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A renaissance in radar-based sensing for mobile robotic applications is underway. Compared to cameras or lidars, millimetre-wave radars have the ability to `see' through thin walls, vegetation, and adversarial weather conditions such as…

We demonstrate two-step phase-shifting interferometry (holography) of complex laser modes generated by a spatial light modulator (SLM), in which the amplitude and phase of the signal are determined directly from measurements of…

Optics · Physics 2024-09-16 Lark E. Bradsby , Andrew A. Voitiv , Mark E. Siemens

Aims. We present a solution to improve the performance of coronagraphs for the detection of exo-planets. Methods. We simulate numerically several kinds of coronagraphic systems, with the aim of evaluating the gain obtained with an adaptive…

Instrumentation and Methods for Astrophysics · Physics 2009-07-03 D. Ricci , H. Le Coroller , A. Labeyrie

The morphology of blood vessels in retinal fundus images is an important indicator of diseases like glaucoma, hypertension and diabetic retinopathy. The accuracy of retinal blood vessels segmentation affects the quality of retinal image…

Computer Vision and Pattern Recognition · Computer Science 2018-03-02 A. M. R. R. Bandara , P. W. G. R. M. P. B. Giragama

To achieve a distributed reflectivity measurement along an optical fiber, we develop a simplified cost-effective configuration of optical correlation- (or coherence-) domain reflectometry based on a synthesized optical coherence function by…

The LOFAR Two-metre Sky Survey (LoTSS) is a sensitive, high-resolution 120-168 MHz survey of the Northern sky. The LoTSS First Data Release (DR1) presents 424 square degrees of radio continuum observations over the HETDEX Spring Field…

Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps useful for capturing, moving and transforming mesoscopic objects. Through a combination of…

Soft Condensed Matter · Physics 2009-11-11 David G. Grier , Yael Roichman

Photoacoustic tomography (PAT) offers high optical contrast with acoustic imaging depth, making it essential for biomedical applications. While many all-optical systems have been developed to address limitations of ultrasound transducers,…

Optics · Physics 2024-10-11 Taeil Yoon , Hakseok Ko , Jeongmyo Im , Euiheon Chung , Wonshik Choi , Byeong Ha Lee

IR absorption spectroscopy of hemoglobin was performed using an IR optical parametric oscillator laser and a commercial atomic force microscope in a novel experimental arrangement based on the use of a bottom-up excitation alignment. This…

Biological Physics · Physics 2010-10-29 Fiona Yarrow , James H. Rice

Traditional optical imaging faces an unavoidable trade-off between resolution and depth of field (DOF). To increase resolution, high numerical apertures (NA) are needed, but the associated large angular uncertainty results in a limited…

Optical coherence tomography (OCT) angiography is a well-established in vivo imaging technique to assess the overall vascular morphology of tissues and is an emerging field of research for the assessment of blood flow dynamics and…

Medical Physics · Physics 2019-07-02 Cerine Lal , Hrebesh M Subhash , Sergey Alexandrov , Martin J Leahy

Extreme ultraviolet pulses as generated by high harmonic generation (HHG) are a powerful tool for both time-resolved spectroscopy and coherent diffractive imaging. However, the integration of spectroscopy and microscopy to harness the…

One of the fundamental limitations in photonics is the lack of a bidirectional transducer that can convert optical information into electronic signals or vice versa. In acoustics or at microwave frequencies, wave signals can be…

Optics · Physics 2019-08-28 Seungwoo Shin , KyeoReh Lee , YoonSeok Baek , YongKeun Park

The process of data taking, reduction and calibration of near-infrared imaging polarimetry data taken with the ESO Adaptive Optics System ADONIS is described. The ADONIS polarimetric facility is provided by a rotating wire grid polarizer.…

Astrophysics · Physics 2009-10-31 N. Ageorges , J. R. Walsh

Holographic coherent X-ray imaging enables nanoscale imaging of biological cells and tissues, rendering both phase and absorption contrast, i.e. real and imaginary parts of the refractive index. Unlike the standard model, which assumes a…

Analysis of PDEs · Mathematics 2026-05-29 Thorsten Hohage , Milad Karimi , Björn Müller

Diffraction limit is manifested in the loss of high spatial frequency information that results from decay of evanescent waves. As a result, conventional far-field optics yields no information about an object's subwavelength features. Here…

Optics · Physics 2012-01-24 Leonid Alekseyev , Evgenii Narimanov , Jacob Khurgin

We present PanoHDR-NeRF, a neural representation of the full HDR radiance field of an indoor scene, and a pipeline to capture it casually, without elaborate setups or complex capture protocols. First, a user captures a low dynamic range…

Computer Vision and Pattern Recognition · Computer Science 2022-10-20 Pulkit Gera , Mohammad Reza Karimi Dastjerdi , Charles Renaud , P. J. Narayanan , Jean-François Lalonde

High-resolution optical spectrometers are crucial in revealing intricate characteristics of signals, determining laser frequencies, measuring physical constants, identifying substances, and advancing biosensing applications. Conventional…

Nonlinear optical microscopy allows rapid high-resolution microscopy with image contrast generated from intrinsic properties of the sample. Established modalities such as multiphoton excited fluorescence and second/third-harmonic generation…

Remote detection of the cardiac pulse has a number of applications in sports and medicine, and can be used to determine the physiological state of the subject. Previous approaches to estimate Heart Rate from video require the subject to…

Image and Video Processing · Electrical Eng. & Systems 2019-01-03 Arvind Subramaniam , Rajitha K