Efficient implementation of X-ray ghost imaging based on a modified compressive sensing algorithm

Abstract Towards efficient implementation of X-ray ghost imaging (XGI), efficient data acquisition and fast image reconstruction together with high image quality are preferred. In view of radiation dose resulted from the incident X-rays, fewer measurements with sufficient signal-to-noise ratio (SNR) are always anticipated. Available methods based on linear and compressive sensing algorithms cannot meet all the requirements simultaneously. In this paper, a method based a modified compressive sensing algorithm called CGDGI, is developed to solve the problem encountered in available XGI methods. Simulation and experiments demonstrated the practicability of CGDGI-based method for the efficient implementation of XGI. The image reconstruction time of sub-second implicates that the proposed method has the potential for real time XGI.

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Simulated Annealing-Based Image Reconstruction for Patients With COVID-19 as a Model for Ultralow-Dose Computed Tomography

Frontiers in Physiology ◽

10.3389/fphys.2021.737233 ◽

2022 ◽

Vol 12 ◽

Author(s):

Shahzad Ahmad Qureshi ◽

Aziz Ul Rehman ◽

Adil Aslam Mir ◽

Muhammad Rafique ◽

Wazir Muhammad

Keyword(s):

Computed Tomography ◽

Simulated Annealing ◽

Image Reconstruction ◽

Image Quality ◽

Radiation Dose ◽

Signal To Noise Ratio ◽

Absolute Error ◽

Signal To Noise ◽

X Ray ◽

Squared Error

The proposed algorithm of inverse problem of computed tomography (CT), using limited views, is based on stochastic techniques, namely simulated annealing (SA). The selection of an optimal cost function for SA-based image reconstruction is of prime importance. It can reduce annealing time, and also X-ray dose rate accompanying better image quality. In this paper, effectiveness of various cost functions, namely universal image quality index (UIQI), root-mean-squared error (RMSE), structural similarity index measure (SSIM), mean absolute error (MAE), relative squared error (RSE), relative absolute error (RAE), and root-mean-squared logarithmic error (RMSLE), has been critically analyzed and evaluated for ultralow-dose X-ray CT of patients with COVID-19. For sensitivity analysis of this ill-posed problem, the stochastically estimated images of lung phantom have been reconstructed. The cost function analysis in terms of computational and spatial complexity has been performed using image quality measures, namely peak signal-to-noise ratio (PSNR), Euclidean error (EuE), and weighted peak signal-to-noise ratio (WPSNR). It has been generalized for cost functions that RMSLE exhibits WPSNR of 64.33 ± 3.98 dB and 63.41 ± 2.88 dB for 8 × 8 and 16 × 16 lung phantoms, respectively, and it has been applied for actual CT-based image reconstruction of patients with COVID-19. We successfully reconstructed chest CT images of patients with COVID-19 using RMSLE with eighteen projections, a 10-fold reduction in radiation dose exposure. This approach will be suitable for accurate diagnosis of patients with COVID-19 having less immunity and sensitive to radiation dose.

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High Spatial Resolution in X-Ray Fluorescence

Advances in X-ray Analysis ◽

10.1154/s0376030800021169 ◽

1986 ◽

Vol 30 ◽

pp. 77-83

Author(s):

John D. Zahrt

Keyword(s):

Spatial Resolution ◽

Amorphous Materials ◽

High Spatial Resolution ◽

Signal To Noise Ratio ◽

Bragg Angle ◽

X Rays ◽

Bremsstrahlung Radiation ◽

Signal To Noise ◽

X Ray ◽

The Past

During the past eight years or so there has been growing interest in using a polarized x-ray source in energy dispersive x-ray fluorescence spectrometers (1,2,3,4). The effect is to annihilate the source x rays before they scatter into the detector, thus significantly increasing the signal to noise ratio.Both characteristic or Bremsstrahlung radiation can be polarized by 90° scattering from crystals (Bragg angle = 45°) or from amorphous materials respectively. This 90° polarizing scatter event greatly reduces the incident source radiation on a sample. In an effort to regain some intensity use is made of concave surfaces to utilize a manifold of beams (5,6,7).

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X-Ray Detectors: Present and Future

Microscopy Today ◽

10.1017/s1551929500067912 ◽

1996 ◽

Vol 4 (3) ◽

pp. 8-9

Author(s):

Don Chernoff

Keyword(s):

Trace Elements ◽

Detection Limit ◽

Background Radiation ◽

Signal To Noise Ratio ◽

Energy Dispersive Spectrometer ◽

Data Gathering ◽

X Rays ◽

Signal To Noise ◽

X Ray ◽

Wavelength Dispersive Spectrometer

If you want to collect X-rays on your SEM or TEM you have the choice of using an energy dispersive spectrometer (EDS) or a wavelength dispersive spectrometer (WDS). Which is better? That depends on what you want to do with it.WDS is much more sensitive and has much higher resolution than EDS. Sensitivity means that WDS has a much lower minimum detection limit for trace elements. WDS can be up to several orders of magnitude more sensitive. This does not mean it is more accurate. Accuracy of analysis can be just as good for EDS as with WDS if the analyst takes the same care in sample prep, data gathering, and standardizing. Sensitivity simply means that WDS can detect much smaller amounts of a particular element than EDS. Why? Because the superior resolution provides much better signal to noise ratio than with EDS. Noise, in this case, is mostly contributed by background radiation from the sample. Because of its superior resolution, WDS can also resolve peak overlaps.

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Miniature diamond anvils for X-ray Raman scattering spectroscopy experiments at high pressure

Journal of Synchrotron Radiation ◽

10.1107/s1600577516017112 ◽

2017 ◽

Vol 24 (1) ◽

pp. 276-282 ◽

Cited By ~ 7

Author(s):

Sylvain Petitgirard ◽

Georg Spiekermann ◽

Christopher Weis ◽

Christoph Sahle ◽

Christian Sternemann ◽

...

Keyword(s):

High Pressure ◽

Raman Scattering ◽

Signal To Noise Ratio ◽

High Energy ◽

X Rays ◽

Signal To Noise ◽

X Ray ◽

Custom Made ◽

Diamond Anvils ◽

Noise Ratio

X-ray Raman scattering (XRS) spectroscopy is an inelastic scattering method that uses hard X-rays of the order of 10 keV to measure energy-loss spectra at absorption edges of light elements (Si, Mg, Oetc.), with an energy resolution below 1 eV. The high-energy X-rays employed with this technique can penetrate thick or dense sample containers such as the diamond anvils employed in high-pressure cells. Here, we describe the use of custom-made conical miniature diamond anvils of less than 500 µm thickness which allow pressure generation of up to 70 GPa. This set-up overcomes the limitations of the XRS technique in very high-pressure measurements (>10 GPa) by drastically improving the signal-to-noise ratio. The conical shape of the base of the diamonds gives a 70° opening angle, enabling measurements in both low- and high-angle scattering geometry. This reduction of the diamond thickness to one-third of the classical diamond anvils considerably lowers the attenuation of the incoming and the scattered beams and thus enhances the signal-to-noise ratio significantly. A further improvement of the signal-to-background ratio is obtained by a recess of ∼20 µm that is milled in the culet of the miniature anvils. This recess increases the sample scattering volume by a factor of three at a pressure of 60 GPa. Examples of X-ray Raman spectra collected at the OK-edge and SiL-edge in SiO2glass at high pressures up to 47 GPa demonstrate the significant improvement and potential for spectroscopic studies of low-Zelements at high pressure.

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Counterfactual ghost imaging

npj Quantum Information ◽

10.1038/s41534-021-00411-4 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Jonte R. Hance ◽

John Rarity

Keyword(s):

Signal To Noise Ratio ◽

Ghost Imaging ◽

Signal To Noise ◽

Interesting Phenomenon ◽

Order Of Magnitude ◽

Noise Ratio

AbstractWe give a protocol for ghost imaging in a way that is always counterfactual—while imaging an object, no light interacts with that object. This extends the idea of counterfactuality beyond communication, showing how this interesting phenomenon can be leveraged for metrology. Given, in the infinite limit, no photons ever go to the imaged object, it presents a method of imaging even the most light-sensitive of objects without damaging them. Even when not in the infinite limit, it still provides a many-fold improvement in visibility and signal-to-noise ratio over previous protocols, with over an order of magnitude reduction in absorbed intensity.

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Transient phase fraction and dislocation density estimation from in-situ X-ray diffraction data with a low signal-to-noise ratio using a Bayesian approach to the Rietveld analysis

Materials Characterization ◽

10.1016/j.matchar.2020.110860 ◽

2020 ◽

pp. 110860

Author(s):

Manfred Wiessner ◽

Paul Angerer ◽

Sybrand van der Zwaag ◽

Ernst Gamsjäger

Keyword(s):

Dislocation Density ◽

Density Estimation ◽

Diffraction Data ◽

Signal To Noise Ratio ◽

Rietveld Analysis ◽

Transient Phase ◽

X Ray Diffraction ◽

Signal To Noise ◽

X Ray

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From Femtoseconds to Hours–Measuring Dynamics over 18 Orders of Magnitude with Coherent X-rays

Applied Sciences ◽

10.3390/app11136179 ◽

2021 ◽

Vol 11 (13) ◽

pp. 6179

Author(s):

Felix Lehmkühler ◽

Wojciech Roseker ◽

Gerhard Grübel

Keyword(s):

Time Scales ◽

Free Electron Laser ◽

Photon Correlation Spectroscopy ◽

Signal To Noise Ratio ◽

Coherent Scattering ◽

Correlation Spectroscopy ◽

X Rays ◽

Photon Correlation ◽

X Ray ◽

Scattering Technique

X-ray photon correlation spectroscopy (XPCS) enables the study of sample dynamics between micrometer and atomic length scales. As a coherent scattering technique, it benefits from the increased brilliance of the next-generation synchrotron radiation and Free-Electron Laser (FEL) sources. In this article, we will introduce the XPCS concepts and review the latest developments of XPCS with special attention on the extension of accessible time scales to sub-μs and the application of XPCS at FELs. Furthermore, we will discuss future opportunities of XPCS and the related technique X-ray speckle visibility spectroscopy (XSVS) at new X-ray sources. Due to its particular signal-to-noise ratio, the time scales accessible by XPCS scale with the square of the coherent flux, allowing to dramatically extend its applications. This will soon enable studies over more than 18 orders of magnitude in time by XPCS and XSVS.

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