References of "Thizy, Cédric"
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See detailDigital holographic interferometry in the long-wave infrared and temporal phase unwrapping for measuring large deformations and rigid body motions of segmented space detector in cryogenic test (invited paper)
Vandenrijt, Jean-François ULg; Thizy, Cédric ULg; Martin, Laurent et al

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (2016), 55(12), 121723

We present digital holographic interferometry in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array (FPA) to be used in a space mission. The ... [more ▼]

We present digital holographic interferometry in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array (FPA) to be used in a space mission. The long wavelength was chosen for its ability to allow measurement of displacements 20 times larger than DHI in the visible and which were foreseen with the test object under large temperature variations. The latter is a mosaic of 4×4 detectors assembled on a frame. DHI was required to assess the global deformation of the assembly, the deformation of each detector, and piston movements of each of them with respect to their neighbors. For that reason we incorporated the temporal phase unwrapping by capturing a sufficiently high number of holograms between which the phase does not undergo large variations. At last, since the specimen exhibits specular reflectivity at that wavelength, it is illuminated by means of a reflective diffuser. [less ▲]

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See detailHolographie numérique en infrarouge lointain - Applications aérospatiales
Georges, Marc ULg; Vandenrijt, Jean-François ULg; Languy, Fabian ULg et al

Conference (2016, November)

L'holographie numérique en infrarouge lointain, utilisant un laser CO2 émettant vers 10 µm et des caméras thermiques à microbolomètres, permet la mesure de grandes déformations et de s'affranchir des ... [more ▼]

L'holographie numérique en infrarouge lointain, utilisant un laser CO2 émettant vers 10 µm et des caméras thermiques à microbolomètres, permet la mesure de grandes déformations et de s'affranchir des perturbations environnementales plus facilement qu'en lumière visible. Nous l'appliquons dans le cas de structures spatiales subissant des cyclages thermiques en régime cryogénique sous vide, ce qui induit des déplacements de grande ampleur. Nous passerons en revue les différentes expériences effectuées au Centre Spatial de Liège et discuterons des recherches en cours, notamment pour utiliser des longueurs d'onde plus grande (ondes Terahertz) [less ▲]

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See detailVibration mode shapes visualization in industrial environment by real-time time-averaged phase-stepped electronic speckle pattern interferometry at 10.6  μm and shearography at 532 nm
Languy, Fabian ULg; Vandenrijt, Jean-François ULg; Thizy, Cédric ULg et al

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (2016), 55(12), 121704

We present our investigations on two interferometric methods suitable for industrial conditions dedicated to the visualization of vibration modes of aeronautic blades. First, we consider long-wave ... [more ▼]

We present our investigations on two interferometric methods suitable for industrial conditions dedicated to the visualization of vibration modes of aeronautic blades. First, we consider long-wave infrared (LWIR) electronic speckle pattern interferometry (ESPI). The use of long wavelength allows measuring larger amplitudes of vibrations compared with what can be achieved with visible light. Also longer wavelengths allow lower sensitivity to external perturbations. Second, shearography at 532 nm is used as an alternative to LWIR ESPI. Both methods are used in time-averaged mode with the use of phase-stepping. This allows transforming Bessel fringes, typical to time averaging, into phase values that provide higher contrast and improve the visualization of vibration mode shapes. Laboratory experimental results with both techniques allowed comparison of techniques, leading to selection of shearography. Finally a vibration test on electrodynamic shaker is performed in an industrial environment and mode shapes are obtained with good quality by shearography. [less ▲]

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See detailRecent achievements on ASPIICS, an externally occulted coronagraph for PROBA-3.
Renotte, Etienne ULg; Denis, François ULg; Desselle, Richard ULg et al

in Proceedings of SPIE (2016, June)

This paper presents the current status of ASPIICS, a solar coronagraph that is the primary payload of ESA’s formation flying in-orbit demonstration mission PROBA-3. The “sonic region” of the Sun corona ... [more ▼]

This paper presents the current status of ASPIICS, a solar coronagraph that is the primary payload of ESA’s formation flying in-orbit demonstration mission PROBA-3. The “sonic region” of the Sun corona remains extremely difficult to observe with spatial resolution and sensitivity sufficient to understand the fine scale phenomena that govern the quiescent solar corona, as well as phenomena that lead to coronal mass ejections (CMEs), which influence space weather. Improvement on this front requires eclipse-like conditions over long observation times. The space-borne coronagraphs flown so far provided a continuous coverage of the external parts of the corona but their over-occulting system did not permit to analyse the part of the white-light corona where the main coronal mass is concentrated. The PROBA-3 Coronagraph System, also known as ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun) is designed as a classical externally occulted Lyot coronagraph but it takes advantage of the opportunity to place the external occulter on a companion spacecraft, about 150m apart, to perform high resolution imaging of the inner corona of the Sun as close as ~1.1 solar radii. The images will be tiled and compressed on board in an FPGA before being down-linked to ground for scientific analyses. ASPIICS is built by a large European consortium including about 20 partners from 7 countries under the auspices of the European Space Agency. This paper is reviewing the recent development status of the ASPIICS instrument as it is approaching CDR. [less ▲]

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See detailThe satellite formation flying in lab: PROBA-3/ASPIICS metrology
Capobianco, G; Thizy, Cédric ULg; Renotte, Etienne ULg

in Proceedings of SPIE (2016, June)

Formation flying is one of the most promising techniques for the future of astronomy and astrophysics from the space. The capabilities of the rockets strongly affect the dimensions and the weights of ... [more ▼]

Formation flying is one of the most promising techniques for the future of astronomy and astrophysics from the space. The capabilities of the rockets strongly affect the dimensions and the weights of telescopes and instrumentation to be launched. Telescopes composed by several smallest satellites in formation flying, could be the key for build big space telescopes. With this aim, the ESA PROBA-3 mission will demonstrate the capabilities of this technology, maintaining two satellites aligned within 1 mm (longitudinal) when the nominal distance between the two is of around 144m. The scientific objective of the mission is the observation of the solar corona down to 1.08 solar radii. The Coronagraph Spacecraft (CSC) will observe the Sun, when the second spacecraft, the Occulter Spacecraft (OSC) will work as an external occulter, eclipsing to the CSC the sun disk. The finest metrology sub-systems, the Shadow Position Sensors (SPS) and the Occulter Position Sensor Emitters (OPSE) identifying respectively the CSC-Sun axis and the formation flying (i.e., CSC-OSC) axis will be considered here. In particular, this paper is dedicated to the test-bed for the characterization, the performance analysis and the algorithms capabilities analysis of the both the metrology subsystems. The test-bed is able to simulate the different flight conditions of the two spacecraft and will give the opportunity to check the response of the subsystems in the conditions as close as possible to the flight ones. [less ▲]

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See detailPreliminary evaluation of the di raction behind the PROBA 3/ASPIICS optimized occulter
Baccani, Cristian; Thizy, Cédric ULg; Renotte, Etienne ULg

in Proceedings of SPIE (2016, June)

PROBA-3 is a technological mission of the European Space Agency (ESA), devoted to the in-orbit demon- stration of formation ying (FF) techniques and technologies. ASPIICS is an externally occulted ... [more ▼]

PROBA-3 is a technological mission of the European Space Agency (ESA), devoted to the in-orbit demon- stration of formation ying (FF) techniques and technologies. ASPIICS is an externally occulted coronagraph approved by ESA as payload in the framework of the PROBA-3 mission and is currently in its C/D phase. FF o ers a solution to investigate the solar corona close the solar limb using a two-component space system: the external occulter on one spacecraft and the optical instrument on the other, separated by a large dis- tance and kept in strict alignment. ASPIICS is characterized by an inter-satellite distance of 144 m and an external occulter diameter of 1.42 m. The stray light due to the di raction by the external occulter edge is always the most critical o ender to a coronagraph performance: the designer work is focused on reducing the stray light and carefully evaluating the residuals. In order to match this goal, external occulters are usually characterized by an optimized shape along the optical axis. Part of the stray light evaluation process is based on the di raction calculation with the optimized occulter and with the whole solar disk as a source. We used the eld tracing software VirtualLabTM Fusion by Wyrowski Photonics [1] to simulate the di raction. As a rst approach and in order to evaluate the software, we simulated linear occulters, through as portions of the ight occulter, in order to make a direct comparison with the Phase-A measurements [2]. [less ▲]

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See detailCharacterization of the ASPIICS/OPSE metrology sub-system and PSF centroiding procedure.
Lorregia, D; Thizy, Cédric ULg; Renotte, Etienne ULg

in Proceedings of SPIE (2016, June)

Metrology in diluted systems for space applications is one of the most important technology research fields that in recent years have raised increasing interest. Many applications of astronomical ... [more ▼]

Metrology in diluted systems for space applications is one of the most important technology research fields that in recent years have raised increasing interest. Many applications of astronomical observation techniques, as coronography and interferometry get great benefit when moved in space and the employment of diluted systems represents a milestone to step-over in astronomical research. In this work, we present the Optical Position Sensors Emitter (OPSE) metrological sub-system on-board of the PROBA3. PROBA3 is an ESA technology mission that will test in-orbit many metrology techniques for the maintenance of a Formation Flying with two satellites, in this case an occulter and a main satellite housing a coronagraph named ASPIICS, kept at an average inter-distance of 144m. The scientific task is the observation of the Sun’s Corona at high spatial and temporal resolution down to 1.08R⊙. The OPSE will monitor the relative position of the two satellites and consists of 3 emitters positioned on the rear surface of the occulter, that will be observed by the coronagraph itself. A Centre of Gravity (CoG) algorithm is used to monitor the emitter’s PSF at the focal plane of the Coronagraph retrieving the Occulter position with respect to the main spacecraft. The 3 location target accuracy is 300m for lateral movement and 21cm for longitudinal movements. A description of the characterization tests on the OPSE LED sources, and of the design for a laboratory set-up for on ground testing is given with a preliminary assessment of the performances expected from the OPSE images centroiding algorithm. [less ▲]

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See detailThe shadow position sensors (SPS) formation flying metrology
Focardi, Mauro; Thizy, Cédric ULg; Renotte, Etienne ULg

in Proceedings of SPIE (2016, June)

PROBA-3 [1] [2] is a Mission of the European Space Agency (ESA) composed of two formation-flying satellites, planned for their joint launch by the end of 2018. Its main purposes have a dual nature ... [more ▼]

PROBA-3 [1] [2] is a Mission of the European Space Agency (ESA) composed of two formation-flying satellites, planned for their joint launch by the end of 2018. Its main purposes have a dual nature: scientific and technological. In particular, it is designed to observe and study the inner part of the visible solar corona, thanks to a dedicated coronagraph called ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), and to demonstrate the in-orbit formation flying (FF) and attitude control capability of its two satellites. The Coronagraph payload on-board PROBA-3 consists of the following parts: the Coronagraph Instrument (CI) with the Shadow Position Sensor (SPS) on the Coronagraph Spacecraft (CSC), the Occulter Position Sensor (OPSE) [3] [4] and the External Occulting (EO) disk on the Occulter Spacecraft (OSC). The SPS subsystem [5] is one of the main metrological devices of the Mission, adopted to control and to maintain the relative (i.e. between the two satellites) and absolute (i.e. with respect to the Sun) FF attitude. It is composed of eight micro arrays of silicon photomultipliers (SiPMs) [6] that shall be able to measure, with the required sensitivity and dynamic range as asked by ESA, the penumbral light intensity on the Coronagraph entrance pupil. With the present paper we describe the testing activities on the SPS breadboard (BB) and Development Model (DM) as well as the present status and future developments of this PROBA-3 metrological subsystem. [less ▲]

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See detailPhotorefractive holographic camera for monitoring deformations of MEMS
Georges, Marc ULg; Thizy, Cédric ULg

in Journal of Micro/Nanolithography, MEMS, and MOEMS (2015), 14(4), 041301

We present the development of a holographic interferometer based on dynamic hologram recording with photorefractive crystals of the sillenite family and which is adapted for the observation of MEMS. A ... [more ▼]

We present the development of a holographic interferometer based on dynamic hologram recording with photorefractive crystals of the sillenite family and which is adapted for the observation of MEMS. A compact portable system was already presented in the past and used in various metrology and nondestructive applications on large scattering objects. It was emphasized the great versatility of the instrument which allows high resolution measurements. Here we show the development and achievement of an optical module which can be easily interfaced on the basic instrument, allowing small specular objects observation. Results of deformation of electrically actuated MEMS are shown. [less ▲]

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See detailFormation flying metrology for the ESA-PROBA3 mission: the Shadow Position Sensors (SPS) silicon photomultipliers (SiPMs) readout electronics
Focardi, M.; Bemporad, A.; Buckley, S. et al

in Proc. SPIE Volume 9604 Solar Physics and Space Weather Instrumentation VI (2015, September 21)

The European Space Agency (ESA) is planning to launch in 2018 the PROBA3 Mission, designed to demonstrate the inorbit formation flying (FF) attitude capability of its two satellites and to observe the ... [more ▼]

The European Space Agency (ESA) is planning to launch in 2018 the PROBA3 Mission, designed to demonstrate the inorbit formation flying (FF) attitude capability of its two satellites and to observe the inner part of the visible solar corona as the main scientific objective. The solar corona will be observed thanks to the presence on the first satellite, facing the Sun, of an external occulter producing an artificial eclipse of the Sun disk. The second satellite will carry on the coronagraph telescope and the digital camera system in order to perform imaging of the inner part of the corona in visible polarized light, from 1.08 Rsun up to about 3 Rsun. One of the main metrological subsystems used to control and to maintain the relative (i.e. between the two satellites) and absolute (i.e. with respect to the Sun) FF attitude is the Shadow Position Sensor (SPS) assembly. It is composed of eight micro arrays of silicon photomultipliers (SiPMs) able to measure with the required sensitivity and dynamic range the penumbral light intensity on the Coronagraph entrance pupil. In the following of the present paper we describe the overall SPS subsystem and its readout electronics with respect to the capability to satisfy the mission requirements, from the light conversion process on board the silicon-based SPS devices up to the digital signal readout and sampling. [less ▲]

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See detailThe Shadow Positioning Sensors (SPS) for formation flying metrology on-board the ESA-PROBA3 mission
Bemporad, A.; Baccani, C.; Capobianco, G. et al

in Proc. SPIE Volume 9604 Solar Physics and Space Weather Instrumentation VI (2015, September 21)

PROBA3 is an ESA technology mission devoted to in-orbit demonstration of the formation flight (FF) technique, with two satellites kept at an average inter-distance by about 144 m. The ASPIICS instrument ... [more ▼]

PROBA3 is an ESA technology mission devoted to in-orbit demonstration of the formation flight (FF) technique, with two satellites kept at an average inter-distance by about 144 m. The ASPIICS instrument on-board PROBA3 will be the first ever space-based coronagraph working on one satellite and having the external occulter located on the second satellite, thus allowing observations of the inner solar corona with unprecedented reduction of stray light. During the observational periods, the FF configuration will be maintained with very high precision and two different techniques will be implemented: the use of Shadow Positioning Sensors (SPS) located on the Coronagraph Spacecraft (diodes measuring the penumbral light intensity on the entrance pupil plane) and the use of Occulter Position Sensor LEDs (OPSE) located on the back side of the Occulter Spacecraft. This paper will review the main instrumental requirements on the SPS needed to determine the 3-dimensional relative positioning of the two PROBA3 satellites with the high precision and frequency. [less ▲]

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See detailSignificance of the occulter diffraction for the PROBA3/ASPIICS formation flight metrology
Landini, F.; Bemporad, A.; Focardi, M. et al

in Proc. SPIE Volume 9604 Solar Physics and Space Weather Instrumentation VI (2015, September 21)

PROBA-3/ASPIICS is a formation Flying coronagraph selected by ESA and currently in its C/D phase. It is constituted by two spacecrafts (OSC, Occulter SpaceCraft, carrying the occulter, diameter 142 cm ... [more ▼]

PROBA-3/ASPIICS is a formation Flying coronagraph selected by ESA and currently in its C/D phase. It is constituted by two spacecrafts (OSC, Occulter SpaceCraft, carrying the occulter, diameter 142 cm, and CSC, Coronagraph SpaceCraft, with the telescope) separated by ~144 m, kept in strict alignment by means of an active custom system. The alignment active system most critical components are the Shadow Positioning Sensors (SPS), a series of Si-PM (Silicon Photomultiplier) measuring the penumbra generated by the occulter. The arrangement of the SPSs around the telescope entrance aperture is defined as a trade-off between mechanical constraints and maximum sensitivity to misalignments. The signal detected by the SPSs can be approximately simulated with a geometrical analysis based on the variation of the penumbra generated by the external occulter. The stray light generated by the diffraction from the external occulter may affect the SPSs signal. It is mandatory to carefully evaluate its level in order to refine the active alignment adjustment algorithm. This work is dedicated to the description of the preliminary investigation performed in order to evaluate the impact of the diffraction on the SPSs signal. [less ▲]

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See detailDesign status of ASPIICS, an externally occulted coronagraph for PROBA-3
Renotte, Etienne ULg; Alia, A.; Bemporad, A. et al

in Proc. SPIE Volume 9604 Solar Physics and Space Weather Instrumentation VI (2015, September 21)

The “sonic region” of the Sun corona remains extremely difficult to observe with spatial resolution and sensitivity sufficient to understand the fine scale phenomena that govern the quiescent solar corona ... [more ▼]

The “sonic region” of the Sun corona remains extremely difficult to observe with spatial resolution and sensitivity sufficient to understand the fine scale phenomena that govern the quiescent solar corona, as well as phenomena that lead to coronal mass ejections (CMEs), which influence space weather. Improvement on this front requires eclipse-like conditions over long observation times. The space-borne coronagraphs flown so far provided a continuous coverage of the external parts of the corona but their over-occulting system did not permit to analyse the part of the white-light corona where the main coronal mass is concentrated. The proposed PROBA-3 Coronagraph System, also known as ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), with its novel design, will be the first space coronagraph to cover the range of radial distances between ~1.15 and 3 solar radii where the magnetic field plays a crucial role in the coronal dynamics, thus providing continuous observational conditions very close to those during a total solar eclipse. PROBA-3 is first a mission devoted to the in-orbit demonstration of precise formation flying techniques and technologies for future European missions, which will fly ASPIICS as primary payload. The instrument is distributed over two satellites flying in formation (approx. 150m apart) to form a giant coronagraph capable of producing a nearly perfect eclipse allowing observing the sun corona closer to the rim than ever before. The coronagraph instrument is developed by a large European consortium including about 20 partners from 7 countries under the auspices of the European Space Agency. This paper is reviewing the recent improvements and design updates of the ASPIICS instrument as it is stepping into the detailed design phase. [less ▲]

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See detailOPSE metrology system onboard of the PROBA3 mission of ESA
Loreggia, D.; Bemporad, A.; Capobianco, G. et al

in Proc. SPIE Volume 9604 Solar Physics and Space Weather Instrumentation VI (2015, September 21)

In recent years, ESA has assessed several mission involving formation flying (FF). The great interest in this topics is mainly driven by the need for moving from ground to space the location of next ... [more ▼]

In recent years, ESA has assessed several mission involving formation flying (FF). The great interest in this topics is mainly driven by the need for moving from ground to space the location of next generation astronomical telescopes overcoming most of the critical problems, as example the construction of huge baselines for interferometry. In this scenario, metrology systems play a critical role. PROBA3 is an ESA technology mission devoted to in-orbit demonstration of the FF technique, with two satellites, an occulter and a main satellite housing a coronagraph named ASPIICS, kept at an average inter-distance by about 144m, with micron scale accuracy. The guiding proposal is to test several metrology solution for spacecraft alignment, with the important scientific return of having observation of Corona at never reached before angular field. The Shadow Position Sensors (SPS), and the Optical Position Emitters Sensors (OPSE) are two of the systems used for FF fine tracking. The SPS are finalized to monitor the position of the two spacecraft with respect to the Sun and are discussed in dedicated papers presented in this conference. The OPSE will monitor the relative position of the two satellites and consists of 3 emitters positioned on the rear surface of the occulter, that will be observed by the coronagraph itself. By following the evolution of the emitters images at the focal plane the alignment of the two spacecrafts is retrieved via dedicated centroiding algoritm. We present an overview of the OPSE system and of the centroiding approach. [less ▲]

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See detailDesign and modelisation of ASPIICS optics
Galy, Camille ULg; Fineschi, S.; Galano, D. et al

in Proc. SPIE Volume 9604 Solar Physics and Space Weather Instrumentation VI (2015, September 21)

In the framework of development of ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), the Centre Spatial de Liege is responsible of the optical design ... [more ▼]

In the framework of development of ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), the Centre Spatial de Liege is responsible of the optical design of the coronagraph and the optics will be manufactured by TOPTEC. The particularity of this coronagraph is to have an external occulter located 150 m ahead of the first imaging lens. This external occulter is re-imaged on an internal occulter which function is - as in a classical externally occulted Lyot coronagraph - to block the sun light diffracted by the external occulter and to reduce the straylight on the detector. The selection of this configuration is driven by the requirement to observe the corona as close as possible to the solar limb (i.e. 1 RSun) without imaging the limb itself. A requirement of 1.08 RSun is specified at optical design level to grant 1.2 Rsun at instrument level. The coronograph instrument is designed to have a field of view of 1.6° x 1.6° with a resolution of less than 6 arcsec. Its performances are limited by diffraction in a 530 – 590 nm wavelength range. This paper presents the optical design and demonstrates that by design the requirements are fulfilled within the misalignment, manufacturing and thermo-elastic error contributions. [less ▲]

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See detailCombination of temporal phase unwrapping and long-wave infrared digital holographic interferometry for metrology of mosaic detector under space simulated conditions
Vandenrijt, Jean-François ULg; Thizy, Cédric ULg; Beaumont, Florent et al

in Mendoza Santoyo, Fernando (Ed.) SPECKLE 2015: VI International Conference on Speckle Metrology (2015, August)

We present digital holographic interferometry (DHI) in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array to be used in a space mission. The ... [more ▼]

We present digital holographic interferometry (DHI) in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array to be used in a space mission. The long wavelength was chosen for its ability to allow measurement of displacements 20 times larger than DHI in the visible and which were foreseen with the test object under such temperature changes. The specimen consists of 4x4 mosaic of detectors assembled on a frame. It was required to assess the global deformation of the ensemble, the deformation of each detector, and piston movements of each of them with respect to their neighbors. For that reason we incorporated the temporal phase unwrapping by capturing a sufficiently high number of holograms between which the phase does not suffer strong variations. At last since the specimen exhibit specular reflectivity at that wavelength, it is illuminated through a reflective diffuser [less ▲]

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See detailTime-averaged phase-stepped ESPI with CO2 laser and shearography in the visible for identification of vibration mode shapes
Vandenrijt, Jean-François ULg; Thizy, Cédric ULg; Georges, Marc ULg

in Mendoza Santoyo, Fernando (Ed.) SPECKLE 2015: VI International Conference on Speckle Metrology (2015, August)

We present investigation of interferometric methods for vibration mode identification to be applied on shakers in industrial environment. We consider long wave infrared ESPI in time-averaged mode with the ... [more ▼]

We present investigation of interferometric methods for vibration mode identification to be applied on shakers in industrial environment. We consider long wave infrared ESPI in time-averaged mode with the use of phase-stepping which allows transforming Bessel fringes, typical to the time averaging, into phase values which provide a better way for identification of vibration mode shapes. The use of long laser wavelength allows measuring larger amplitudes of vibrations compared to what is achieved in visible light. Also longer wavelengths allow lower sensitivity to external perturbations. Time-averaged phase-stepped shearography in visible is also used as a compared alternative to LWIR ESPI for working in industrial environments. Although not demonstrated here, an interesting feature for the future investigations on LWIR ESPI is its potentiality of simultaneous temperature measurement during vibrations [less ▲]

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See detailDevelopment of a full fiber-coupled laser ultrasound robotic system using two-wave mixing 1064 nm detection and 532 nm YAG generation
Vandenrijt, Jean-François ULg; Simar, Juan Felipe ULg; Thizy, Cédric ULg et al

in Laser Ultrasonics and Advanced Sensing (2015, June)

An all-fibered laser ultrasonic system for complex shape composite parts is presented. It is based on two-wave mixing detection and a long pulse laser working at 1064 nm and generation by a fibered YAG Q ... [more ▼]

An all-fibered laser ultrasonic system for complex shape composite parts is presented. It is based on two-wave mixing detection and a long pulse laser working at 1064 nm and generation by a fibered YAG Q-switch laser working at 532 nm. A compact optical head combining both beams is interfaced to a robot system for scanning. Some practical issues of this system are studied. [less ▲]

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