Prof. Armando Albertazzi Gonçalves Profile

Prof. Armando Albertazzi Gonçalves

Professor/Head of Metrology Lab at Univ Federal de Santa Catarina

Publications (77)

Proceedings Article | 15 August 2023 Presentation + Paper

Simultaneous orthogonal shearography using two pairs of parallel slits and a tetra-split lens

Tainara Pedrosa Lima, Estiven Sánchez Barrera, Bernardo C. de Oliveira, Armando Albertazzi G.

Proceedings Volume 12618, 126180C (2023) https://doi.org/10.1117/12.2673473

KEYWORDS: Shearography, Deformation, Nondestructive evaluation, Lenses, Composites, Cameras, Fourier transforms, Signal to noise ratio, Industrial applications

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There are a growing number of industrial applications for shearography, especially in non-destructive testing of composite materials. Its tolerance to hostile environments is probably the most relevant success factor for industrial applications. The introduction of carrier fringes for phase recovery, replacing temporal phase shift techniques, allows measurements with a single exposure for each loading state, making shearography even more robust. Some defects are better evident when the shearing direction is horizontal. Others are best viewed with a vertical shearing direction. Thus, it is desirable to inspect in both directions. Fortunately, the literature reports some configurations capable of using carrier fringes to perform simultaneous measurements in more than one shearing direction. These systems work well, but since they use a mask with circular holes, they require a high amount of light. An alternative is the use of a pair of oblong slits, which increases the amount of light captured. This paper extends the use of oblong slit pairs for simultaneous measurement in two orthogonal shearing directions. Two pairs of parallel oblong slits are arranged orthogonally on the system mask. Although the Fourier transform of the resulting signal at the camera sensor contains the desired signals as well as a crosstalk between the slit pairs. However, the mask can be designed in such a way that the orthogonal signals are separable. To promote shearing in orthogonal directions, a polymeric lens was sectioned, forming four quadrants of 90°. The quadrants were radially displaced and arranged so that each oblong slit covers only one quadrant of the lens. As a result, four laterally shifted images are formed, two of them with horizontal shearing and the other two with vertical shearing. A proof-of-concept prototype was developed and the first results were evaluated by the authors in the laboratory environment and are presented in this article. The paper also shows details of the resulting Fourier spectrum and the strategy used to separate the orthogonal components and recover the phase using carrier fringes. The performance of the prototype met expectations and validated the concept. Future works involve miniaturization of the prototype and tests in industrial environments.

Proceedings Article | 20 June 2021 Presentation + Paper

Roundness measurement with deflectometry: principles and first results

M. J. Carvalho, C. L. Veiga, A. Albertazzi

Proceedings Volume 11782, 1178216 (2021) https://doi.org/10.1117/12.2593196

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Precision cylindrical surfaces are very important elements in mechanical engineering applications involving sealing and guiding for precise movements. It is always important to measure the geometry of these parts to ensure smooth operation. There are several devices on the market that use tactile methods to measure the roundness of cylindrical sections. Although the metrological performance is very good, there is always a risk of scratching the measured part. Non-contact optical methods are very attractive alternatives. Deflectometry is one of those methods with great potential to accomplish this task. It is based on the indirect measurement by analyzing the distortions observed in the image of a structured pattern reflected by the measured surface. However, the application of deflectometry in precision measurement is restricted to flat or near flat surfaces. This paper presents principles and configurations for extending deflectometry to measure external and internal high quality cylindrical surfaces. In both cases the central element is a 45° conical mirror, capable of optically transforming cylindrical surfaces into planar images. An on-axis configuration allows the observation of a sequence of phase-shifted images of appropriate structured patterns reflected on the measured cylindrical surface. The patterns are formed by radial lines with sinusoidal profiles, which are rotated to promote the phase shift. An integration algorithm, suitable for periodic signals, reconstructs the geometry of cylindrical sections. As a result, it is possible to reconstruct the profile of cylindrical sections with great precision, and to determine the roundness parameters. However, it is not possible to determine the absolute radius of the measured section. The paper presents calibration considerations and the first measurements results of sections of precision pin gages. Comparisons with tactile measurements showed deviations of up to 0.07 µm in high polished cylindrical surfaces. The paper also discusses the main limitations and needed improvements. There is much work to be done before the concepts developed can be the basis of a new commercial system. However, there is great potential for the emergence of a new family of optical measurement systems.

Proceedings Article | 22 August 2020 Poster + Paper

A cost-effective alternative for chessboard pattern to calibrate industrial infrared cameras used in defect measurement with active lock-in thermography

Bernardo Cassimiro Fonseca de Oliveira, Artur Antonio Seibert, Kai Winands, Marina de Sá Brant, Tiago Junior de Bortoli, Crhistian Raffaelo Baldo, Armando Albertazzi Gonçalves Júnior

Proceedings Volume 11503, 115030T (2020) https://doi.org/10.1117/12.2566822

KEYWORDS: Calibration, Infrared cameras, Thermography, Nondestructive evaluation, Cameras, Infrared radiation, Inspection, Infrared imaging, Metrology

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Proceedings Article | 21 August 2020 Presentation + Paper

Comparison of principal component analysis and multi-dimensional ensemble empirical mode decomposition for impact damage segmentation in square pulse shearography phase images

Herberth Birck Fröhlich, Bernardo Cassimiro Fonseca de Oliveira, Estiven Sanchez Barrera, Tiago Júnior de Bortoli, Armando Albertazzi

Proceedings Volume 11510, 115101G (2020) https://doi.org/10.1117/12.2566634

KEYWORDS: Image segmentation, Principal component analysis, Shearography, Image processing, Nondestructive evaluation, Composites

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Proceedings Article | 21 August 2020 Presentation + Paper

Underwater shearography – considerations and first results

T. Figueredo, E. Vieira, M. Benedet, A. Fantin, D. Willemann, F. Broetto, C. Schimitz, A. Albertazzi

Proceedings Volume 11490, 114900S (2020) https://doi.org/10.1117/12.2569388

KEYWORDS: Shearography, Water, Composites, Fringe analysis, Nondestructive evaluation, Optical interferometry, Underwater imaging

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SPIE Journal Paper | 19 February 2020

Comparison between segmentation performances of a tool based on wavelet decomposition and multithreshold and of a U-net convolutional neural network applied to shearography images of carbon fiber reinforced plastic plates with low-velocity impact damages

Bernardo C. de Oliveira, Vicente Borges, Crhistian Baldo, Armando Albertazzi G.

OE, Vol. 59, Issue 05, 051406, (February 2020) https://doi.org/10.1117/12.10.1117/1.OE.59.5.051406

KEYWORDS: Image segmentation, Shearography, Nondestructive evaluation, Carbon, Wavelets, Convolutional neural networks, Image processing, Optical engineering, Image fusion, Defect detection

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Proceedings Article | 21 June 2019 Presentation + Paper

Diameter quantification of through holes in pipelines hidden by protective layers of composite materials using instantaneous shearography simultaneously in three shearing directions

Tiago Bortoli, Analucia Fantin, Estiven Barrera, Mauro Benedet, Daniel Willemann, Armando Albertazzi

Proceedings Volume 11056, 1105621 (2019) https://doi.org/10.1117/12.2527165

KEYWORDS: Composites, Shearography, Nondestructive evaluation, Data modeling, Corrosion, Finite element methods, Inspection

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Pipelines usually transport hydrocarbons in the oil and gas industry. Small amounts of salt water may be present, which can cause corrosion from the inside to outside. Severe corrosion may produce through holes in the pipe wall. External protective layers of fiber reinforced plastics has been applied to postpone the need to stop production to perform a definitive repair, but do not stop the internal corrosion. It is very important to monitor the dimensions of through holes hidden by the protective layers of composite materials, which cannot exceed critical size and compromise pipe safety. Classical methods, such as ultrasound, do not give very reliable answers when composite materials and steel are combined. There is a great demand for a reliable and practical in field non-destructive inspection method. This work brings a hybrid and reliable solution, which combines a new configuration of a portable one-shot shearography system with finite element methods, resulting in a portable and easy to apply solution. The paper describes the principle of the portable one-shot shearography system that is able of simultaneously measuring in three shearing directions[1]. Considerations and modeling of finite element to determine the response of the composite material to the variation of the internal pressure of the duct are discussed. The report details how the experimental data and numerical model results are combined through an iterative process to determine the diameter of the hidden hole. Instead of integrating the experimental results of shearography, the authors differentiate the results of finite element in the same directions as the one-shot shearography system does simultaneously. The minimum of the square error results in an estimation of the hidden hole diameter. Experiments were performed with 150 mm diameter tubes with 20 to 50 mm diameter holes hidden by 6 to 24 mm thick glass fiber reinforced plastic protective layers. Smaller thickness and bigger diameters led to better results. Mean deviations of the order of 10% were found for the whole set of tests. Although the authors consider it is possible to improve the results, deviations of the order of up to 10% are very acceptable results and represent a significant improvement over the classic methods used today. The robustness of the optical system, the ease of use of the algorithm and the level of uncertainty already achieved make the authors believe that the techniques developed here achieve the requirements and will be very useful for the oil and gas industry demands.

Proceedings Article | 21 June 2019 Paper

Sensitivity of an image-plane digital holography interferometer for the measurement of pile-up

Matias Viotti, Armando Albertazzi, Denis Boing, Rodrigo Blödorn

Proceedings Volume 11056, 1105649 (2019) https://doi.org/10.1117/12.2526002

KEYWORDS: Interferometers, Digital holography, Phase measurement, Spherical lenses, Holograms, 3D metrology, Microscopes, CCD image sensors, Helium neon lasers, Collimation

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Proceedings Article | 21 June 2019 Paper

A robust integration algorithm for out-of-plane displacement field measurements applied to multiple images of shearography

Estiven Barrera, Analucia Fantin, Daniel Willemann, Mauro Benedet, Armando Albertazzi

Proceedings Volume 11056, 110560H (2019) https://doi.org/10.1117/12.2526103

KEYWORDS: Shearography, Interferometry, Reconstruction algorithms, Phase measurement, Algorithm development, Nondestructive evaluation, Computer simulations, Image processing

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Proceedings Article | 21 June 2019 Paper

Impact damage characterization in CFRP plates using PCA and MEEMD decomposition methods in optical lock-in thermography phase images

Bernardo C. de Oliveira, Herberth Fröhlich, Estiven Barrera, Crhistian Baldo, Armando Albertazzi G., Robert Schmitt

Proceedings Volume 11056, 110562N (2019) https://doi.org/10.1117/12.2526357

KEYWORDS: Principal component analysis, Image segmentation, Thermography, Nondestructive evaluation, Image processing, Statistical analysis

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Carbon fiber reinforced plastics (CFRP) are composite materials which are an interesting alternative to metal alloys in fields such as oil, aerospace, automotive, since CFRP have mechanical properties like metals but with a fraction of their weights. However, these materials have typically a highly anisotropic behavior, which may hinder the characterization of their integrity for example when subjected to an impact, because of its stochastic nature. Non-destructive testing (NDT) methods are interesting for integrity assessment, as they can evaluate the damage extension without affecting any part characteristics. Optical lock-in thermography (OLT) is an convenient NDT inspection alternative since it is a depth-wise method in which one can set different loading frequencies, leading to different scan depths. Pre-processing techniques like Principal Component Analysis (PCA) and Empirical Mode Decomposition (EMD) can be used to more accurately evaluate the damaged area. Their dimensionality reduction capability is highly desired as OLT images of CFRP laminates do not only show the defect, but also undesired information such as changes of background radiation, noise and the disposition of the fiber tissue. Traditional feature extraction methods must be highly tuned to obtain useful results. PCA and EMD methods may be considered non-supervised approaches, making them useful for a wide variety of inputs. However, PCA and EMD have their own natural limitations when being applied to images. While PCA may require high computational effort because of mathematical manipulation of matrices due to the mathematical manipulation of large matrices, problems due to mode superposition may occur if EMD original method is applied on images. In this sense, in this work it has been performed a comparison between PCA, with a new input vector architecture used to mitigate its problem with matrix dimensions, and a derivation of EMD method, called Multi-dimensional Ensemble Empirical Mode Decomposition (MEEMD), applied to prevent the previously mentioned superposition but without a higher computational effort, when segmenting OLT phase images. Outputs in both cases are binary masks with an estimation of the defect region, which were compared to a ground truth manually defined by a specialist. Matthews Correlation Coefficient (MCC) was chosen as segmentation comparison metric instead of F-score, since the last one does not take true negatives into account. The main difference during the application of PCA and MEEMD is that MEEMD yields two kinds of results, one for each frequency image and one average for the whole frequency set, whereas PCA gives only results in relation to the average. This study shown that PCA has better performance than MEEMD when the average results are compared, but MEEMD provides better results if onlt the best image per frequency set is used. Both PCA and MEEMD can yet provide interesting results for three-dimensional reconstruction with OLT images, thus further investigation of such techniques is desirable.

Proceedings Article | 7 September 2018 Paper

Investigation of influence of illumination in a latent fingerprint acquisition system based on a smartphone

Maryah E. M. Haertel, André L. de Melo, Eduardo J. Linhares, Armando Albertazzi G.

Proceedings Volume 10751, 107510I (2018) https://doi.org/10.1117/12.2321325

KEYWORDS: Image processing, Light emitting diodes, Forensic science, Cameras, Light sources, Optical design, Criminalistics

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Proceedings Article | 7 September 2018 Paper

A single shot shearography device for simultaneous measurement in three shearing directions

E. Barrera, A. Fantin, M. Benedet, D. Willemann, A. Albertazzi

Proceedings Volume 10834, 108340U (2018) https://doi.org/10.1117/12.2318706

KEYWORDS: Shearography, Speckle pattern, Speckle, Phase measurement, Fourier transforms, Fringe analysis, Phase shifts

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Shearography is a quite robust optical measurement technique frequently used for in-field testing. Defect inspections with shearography on fiber-reinforced plastics parts, widely used in aircrafts, ships, chemical and oil and gas industries, are often performed outside of the lab. However, environmental disturbances can make this task difficult or even impossible. Mechanical vibrations, air and thermal instabilities are among the most disturbing agents in harsh environments that can destroy the interference signal or, at least, dramatically reduce the interference signal quality, what raises the measurement uncertainty to unacceptable levels. For a successful testing, it is crucial to neutralize the influence of those agents. Compactness, high stiffness, robust mechanical design and an effective clamping system are very important design considerations to minimize the influence of those agents. However, the most effective solution is using a single-shot measurement technique; namely, acquiring a single image instead of a series of images. The exposure time is kept short enough to “freeze” any relative motion between the parts or drift of the measurement signal. This paper presents, describes and explores two configurations of multiple aperture single-shot shearography used by the authors for testing fiber-reinforced plastics used in the oil and gas industry outside the lab. The first one is a two-aperture setup variation based in an already existing configuration that produces carrier fringes on the speckle pattern and allows fringe processing in the 2D Fourier plane. The second one is a new three-aperture configuration that allows acquiring three fringe patterns simultaneously form three different shearing directions for each given loading state. A set of three wedges are used in combination with the three apertures to produce simultaneous shearing interferograms in three different orientations. One single shot image is acquired using a single high-resolution camera before a loading is applied to the specimen and another single shot image for each different loading levels. Since the resulting fringe patterns have carrier fringes in different orientations they are easily separated in the Fourier plane. Once the device has no movable parts and a single shot image is acquired, it is very compact, robust and can be successfully used outside of the optical bench. The paper presents applications of both devices. They have a great potential to expand the use of shearography for testing in harsh environments.

Proceedings Article | 24 May 2018 Paper

Speckle Interferometry in harsh environments: design considerations and successful examples

A. Albertazzi, M. Viotti, F. Silva, C. Veiga, E. S. Barrera, M. Benedet, A. Fantin, D. Willemann

Proceedings Volume 10678, 1067802 (2018) https://doi.org/10.1117/12.2317941

KEYWORDS: General applications engineering, Interferometers, Speckle, Speckle interferometry, Shearography, Speckle pattern, Optical components, Diffraction

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Mechanical vibrations, air and thermal instabilities are among the most disturbing agents that make difficult or impossible a successful speckle interferometry measurement in harsh environments. Usually, they destroy the interference signal or, at least, dramatically reduce the interference signal quality, what raises the measurement uncertainty to unacceptable levels. Understanding the effects of disturbing agents on speckle interferometry is a first step towards finding strategies to perform effective measurements in harsh environments. There are three main strategies to successfully measure under unfavorable conditions: isolation, robustness and both. By isolation, we mean ways to avoid the action of the disturbing agents on the speckle interferometer and on the measurand. By robustness, we mean using a robust mechanical design, a robust optical technique, a robust data reduction algorithm and/or a robust configuration that is not much disturbed by mechanical, thermal or air instabilities. Compactness, high stiffness, robust mechanical design and an effective clamping system are very important considerations to minimize the influence of mechanical vibrations. One-shot measurement and averaging are also robust strategies to minimize the negative effects of mechanical vibrations as well as air and thermal instabilities. Protective enclosures are useful solutions for reducing air instabilities effects, but sometimes ineffective for achieving thermal stability outside the lab. Robust optical techniques are perhaps the most effective way to reduce the effects of thermal dilatation. The paper describes these concepts and discusses four speckle interferometry systems developed and successfully used by the authors in harsh environments: An achromatic speckle interferometer, using a diffractive optical element, was developed and has been applied to in-situ measure of residual stresses in pipelines. The second and third systems are compact and attachable shearography systems for in-field testing of the adhesion of joints of composite material pipes. Finally, the fourth system is a configuration of a shearography system using two apertures to produce carrier fringes for the measurement from a single image for each loading stage.

Proceedings Article | 24 August 2017 Presentation + Paper

Robust shearography system for inspection of defects in composite material using diffractive optics

Fabio A. da Silva, Daniel Willemann, Analucia Fantin, Mauro Benedet, Sérgio Soares, Armando Albertazzi

Proceedings Volume 10376, 103760O (2017) https://doi.org/10.1117/12.2274138

KEYWORDS: Diffractive optical elements, Shearography, Composites, Defect inspection, Inspection, Optical inspection, Interferometers

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Proceedings Article | 26 June 2017 Paper

An endoscopic shearography system with radial sensitivity for inner inspection of adhesion faults in composite material pipes

M. Benedet, F. Macedo, A. Fantin, D. Willemann, F. A. Silva, S. Soares, A. Albertazzi

Proceedings Volume 10329, 103291V (2017) https://doi.org/10.1117/12.2270289

KEYWORDS: Shearography, Inspection, Mirrors, Composites, Endoscopy, Interferometers, Analytical research

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SPIE Journal Paper | 7 December 2016 Open Access

Special Section Guest Editorial:Speckle Metrology

Fernando Mendoza Santoyo, Marc Georges, Peter Lehmann, Wolfgang Osten, Armando Albertazzi Gonçalves

OE, Vol. 55, Issue 12, 121701, (December 2016) https://doi.org/10.1117/12.10.1117/1.OE.55.12.121701

KEYWORDS: Speckle, Metrology, Optical metrology, Image processing, Physics, Speckle metrology, Laser metrology, Interferometry, Nondestructive evaluation, Electrical engineering

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Proceedings Article | 28 August 2016 Paper

Analysis of a shearography device using a Wollaston prism and polarization phase shifting

E. Sanchez, M. Benedet, D. Willemann, A. Fantin, A. Albertazzi

Proceedings Volume 9960, 996015 (2016) https://doi.org/10.1117/12.2237395

KEYWORDS: Shearography, Phase shifting, Interferometry, Prisms, Polarization, Interferometers, Environmental sensing, Inspection, Prisms, Environmental sensing, Interferometers, Polarizers, Phase shifts

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Proceedings Article | 28 August 2016 Presentation + Paper

A non-linear piezoelectric actuator calibration using N-dimensional Lissajous figure

A. Albertazzi, M. Viotti, C. L. Veiga, A. Fantin

Proceedings Volume 9960, 99600L (2016) https://doi.org/10.1117/12.2237367

KEYWORDS: Phase shifting, Calibration, Phase shifts, Actuators, Interferometry, Ferroelectric materials, Sensors, Feedback control, Ions, Mirrors

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Proceedings Article | 24 August 2015 Paper

Bending moment evaluation of a long specimen using a radial speckle pattern interferometer in combination with relaxation methods

Anderson Pacheco, Filipe Fontana, Matias Viotti, Celso Veiga, Lívia Lothhammer, Armando Albertazzi G. Jr.

Proceedings Volume 9660, 966006 (2015) https://doi.org/10.1117/12.2189321

KEYWORDS: Ions, Neodymium, Interferometers, Calibration, Mirrors, Speckle pattern, Data modeling, Diffractive optical elements, Digital signal processing, Speckle

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Proceedings Article | 22 June 2015 Paper

Robust speckle metrology for stress measurements outside the lab

Matias Viotti, Armando Albertazzi G. Jr.

Proceedings Volume 9525, 95250T (2015) https://doi.org/10.1117/12.2184739

KEYWORDS: Interferometers, Mirrors, Speckle, Sensors, Photography, Diffractive optical elements, Semiconductor lasers, Interferometry, Nondestructive evaluation, Speckle metrology

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Proceedings Article | 22 June 2015 Paper

Bending stress determination in pipes using a radial in-plane digital speckle pattern interferometer combined with instrumented indentation

Filipe Fontana, Matias Viotti, Armando Albertazzi G. Jr.

Proceedings Volume 9525, 95250V (2015) https://doi.org/10.1117/12.2184732

KEYWORDS: Interferometers, Diffractive optical elements, Mirrors, Speckle pattern, Interferometry, Actuators, Phase shift keying, Phase measurement, Computing systems, Ferroelectric materials

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SPIE Press Book | 7 October 2014

Robust Speckle Metrology Techniques for Stress Analysis and NDT

Matias Viotti, Armando Albertazzi

KEYWORDS: Interferometers, Speckle, Nondestructive evaluation, Interferometry, Mirrors, Cameras, Shearography, Inspection, Speckle pattern, Digital image correlation

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Robust Speckle Metrology Techniques for Stress Analysis and NDT

Proceedings Article | 18 August 2014 Paper

Performance evaluation of a phase retrieval algorithm from sequences of interferograms with unknown phase shifts using generalized N-dimensional Lissajous figures

Armando Albertazzi Jr., Analucia Fantin, Mauro Benedet, Daniel Willemann, Allison Maia

Proceedings Volume 9203, 92030O (2014) https://doi.org/10.1117/12.2063352

KEYWORDS: Phase shifts, Phase shifting, Phase retrieval, Interferometry, Field emission displays, Fourier transforms, Modulation, Neodymium, Phase shift keying, Fringe analysis

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Proceedings Article | 18 August 2014 Paper

Application of a swarm-based approach for phase unwrapping

Lucas da S. Maciel, Armando Albertazzi G. Jr.

Proceedings Volume 9203, 92030R (2014) https://doi.org/10.1117/12.2060546

KEYWORDS: Evolutionary algorithms, Reliability, Image processing, Algorithm development, Phase shift keying, Floods, Interferometry, Artificial intelligence, Reconstruction algorithms, Modulation

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Proceedings Article | 13 May 2013 Paper

A computational tool to highlight anomalies on shearographic images in optical flaw detection

A. Fantin, D. Willemann, M. Viotti, A. Albertazzi

Proceedings Volume 8788, 87880L (2013) https://doi.org/10.1117/12.2020978

KEYWORDS: Shearography, Inspection, Image processing, Nondestructive evaluation, Composites, Fringe analysis, Damage detection, Visualization, Interferometry, Holography

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Proceedings Article | 13 May 2013 Paper

Optical profilometer using laser based conical triangulation for inspection of inner geometry of corroded pipes in cylindrical coordinates

Pedro Buschinelli, João Ricardo Melo, Armando Albertazzi, João Santos, Claudio Camerini

Proceedings Volume 8788, 87881H (2013) https://doi.org/10.1117/12.2020966

KEYWORDS: Profilometers, Cameras, Inspection, Laser optics, Mirrors, Corrosion, Image processing, Clouds, Calibration, Imaging systems

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Proceedings Article | 13 May 2013 Paper

Measurement of residual stress fields in FHPP welding: a comparison between DSPI combined with hole-drilling and neutron diffraction

Matias Viotti, Armando Albertazzi, Peter Staron, Marcelo Pisa

Proceedings Volume 8788, 87882X (2013) https://doi.org/10.1117/12.2020960

KEYWORDS: Diffraction, Diffractive optical elements, Mirrors, Speckle pattern, Measurement devices, Neodymium, Interferometry, Kinematics, Collimation, Ferroelectric materials

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SPIE Journal Paper | 7 May 2013

Compact sensor combining digital speckle pattern interferometry and the hole-drilling technique to measure nonuniform residual stress fields

Matias Viotti, Armando Albertazzi

OE, Vol. 52, Issue 10, 101905, (May 2013) https://doi.org/10.1117/12.10.1117/1.OE.52.10.101905

KEYWORDS: Diffractive optical elements, Sensors, Interferometry, Speckle pattern, Seaborgium, Mirrors, Phase measurement, Optical engineering, Interferometers, Kinematics

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Proceedings Article | 15 October 2012 Paper

A GPU based real-time image processing for an axis-symmetrical optical laser triangulation system

Pedro D. Buschinelli, Gabriel A. Landeira, Christian Kohler, Armando Albertazzi, Guilherme Teixeira da Silva

Proceedings Volume 8498, 849802 (2012) https://doi.org/10.1117/12.930181

KEYWORDS: Image processing, Laser optics, Profilometers, Cameras, Laser processing, Visualization, Laser systems engineering, Algorithm development, Real time image processing, Laser development

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Proceedings Article | 15 October 2012 Paper

Development of an optical system for geometric inspection of external surface of pipelines

Maryah E. Haertel, Armando Albertazzi G., João Melo, Maurício Reck, Darlan Becker, João M. Santos, Claudio Camerini

Proceedings Volume 8498, 84980M (2012) https://doi.org/10.1117/12.930268

KEYWORDS: Inspection, Projection systems, Prototyping, 3D metrology, Photogrammetry, Phase shifting, Fringe analysis, Light sources, 3D modeling, Cameras

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Proceedings Article | 13 September 2012 Paper

Image quality improvement of an achromatic DSPI interferometer

Matias Viotti, Armando Albertazzi G.

Proceedings Volume 8493, 84930Z (2012) https://doi.org/10.1117/12.930499

KEYWORDS: Diffractive optical elements, Semiconductor lasers, Modulation, Phase shift keying, Image quality, Interferometers, Laser sources, Speckle, Mirrors, Polarizers

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Proceedings Article | 13 September 2012 Paper

Improvements in the marking of defects on large structures surfaces during shearographic inspection

A. Fantin, D. Willemann, A. Albertazzi

Proceedings Volume 8494, 84940B (2012) https://doi.org/10.1117/12.929553

KEYWORDS: Inspection, Projection systems, Cameras, Composites, Shearography, Nondestructive evaluation, Image processing, Multimedia, Fringe analysis, Calibration

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Proceedings Article | 11 September 2012 Paper

Compact sensor combining DSPI and the hole-drilling technique to measure non-uniform residual stress fields

Matias Viotti, Armando Albertazzi

Proceedings Volume 8413, 841310 (2012) https://doi.org/10.1117/12.978183

KEYWORDS: Diffractive optical elements, Mirrors, Phase measurement, Interferometers, Sensors, Kinematics, Ferroelectric materials, Speckle pattern, Interferometry, Speckle

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Proceedings Article | 27 May 2011 Paper

Simultaneous out-of-plane and in-plane displacements measurement by using digital holography around a hole or indentation

Matias Viotti, Christian Kohler, Armando Albertazzi

Proceedings Volume 8082, 80820E (2011) https://doi.org/10.1117/12.889318

KEYWORDS: Holograms, Digital holography, Mirrors, Diffractive optical elements, Cameras, Phase measurement, Speckle, Prototyping, Spherical lenses, Wavefronts

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Proceedings Article | 27 May 2011 Paper

Optical measurement and comparison of large free form surfaces through a regular mesh

Tiago Pinto, Christian Kohler, Armando Albertazzi

Proceedings Volume 8082, 80821A (2011) https://doi.org/10.1117/12.889526

KEYWORDS: Cameras, Clouds, Stereo vision systems, Projection systems, Calibration, Imaging systems, 3D acquisition, Optical spheres, Optical testing, 3D image processing

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Proceedings Article | 27 May 2011 Paper

Measurement and characterization of cylindrical surfaces by deflectometry applied to ballistic identification

A. Fantin, C. Veiga, A. Albertazzi

Proceedings Volume 8082, 808214 (2011) https://doi.org/10.1117/12.888201

KEYWORDS: Deflectometry, Mirrors, Weapons, Cameras, Firearms, Reflectivity, Optical components, Forensic science, Optical testing, Signal processing

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