Synthetic Aperture Radars (SAR) are classified as active sensors. It has been capable of producing images with high spatial resolution, and able to observe at day and night and in all-weather condition. With these advantages, SAR image becomes more popular than the Optical image. SAR image formation process led to speckle noise; it causes difficulties in the process of interpretation and analys...

Speckle intensity measurements utilized for phase retrieval (PR) are sequentially taken with a digital camera, which introduces quantization error that diminishes the signal quality. Influences of quantization on the speckle intensity distribution and PR are investigated numerically and experimentally in the static wavefront sensing setup. Results show that 3 to 4 bits are adequate to represent...

This report about backscattering measure-ments of the speckle produced by strongly-scattering liquid media shows that the size of the backscattered speckle depends on scattering and anisotropy coefficients. These measurements were aimed at assessing the effects of polarization characteristics of the incident laser beam and of the scattered light on speckle size. The samples under study consiste...

Laplacian pyramid based nonlinear diffusion (LPND) method is proposed for speckle noise reduction in medical ultrasound imaging. In this method, speckle is removed by nonlinear diffusion filtering of bandpass ultrasound images in Laplacian pyramid domain. For nonlinear diffusion in each pyramid layer, a Bayesian threshold is automatically determined by a variation of robust median estimator. Th...

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...

In order to realize high-yield speckle modulation, we developed a novel spatial light modulator using zinc oxide single crystal doped with nitrogen ions. The distribution of dopants was optimized to induce characteristic optical functions by applying an annealing method developed by us. The device is driven by a current in the in-plane direction, which induces magnetic fields. These fields stro...

An optical identification system of a three-dimensional (3D) random phase object by use of speckle patterns in different propagation distances is proposed and evaluated experimentally. The 3D random phase object is used as a 3D key. It can be secure when the scattering is strong enough because the interferometric measurement is not applied. The identification is implemented by evaluating crossc...

Modern industry needs quick and reliable measurement methods for measuring deformation, position, shape, roughness, etc. This thesis is mainly concerned with industrial applications of speckle metrology. Speckle metrology is an optical non-contact whole field technique that provides the means to measure; deformation and displacement, object shape, surface roughness, vibration, and dynamic event...

Speckle contrast imaging enables rapid mapping of relative blood flow distributions using camera detection of back-scattered laser light. However, speckle derived flow measures deviate from direct measurements of erythrocyte speeds by 47 ± 15% (n = 13 mice) in vessels of various calibers. Alternatively, deviations with estimates of volumetric flux are on average 91 ± 43%. We highlight and attem...

Image denoising has become a very essential exercise all through the diagnosis especially in case of medical image processing involving ultrasound. Speckle is a multiplicative noise that degrades ultrasound images. The existence of speckle noise in ultrasound images reduces its resolution and contrast there by degrading the diagnostic accuracy of the ultrasound image. The presence of speckle no...