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We propose a new technique for estimating spatially varying parametric materials from a single image of an object with unknown shape in unknown illumination. Our method uses a low-order parametric reflectance model, and incorporates strong…

Graphics · Computer Science 2019-12-30 Kevin Karsch , David Forsyth

Shape-from-Template (SfT) methods estimate 3D surface deformations from a single monocular RGB camera while assuming a 3D state known in advance (a template). This is an important yet challenging problem due to the under-constrained nature…

Computer Vision and Pattern Recognition · Computer Science 2022-03-23 Navami Kairanda , Edith Tretschk , Mohamed Elgharib , Christian Theobalt , Vladislav Golyanik

In ultrasound nondestructive testing, a widespread approach is to take synthetic aperture measurements from the surface of a specimen to detect and locate defects within it. Based on these measurements, imaging is usually performed using…

Signal Processing · Electrical Eng. & Systems 2020-12-09 Jan Kirchhof , Sebastian Semper , Christoph W. Wagner , Eduardo Pérez , Florian Römer , Giovanni Del Galdo

This paper investigates the shape reconstructions of sub-wavelength objects from near-field measurements in transverse electromagnetic scattering. This geometric inverse problem is notoriously ill-posed and challenging. We develop a novel…

Mathematical Physics · Physics 2023-05-03 M. H. Ding , H. Y. Liu , G. H. Zheng

Context. Solar Shack-Hartmann wavefront sensors measure differential wavefront tilts as the relative shift between images from different subapertures. There are several methods in use for measuring these shifts. Aims. We evaluate the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 Mats G. Löfdahl

Optical aberrations prevent telescopes from reaching their theoretical diffraction limit. Once estimated, these aberrations can be compensated for using deformable mirrors in a closed loop. Focal plane wavefront sensing enables the…

Shape-from-Focus (SFF) is a passive depth estimation technique that infers scene depth by analyzing focus variations in a focal stack. Most recent deep learning-based SFF methods typically operate in two stages: first, they extract focus…

Computer Vision and Pattern Recognition · Computer Science 2026-04-03 Khurram Ashfaq , Muhammad Tariq Mahmood

Today, three-dimensional reconstruction of objects has many applications in various fields, and therefore, choosing a suitable method for high resolution three-dimensional reconstruction is an important issue and displaying high-level…

Computer Vision and Pattern Recognition · Computer Science 2024-06-24 F. S. Mortazavi , S. Dajkhosh , M. Saadatseresht

Shack Hartmann Sensor (SHS) is inflicted with significant background noise that deteriorates the wave-front reconstruction accuracy. In this paper, a simple method to remove the back ground noise with the use of Zernike polynomials is…

Instrumentation and Methods for Astrophysics · Physics 2011-09-14 Akondi Vyas , M B Roopashree , B Raghavendra Prasad

In recent years, the usefulness of 3D shape estimation is being realized in microscopic or close-range imaging, as the 3D information can further be used in various applications. Due to limited depth of field at such small distances, the…

Computer Vision and Pattern Recognition · Computer Science 2017-01-02 Arnav Bhavsar

We consider the inverse elastic scattering of incident plane compressional and shear waves from the knowledge of the far field patterns. Specifically, three direct sampling methods for location and shape reconstruction are proposed using…

Numerical Analysis · Mathematics 2018-03-14 Xia Ji , Xiaodong Liu , Yingxia Xi

Point-spread function (PSF) estimation in spatially undersampled images is challenging because large pixels average fine-scale spatial information. This is problematic when fine-resolution details are necessary, as in optimal photometry…

Instrumentation and Methods for Astrophysics · Physics 2021-02-03 Teresa Symons , Michael Zemcov , James Bock , Yun-Ting Cheng , Brendan Crill , Christopher Hirata , Stephanie Venuto

Access to knowledge of the point spread function (PSF) of adaptive optics(AO)-assisted observations is still a major limitation when processing AO data. This limitation is particularly important when image analysis requires the use of…

Instrumentation and Methods for Astrophysics · Physics 2023-05-10 A. Lau , R. JL. Fétick , B. Neichel , O. Beltramo-Martin , T. Fusco

In the case of ground-based telescopes equipped with adaptive optics systems, the point spread function (PSF) is only poorly known or completely unknown. Moreover, an accurate modeling of the PSF is in general not available. Therefore in…

Numerical Analysis · Mathematics 2015-06-09 M. Prato , A. La Camera , S. Bonettini , S. Rebegoldi , M. Bertero , P. Boccacci

We show that a broad class of signal acquisition schemes can be interpreted as recording data from a signal $x$ in a space $\cal U$ (typically, though not exclusively, a space of bandlimited functions) via an orthogonal projection $w =…

Signal Processing · Electrical Eng. & Systems 2025-05-15 Nguyen T. Thao , Marek Miskowicz

Shape-constrained functional data encompass a wide array of application fields, such as activity profiling, growth curves, healthcare and mortality. Most existing methods for general functional data analysis often ignore that such data are…

Methodology · Statistics 2024-08-13 Poorbita Kundu , Hans-Georg Müller

Flat-panel cone-beam CT (CBCT) has been applied clinically in a number of high-resolution applications. Increasing geometric magnification can potentially improve resolution, but also increases blur due to an extended x-ray focal-spot. We…

Medical Physics · Physics 2016-10-18 Steven Tilley , Wojciech Zbijewski , Jeffrey H. Siewerdsen , J. Webster Stayman

We present a parametric deformable model which recovers image components with a complexity independent from the resolution of input images. The proposed model also automatically changes its topology and remains fully compatible with the…

Computer Vision and Pattern Recognition · Computer Science 2009-06-18 Jacques-Olivier Lachaud , Benjamin Taton

We present a progressive image decomposition method based on a novel non-linear filter named Sub-window Variance filter. Our method is specifically designed for image detail enhancement purpose; this application requires extraction of image…

Computer Vision and Pattern Recognition · Computer Science 2021-07-23 Kin-Ming Wong

In this paper we propose a new approach for tomographic reconstruction with spatially varying regularization parameter. Our work is based on the SA-TV image restoration model proposed in [3] where an automated parameter selection rule for…

Numerical Analysis · Mathematics 2018-11-27 Yiqiu Dong , Carola-Bibiane Schönlieb