The impact of multiplicative speckle noise on data acquisition in coherent imaging is studied. This demonstrates the possibility to optimally adjust the level of the speckle noise in order to deliberately exploit, with maximum efficacy, the saturation naturally limiting linear image sensors such as CCD cameras, for instance. This constructive action of speckle noise cooperating with saturation ...

In this paper, we develop a random process theory to explain the laser speckle phenomena. The relation between the probability distribution of speckle's integrated intensity random process Y(t) and the relative velocity v(t) is derived. Based on the random process theory, traditional spatial or temporal laser speckle contrast analysis (i.e. spatial or temporal LASCA) can be derived as the spati...

BACKGROUND The use of objective methods for assessment of burns is limited. Laser Speckle Contrast Imaging (LSCI) is a non-invasive technique for instant measurement of tissue perfusion, making it potentially valuable for early prediction of burn wound outcome. AIM To evaluate the influence of technical factors on perfusion and to measure perfusion in burns 0-14 days post-burn and compare thi...

In this chapter, coherent effects that accompany the propagation of laser radiation in tissues and the interaction of laser radiation with cell flows are considered. These effects include diffraction, formation of speckle structures, interference of speckle fields, scattering from moving particles, etc. Principles of quasi-elastic light scattering (QELS) spectroscopy, diffusion wave spectroscop...

In practice, SAR images are very often disturbed by a correlated speckle noise. Correlation influence on wavelet coefficients is a difficult problem degrading detection and filtering performances dramatically. We establish a simple analytic relation between high order wavelet coefficient moments/cumulants and speckle second order statistics. The proposed solution is shown to improve detection a...

The reeectivity due to stimulated Brillouin backscattering (SBS) from an ensemble of independent laser speckles is investigated for diierent speckle statistics. Calculations are based on numerical simulations with a multidi-mensional code and a compact model describing the main features of speckle self-focusing. In particular, the simulations and the model are applied to speckle ensembles due t...

Holographic speckle is a major impediment for the emerging applications of multiphoton holographic projection in biomedical imaging, photo-stimulation and micromachining. Time averaging of multiple shifted versions of a single hologram ("shift-averaging") is a computationally-efficient method that was recently shown to deterministically eliminate holographic speckle in single-photon application...

ultrasound images suffer of multiplicative noise named speckle. different de-speckling algorithms run either in spatial domain or in transformed domain. in this paper, an adaptive filter in spatial domain according to assume the nakagami distribution as the statistic of log-compressed ultrasound images is used. for de-speckling in transformed domain, the non-sub sampled shearlet transform is us...

Imaging observations are generally affected by a fluctuating background of speckles, a particular problem when detecting faint stellar companions at small angular separations. These speckles can be created by both short-lived atmopsheric aberrations and slowly changing distortions in the optical system. Over the course of a long-exposure image, the combination of many independent realizations o...

This article is a short overview of some recent research activity in the Laboratory of Inorganic Synthesis and Catalysis (LSCI) at EPFL-ISIC. It summarizes the work on Ni-catalyzed cross-coupling reactions of non-activated alkyl halides. It then describes and discusses the work on the bio-mimetic chemistry of [Fe]-hydrogenase.