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Background: Spectral shaping is a computed tomography (CT) dose optimization technique that adjusts source voltage and filtration to reduce patient radiation exposure without compromising image quality. Traditionally, radiation dose has…

21cm tomography promises to be a powerful tool for estimating cosmological parameters, constraining the epoch of reionization, and probing the so-called dark ages. However, realizing this promise will require the extraction of a…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-02 Adrian Liu , Max Tegmark

Purpose: With the development of spectral CT, several novel spectral filters have been introduced to modulate the spectra, such as split filters and spectral modulators. However, due to the finite size of the focal spot of X-ray source,…

Medical Physics · Physics 2024-11-05 Yifan Deng , Hao Zhou , Hewei Gao

This paper studies two spectrum estimation methods for the case that the samples are obtained at a rate lower than the Nyquist rate. The first method is the correlogram method for undersampled data. The algorithm partitions the spectrum…

Statistics Theory · Mathematics 2013-11-25 Mahdi Shaghaghi , Sergiy A. Vorobyov

We propose a new modeling approach for scatter estimation and descattering in polyenergetic X-ray computed tomography (CT) based on fitting models to local neighborhoods of a training set. X-ray CT is widely used in medical and industrial…

Image and Video Processing · Electrical Eng. & Systems 2021-09-30 Michael T. McCann , Marc L. Klasky , Jennifer L. Schei , Saiprasad Ravishankar

In this paper, we present a wideband subspace estimation method that characterizes the signal subspace through its orthogonal projection matrix at each frequency. Fundamentally, the method models this projection matrix as a function of…

Information Theory · Computer Science 2021-11-29 J. Selva

Blind methods often separate or identify signals or signal subspaces up to an unknown scaling factor. Sometimes it is necessary to cope with the scaling ambiguity, which can be done through reconstructing signals as they are received by…

Sound · Computer Science 2017-08-02 Zbyněk Koldovský , Francesco Nesta

The paper presents an analysis of the possible spectra manipulation and its consequence for the specific application of XCT. The focus was on the modification of the registered spectra dominantly by the sewing/stitching method. A model…

Atomic Physics · Physics 2024-06-04 A. J. Arikkat , K. A. Janulewicz , C. M. Kim , P. Wachulak

Dark-field imaging based on grating interferometry is an emerging X-ray modality in medical imaging, which is particularly capable of providing complementary diagnostic information by visualizing the microstructural properties of lung…

Medical Physics · Physics 2026-05-29 Longchao Men , Peiyuan Guo , Jincheng Lu , Yan Xu , Hongxia Yin , Zhenchang Wang , Li Zhang , Zhentian Wang

Quantitative estimation of contrast agent concentration is made possible by spectral CT and material decomposition. There are several approaches to modulate the sensitivity of the imaging system to obtain the different spectral channels…

Medical Physics · Physics 2020-10-16 Matthew Tivnan , Wenying Wang , Grace Gang , Eleni Liapi , Peter Noel , J. Webster Stayman

X-ray dark-field or ultra-small angle scatter imaging has become increasingly important since the introduction of phase-based x-ray imaging and is having transformative impact in fields such as in vivo lung imaging and explosives detection.…

A new method for measuring \ngr cross sections aiming at enhanced signal-to-background ratio is presented. This new approach is based on the combination of the pulse-height weighting technique with a total energy detection system that…

Instrumentation and Detectors · Physics 2015-10-15 César Domingo-Pardo

-Purpose: A neural network estimator to process x-ray spectral measurements from photon counting detectors with pileup. The estimator is used with an expansion of the attenuation coefficient as a linear combination of functions of energy…

Medical Physics · Physics 2017-02-06 Robert Alvarez

X-ray scatter remains a major physics challenge in volumetric computed tomography (CT), whose physical and statistical behaviors have been commonly leveraged in order to eliminate its impact on CT image quality. In this work, we conduct an…

Medical Physics · Physics 2021-03-05 Tao Zhang , Zhiqiang Chen , Hao Zhou , N. Robert Bennett , Adam S. Wang , Hewei Gao

Single-photon emission computed tomography (SPECT) provides a mechanism to estimate regional isotope uptake in lesions and at-risk organs after administration of {\alpha}-particle-emitting radiopharmaceutical therapies ({\alpha}-RPTs).…

Algorithmic X-ray scatter compensation is a desirable technique in flat-panel X-ray imaging and cone-beam computed tomography. State-of-the-art U-net based image translation approaches yielded promising results. As there are no physics…

Speckle is an intrinsic pattern in optical coherence tomography (OCT) that obscures fine image features and degrades effective resolution. In this study, we propose a numerical speckle reduction method based on the dispersed scatterer model…

Intelligent spectrum management is crucial for improving spectrum efficiency and achieving secure utilization of spectrum resources. However, existing intelligent spectrum management methods, typically based on small-scale models, suffer…

Signal Processing · Electrical Eng. & Systems 2025-12-16 Fuhui Zhou , Chunyu Liu , Hao Zhang , Wei Wu , Qihui Wu , Tony Q. S. Quek , Chan-Byoung Chae

We present a new method, called "forced-spectrum fitting", for physically-based spectral modelling of radio sources during deconvolution. This improves upon current common deconvolution fitting methods, which often produce inaccurate…

X-ray echo spectroscopy, a counterpart of neutron spin-echo, is being introduced here to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a point-like x-ray…

Optics · Physics 2016-02-26 Yuri Shvyd'ko