Relevant bibliographies by topics / Laser speckle

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

Academic literature on the topic 'Laser speckle'

Author: Grafiati
Published: 4 June 2021
Last updated: 30 January 2023

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Journal articles on the topic "Laser speckle"

1

Fan, Ji Jun, and Nan Hui Yu. "Velocities of Starch Particles in ER Fluids Measured with Laser Speckle." Advanced Materials Research 287-290 (July 2011): 2781–84. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2781.

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In this paper, the principle of measuring infinitesimal displacement by laser speckle is proposed to measure the velocities of particles in ER fluids. It is verified that speckles can be formed by illuminating laser beam on the starch ER fluids. The speckle patterns was recorded with high speed CCD camera, and the speckle patterns sequences with short time intervals was obtained by intercepting laser speckle video. Displacements parallel to the direction of electric field and that perpendicular to the direction of electric field were obtained by processing the two consecutive speckle patterns. The experimental results showed that the velocities of particles decreased oscillatorily with time. There is a critical electric field and a critical sample concentration, when lower than this critical electric field (concentration), the mean particle velocity increased; otherwise, it decreased.
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Zimnyakov, Dmitry, Marina Alonova, Ekaterina Ushakova, Sergey Volchkov, Olga Ushakova, Daniil Klimov, Ilya Slavnetskov, and Anna Kalacheva. "Speckle-Based Sensing of Microscopic Dynamics in Expanding Polymer Foams: Application of the Stacked Speckle History Technique." Sensors 21, no. 20 (October 9, 2021): 6701. http://dx.doi.org/10.3390/s21206701.

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Microscopic structural rearrangements in expanding polylactide foams were probed using multiple dynamic scattering of laser radiation in the foam volume. Formation and subsequent expansion of polylactide foams was provided by a rapid or slow depressurization of the “plasticized polylactide–supercritical carbon dioxide” system. Dynamic speckles induced by a multiple scattering of laser radiation in the expanding foam were analyzed using the stacked speckle history technique, which is based on a joint mapping of spatial–temporal dynamics of evolving speckle patterns. A significant decrease in the depressurization rate in the case of transition from a rapid to slow foaming (from 0.03 MPa/s to 0.006 MPa/s) causes dramatic changes in the texture of the synthesized stacked speckle history maps. These changes are associated with transition from the boiling dynamics of time-varying speckles to their pronounced translational motions and are manifested as significant slopes of individual speckle traces on the recovered stacked speckle history maps. This feature is interpreted in terms of the actual absence of a new cell nucleation effect in the expanding foam upon slow depressurization on the dynamic scattering of laser radiation.
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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.
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Pereira, António J., Paulo Aguiar, Michael Belsley, and Helder Maiato. "Inducible fluorescent speckle microscopy." Journal of Cell Biology 212, no. 2 (January 18, 2016): 245–55. http://dx.doi.org/10.1083/jcb.201506128.

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The understanding of cytoskeleton dynamics has benefited from the capacity to generate fluorescent fiducial marks on cytoskeleton components. Here we show that light-induced imprinting of three-dimensional (3D) fluorescent speckles significantly improves speckle signal and contrast relative to classic (random) fluorescent speckle microscopy. We predict theoretically that speckle imprinting using photobleaching is optimal when the laser energy and fluorophore responsivity are related by the golden ratio. This relation, which we confirm experimentally, translates into a 40% remaining signal after speckle imprinting and provides a rule of thumb in selecting the laser power required to optimally prepare the sample for imaging. This inducible speckle imaging (ISI) technique allows 3D speckle microscopy to be performed in readily available libraries of cell lines or primary tissues expressing fluorescent proteins and does not preclude conventional imaging before speckle imaging. As a proof of concept, we use ISI to measure metaphase spindle microtubule poleward flux in primary cells and explore a scaling relation connecting microtubule flux to metaphase duration.
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Cheng, Jin, Yibo Xie, Shun Zhou, Anjiang Lu, Xishun Peng, and Weiguo Liu. "Improved Weighted Non-Local Mean Filtering Algorithm for Laser Image Speckle Suppression." Micromachines 14, no. 1 (December 30, 2022): 98. http://dx.doi.org/10.3390/mi14010098.

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Laser speckle noise caused by coherence between lasers greatly influences the produced image. In order to suppress the effect of laser speckles on images, in this paper we set up a combination of a laser-structured light module and an infrared camera to acquire laser images, and propose an improved weighted non-local mean (IW-NLM) filtering method that adopts an SSI-based adaptive h-solving method to select the optimal h in the weight function. The analysis shows that the algorithm not only denoises the laser image but also smooths pixel jumps in the image, while preserving the image details. The experimental results show that compared with the original laser image, the equivalent number of looks (ENL) index of the IW-NLM filtered image improved by 0.80%. The speckle suppression index (SSI) of local images dropped from 4.69 to 2.55%. Compared with non-local mean filtering algorithms, the algorithm proposed in this paper is an improvement and provides more accurate data support for subsequent image processing analysis.
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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 22, 2022): 503. http://dx.doi.org/10.12688/f1000research.53214.4.

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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.
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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 (November 8, 2021): 503. http://dx.doi.org/10.12688/f1000research.53214.3.

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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.
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8

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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Abstract:
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.
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9

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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Abstract:
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.
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Ruocco, A., G. Duchateau, and V. T. Tikhonchuk. "Self-focusing of a spatially modulated beam within the paraxial complex geometrical optics framework in low-density plasmas." Plasma Physics and Controlled Fusion 63, no. 12 (November 9, 2021): 125019. http://dx.doi.org/10.1088/1361-6587/ac2e43.

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Abstract Accurate modelling of ponderomotive laser self-focusing may represent a key for the success of inertial confinement fusion, especially within the shock ignition approach. From a numerical point of view, implementation of a paraxial complex geometrical optics (PCGO) method has improved the performance of the hydrodynamics code CHIC, but (1) overestimating ponderomotive speckle self-focusing in reduced two-dimensional geometry, and (2) not accounting for speckle intensity statistics. The first issue was addressed in our previous work (Ruocco et al 2019 Plasma Phys. Control. Fusion 61 115009). Based on those results, here we propose a novel PCGO scheme for modelling spatially modulated laser beams by (1) creating Gaussian speckles, and (2) emulating the realistic speckle intensity statistics. Self-focusing of spatially modulated beams in a homogeneous stationary plasma with this method is studied. This investigation evidences that plasma smoothing does not reduce the speckle intensity enhancement at long time scales when the average beam intensity is twice above the speckle critical intensity. Comparison against electromagnetic simulations confirms that this approach improves the description of self-focusing of high-intensity speckles within the PCGO model.
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Dissertations / Theses on the topic "Laser speckle"

1

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.
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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.
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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.
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4

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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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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Shilpiekandula, Vijay 1979. "A laser speckle based position sensing technique." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27131.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
Includes bibliographical references (p. 129-131).
This thesis presents the design and development of a novel laser-speckle-based position sensing technique. In our prototype implementation, a He-Ne laser beam is directed at the surface of an air-bearing spindle. An imaging system is set up to capture speckle patterns scattered from the spindle surface. These patterns are highly correlated over small angular displacements of the spindle. We use correlation-based image-processing algorithms to measure offsets between the speckle patterns. These offsets are calibrated against the counts of a commercial incremental optical encoder. A custom-built bicell photointerrupter unit is used as a reference sensor for the incremental optical encoder. To test for the control performance of this speckle-based sensor, we have constructed a transmission drive to run the air-bearing spindle. Our speckle-based metrology system is able to run at update rates of 10 Hz with a measured closed loop -3 dB bandwidth of about 2 Hz. Using a real-time processor interfaced with a desktop PC, we have implemented a novel algorithm that interpolates position estimates with respect to two pre-stored global images. We predict that this technique can potentially achieve resolutions of 0.1 [mu]m for translational and 5 [mu]rad for rotational motion. The limitation of our current implementation is the low update rates resulting from the time-intensive nature of correlation-based methods. Possible methods to overcome this limitation are addressed and ideas for follow-on work are presented.
by Vijay Shilpiekandula.
S.M.
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Riechert, Falko. "Speckle reduction in projection systems." Karlsruhe Univ.-Verl. Karlsruhe, 2009. http://d-nb.info/997279346/04.

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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.

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Mo, Ning. "Mechanical characterisation of bone with laser speckle photography." Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339170.

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Martin, Peter. "Uncertainty due to speckle noise in laser vibrometry." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/7139.

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This thesis presents fundamental research in the field of laser vibrometry for the application to vibration measurements. A key concern for laser vibrometry is the effect of laser speckle which appears when a coherent laser beam scatters from an optically rough surface. The laser vibrometer is sensitive to changes in laser speckle which result from surface motions not in the direction of the incident beam. This adds speckle noise to the vibrometer output which can be indistinguishable from the genuine surface vibrations. This has been termed ‘pseudo-vibration' and requires careful data interpretation by the vibration engineer. This research has discovered that measurements from smooth surfaces, even when no identifiable speckle pattern is generated, can produce noise and therefore reference to speckle noise, in such circumstances, is inappropriate. This thesis has, therefore, adopted the more general term of pseudo-vibration to include noise generated from any surface roughness or treatment, i.e. including but not limited to speckle noise. This thesis develops and implements novel experimental methods to quantify pseudovibration sensitivities (transverse, tilt and rotation sensitivity) with attention focussed on commercially available laser vibrometers and consideration is given to a range of surface roughnesses and treatments. It investigates, experimentally, the fundamental behaviour of speckles and attempts to formulate, for the first time, a relationship between changes in intensity to pseudo-vibration sensitivity levels. The thesis also develops and implements models for computational simulation of pseudo-vibrations using the fundamental behaviour of speckles. The combination of experimentation and simulation improves current understanding of the pseudo-vibration mechanisms and provides the vibration engineer with a valuable resource to improve data interpretation. Two experimental methods of quantifying pseudo-vibration sensitivity are developed and successfully applied in the evaluation of transverse, tilt and rotation sensitivity for two models of commercial laser vibrometer. These evaluations cover both single beam (translational vibration measurement) and parallel beam (for angular vibration measurement) modes. The first method presented requires correction of the vibrometer measurement with an independent measurement of genuine velocity to produce an iii apparent velocity dominated by the required noise components. The second method requires a differential measurement using two vibrometers to cancel common components such as genuine velocity, leaving only uncorrelated noise from each measurement in the resulting apparent velocity. In each case, a third measurement is required of the surface motion component causing pseudo-vibration and this is used to normalise the apparent velocity. Pseudo-vibration sensitivity is then presented as a map showing the spectral shape of the noise, as a mean and standard deviation of harmonic peaks in the map and as a total rms level across a defined bandwidth. The simulations employ a novel and effective approach to modelling speckle evolution. Transverse and tilt sensitivity are predicted for the first time and are verified by the experimental study. They provide the vibration engineer with the potential to estimate pseudo-vibrations using a simple piece of software. The laser beam spot diameter has a large influence on the pseudo-vibration sensitivity. Transverse sensitivity has been quantified as around 0.03% and 0.01% (per order) of the transverse velocity of the surface for beam spot diameters of 100 μm and 600 μm respectively. Larger beam spots have been shown to significantly reduce transverse sensitivity and measurements from smoother surfaces have also shown a reduced level of transverse sensitivity. Tilt sensitivity has been quantified at about 0.1 μms-1/degs-1 and 0.3 μms-1/degs-1 (per order) of angular velocity of the surface for beam spot diameters of 100 μm and 600 μm respectively. Smaller beam spot diameters significantly reduce tilt sensitivity. The surface roughness or treatment has been shown to have little effect on the level of tilt sensitivity. Rotation sensitivity has been quantified at approximately 0.6 μms- 1/rads-1 and 1.9μms-1/rads-1 (per order) of rotation velocity of the rotor for 90 μm and 520 μm. Smaller beam spot diameters have shown a significant reduction in rotation sensitivity and measurements on smoother surfaces have shown a reduced rotation sensitivity. Focussing the laser beam approximately on the rotation axis has also shown a significant reduction in rotation sensitivity. Parallel beam rotation sensitivity has been quantified at 0.016 degs-1/rads-1 and it is demonstrated that this can adequately be estimated using the single beam rotation sensitivity.
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Rothberg, Steven Joseph. "Laser speckle studies for vibration and torque measurement." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241481.

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Books on the topic "Laser speckle"

1

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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3

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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4

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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1944-, Wykes Catherine, ed. 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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Zelʹdovich, B. I͡A. Speckle-wave interactions in application to holography and nonlinear optics. Boca Raton: CRC Press, 1995.

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7

Rabal, Hector J., and Roberto A. Braga Jr. Dynamic Laser Speckle and Applications. Taylor & Francis Group, 2018.

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Rabal, Hector J., and Roberto A. Braga Jr. Dynamic Laser Speckle and Applications. Taylor & Francis Group, 2018.

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Rabal, Hector J., and Roberto A. Braga Jr. Dynamic Laser Speckle and Applications. Taylor & Francis Group, 2018.

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Rabal, Hector J., and Roberto A. Braga Jr. Dynamic Laser Speckle and Applications. Taylor & Francis Group, 2019.

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Book chapters on the topic "Laser speckle"

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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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Zhao, Honghua, Gangqiang Kong, and Wanghua Sui. "Laser Speckle Effect." In Transparent Soil Modelling Technique and Its Application, 135–39. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-6825-9_7.

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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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Schlosser, W., T. Schmidt-Kaler, and E. F. Milone. "Laser Light and Speckle Interferometry." In Challenges of Astronomy, 119–23. New York, NY: Springer New York, 1991. http://dx.doi.org/10.1007/978-1-4612-4434-9_22.

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Conference papers on the topic "Laser speckle"

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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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Craggs, Gordon M. J., Falko Riechert, Youri Meuret, Hugo Thienpont, Jan Danckaert, Uli Lemmer, and Guy Verschaffelt. "Speckle characteristics of a laser projector using nonmodal laser emission of a semiconductor laser." In Speckle 2010, edited by Armando Albertazzi Goncalves, Jr. and Guillermo H. Kaufmann. SPIE, 2010. http://dx.doi.org/10.1117/12.868299.

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Cikalova, Ulana, Beatrice Bendjus, Tobias Stüwe, and Ruth Veronica Reyes de Acosta. "Defect detection during laser welding by laser speckle photometry." In SPECKLE 2018: VII International Conference on Speckle Metrology, edited by Michal Józwik, Leszek R. Jaroszewicz, and Malgorzata Kujawińska. SPIE, 2018. http://dx.doi.org/10.1117/12.2318535.

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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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Smausz, Tomi, Dániel Zölei, and Béla Hopp. "Laser power modulation with wavelength stabilization in multiple exposure laser speckle contrast analysis." In SPECKLE 2012: V International Conference on Speckle Metrology, edited by Ángel F. Doval and Cristina Trillo. SPIE, 2012. http://dx.doi.org/10.1117/12.978230.

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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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Bendjus, Beatrice, Ulana Cikalova, and Juergen Schreiber. "Material characterization by laser speckle photometry." In SPECKLE 2012: V International Conference on Speckle Metrology, edited by Ángel F. Doval and Cristina Trillo. SPIE, 2012. http://dx.doi.org/10.1117/12.978246.

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Rosendahl, S,, E. Hällstig, P. Gren, and M. Sjödahl. "Phase errors in speckle reduced laser fringe projection." In Speckle 2010, edited by Armando Albertazzi Goncalves, Jr. and Guillermo H. Kaufmann. SPIE, 2010. http://dx.doi.org/10.1117/12.869659.

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Kobayashi, Koichi, Hirofumi Kadono, and Ichirou Yamaguchi. "Measurement of vegetable growth by laser-speckle correlation." In Speckle 2010, edited by Armando Albertazzi Goncalves, Jr. and Guillermo H. Kaufmann. SPIE, 2010. http://dx.doi.org/10.1117/12.871220.

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Guzman, Marcelo, Gustavo J. Meschino, Ana L. Dai Pra, Marcelo Trivi, Lucía I. Passoni, and Héctor Rabal. "Dynamic laser speckle: decision models with computational intelligence techniques." In Speckle 2010, edited by Armando Albertazzi Goncalves, Jr. and Guillermo H. Kaufmann. SPIE, 2010. http://dx.doi.org/10.1117/12.870688.

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Reports on the topic "Laser speckle"

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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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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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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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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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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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