Results 31 to 40 of about 85,035 (307)

Speckle Interferometry, Speckle Masking, Speckle Spectroscopy and Speckle Frame Selection [PDF]

open access: yesInternational Astronomical Union Colloquium, 1984
AbstractHigh-resolution speckle imaging is one of the most fascinating possibilities of a Very Large Telescope (VLT). Various speckle methods can yield a resolution of about 0.01" with a 8-m to 10-m VLT. As exiting as the resolution is the limiting magnitude of the speckle methods. The limiting magnitude is extremely seeingdependent.
openaire   +1 more source

Low-coherence optical fibre speckle interferometry [PDF]

open access: yes, 2006
This paper describes the development of optical fibre low-coherence speckle interferometers capable of three-dimensional surface profiling with a resolution of 10–20 µm and a depth range of typically tens of centimetres.
Balboa, Itziar   +2 more
core   +1 more source

Speckle filtering of Synthetic Aperture Radar images using filters with object-size-adapted windows

open access: yesInternational Journal of Digital Earth, 2018
Speckle degrades the radiometric quality of a Synthetic Aperture Radar (SAR) image. Previous methods for speckle reduction have used a fixed-size window for filtering the entire image.
Sahel Mahdavi   +4 more
doaj   +1 more source

Speckle tracking approaches in speckle sensing [PDF]

open access: yesSPIE Proceedings, 2017
This paper reports some initial investigations into the application of feature tracking algorithms as an alternative data processing method for speckle correlation sensors capable of determining both the speckle pattern translation and rotation. The accuracy of translation measurements using the feature tracking approach was found to be similar to that
Charrett, Thomas O. H.   +2 more
openaire   +1 more source

Review of speckle on high resolution synthetic aperture radar imagery

open access: yesNantong Daxue xuebao. Ziran kexue ban, 2022
Understanding the speckle mechanism and modelling the physical representation is the theoretical basis for understanding synthetic aperture radar(SAR) images.
XU Zhihuo; LI Hengchao
doaj   +1 more source

An experimental study of particle sedimentation using ultrasonic speckle velocimetry [PDF]

open access: yes, 2010
Ultrasonic speckle velocimetry (USV) is a non-invasive technique that allows the measurement of fluid velocity in flow and also that of powders under sedimentation.
Delaunay, Thomas   +5 more
core   +1 more source

Demonstration of a Speckle Based Sensing with Pulse-Doppler Radar for Vibration Detection

open access: yesSensors, 2018
In previous works, an optical technique for extraction and separation of remote static vibrations has been demonstrated. In this paper, we will describe an approach in which RF speckle movement is used to extract remote vibrations of a static target. The
Nisan Ozana   +6 more
doaj   +1 more source

Single-Shot Structured Light Sensor for 3D Dense and Dynamic Reconstruction

open access: yesSensors, 2020
Structured light (SL) has a trade-off between acquisition time and spatial resolution. Temporally coded SL can produce a 3D reconstruction with high density, yet it is not applicable to dynamic reconstruction.
Feifei Gu, Zhan Song, Zilong Zhao
doaj   +1 more source

Superoscillation in speckle patterns [PDF]

open access: yes, 2008
Waves are superoscillatory where their local phase gradient exceeds the maximum wavenumber in their Fourier spectrum. We consider the superoscillatory area fraction of random optical speckle patterns.
Hamilton, AC   +11 more
core   +1 more source

SAR Image Despeckle With CNN Using a Novel Logarithmic Discrete Cosine Transform-Based Loss

open access: yesIEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
The coherent nature of imaging in synthetic aperture radar (SAR) inevitably gives rise to speckle noise, a challenge exacerbated by the constrained bandwidth and limited look angles.
Ammar Saleem   +2 more
doaj   +1 more source

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