Topic
Speckle pattern
About: Speckle pattern is a research topic. Over the lifetime, 19786 publications have been published within this topic receiving 295743 citations. The topic is also known as: speckle.
Papers published on a yearly basis
Papers
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TL;DR: This work model the speckle according to the exact physical process of coherent image formation and accurately represents the higher order statistical properties of speckel that are important to the restoration procedure.
Abstract: Speckle is a granular noise that inherently exists in all types of coherent imaging systems. The presence of speckle in an image reduces the resolution of the image and the detectability of the target. Many speckle reduction algorithms assume speckle noise is multiplicative. We instead model the speckle according to the exact physical process of coherent image formation. Thus, the model includes signal-dependent effects and accurately represents the higher order statistical properties of speckle that are important to the restoration procedure. Various adaptive restoration filters for intensity speckle images are derived based on different model assumptions and a nonstationary image model. These filters respond adaptively to the signal-dependent speckle noise and the nonstationary statistics of the original image.
701 citations
TL;DR: This technique can visualize vessel-size-dependent vascular shutdown and transient vascular occlusion during Visudyne photodynamic therapy and may provide opportunities for studying therapeutic effects of antivascular treatments without on exogenous contrast agent.
Abstract: We report on imaging of microcirculation by calculating the speckle variance of optical coherence tomography (OCT) structural images acquired using a Fourier domain mode-locked swept-wavelength laser. The algorithm calculates interframe speckle variance in two-dimensional and three-dimensional OCT data sets and shows little dependence to the Doppler angle ranging from 75 degrees to 90 degrees . We demonstrate in vivo detection of blood flow in vessels as small as 25 microm in diameter in a dorsal skinfold window chamber model with direct comparison with intravital fluorescence confocal microscopy. This technique can visualize vessel-size-dependent vascular shutdown and transient vascular occlusion during Visudyne photodynamic therapy and may provide opportunities for studying therapeutic effects of antivascular treatments without on exogenous contrast agent.
677 citations
TL;DR: A new noninvasive technique for monitoring capillary blood flow based on the phenomenon of time-varying laser speckle, which provides a velocity map of the area of interest in real time without the need for scanning.
Abstract: A new noninvasive technique for monitoring capillary blood flow has been developed. Based on the phenomenon
of time-varying laser speckle, it is a digital version of single-exposure speckle photography. It
provides a velocity map of the area of interest in real time without the need for scanning. The results of some initial experiments on volunteers are presented.
669 citations
TL;DR: The product of spatial resolutions of the ghost image and ghost diffraction experiments is shown to overcome a limit which seemed to be achievable only with entangled photons.
Abstract: High-resolution ghost image and ghost diffraction experiments are performed by using a single classical source of pseudothermal speckle light divided by a beam splitter. Passing from the image to the diffraction result solely relies on changing the optical setup in the reference arm, while leaving the object arm untouched. The product of spatial resolutions of the ghost image and ghost diffraction experiments is shown to overcome a limit which seemed to be achievable only with entangled photons.
648 citations
Journal Article•
644 citations