Search results for " speckle"

Analisi del comportamento flessionale del legno attraverso la interferometria Speckle

2009

Nel lavoro vengono presentati i risultati di uno studio sperimentale effettuato sul comportamento flessionale di due differenti essenze di legno: l’abete rosso ed il ciliegio. L’analisi viene effettuata sottoponendo il provino al test di flessione a quattro punti ed utilizzando la interferometria speckle, una tecnica di misura non a contatto ed a campo intero, che consente di ottenere i campi di spostamento e di deformazione sulla superficie del provino. Al fine di mettere in evidenza le peculiarità del comportamento flessionale del legno i risultati ottenuti vengono confrontati con quelli di un provino di Plexiglas nelle stesse condizioni. Tale confronto conferma la complessità del comport…

A Portable Dynamic Laser Speckle System for Sensing Long-Term Changes Caused by Treatments in Painting Conservation

2018

[EN] Dynamic laser speckle (DLS) is used as a reliable sensor of activity for all types of materials. Traditional applications are based on high-rate captures (usually greater than 10 frames-per-second, fps). Even for drying processes in conservation treatments, where there is a high level of activity in the first moments after the application and slower activity after some minutes or hours, the process is based on the acquisition of images at a time rate that is the same in moments of high and low activity. In this work, we present an alternative approach to track the drying process of protective layers and other painting conservation processes that take a long time to reduce their levels …

New insight into the interplay of baculovirus and subnuclear structures in HepG2 cells

2007

Analisi sperimentale delle tensioni con la fotomeccanica

2009

Laser Vibrometer Interferometry for Speckle Patterns Tracking Systems

2017

In this paper we propose a modulated laser system combining a speckle pattern tracking method for surface tilting changes sensing with an interferometer for surface z-axis changes sensing at the same scan time.

Demonstration of remote optical measurement configuration that correlates to glucose concentration in blood

2010

An optical approach allowing the extraction and the separation of remote vibration sources has recently been proposed. The approach has also been applied for medical related applications as blood pressure and heart beats monitoring. In this paper we demonstrate its capability to monitor glucose concentration in blood stream. The technique is based on the tracking of temporal changes of reflected secondary speckle produced in human skin (wrist) when being illuminated by a laser beam. A temporal change in skin’s vibration profile generated due to blood pulsation is analyzed for estimating the glucose concentration. Experimental tests that were carried out in order to verify the proposed appro…

Young's modulus measurement of the radius bone using a shearing interferometer with carrier fringes

2010

Abstract A technique for measuring Young's modulus of the radius bone by using electronic speckle-shearing pattern interferometry is proposed. The technique is based on the introduction of carrier fringes and the use of a phase unwrapping algorithm to obtain a phase map corresponding to the out-of-plane displacements of a radius bone without sign ambiguities. The carrier fringes are obtained by the correlation algorithm of two consecutive speckle fields with a translation of the illuminating beam between each recording, then the spatial synchronous detection (SSD), an unwrapping phase algorithm and integration process along shear direction are successfully applied for obtaining a displaceme…

ISWI ATP-dependent remodeling of nucleoplasmic ω-speckles in the brain of Drosophila melanogaster.

2017

Heterogeneous nuclear ribonucleoproteins (hnRNPs) belong to the RNA-binding proteins family. They are involved in processing heterogeneous nuclear RNAs (hnRNAs) into mature mRNAs. These proteins participate in every step of mRNA cycle, such as mRNA export, localization, translation, stability and alternative splicing. At least 14 major hnRNPs, which have structural and functional homologues in mammals, are expressed in Drosophila melanogaster. Until now, six of these hnRNPs are known to be nucleus-localized and associated with the long non-coding RNA (lncRNA) heat shock responsive ω (hsrω) in the omega speckle compartments (ω-speckles). The chromatin remodeler ISWI is the catalytic subunit …

Phase-shifting of correlation fringes created by image processing as an alternative to improve digital shearography

2016

Abstract The adoption of digital speckle pattern shearing interferometry, or speckle shearography, is well known in many areas when one needs to measure micro-displacements in-plane and out of the plane in biological and non-biological objects; it is based on the Michelson's Interferometer with the use of a piezoelectric transducer (PZT) in order to provide the phase-shift of the fringes and then to improve the quality of the final image. The creation of the shifting images using a PZT, despite its widespread use, has some drawbacks or limitations, such as the cost of the apparatus, the difficulties in applying the same displacement in the mirror repeated times, and when the phase-shift can…

Displacement measurements in structural elements by optical techniques

2000

Speckle metrology and holographic interferometry (HI) have been used in several civil engineering applications. We present the results obtained by applying speckle photography (SP) to the study of two quadratic shearwalls with different boundary conditions, and the potential of the technique in the study of this kind of structures is described. The analysis of Young's fringes obtained with this technique at certain points on each shearwall provides the whole field of displacement measurements. HI has been used to measure the three components of absolute displacement, verifying that the bulging phenomenon does not affect the in-plane components when the applied load remains on the same plane…