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Imaging in radio astronomy is usually carried out with a single-dish radio telescope doing a raster scan of a region of the sky or with an interferometer that samples the visibility function of the sky brightness. Mosaic observations are…

Instrumentation and Methods for Astrophysics · Physics 2019-06-12 Urvashi Rau , Nikhil Naik , Timothy Braun

Image Fusion, a technique which combines complimentary information from different images of the same scene so that the fused image is more suitable for segmentation, feature extraction, object recognition and Human Visual System. In this…

Information Theory · Computer Science 2008-12-04 R. Balasubramanian , Gaurav Bhatnagar

Holography is an established technique for measuring the wavefront of optical signals through interferometric combination with a reference wave. Conventionally the integration time of a hologram is limited by the interferometer coherence…

Optics · Physics 2023-12-13 Guillaume Thekkadath , Duncan England , Benjamin Sussman

Fourier-based optical computing operations, such as spatial differentiation, have recently been realized in compact form factors using flat optics. Experimental demonstrations, however, have been limited to coherent light requiring laser…

Optics · Physics 2021-12-07 Xiaomeng Zhang , Benfeng Bai , Hong-Bo Sun , Guofan Jin , Jason Valentine

Integration of aerial and ground images has been proved as an efficient approach to enhance the surface reconstruction in urban environments. However, as the first step, the feature point matching between aerial and ground images is…

Computer Vision and Pattern Recognition · Computer Science 2020-11-24 Qing Zhu , Zhendong Wang , Han Hu , Linfu Xie , Xuming Ge , Yeting Zhang

Double-Fourier interferometry is the most viable path to sub-arcsecond spatial resolution for future astronomical instruments that will observe the universe at far-infrared wavelengths. The double transform spatio-spectral interferometry…

In close binary systems the atmosphere of one or both components can be significantly influenced by irradiation from the companion. Often the irradiated atmosphere is simulated with a single-temperature approximation for the entire…

Solar and Stellar Astrophysics · Physics 2015-03-17 H. M. Guenther , A. C. Wawrzyn

Diffraction tomography is a widely used inverse scattering technique for quantitative imaging of weakly scattering media. In its conventional formulation, diffraction tomography assumes monochromatic plane wave illumination. This…

Numerical Analysis · Mathematics 2026-03-11 Peter Elbau , Noemi Naujoks , Otmar Scherzer

Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event…

Instrumentation and Methods for Astrophysics · Physics 2009-07-31 G. K. Skinner , J. F. Krizmanic

Several devices for substrate texture detection based on diffractive optics, for paper, textiles and non-wovens have been proposed in the past for direct inspection during the production processes. In spite of the presence of devices…

Popular Physics · Physics 2008-01-21 Amelia Sparavigna , Rory A. Wolf

We present a new technique for removing twin image in in-line digital Fourier holography using a combination of Fourier transformations. Instead of recording only a Fourier transform hologram of the object, we propose to record a combined…

Optics · Physics 2013-11-26 Debesh Choudhury , Gautam Lohar

Reconstruction of the point spread function (PSF) plays an important role in many areas of astronomy, including photometry, astrometry, galaxy morphology, and shear measurement. The atmospheric and instrumental effects are the two main…

Instrumentation and Methods for Astrophysics · Physics 2024-04-25 Pedro Alonso , Jun Zhang , Cong Liu

Light microscopy enables multifunctional imaging of biological specimens at unprecedented depths and resolutions. However, the performance of all optical methods degrades with the imaging depth due to sample-induced aberrations. Methods of…

Optics · Physics 2019-02-06 Lyubov V. Amitonova

We experimentally probe complex bio-photonic architecture of microstructures on the transparent insect wings by a simple, non-invasive, real time optical technique. A stable and reproducible far-field diffraction pattern in transmission was…

We show that Fourier-plane imaging in conjunction with the Kretschmann-Raether configuration can be used for measuring polariton dispersion with spatial discrimination of the sample, over the whole visible spectral range. We demonstrate the…

Bandwidth smearing is a chromatic aberration due to the finite frequency bandwidth. In long-baseline optical interferometry terms, it is when the angular extension of the source is greater than the coherence length of the interferogram. As…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 Régis Lachaume , Jean-Philippe Berger

We show star images obtained with a miniature ``densified pupil imaging interferometer'' also called a hyper-telescope. The formation of such images violates a ``golden rule of imaging interferometers'' which appeared to forbid the use of…

Astrophysics · Physics 2009-10-31 E. Pedretti , A. Labeyrie , L. Arnold , N. Thureau , O. Lardiere , A. Boccaletti , P. Riaud

Recent developments in machine learning and signal processing have resulted in many new techniques that are able to effectively capture the intrinsic yet complex properties of hyperspectral imagery. Tasks ranging from anomaly detection to…

Computer Vision and Pattern Recognition · Computer Science 2020-11-24 Ilya Kavalerov , Weilin Li , Wojciech Czaja , Rama Chellappa

The fast algorithms in Fourier optics have invigorated multifunctional device design and advanced imaging technologies. However, the necessity for fast computations has led to limitations in the widely used conventional Fourier methods,…

Applied Physics · Physics 2024-06-25 Zhi Li , Xuhao Luo , Jing Wang , Xin Yuan , Dongdong Teng , Qiang Song , Huigao Duan
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