Reduction of speckle noise is one of the most important processes to increase the quality of radar coherent images. Image variances or speckle is a granular noise that inherently exists in and degrades the quality of the active radar and SAR images. Before using active radar and SAR imageries, the very first step is to reduce the effect of Speckle noise. Most of speckle reduction techniques hav...

When a diffuse object is illuminated with laser light, a random interference effect known as a speckle pattern is produced. If there is movement in the object, the speckles fluctuate in intensity. These fluctuations can be used to provide information about the movement. A simple way of accessing this information is to image the speckle pattern the fluctuations cause a blurring of the speckle, l...

One of the major factors plaguing the performance of synthetic aperture radar (SAR) imagery is the presence of signal-dependent speckle noise. Grainy in appearance, speckle noise is primarily due to the phase fluctuations of the electromagnetic return signals. Since inherent spatial-correlation characteristics of speckle in SAR images are not exploited in existing multiplicative models for spec...

The potential of ultrasonic image speckle tracking to characterize tissue dynamics has been illustrated and validated elsewhere. In this paper we wish to extend this speckle tracking methodology to 3D. To investigate the feasibility of such an approach we first model the image formation process and simulate the 3D speckle motion inherent to tissue linear transformations (translation, rotation a...

There commonly exists speckle noise in the SAR images. It badly disturbs the extraction and interpretation of the information of the objects, influences the application of the SAR images. So it has important meaning to reduce the speckle noise in the SAR images. In this paper, the mechanism and mathematical model of the speckle noise is firstly analyzed. Then the methods of filtering speckle no...

Abstract In this paper, a detailed description and comparison of speckle reduction of medical ultrasound is presented. Four speckle reduction filters are described in a detailed fashion to facilitate implementation for research and evaluation. The filtering techniques considered include Lee,Kuan,Frost and Oriented Speckle Reducing Anisotropic Diffusion(OSRAD). These filtering techniques are app...

We calculate the statistical distribution P2(I2) of the speckle pattern produced by a photon pair current I2 transmitted through a random medium, and compare it with the single-photon speckle distribution P1(I1). We show that the purity of a two-photon density matrix can be directly extracted from the first two moments of P1 and P2. A one-to-one relationship is derived between P1 and P2 if the ...

Ultra-high luminance lamps emitting white light with a well-scattered blue spectrum from InGaN/GaN laser diodes and a phosphor-converted yellow spectrum show speckle contrast values as low as LED. Spectral behavior of the laser diodes is analyzed to find the reason why such low values are obtained. As a result, the PWM-driven, multilongitudinal mode with dynamically broadened line-width is foun...

We demonstrate the effectiveness of the nonlocal means (NLM) filter for speckle denoising in digital holography. The speckle noise adapted version of the NLM filter is compared with other common speckle denoising filters and is found to give better visual and quantitative results.

Focal-plane speckles set important sensitivity limits on groundor space-based imagers and coronagraphs that may be used to search for faint companions, perhaps ultimately including exoplanets, around stars. As speckles vary with atmospheric fluctuations or with drifting beamtrain aberrations, they contribute speckle noise proportional to their full amplitude. Schemes to suppress speckles are th...