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Academic literature on the topic 'Laser speckles'

Author: Grafiati
Published: 18 August 2021
Last updated: 12 February 2022

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Journal articles on the topic "Laser speckles":

1

Hüller, S., and A. Porzio. "Order statistics and extreme properties of spatially smoothed laser beams in laser-plasma interaction." Laser and Particle Beams 28, no. 3 (September 2010): 463–77. http://dx.doi.org/10.1017/s0263034610000418.

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AbstractThe order statistics of intense speckles or “laser hot spots” are studied in the context of the so-called “optically smoothed” light beams of laser-matter interaction. We investigate theoretically and by means of numerical simulations the distribution function for the k-th most intense speckle maxima in the upper tail speckle distribution. From these distributions for each order k, a distribution function for the intense speckles as a function of their peak intensity can be established, which allows to compute their impact on nonlinear processes, like parametric instabilities. This is done for the example of stimulated Brillouin scattering, using the so-called independent hot spot model, for which the backscatter reactivity level is computed, which proves to be in very good agreements with numerical simulations. This result is of great interest for nonlinear processes, like instabilities, where extreme speckles play an important role.
2

Ulianova, Onega, Yury Saltykov, Sergey Ulyanov, Sergey Zaytsev, Alexander Ulyanov, and Valentina Feodorova. "Discrimination of the SARS–CoV-2 strains using of coloured s-LASCA-imaging of GB-speckles, developed for the gene “S” nucleotide sequences." F1000Research 10 (June 25, 2021): 503. http://dx.doi.org/10.12688/f1000research.53214.1.

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Background: A recent bioinformatics technique involves changing nucleotide sequences into 2D speckles. This technique produces speckles called GB-speckles (Gene Based speckles). All classical strategies of speckle-optics, namely speckle-interferometry, subtraction of speckle-images as well as speckle-correlometry have been inferred for processing of GB-speckles. This indicates the considerable improvement in the present tools of bioinformatics. Methods: Colour s-LASCA imaging of virtual laser GB-speckles, a new method of high discrimination and typing of pathogenic viruses, has been developed. This method has been adapted to the detecting of natural mutations in nucleotide sequences, related to the spike glycoprotein (coding the gene «S») of SARS–CoV-2 gene as the molecular target. Results: The rate of the colouring images of virtual laser GB-speckles generated by s-LASCA can be described by the specific value of R. If the nucleotide sequences compared utilizing this approach the relevant images are completely identical, then the three components of the resulting colour image will be identical, and therefore the value of R will be equal to zero. However, if there are at least minimal differences in the matched nucleotide sequences, then the value of R will be positive. Conclusion: The high effectiveness of an application of the colour images of GB-speckles that were generated by s-LASCA- has been demonstrated for discrimination between different variants of the SARS–CoV-2 spike glycoprotein gene.
3

Ulianova, Onega, Yury Saltykov, Sergey Ulyanov, Sergey Zaytsev, Alexander Ulyanov, and Valentina Feodorova. "Discrimination of the SARS–CoV-2 strains using of coloured s-LASCA-imaging of GB-speckles, developed for the gene “S” nucleotide sequences." F1000Research 10 (September 6, 2021): 503. http://dx.doi.org/10.12688/f1000research.53214.2.

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Background: A recent bioinformatics technique involves changing nucleotide sequences into 2D speckles. This technique produces speckles called GB-speckles (Gene Based speckles). All classical strategies of speckle-optics, namely speckle-interferometry, subtraction of speckle-images as well as speckle-correlometry have been inferred for processing of GB-speckles. This indicates the considerable improvement in the present tools of bioinformatics. Methods: Colour s-LASCA imaging of virtual laser GB-speckles, a new method of high discrimination and typing of pathogenic viruses, has been developed. This method has been adapted to the detecting of natural mutations in nucleotide sequences, related to the spike glycoprotein (coding the gene «S») of SARS–CoV-2 gene as the molecular target. Results: The rate of the colouring images of virtual laser GB-speckles generated by s-LASCA can be described by the specific value of R. If the nucleotide sequences compared utilizing this approach the relevant images are completely identical, then the three components of the resulting colour image will be identical, and therefore the value of R will be equal to zero. However, if there are at least minimal differences in the matched nucleotide sequences, then the value of R will be positive. Conclusion: The high effectiveness of an application of the colour images of GB-speckles that were generated by s-LASCA- has been demonstrated for discrimination between different variants of the SARS–CoV-2 spike glycoprotein gene.
4

Yu, Hongfei, Jian Han, and Dong Xiao. "Laser Speckles from Multimode Fiber under Scrambling." Proceedings of the International Astronomical Union 8, S293 (August 2012): 385–87. http://dx.doi.org/10.1017/s1743921313013215.

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AbstractWhen a laser beam transmits through a multi-mode fiber, speckles show in the output beam. In this work, we study the laser speckle under static and dynamic scrambling by the histogram and line profile of far-field pattern. The results show that static scrambling has little effect on the intensity distribution. The dynamic scrambling reduces the speckles without changing the line profile. Two possible explanations are proposed.
5

Matrosova, Y. V., and O. L. Fabrikantov. "Laser Speckles in Anisometropic Amblyopia Treatment." Ophthalmology in Russia 15, no. 2S (July 28, 2018): 52–57. http://dx.doi.org/10.18008/1816-5095-2018-2s-52-57.

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Purpose. To perform the comparative efficacy assessment of complex treatment for average degree anisometropic amblyopia in children using red, green laser speckles and their combination.Patients and methods. 216 children aged 5–9 years old with anisohypermetropia and anisometropic amblyopia of average degree were followed up. Cycloplegic refraction of sighting eye was from +1.5 to +3.0 D, of the amblyopic one — from +3.5 to +8.5 D. All patients underwent the basic treatment course using magnetostimulation and computer programs. Depending on the applied laser the children were divided into three groups: patients of group I underwent the basic course of pleoptics using laser in the red wavelength range, in patients of group II the basic course was supplemented with laser stimulation in the green wavelength range, group III — along with the basic treatment the alternate stimulation by red and green speckles was used, control group IV — received only basic course without any laser stimulation. The best corrected visual acuity before and after the treatment was estimated.Results. Before treatment there were no any significant differences between groups according to age, refraction and best corrected visual acuity. As a result of treatment we received the reliable increase in visual acuity in all groups. The minimum increase was noted in patients who received the basic course of treatment, 15% increase was noted in patients stimulated with green speckle, in patients who underwent red speckle stimulation visual acuity increased by 27%, the maximum increase in visual acuity was achieved in patients who received the combined stimulation by red and green speckles.Conclusion. The paper has proved the high efficacy of combined application of red and green speckles in pleoptic treatment in comparison with their separate usage and traditional basic course.
6

Liu, Wenjun, and Changhe Zhou. "Femtosecond laser speckles." Applied Optics 44, no. 30 (October 20, 2005): 6506. http://dx.doi.org/10.1364/ao.44.006506.

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7

Ulianova, Onega, Sergey Ulyanov, Sergey Zaytsev, Yuriy Saltykov, Alexander Ulyanov, and Valentina Feodorova. "Could LASCA-imaging of GB-speckles be applied for a high discrimination and typing of pathogenic bacteria?" PLOS ONE 16, no. 1 (January 28, 2021): e0245657. http://dx.doi.org/10.1371/journal.pone.0245657.

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In this article, the method of analysis of GB-speckles (gene-based speckles) has been adapted to the problem of detecting the differences in a group of genes (usually 5–7), used in Multi Locus Sequence Typing (MLST). This method is based on s-LASCA imaging (spatial Laser Speckle Contrast Analysis) of virtual GB-speckle and on the technique of RGB coordinates for GB-speckles, processed by the s-LASCA method. A very high sensitivity and accuracy of the new method for detecting gene polymorphism as a great alternative to classical MLST has been demonstrated. The analysis of GB-speckles, obtained for the concatenated sequences of seven genes (gatA, gidA, enoA, fumC, hemN, hflX, oppA) of three different Chlamydia trachomatis strains (E/Bour, ST94; G/9301, ST95; G/11222, ST94) has been applied as the model. The high efficiency of usage of s-LASCA-imaging of GB-speckles has been shown. The data obtained represent a significant progress in digital biology as a whole and improvements in the bio-digitalization of bacterial DNA.
8

Abramovich, N. D., and S. K. Dick. "DEPENDENCE OF THE SPECKLE-PATTERNS SIZE AND THEIR CONTRAST ON THE BIOPHYSICAL AND STRUCTURAL PARAMETERS OF BIOLOGICAL TISSUES." Devices and Methods of Measurements 8, no. 2 (June 9, 2017): 177–87. http://dx.doi.org/10.21122/2220-9506-2017-8-2-177-187.

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Speckle fields are widely used in optical diagnostics of biotissues and evaluation of the functional state of bioobjects. The speckle field is formed by laser radiation scattered from the object under study. It bears information about the average dimensions of the scatterers, the degree of surface roughness makes it possible to judge the structural and biophysical characteristics of individual tissue cells (particles), on the one hand, and the integral optical characteristics of the entire biological tissue. The aim of the study was – the determination of connections between the biophysical and structural characteristics of the biotissue and the light fields inside the biotissues.The model developed of the medium gives a direct relationship between the optical and biophysical parameters of the biotissue. Calculations were carried out using known solutions of the radiation transfer equation, taking into account the multilayer structure of the tissue, multiple scattering in the medium, and multiple reflection of irradiation between the layers.With the increase wavelength, the size of speckles formed by the non-scattered component (direct light) of laser radiation increases by a factor of 2 from 400 to 800 μm in the stratum corneum and 5 times from 0.6 to 3 μm for the epidermis and from 0.27 to 1.4 μm to the dermis. Typical values of sizes of speckles formed by the diffraction component of laser radiation for the stratum corneum and epidermis range from 0.02 to 0.15 μm. For the dermis typical spot sizes are up to 0.03 μm. The speckle-spot size of the diffusion component in the dermis can vary from ±10 % at 400 nm and up to ±23 % for 800 nm when the volume concentration of blood capillaries changes. Characteristic dependencies are obtained and biophysical factors associated with the volume concentration of blood and the degree of it’s oxygenation that affect the contrast of the speckle structure in the dermis are discussed.The of speckles׳ size in the layers of tissue varies from a share of micrometer to millimeter. The established dependence makes it possible to determine the depth of penetration of light into the biotissue based on the dimensions of speckles. Calculation of the contrast of the speckle structure of scattered light in visible spectral range at different depths in the biotissue made it possible to establish the dependence of the contrast value of the interference pattern on the degree of oxygenation of the blood and the volume concentration of capillaries in the dermis.
9

Karamanii, M., H. Elghandoor, and H. Ramadan. "THE DATA REDUCTION USING MATLAB FOR DIFFERENT SPECKLE IMAGES FORM SMALL SURFACES ROUGHNESS." International Journal of Advanced Research 9, no. 4 (April 30, 2021): 563–72. http://dx.doi.org/10.21474/ijar01/12732.

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The so-called laser speckles are bright spots and dark spots formed when a coherent ray is incident on a rough surface which scattered randomly in all directions, the interference of these scattered rays form these bright and dark spots (Laser Speckles).In this paper we are concerned with the formation of Objective speckles calculations. Using MATLAB the image can be converted into binary object (0 and 1) as the speckle spots intensities are dark and bright, respectively.To simplify the calculations, two processes (transform and predictive) may be used, and according to the loss of many data for the using of predictive process, the transform process is considered.The calculations are based on the evaluation on small roughness of surfaces in range 0.1 – 1 μm, on the same footing the contrast was considered in the range from zero to one.Fraunhofer diffraction Unfortunately, no calculations in this field had been done from other researchers.
10

LaFountain, James R., Christopher S. Cohan, and Rudolf Oldenbourg. "Functional states of kinetochores revealed by laser microsurgery and fluorescent speckle microscopy." Molecular Biology of the Cell 22, no. 24 (December 15, 2011): 4801–8. http://dx.doi.org/10.1091/mbc.e11-06-0494.

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The impact of mechanical forces on kinetochore motility was investigated using laser microsurgery to detach kinetochores with associated chromatin (K fragment) from meiotic chromosomes in spermatocytes from the crane fly Nephrotoma suturalis. In spermatocytes, elastic tethers connect telomeres of homologues during anaphase A of meiosis I, thus preventing complete disjunction until mid- to late anaphase A. K fragments liberated from tethered arms moved at twice the normal velocity toward their connected poles. To assess functional states of detached and control kinetochores, we loaded cells with fluorescently labeled tubulin for fluorescent speckle microscopy on kinetochore microtubules. Control kinetochores added fluorescent speckles at the kinetochore during anaphase A, whereas kinetochores of K fragments generally did not. In cases in which speckles reappeared in K-fragment K fibers, speckles and K fragments moved poleward at similar velocities. Thus detached kinetochores convert from their normal polymerization (reverse pac-man) state to a different state, in which polymerization is not evident. We suggest that the converted state is “park,” in which kinetochores are anchored to plus ends of kinetochore microtubules that shorten exclusively at their polar ends.
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Journal articles Dissertations / Theses Books

Dissertations / Theses on the topic "Laser speckles":

1

Rajan, Vinayakrishnan. "Speckles in laser doppler perfusion imaging." Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/58017.

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Valdés, Escobar Claudia Patricia. "New laser speckle methods for in vivo blood flow imaging and monitoring." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4367/document.

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Le débit sanguin et sa régulation sont des indicateurs importants de la santé des tissus. Leur mesure a de nombreuses applications en recherche fondamentale et clinique. Certaines techniques optiques constituent un moyen intéressant pour la mesure du débit sanguin, car en général elles sont peu invasives et relativement abordables car elles utilisent des systèmes d'illumination continus. Pendant ma thèse, j'ai contribué au développement de techniques de suivi de la circulation sanguine dans des modèles animaux avec la construction d'un dispositif multimodal basé sur la fluxmétrie laser et sur l'imagerie des signaux optiques intrinsèques, capable de mesurer les paramètre hémodynamiques microvasculaire au niveau superficiel du cerveau. Ce dispositif, testé sur des modèles animaux d'accident vasculaire cérébral, est adaptable et peut être utilisé à d'autres fins. En parallèle, j'ai mis au point des nouvelles méthodes expérimentales et des protocoles de traitement d'images qui ont permis de réaliser des études longitudinales. En outre, ce dispositif a été utilisé dans une étude multidisciplinaire pour comprendre le rôle d'une protéine impliquée dans le cas de lésions de reperfusion après un accident vasculaire cérébral ischémique dans des modèles animaux. Ma contribution majeure réside dans le développement de l'imagerie de contraste de speckle spectroscopique et tomographique, nouvelle technique d'imagerie 3D non invasive pour la mesure du débit sanguin en profondeur. Dans l'ensemble, ces contributions permettront le développement de méthodes tomographiques non invasives rentables pour la mesure du débit sanguin chez l'homme
Blood flow and its regulation are important for the health of tissues and its measurement has many applications in research and clinical environments. Optical techniques are often attractive for the non- or minimally-invasive, continuous and relatively inexpensive measurement of blood flow. This work contributes to the monitoring of blood flow in translational research with the construction of a multimodal device, based on laser speckle flowmetry and optical intrinsic signals, capable of measuring superficial microvascular cerebral blood flow, blood oxygenation and blood volume. This device was applied in animal models of ischemic stroke and is flexible to be modified and used for other purposes. In doing so, I have developed new experimental methods and image processing protocols that allowed us to perform longitudinal studies where the animal can be removed from the device several times. This device has also been used to elucidate the role of the Mannose-binding lectin protein in reperfusion injury after an ischemic stroke in animal models. This led to the main contribution of this work: the development of the speckle contrast optical spectroscopy and tomography, a new non-invasive, optical technique for deep blood flow measurement that paves the way for deeper and three dimensional imaging of blood flow. This new method was first developed from a theoretical perspective. Then it was validated in tissue simulating phantoms and demonstrated to be feasible in measurements on the human arm muscle. Overall, these contributions will allow the development of cost-effective, non-invasive tomographic methods for the measurement of blood flow even in humans
3

Newberry, Shawn. "Laser Speckle Patterns with Digital Image Correlation." OpenSIUC, 2021. https://opensiuc.lib.siu.edu/theses/2885.

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Digital Laser Speckle Image Correlation (DiLSIC) is a technique that utilizes a laser generated speckle pattern with Digital Image Correlation (DIC). This technology eliminates the need to apply an artifact speckle pattern to the surface of the material of interest, and produces a finer speckle pattern resulting in a more sensitive analysis. This investigation explores the parameters effecting laser speckle patterns for DIC and studies DiLSIC as a tool to measure surface strain and detect subsurface defects on pressure vessels. In this study a 632.8 nm 30 mW neon-helium laser generated the speckle pattern by passing through the objective end of an objective lens. All experiments took place in a lab setting on a high performance laminar flow stabilizer optical table.This investigation began with a deeper look at the camera settings that effect the effectiveness of using laser speckles with DIC. The first studies were concentrated on the aperture size (f-stop), shutter speed, and gain (ISO) of the camera. Through a series of zero-correlation studies, translation tests, and settings studies, it was discovered that, much like white light DIC, an increased gain allowed for more noise and less reliable measurements when using DiLSIC. It was shown that the aperture size and shutter speed will largely depend on the surface composition of the material, and that these factors should be investigated with each new sample of different surface finish.To determine the feasibility of using DiLSIC on pressure vessels two samples were acquired. The first was a standard ASTM filament wound composite pressure vessel (CPV) which had an upper load limit of 40 psi. The second was a plastic vessel that had internal subsurface defects added with the use of an air pencil grinder. Both vessels were put under a pressure load with the use of a modified air compressor that allowed for multiple loading cycles through the use of a pressure relief valve. The CPV was mapped out in 10-degree increments between the 90° and 180° markings that were on the pressure vessel, occurring in three areas, each one inch apart. The CPV had a pressure load applied to at 10, 20, 30,and 40 psi. DiLSIC was able to measure increasing displacement with increased loading on the surface of the CPV, however with a load limit of 40 psi no strains were detected. The plastic vessel had known subsurface defects, and these areas were the focus of the investigation. The plastic vessel was loaded with a pressure load at 5, 10, 12, 15, 17, and 20 psi. The 5 psi loaded image was used as a reference image for the correlation and decorrelation consistently occurred at 20 psi. This investigation proved that DiLSIC can detect and locate subsurface defects through strain measurement. The results were verified with traditional white light DIC, which also showed that the subsurface defects on pressure vessels were detectable. The DIC and DiLSIC results did not agree on maximum strain measurement, with the DiLSIC prediciting much larger strains than traditional DIC. This is due to the larger effect out-of-plane displacement has on DiLSIC. DiLSIC was able to detect subsurface defects on a pressure vessel. The median measured hoop strain was in agreement for DiLSIC, DIC and the predicted hoop strain for a wall thickness of 0.1 inches. However, DiLSIC also produced unreliable maximum strain measurements. This technique shows potential for future applications, but more investigations will be needed to implement it for industrial use. A full investigation into the parameters surrounding this technique, and the factors that contribute the most to added noise and unreliability should be conducted. This technology is being developed by multiple entities and shows promising results, and once further advanced could be a useful tool for rapid surface strain measurement and subsurface defect detection in nondestructive evaluation applications. Therefore, it is recommended to continue further investigations into this technology and its applications.
4

Johansson, Louise. "Analysis of cartilage surfaces using laser speckle imaging." Thesis, Linköping University, Department of Biomedical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5830.

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An arthroscope is a diagnostic instrument for visualisation of the interior of a joint. By adding a laser to an arthroscope and feeding the images to a computer, one gets an method to measure the structure of the cartilage covering the joint. This gives an added diagnostic value. The laser will create laser speckles and this report covers the basic theories behind this. The anatomy of the joints, the properties of cartilage and the background on the disease arthritis are also covered, as well as the field of surface topography and image processing.

Experiments were performed on three different materials - metals of different definite surface roughness, polymerised collagen and bovine articular cartilage.

The conclusion is that the technique would work, providing that some obstacles could be overcome. The technique itself is very precise and detects nanometric differences in the surface structure, making it extremely interesting for research purposes, such as follow-ups on treatments and studies of arthritis and cartilage repair.

5

Glize, Kevin. "Étude du comportement collectif des speckles dans le développement de la diffusion Raman stimulée lors de l’interaction laser-plasma." Palaiseau, Ecole polytechnique, 2015. https://tel.archives-ouvertes.fr/tel-01226783/document.

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Strömbom, Johannes. "Natural Fingerprinting of Steel." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-85531.

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A cornerstone in the industry's ongoing digital revolution, which is sometimes referred to as Industry 4.0, is the ability to trace products not only within the own production line but also throughout the remaining lifetime of the products. Traditionally, this is done by labeling products with, for instance, bar codes or radio-frequency identification (RFID) tags. In recent years, using the structure of the product itself as a unique identifier, a "fingerprint", has become a popular area of research. The purpose of this work was to develop software for an identification system using laser speckles as a unique identifier of steel components. Laser speckles, or simply speckles, are generated by illuminating a rough surface with coherent light, typically laser light. As the light is reflected, the granular pattern known as speckles can be seen by an observer. The complex nature of a speckle pattern together with its sensitivity to changes in the setup makes it robust against false-positive identifications and almost impossible to counterfeit. Because of this, speckles are suitable to be used as unique identifiers. In this work, three different identification algorithms have been tested in both simulations and experiments. The tested algorithms included one correlation-based, one method based on local feature extraction, and one method based on global feature extraction. The results showed that the correlation-based identification is most robust against speckle decorrelation, i.e changes in the speckle pattern, while being quite computationally expensive. The local feature-based method was shown to be unfit for this current application due to its sensitivity to speckle decorrelation and erroneous results. The global feature extraction method achieved high accuracy and fast computational speed when combined with a clustering method based on overlapping speckle patterns and a k-nearest neighbours (k-NN) search. In all the investigated methods, parallel calculations can be utilized to increase the computational speed.
7

Mosayebi, Mahshad. "Digital Laser Speckle Image Correlation." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2131.

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This thesis examines the feasibility of combining Digital Image Correlation (DIC) with laser speckle based methods to form a new hybrid deformation measurement method called Digital Laser Speckle Image Correlation (DilSIC). Consequently, this method does not require any sample preparation and allows for the measurement of displacement of micro structures in addition to large displacements. In this technique, a coherent 30mW-632nm laser beam is expanded with 40X lens and then illuminated on the target surface to produce a fine, homogenous laser speckle pattern. Images were captured before and after deformation due to external load and the whole field displacement and strain were determined by the DIC method. This technique could measure displacement less than 30-μm with high accuracy when a 120mm × 80mm area of the surface was inspected. Up to 10% strain was measured by this technique with high accuracy during the whole range. Eventually the sub-surface crack was located successfully, which is a revolutionary achievement in NDT optical methods. This method was tested in different material, with different roughness. Aluminum sheet and rubber material were used mostly. This method could broaden the capability of displacement measurement and subsurface crack detection in wide range of materials.
8

Saito, Edson Hiroshi. "Medição de tensões em componentes mecânicos utilizando a técnica ESPI." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263913.

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Orientador: Auteliano Antunes dos Santos Junior
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-16T17:18:43Z (GMT). No. of bitstreams: 1 Saito_EdsonHiroshi_M.pdf: 2483546 bytes, checksum: f0889b176e6cc7896851b8620c53c361 (MD5) Previous issue date: 2010
Resumo: A técnica ESPI, sigla em inglês - Electronic Speckle Pattern Interferometry -, ou ainda, Interferometria Eletrônica por Padrão de Speckle, surgiu em conseqüência do desenvolvimento da metrologia a laser, que possui como característica o chamado efeito speckle. Este efeito é o fenômeno óptico de interferência de ondas eletromagnéticas coerentes - que é o caso do Laser - que possibilita a geração de padrões de franjas de interferência, a partir das quais é possível medir o deslocamento de superfícies e posteriormente calcular as tensões e deformações. Por se tratar de uma metodologia não destrutiva e sensível a pequenos deslocamentos, essa metodologia tem se difundido na indústria para medição de Tensões em componentes mecânicos de formas complexas e como aplicação de apoio para outras técnicas como análise por Elementos Finitos. O objetivo deste trabalho é a aplicação da técnica ESPI em componentes mecânicos fazendo uso de uma metodologia através da qual seja possível estabelecer um procedimento de medição da tensão com confiabilidade. O desafio é estabelecer a adequada aplicação da ferramenta em ambiente industrial, onde há a interferência de ruídos, temperatura, vibração, além de uma adequação de equipamentos de ensaio que pode influenciar diretamente nos resultados de medições. A correta medição das tensões e deformações através de um ensaio não destrutivo e de rápido diagnóstico pode trazer diversos benefício, dentre os quais as cifras gastas em peças destruídas, tempo de medição e economia de mão-de-obra. Os resultados do presente trabalho são a determinação das variáveis influentes na aplicação do ESPI, levantamento das causas raízes dos problemas de medição e, a partir dessas informações, consolidar um procedimento padrão para aplicação em medição de tensões em componentes utilizando a técnica ESPI
Abstract: The ESPI technique - Electronic Speckle Pattern Interferometry - has emerged as a result of the development of laser metrology, which is characterized as the so-called speckle effect. This effect is an optical phenomenon of coherent electromagnetic waves interference - as Laser. It allows the generation of fringes interference from which it can be measured the displacement of surfaces and therefore calculated the stresses and strains. As a no-destructive methodology and being sensible to small displacements, it has being spread out in the industry by measuring Stress and Displacements in complex mechanical components and as a support to Finite Elements Analysis (FEA) and others techniques. The objective of this work is the application of the ESPI technique testing mechanical components making use of a systematic methodology by which it will be able to establish a procedure for measuring stress with reliability. The challenge is to establish the application procedure in the industrial environment, where there are a lot of interferences like noises, temperature variation, vibration etc., besides the fact that the testing equipment to be adapted to static tests can influences in the results. The stress and displacements measurement in a nodestructive test and fast result diagnose can bring a lot of benefits in financial terms serving as a support tool for other testing procedures. The results from this project are the determination of main variables for ESPI application, establishment of root causes in measurements problems using ESPI, and hence consolidate a standard procedure for ESPI application in strain /stress measurement in mechanical components
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
9

Shih, YiChang. "Laser speckle photography for surface tampering detection." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/75686.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 59-61).
It is often desirable to detect whether a surface has been touched, even when the changes made to that surface are too subtle to see in a pair of before and after images. To address this challenge, we introduce a new imaging technique that combines computational photography and laser speckle imaging. Without requiring controlled laboratory conditions, our method is able to detect surface changes that would be indistinguishable in regular photographs. It is also mobile and does not need to be present at the time of contact with the surface, making it well suited for applications where the surface of interest cannot be constantly monitored. Our approach takes advantage of the fact that tiny surface deformations cause phase changes in reflected coherent light which alter the speckle pattern visible under laser illumination. We take before and after images of the surface under laser light and can detect subtle contact by correlating the speckle patterns in these images. A key challenge we address is that speckle imaging is very sensitive to the location of the camera, so removing and reintroducing the camera requires high-accuracy viewpoint alignment. To this end, we use a combination of computational rephotography and correlation analysis of the speckle pattern as a function of camera translation. Our technique provides a reliable way of detecting subtle surface contact at a level that was previously only possible under laboratory conditions. With our system, the detection of these subtle surface changes can now be brought into the wild.
by YiChang Shih.
S.M.
10

Binder, Bradley Thomas 1960. "Laser radar tomography--the effects of speckle." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/34312.

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Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1991.
Vita.
Includes bibliographical references (leaves 165-169).
by Bradley Thomas Binder.
Ph.D.
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Books on the topic "Laser speckles":

1

Schwarz, Oliver. Hybrid phase unwrapping in laser speckle interferometry with overlapping windows. Aachen: Shaker, 2004.

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Schwarz, Oliver. Hybrid phase unwrapping in laser speckle interferometry with overlapping windows. Aachen: Shaker, 2004.

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Krothapalli, Anjaneyulu. The development of laser speckle velocimetry for the study of vortical flows. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1991.

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Gauthier, V. Application of PIDV to complex flows: Velocity field measurements in the front of a heavy gas cloud. Rhode Saint Genese, Belgium: Von Karman Institute for Fluid Dynamics, 1988.

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Zelʹdovich, B. I͡A. Speckle-wave interactions in application to holography and nonlinear optics. Boca Raton: CRC Press, 1995.

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Robert, Jones. Holographic and speckle interferometry: A discussion of the theory, practice, and application of the techniques. 2nd ed. Cambridge [England]: Cambridge University Press, 1989.

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7

Rabal, Hector J., and Roberto A. Braga Jr. Dynamic Laser Speckle and Applications (Optical Science and Engineering Series). CRC, 2008.

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Rabal, Hector J., and Roberto A. Braga, eds. Dynamic Laser Speckle and Applications. CRC Press, 2018. http://dx.doi.org/10.1201/9781315219080.

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J, Rabal Hector, and Braga Roberto A. Jr, eds. Dynamic laser speckle and applications. Boca Raton: CRC/Taylor & Francis, 2009.

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Rabal, Hector, and Roberto Braga, eds. Dynamic Laser Speckle and Applications. CRC Press, 2008. http://dx.doi.org/10.1201/9781420060164.

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Book chapters on the topic "Laser speckles":

1

Markov, Vladimir. "Spatial Characterization of the Laser Speckles at Volume Hologram Reconstruction." In Interferometry in Speckle Light, 19–26. Berlin, Heidelberg: Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-642-57323-1_3.

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Tuchin, Valery V., Lihong V. Wang, and Dmitry A. Zimnyakov. "Degree of Polarization in Laser Speckles from Turbid Media." In Optical Polarization in Biomedical Applications, 139–47. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/978-3-540-45321-5_8.

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Yadav, Rahul. "Laser Speckle." In Encyclopedia of Ophthalmology, 1–3. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-35951-4_635-1.

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Yadav, Rahul. "Laser Speckle." In Encyclopedia of Ophthalmology, 1032–34. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-540-69000-9_635.

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Hecht, Nils, Ulf C. Schneider, Johannes Woitzik, and Peter Vajkoczy. "Laser Speckle Imaging." In Springer Protocols Handbooks, 517–23. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-61779-576-3_41.

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6

Sjödahl, Mikael. "Electronic Speckle Photography: Some Applications." In Laser in der Technik / Laser in Engineering, 166–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-662-08251-5_37.

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Ströbel, B. "Faseroptisches modulares Speckle-Interferometer." In Laser in Forschung und Technik / Laser in Research and Engineering, 664–67. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-80263-8_137.

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Jahn, G., and H. J. Tiziani. "Heterodyn-Speckle-Interferometrie zur Schwingungsmessung." In Laser/Optoelektronik in der Technik / Laser/Optoelectronics in Engineering, 250–53. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-83174-4_55.

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Pedrini, G., and H. Tiziani. "Double Pulse-Electronic Speckle Interferometry (DP-ESPI)." In Laser in der Technik / Laser in Engineering, 162–65. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-662-08251-5_36.

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Rothe, Hendrik, and Horst Truckenbrodt. "High Precision Laser Triangulation by Speckle Decorrelation." In Laser in der Technik / Laser in Engineering, 223–26. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-662-08251-5_50.

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Conference papers on the topic "Laser speckles":

1

Sjödahl, Mikael, Per Gren, Istvan Sárady, and Natalia Miroshnicova. "Laser hole drilling process studied using laser speckle correlation." In Speckle06: Speckles, From Grains to Flowers, edited by Pierre Slangen and Christine Cerruti. SPIE, 2006. http://dx.doi.org/10.1117/12.695845.

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Han, Daofu, Ming Wang, and Junping Zhou. "Self-mixing speckle interference in DFB laser diode." In Speckle06: Speckles, From Grains to Flowers, edited by Pierre Slangen and Christine Cerruti. SPIE, 2006. http://dx.doi.org/10.1117/12.695463.

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Muramatsu, Mikiya, Eduardo A. Barbosa, Eduardo A. Lima, and Marcos R. R. Gesualdi. "Enhanced multi-wavelength holographic profilometry by laser mode selection." In Speckle06: Speckles, From Grains to Flowers, edited by Pierre Slangen and Christine Cerruti. SPIE, 2006. http://dx.doi.org/10.1117/12.695337.

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4

Zagar, Bernhard G., Peter Zimprich, and Brigitte Weiss. "Exploring the world of micromaterials using laser-speckle techniques." In Speckle06: Speckles, From Grains to Flowers, edited by Pierre Slangen and Christine Cerruti. SPIE, 2006. http://dx.doi.org/10.1117/12.695998.

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Kanev, Feodor, Natalya Atepaeva, Vladimir Lukin, and Nailya Makenova. "Adaptive control of laser beams propagating in the atmosphere." In Speckle06: Speckles, From Grains to Flowers, edited by Pierre Slangen and Christine Cerruti. SPIE, 2006. http://dx.doi.org/10.1117/12.695999.

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Czarske, Jürgen, Thorsten Pfister, and Lars Büttner. "Laser Doppler position sensor for position and shape measurements of fast rotating objects." In Speckle06: Speckles, From Grains to Flowers, edited by Pierre Slangen and Christine Cerruti. SPIE, 2006. http://dx.doi.org/10.1117/12.695462.

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Murialdo, Silvia, Lucía Passoni, Gonzalo Sendra, Héctor Rabal, Ricardo Arizaga, Nelly Cap, and Marcelo Trivi. "Application of a laser speckle method for determining chemotactic responses of Pseudomonas aeruginosa toward attractants." In Speckle06: Speckles, From Grains to Flowers, edited by Pierre Slangen and Christine Cerruti. SPIE, 2006. http://dx.doi.org/10.1117/12.695500.

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Trillo, Cristina, Ángel F. Doval, and Mariano Pérez-Amor. "Enhanced measurement of ultrasonic surface acoustic waves with TV holography by correction of phase mismatch between laser cavities." In Speckle06: Speckles, From Grains to Flowers, edited by Pierre Slangen and Christine Cerruti. SPIE, 2006. http://dx.doi.org/10.1117/12.695996.

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Kuzmin, Sergey Y., Sergey S. Ulyanov, and Valery V. Tuchin. "Speckles application for cardiovibration measurements." In Laser Applications in Life Sciences: 5th International Conference, edited by Pavel A. Apanasevich, Nikolai I. Koroteev, Sergei G. Kruglik, and Victor N. Zadkov. SPIE, 1995. http://dx.doi.org/10.1117/12.197468.

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10

Serov, Alexander N., Wiendelt Steenbergen, and Frits F. M. de Mul. "Speckles in laser Doppler blood flowmetry." In Saratov Fall Meeting 2000, edited by Dmitry A. Zimnyakov. SPIE, 2001. http://dx.doi.org/10.1117/12.427759.

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Reports on the topic "Laser speckles":

1

Dayton, David, John Gonglewski, and Chad St. Arnauld. Laser Speckle and Atmospheric Scintillation Dependence on Laser Spectral Bandwidth: POSTPRINT. Fort Belvoir, VA: Defense Technical Information Center, June 2009. http://dx.doi.org/10.21236/ada508353.

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2

MacKerrow, E. P., J. J. Tiee, and C. B. Fite. Laser speckle effects on hard target differential absorption lidar. Office of Scientific and Technical Information (OSTI), April 1996. http://dx.doi.org/10.2172/219305.

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3

Chiang, Fu-Pen. Nondestructive and Noncontact Evaluation of Corrosion and Fatigue by Laser Speckle Sensor (LSS) and Laser Moire. Fort Belvoir, VA: Defense Technical Information Center, February 1998. http://dx.doi.org/10.21236/ada340357.

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4

Hassan, T. A. Multiparticle imaging technique for two-phase fluid flows using pulsed laser speckle velocimetry. Office of Scientific and Technical Information (OSTI), December 1992. http://dx.doi.org/10.2172/6893012.

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5

Hassan, T. A. Multiparticle imaging technique for two-phase fluid flows using pulsed laser speckle velocimetry. Final report, September 1988--November 1992. Office of Scientific and Technical Information (OSTI), December 1992. http://dx.doi.org/10.2172/10140495.

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