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We present a new nonlinear optimization approach for the sparse reconstruction of single-photon absorption and two-photon absorption coefficients in photoacoustic tomography (PAT). This framework comprises of minimizing an objective…

Optimization and Control · Mathematics 2020-06-30 Madhu Gupta , Rohit Kumar Mishra , Souvik Roy

In this paper, we propose a hybrid method to reconstruct the absorption coefficient by fluorescence photoacoustic tomography (FPAT), which combines a squeeze iterative method (SIM) and a nonlinear optimization method. The SIM is to use two…

Numerical Analysis · Mathematics 2019-01-30 Chao Wang , Tie Zhou

Adaptive techniques have important potential for wide applications in enhancing precision of quantum parameter estimation. We present a recursively adaptive quantum state tomography (RAQST) protocol for finite dimensional quantum systems…

We propose a method for finding approximate compilations of quantum unitary transformations, based on techniques from policy gradient reinforcement learning. The choice of a stochastic policy allows us to rephrase the optimization problem…

Quantum Physics · Physics 2022-09-14 David A. Herrera-Martí

Quantitative photoacoustic computed tomography (qPACT) is a promising imaging modality for estimating physiological parameters such as blood oxygen saturation. However, developing robust qPACT reconstruction methods remains challenging due…

Medical Physics · Physics 2025-10-07 Refik Mert Cam , Seonyeong Park , Umberto Villa , Mark A. Anastasio

In this paper, we focus on the numerical analysis of quantitative photoacoustic tomography. Our goal is to reconstruct the optical coefficients, i.e., the diffusion and absorption coefficients, using multiple internal observational data.…

Numerical Analysis · Mathematics 2025-05-09 Giovanni S. Alberti , Siyu Cen , Zhi Zhou

Tomography deals with the reconstruction of objects from their projections, acquired along a range of angles. Discrete tomography is concerned with objects that consist of a small number of materials, which makes it possible to compute…

Computer Vision and Pattern Recognition · Computer Science 2020-09-07 Mathé Zeegers , Felix Lucka , Kees Joost Batenburg

Solving tough clinical questions that require both image and text understanding is still a major challenge in healthcare AI. In this work, we propose Q-FSRU, a new model that combines Frequency Spectrum Representation and Fusion (FSRU) with…

Computer Vision and Pattern Recognition · Computer Science 2025-10-06 Rakesh Thakur , Yusra Tariq , Rakesh Chandra Joshi

In this paper, we present new stochastic methods for solving two important classes of nonconvex optimization problems. We first introduce a randomized accelerated proximal gradient (RapGrad) method for solving a class of nonconvex…

Optimization and Control · Mathematics 2019-08-20 Guanghui Lan , Yu Yang

Quantitative photoacoustic computed tomography (qPACT) is an emerging medical imaging modality that carries the promise of high-contrast, fine-resolution imaging of clinically relevant quantities like hemoglobin concentration and…

Medical Physics · Physics 2024-10-15 Evan Scope Crafts , Mark A. Anastasio , Umberto Villa

Photoacoustic tomography (PAT) is an emerging and non-invasive hybrid imaging modality for visualizing light absorbing structures in biological tissue. The recently invented PAT systems using arrays of 64 parallel integrating line detectors…

Numerical Analysis · Mathematics 2018-08-31 Johannes Schwab , Stephan Antholzer , Robert Nuster , Markus Haltmeier

In this paper, we propose a proximal gradient method and an accelerated proximal gradient method for solving composite optimization problems, where the objective function is the sum of a smooth and a convex, possibly nonsmooth, function. We…

Optimization and Control · Mathematics 2025-07-22 Raghu Bollapragada , Shagun Gupta

Quantitative imaging in MRI usually involves acquisition and reconstruction of a series of images at multi-echo time points, which possibly requires more scan time and specific reconstruction technique compared to conventional qualitative…

Signal Processing · Electrical Eng. & Systems 2021-03-11 Jinwei Zhang , Hang Zhang , Chao Li , Pascal Spincemaille , Mert Sabuncu , Thanh D. Nguyen , Yi Wang

The single-scatter approximation is fundamental in many tomographic imaging problems including x-ray scatter imaging and optical scatter imaging for certain media. In all cases, noisy measurements are affected by both local scatter events…

Image and Video Processing · Electrical Eng. & Systems 2021-04-21 Michael R. Walker , Joseph A. O'Sullivan

In this letter, an accelerated quadratic programming (QP) algorithm is proposed based on the proximal gradient method. The algorithm can achieve convergence rate $O(1/p^{\alpha})$, where $p$ is the iteration number and $\alpha$ is the given…

Optimization and Control · Mathematics 2022-01-25 Jia Wang , Ying Yang

Quantum process tomography (QPT) plays a central role in characterizing quantum gates and circuits, diagnosing quantum devices, calibrating hardware, and supporting quantum error correction. However, conventional QPT methods face challenges…

Quantum Physics · Physics 2026-02-06 Huynh Le Dan Linh , Vu Tuan Hai , Le Bin Ho

Computationally expensive Radiative Transfer Models (RTMs) are widely used} to realistically reproduce the light interaction with the Earth surface and atmosphere. Because these models take long processing time, the common practice is to…

Thermal radiative transfer (TRT) is an essential piece of physics in inertial confinement fusion, high-energy density physics, astrophysics etc. The physical models of this type of problem are defined by strongly coupled differential…

Numerical Analysis · Mathematics 2025-08-06 Dmitriy Y. Anistratov , Terry S. Haut

Quantitative MR imaging is increasingly favoured for its richer information content and standardised measures. However, computing quantitative parameter maps, such as those encoding longitudinal relaxation rate (R1), apparent transverse…

Computer Vision and Pattern Recognition · Computer Science 2021-07-01 Yael Balbastre , Mikael Brudfors , Michela Azzarito , Christian Lambert , Martina F. Callaghan , John Ashburner

Atmospheric retrieval determines the properties of an atmosphere based on its measured spectrum. The low signal-to-noise ratio of exoplanet observations require a Bayesian approach to determine posterior probability distributions of each…