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Compound-refractive lenses (CRL) are a type of x-ray optics that find widespread applications as focusing and imaging lenses. The choice of material is one of the most defining properties of these lenses. In this work, we present a CRL made…

Focal Ration Degradation (FRD) is a change in light angular distribution caused by fiber optics. FRD is important to fiber-fed, spectroscopic astronomical systems because it can cause loss of signal, degradation in spectral resolution, or…

We present a compact two-lens HDPE f/1.6 refractor design that is capable of supporting a 28-deg diffraction-limited field of view at 1-mm wavelengths and contrast it to a similar two-lens refractor using silicon lenses. We compare the…

Instrumentation and Methods for Astrophysics · Physics 2020-04-22 Jon E. Gudmundsson

High-brightness X-ray pulses, as generated at synchrotrons and X-ray free electron lasers (XFEL), are used in a variety of scientific experiments. Many experimental testbeds require optical equipment, e.g Compound Refractive Lenses (CRLs),…

A binocular system developed by the author in terms of projective Fourier transform (PFT) of the conformal camera, which numerically integrates the head, eyes, and visual cortex, is used to process visual information during saccadic eye…

Computer Vision and Pattern Recognition · Computer Science 2009-08-29 Jacek Turski

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…

Context. In the context of direct imaging of exoplanets, coronagraphs are commonly proposed to reach the required very high contrast levels. However, wavefront aberrations induce speckles in their focal plane and limit their performance.…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Johan Mazoyer , Pierre Baudoz , Raphaël Galicher , Gérard Rousset

In addition to the BLINC/MIRAC IR science instruments, the Magellan adaptive secondary AO system will have an EEV CCD47 that can be used both for visible AO science and as a wide-field acquisition camera. The effects of atmospheric…

Instrumentation and Methods for Astrophysics · Physics 2010-10-08 Derek Kopon , Laird M. Close , Victor Gasho

In this work, we present Multi-Level Contrastive Learning for Dense Prediction Task (MCL), an efficient self-supervised method for learning region-level feature representation for dense prediction tasks. Our method is motivated by the three…

Computer Vision and Pattern Recognition · Computer Science 2023-04-05 Qiushan Guo , Yizhou Yu , Yi Jiang , Jiannan Wu , Zehuan Yuan , Ping Luo

Generally, current image manipulation detection models are simply built on manipulation traces. However, we argue that those models achieve sub-optimal detection performance as it tends to: 1) distinguish the manipulation traces from a lot…

Computer Vision and Pattern Recognition · Computer Science 2022-11-22 Wenyan Pan , Zhili Zhou , Guangcan Liu , Teng Huang , Hongyang Yan , Q. M. Jonathan Wu

Microlensing is most sensitive to binary lenses with relatively large orbital separations, and as such, typical binary microlensing events show little or no orbital motion during the event. However, despite the strength of binary…

Astrophysics of Galaxies · Physics 2015-05-28 Matthew T. Penny , Eamonn Kerins , Shude Mao

Ultrasound imaging of the cortex of long bones may enable the measurement of the cortical thickness and the ultrasound wave speed in cortical bone tissue. However, with bone loss, the cortical porosity and the size of the pores increase,…

Medical Physics · Physics 2025-07-14 Amadou S. Dia , Quentin Grimal , Guillaume Renaud

Focal Cortical Dysplasia (FCD) is a primary cause of drug-resistant epilepsy and is difficult to detect in brain {magnetic resonance imaging} (MRI) due to the subtle and small-scale nature of its lesions. Accurate segmentation of FCD…

Image and Video Processing · Electrical Eng. & Systems 2025-10-09 Mehdi Rabiee , Sergio Greco , Reza Shahbazian , Irina Trubitsyna

Major retinal layer segmentation methods from OCT images assume that the retina is flattened in advance, and thus cannot always deal with retinas that have changes in retinal structure due to ophthalmopathy and/or curvature due to myopia.…

Image and Video Processing · Electrical Eng. & Systems 2024-10-03 Tsubasa Konno , Takahiro Ninomiya , Kanta Miura , Koichi Ito , Noriko Himori , Parmanand Sharma , Toru Nakazawa , Takafumi Aoki

Recent self-supervised contrastive learning methods greatly benefit from the Siamese structure that aims to minimizing distances between positive pairs. These methods usually apply random data augmentation to input images, expecting the…

Computer Vision and Pattern Recognition · Computer Science 2023-05-16 Sheng Wang , Zixu Zhuang , Xi Ouyang , Lichi Zhang , Zheren Li , Chong Ma , Tianming Liu , Dinggang Shen , Qian Wang

Fluorescence microscopy is indispensable in nanoscience and biological sciences. The versatility of labeling target structures with fluorescent dyes permits to visualize structure and function at a subcellular resolution with a wide field…

Spectrographs nominally contain a degree of quasi-static optical aberrations resulting from the quality of manufactured component surfaces, imperfect alignment, design residuals, thermal effects, and other other associated phenomena…

Instrumentation and Methods for Astrophysics · Physics 2021-07-28 Eric B. Bechter , Andrew J. Bechter , Justin R. Crepp , Jonathan Crass

Immersive computer graphics systems strive to generate perceptually realistic user experiences. Current-generation virtual reality (VR) displays are successful in accurately rendering many perceptually important effects, including…

Graphics · Computer Science 2020-05-14 Robert Konrad , Anastasios Angelopoulos , Gordon Wetzstein

Light-absorbing materials are widely used, and their optical properties are an important factor. Snell's law does not hold in materials that partially absorb light. Hence, the optical path in refraction is calculated from Maxwell's law. We…

Optics · Physics 2023-01-04 Shosuke Sasaki

We report the fabrication and performance evaluation of single crystal diamond refractive x-ray lenses with a paraboloid of rotation form factor for focusing x-rays in two dimensions simultaneously. The lenses were manufactured using a…

Instrumentation and Detectors · Physics 2015-07-13 S. Antipov , S. V. Baryshev , J. E. Butler , O. Antipova , Z. Liu , S. Stoupin