging without back-scattered waves enables the imaging of high-loss objects, for example, tissues, where the back-scattered waves may not be available due to low signal-to-noise ratio or nonreciprocal measurement setup. The simulation and experimental results demonstrate the satisfactory performance of the proposed method in providing three-dimensional images. Resolution limits are derived and confirmed with simulation examples.

scholarly journals Amyloid-β plaque deposition measured using propagation-based X-ray phase contrast CT imaging

2016 ◽  
Vol 23 (3) ◽  
pp. 813-819 ◽  
Author(s):  
Alberto Astolfo ◽  
Aurélien Lathuilière ◽  
Vanessa Laversenne ◽  
Bernard Schneider ◽  
Marco Stampanoni
Keyword(s):  
Spatial Resolution ◽  
Phase Contrast ◽  
Ex Vivo ◽  
Three Dimensional ◽  
Amyloid Β ◽  
High Sensitivity ◽  
Final Diagnosis ◽  
Pathological Process ◽  
Imaging Method ◽  
X Ray

Amyloid beta accumulation into insoluble plaques (Aβp) is known to play a significant role in the pathological process in Alzheimer's disease (AD). The presence of Aβp is also one of the neuropathological hallmarks for the disease. AD final diagnosis is generally acknowledged after the evaluation of Aβp deposition in the brain. Insoluble Aβp accumulation may also concur to cause AD as postulated in the so-calledamyloid hypothesis. Therefore, the visualization, evaluation and quantification of Aβp are nowadays the keys for a better understanding of the disease, which may point to a possible cure for AD in the near future. Synchrotron-based X-ray phase contrast (XPC) has been demonstrated as the only imaging method that can retrieve the Aβp signal with high spatial resolution (up to 10 µm), high sensitivity and three-dimensional information at the same time. Although at the moment XPC is suitable forex vivosamples only, it may develop into an alternative to positron emission tomography and magnetic resonance imaging in Aβp imaging. In this contribution the possibility of using synchrotron-based X-ray phase propagation computed tomography to visualize and measure Aβp on mouse brains is presented. A careful setup optimization for this application leads to a significant improvement of spatial resolution (∼1 µm), data acquisition speed (five times faster), X-ray dose (five times lower) and setup complexity, without a substantial loss in sensitivity when compared with the classic implementation of grating-based X-ray interferometry.

Using micro-MRI to watch development live and in 3-D

1995 ◽  
Vol 53 ◽  
pp. 90-91
Author(s):  
R. E. Jacobs ◽  
J. Allman ◽  
A. Barr ◽  
S. E. Fraser ◽  
T. Meade
Keyword(s):  
Spatial Resolution ◽  
Temporal Resolution ◽  
Biological Samples ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Clinical Tool ◽  
Signal To Noise ◽  
Mr Image ◽  
Contrast Mechanisms ◽  
Physical Effects

The ability of MRI to provide three dimensional images of thick opaque samples in a noninvasive manner has made it an extremely important clinical tool. In addition, the large number of types of contrast mechanisms in a MR experiment offer the clinician and research scientist the possibility of adapting the image contrast to fit the problem of interest. While typical resolutions employed clinically are on the order of a millimeter, the notion of using MRI at microscopic resolutions arose early in the development of this technique. Spatial resolution in biological samples is typically limited by a number of physical effects as well as signal-to-noise ratio (S/N) considerations. Estimates of the theoretical limits of resolution in the MR image arising from these phenomena range from 2 to 0.5 micron. The practical spatial resolution is currently determined by the S/N which is often limited by the amount of time available to actually acquire the image (i.e. the temporal resolution).

scholarly journals Spatial resolution, signal-to-noise and information capacity of linear imaging systems

2016 ◽  
Vol 24 (15) ◽  
pp. 17168 ◽  
Author(s):  
Timur Gureyev ◽  
Yakov Nesterets ◽  
Frank de Hoog
Keyword(s):  
Spatial Resolution ◽  
Imaging Systems ◽  
Information Capacity ◽  
Signal To Noise

Information capacity and bandwidth limitations in the SEM

1989 ◽  
Vol 47 ◽  
pp. 84-85
Author(s):  
D. C. Joy ◽  
R. D. Bunn
Keyword(s):  
Signal To Noise Ratio ◽  
Critical Dimension ◽  
Information Capacity ◽  
Acquisition Time ◽  
Signal To Noise ◽  
Sem Image ◽  
Probe Size ◽  
Minimum Number ◽  
Noise Ratio ◽  
Signal Channel

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :

Cardiovascular Imaging for Guiding Interventional Therapy in Structural Heart Diseases

2020 ◽  
Vol 16 (2) ◽  
pp. 111-122
Author(s):  
Nora Rat ◽  
Iolanda Muntean ◽  
Diana Opincariu ◽  
Liliana Gozar ◽  
Rodica Togănel ◽  
...  
Keyword(s):  
Heart Diseases ◽  
Interventional Procedure ◽  
Imaging Techniques ◽  
Ductus Arteriosus ◽  
Three Dimensional ◽  
High Specificity ◽  
Interventional Therapy ◽  
Structural Defects ◽  
Imaging Method ◽  
Three Dimensional Echocardiography

Development of interventional methods has revolutionized the treatment of structural cardiac diseases. Given the complexity of structural interventions and the anatomical variability of various structural defects, novel imaging techniques have been implemented in the current clinical practice for guiding the interventional procedure and for selection of the device to be used. Three– dimensional echocardiography is the most used imaging method that has improved the threedimensional assessment of cardiac structures, and it has considerably reduced the cost of complications derived from malalignment of interventional devices. Assessment of cardiac structures with the use of angiography holds the advantage of providing images in real time, but it does not allow an anatomical description. Transesophageal Echocardiography (TEE) and intracardiac ultrasonography play major roles in guiding Atrial Septal Defect (ASD) or Patent Foramen Ovale (PFO) closure and device follow-up, while TEE is the procedure of choice to assess the flow in the Left Atrial Appendage (LAA) and the embolic risk associated with a decreased flow. On the other hand, contrast CT and MRI have high specificity for providing a detailed description of structure, but cannot assess the flow through the shunt or the valvular mobility. This review aims to present the role of modern imaging techniques in pre-procedural assessment and intraprocedural guiding of structural percutaneous interventions performed to close an ASD, a PFO, an LAA or a patent ductus arteriosus.

Pushing the Envelope

2018 ◽  
Author(s):  
Eaton E. Lattman ◽  
Thomas D. Grant ◽  
Edward H. Snell
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Structural Information ◽  
Hydration Shell ◽  
Three Dimensional ◽  
Scattering Data ◽  
Saxs Data ◽  
Electron Density Function ◽  
Angle Scattering ◽  
Iterative Structure

Direct electron density determination from SAXS data opens up new opportunities. The ability to model density at high resolution and the implicit direct estimation of solvent terms such as the hydration shell may enable high-resolution wide angle scattering data to be used to calculate density when combined with additional structural information. Other diffraction methods that do not measure three-dimensional intensities, such as fiber diffraction, may also be able to take advantage of iterative structure factor retrieval. While the ability to reconstruct electron density ab initio is a major breakthrough in the field of solution scattering, the potential of the technique has yet to be fully uncovered. Additional structural information from techniques such as crystallography, NMR, and electron microscopy and density modification procedures can now be integrated to perform advanced modeling of the electron density function at high resolution, pushing the boundaries of solution scattering further than ever before.

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