A5046305377- Optical measurement and interference techniques
- Ultrasonics and Acoustic Wave Propagation
- Digital Holography and Microscopy
- Surface Roughness and Optical Measurements
- Seismic Waves and Analysis
- Non-Destructive Testing Techniques
- Adaptive optics and wavefront sensing
- Advanced Measurement and Metrology Techniques
- Flow Measurement and Analysis
- Geophysical Methods and Applications
- Advanced Optical Imaging Technologies
- Thermography and Photoacoustic Techniques
- Structural Health Monitoring Techniques
- Electromagnetic Launch and Propulsion Technology
- Astronomy and Astrophysical Research
- Optical Systems and Laser Technology
- Sensor Technology and Measurement Systems
- Surface Treatment and Residual Stress
- Image Processing Techniques and Applications
- Astronomical Observations and Instrumentation
- Integrated Circuits and Semiconductor Failure Analysis
- Advanced Fiber Optic Sensors
- Advanced optical system design
- Advanced Electrical Measurement Techniques
- Optical Polarization and Ellipsometry
Universidade de Vigo
2009-2019
Instituto de Astrofísica de Canarias
2000-2016
We present a technique to measure the mechanical complex amplitude, i.e. amplitude and phase of vibration, an ultrasonic plane wavefield nanometric that propagates on surface. Our aim is detect perturbations initially smooth wavefronts indicate presence flaws in material. use bursts surface acoustic waves (SAWs) double-pulsed TV holography system records two correlograms with time separations down 1.5 µs. The phases are calculated separately using spatial Fourier transform method (SFTM)...
We present a novel capability of the TV holography technique applied to non-destructive testing mechanical parts or structures with form plate shell, which consists recording high quality synthetic movies spatio-temporal evolution instantaneous ultrasonic displacement fields surface under inspection. Moreover, in case narrowband acoustic excitation, amplitude and total phase can also be generated. Some examples application flaw detection aluminium plates using waves are presented. As...
OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) was the optical Day One instrument 10.4m Spanish telescope GTC. It is installed at Observatorio del Roque de Los Muchachos (La Palma, Spain). This has been operational since March-2009 covers from 360 to 1000 nm. observing modes include direct imaging with tunable conventional filters, long slit resolution spectroscopy. wide field of view high efficiency provide a powerful tool scientific exploitation developed by...
In this paper we present the visualization of out-of-plane displacement fields produced by Rayleigh and Lamb waves on aluminium surfaces, using a double-pulse TV holography technique. This method presents several interesting characteristics, as possible way making whole-field remote measurements instantaneous acoustic displacements, with good immunity from environmental perturbations. We also show examples where different surface subsurface flaws have been detected, demonstrating great...
This paper describes a technique that numerically reconstructs the complex acoustic amplitude (i.e. and phase) of compression wave in interior volume specimen from set full-field optical measurements instantaneous displacement surface. The thick is probed transmission mode by short bursts narrowband waves generated at one its faces. temporal evolution field induced emerging opposite surface measured pulsed digital holographic interferometry (pulsed TV holography). A spatio-temporal 3D...
Pulsed TV-holography (PTVH) can be used for obtaining two-dimensional maps of instantaneous out-of-plane displacements in plates. In particular, our group has demonstrated that scattering patterns generated by the interaction elastic waves with defects measured PTVH and employed characterization damage nondestructive inspection plate structures. Recently, we have succeeded a quantitative description experimental quasi-Rayleigh (qR) produced holes harmonic regime using finite element method...
The derivation of expressions to evaluate the local standard uncertainty complex amplitude numerically reconstructed field as well phase-change measurements resulting from Fourier- and quasi-Fourier transform digital holographic interferometry is presented. Applying law propagation uncertainty, defined in "Guide expression measurement," reconstruction holograms by Fourier transformation subsequent calculation phase change between two such reconstructions results a set expressions, which...
We present a novel numerical modeling of ultrasonic Lamb and Rayleigh wave propagation scattering by through-thickness defects like holes slots in homogeneous plates, its experimental verification both near far field self-developed pulsed TV holography system. In contrast to rigorous vectorial formulation elasticity theory, our model is based on the 2-D scalar equation over plate surface, with specific boundary conditions edges. The data include complex amplitude maps out-of-plane...
Since the beginning of development Gran Telescopio Canarias (GTC), an Adaptive Optics (AO) system was considered necessary to exploit full diffraction-limited potential telescope. The GTC AO designed during last years is based on a single deformable mirror conjugated telescope pupil, and Shack-Hartmann wavefront sensor with 20 x subapertures, using OCAM2 camera. GTCAO will provide corrected beam Strehl Ratio (SR) 0.65 in K-band bright natural guide stars. Most subsystems have been...
EMIR is a near-IR, multi-slit camera-spectrograph under development for the 10m GTC on La Palma. It will deliver up to 45 independent R equals 3500-4000 spectra of sources over field view 6 feet by 3 feet, and allow NIR imaging foot FOV, with spatial sampling 0.175 inch/pixel. The prime science goal instrument open K-band, wide multi-object spectroscopy class telescopes. Science applications range from study star-forming galaxies beyond z 2, observations substellar objects dust-enshrouded...
Pulsed TV-holography (PTVH) can be used for obtaining two-dimensional maps of instantaneous out-of-plane displacements in plates. In particular, scattering patterns generated by the interaction elastic waves with defects measured PTVH and employed non-destructive inspection damage detection plate structures. For quantitative characterization (position, dimensions, orientation, etc.) on this basis, modeling wave is usually performed terms full-vector three-dimensional formulations based...
Phase evaluation methods based on the 2D spatial Fourier transform of a speckle interferogram with carrier usually assume that spectrum has trimodal distribution, i. e. side lobes corresponding to interferential terms do not overlap other two spectral terms, which are related intensity object and reference beams, respectively.Otherwise, part beam is inside inverse-transform window selected interference lobe induces an error in resultant phase map.We present technique for acquisition...
Estimation of the uncertainty is an essential requisite for high-end measurement systems. In this communication we derive expression to evaluate standard phase-difference measurements resulting from Fourier and quasi-Fourier transform digital holographic interferometry. We apply law propagation uncertainty, as defined in "Guide measurement" (GUM), reconstruction two holograms by transformation subsequent calculation phase change between reconstructions. The allows evaluation difference at...
Pulsed TV-holography (PTVH) can be used for obtaining two-dimensional maps of instantaneous out-of-plane displacements in plates. In particular, our group has demonstrated that scattering patterns generated by the interaction elastic waves with defects measured PTVH and employed quantitative characterization damage non-destructive inspection plate structures. Recently, we have succeeded a description experimental produced holes harmonic regime using finite element method (FEM) applied to...
It has been demonstrated that non-destructive inspection of plates can be performed by using two-dimensional maps instantaneous out-of-plane displacements obtained with a self-developed pulsed TV-holography system. Specifically, the interaction guided elastic waves defects produces scattering patterns contain information about (position, dimensions, orientation, etc.). For quantitative characterization on this basis, modeling wave propagation and is necessary. In fact, development models for...
We study the scattering of transient, high-frequency, narrow-band quasi-Rayleigh elastic waves by through-thickness holes in aluminum plates, framework ultrasonic nondestructive testing (NDT) based on full-field optical detection. Sequences instantaneous two-dimensional (2-D) out-of-plane displacement maps are measured with a self-developed PTVH system. The corresponding simulated sequences obtained means an FC(Gram) elastodynamic solver introduced recently, which implements full...
A novel approach to an established method calculate the frequency spectrum of Lamb waves is introduced.Lamb wavetrains are generated with wedge in aluminium plates, and a sequence instantaneous acoustic out-of-plane displacement fields at plate surface measured self-developed double-pulsed TV holography system.This achieved by emitting two laser pulses synchronized piezoelectric transducer that generates conveniently delayed.As result, 2D optical phase-change map, proportional aforementioned...
The instantaneous out-of-plane displacement two-dimensional (2-D) maps associated to the scattering generated by interaction of Rayleigh-Lamb waves with defects in plate structures can be measured using pulsed TV-holography (PTVH) and employed characterize damage non-destructive inspection applications. On basis visual comparisons we have shown previously that, except for amplitude backscattering zone, a reasonable description experimental patterns produced holes both harmonic transient...
The usual phase-stepping algorithms are employed to evaluate the phase of Fizeau interferograms in topographic measurements. superposition interferogram with a Ronchi grid provides Moire pattern. modulation is obtained by plane displacement grid, while sinusoidal intensity pattern defocusing image acquisition system. In this work, measurement range method function maximum variation height surfaces calculated and verified.
In this work, the phase evaluation of multiple-beam Fizeau interferograms is carried out by usual phase-stepping algorithms superimposing interferogram on a Ronchi grid located at interferometer image plane. The modulation, required for measurement, obtained translating in its own plane, while slight defocusing acquisition system provides suitable sinusoidal intensity pattern. An estimation measurable range surface slopes calculated and experiments spherical have been realized order to...
Transparent object Wave-Front Distortion has been measured in a Mach-Zehnder interferometer employing as evaluation tool the Multiplicative Analogical Moire Phase-Shifting Method. The measuring procedure is based on direct superimposition of transmission grating with phase modulated high-frequency spatial carrier. Latter, set phase-shifted fringe patterns, provided by low-pass filtering obtained multiplicative moire combined Generic Algorithm (GPSA). interesting information achieved once...
In this paper we demonstrate the feasibility of impact- induced transient deformations measurement by single-pulsed subtraction TV holography an Fourier transform method with contouring fringes as spatial carrier. Fringe formation in and phase demodulation are descried. Contouring proved to be well suited for introducing carrier correlation fringe patterns. Experimental results presented. Finally, degree immunity environmental disturbances technique is discussed improvements proposed.