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...

We study screening of optical singularities in random optical fields with two widely different length scales. We call the speckle patterns generated by such fields speckled speckle, because the major speckle spots in the pattern are themselves highly speckled. We study combinations of fields whose components exhibit short- and long-range correlations and find unusual forms of screening.

The probability density function and average contrast of the sum of n uncorrelated, partially developed speckle patterns have been theoretically investigated. A new form of the probability density function is given for the sum of n uncorrelated, partially developed speckle patterns under the assumption that the individual speckle fields to be added follow the circular statistics.

In recent time, ultrasound imaging is a popular modality for various medical applications. The presence of speckle noise affects difficulties on features extraction and quantitative measurement of ultrasound images. This paper proposes a new method to suppress the speckle noise while attempting to preserve the image content using combination of Gaussian filter and discrete cosine transform (DCT...

Image denoising has become a very essential exercise all through the diagnosis especially in case of medical image processing involving ultrasound. Speckle pattern is one of the most complicated multiplicative noise which hardly degrades visual quality of clinical ultrasound images. Real time ultrasound images posses inherited speckle pattern which reduces its resolution and contrast there by d...

The occurrence and smoothing of speckle are studied as a function of the line width for a highly collimated illuminating source. A general theory is presented for speckling in the image of a partially diffuse, phase type of object, which has a variable number of random scattering centers per resolution element. Then, an expression is derived for the wavelength spacing required to decouple the s...