Showing papers in "Optics and Lasers in Engineering in 1999"

TL;DR: In-fibre Bragg grating (FBG) sensor technology has become one of the most rapidly progressing sensing topics of this decade in the field of optical fiber sensors as mentioned in this paper.

TL;DR: In this paper, the authors have discussed laser-based interferometric techniques for measurement of refractive index, temperature and temperature profile of burners with special emphasis on laser speckle techniques and Talbot Interferometric technique.

TL;DR: A camera calibration algorithm, which takes the distortion in the lenses into account, is presented and evaluated by real experiments and the main source of errors is random errors originating from the correlation algorithm.

TL;DR: In this article, a method of defect detection using a short linear scan at the crack location is described, where a simple low-pass filter is used to improve the signal quality.

TL;DR: In this article, a novel type of fiber optic Bragg grating sensor for petroleum hydrocarbon leak detection is presented, which includes attached to the fiber a polymer member, which reversibly expands in hydrocarbon presence and strains the fiber section with the Bragg inside.

TL;DR: A turnkey, high-speed digital imaging system that provides combined real-time flow visualisation and rapidly processed PIV data in an industrial optical research engine facility and gives the potential for the study of cycle-to-cycle flow variability and its effect on combustion stability in a suitably instrumented optical engine.

TL;DR: DFP detects and evaluates corrosion by measuring surface topographical changes caused by corrosion by using a novel digital projection display technology, which provides the capability of digitally projecting fringe patterns with extremely high brightness and contrast ratio.

TL;DR: By using a special Ronchi phase grating and polarization phase shifting method, four phase shifted patterns can be captured simultaneously, and then the dynamic deformation can be measured as discussed by the authors, and the analysis and experiments are given.

TL;DR: This paper proposes a method for automatic teaching of the welding robot for free-formed seam through the range data acquired by the laser vision sensor, which shows that the proposed method performed sucessfully.

TL;DR: In this paper, the authors explored the feasibility of using electric and magnetic fields as a plasma control tool during high-power laser welding and found that both fields can influence the shielding effect of the plasma above the keyhole.

TL;DR: In this paper, an excimer laser-based system for mapping the surface temperature of turbine engine parts coated with thermographic phosphors has been developed, and the intensity measured for Y2O3:Eu over the temperature range ∼500-750°C is presented.

TL;DR: In this article, two families of phase-shifting algorithms with π/2 phase steps are studied, and the error-compensating properties of the algorithms in families I and II are investigated by the Fourier spectra analysing method.

TL;DR: In this paper, the authors present a review of both manufacturers' and users' tests of optical instruments, aimed at optical test engineers and emphasizing the practical aspects of optical testing rather than the theory.

TL;DR: A two-beam laser triangulation method has been proposed to measure the position of a moving object, using two parallel laser beams to judge the moving direction of an object, allowing us to track it and measure its positions.

TL;DR: A new whole field technique for determination of characteristic parameters in integrated photoelasticity using phase-shifting methodology is proposed and verified experimentally for the problem of a circular disk under diametral compression viewed in oblique incidence.

TL;DR: This paper describes the application of a previously proven analysis technique to dynamic deformation of a fine grid ruled onto a specimen's surface and the results show simple sample preparation and experimental operation make this technique ideal for the dynamic regime.

TL;DR: In this article, a high spatial resolution and high-sensitivity geometric micron-moire method is presented, which is based upon classical geometric moire method and microscopic principle, the frequency of the specimen and reference gratings used in this method can be higher than 1000 lines/mm.

TL;DR: In this article, the authors describe the latest improvements in holographic interferometry that enable the real-time measurement of vibrational modes and static deformations in surfaces using low-power laser illumination and a photorefractive Bi 12 TiO 20 crystal as the recording medium.

TL;DR: In this paper, high-power diode laser (HPDL) surface treatment of a common engineering carbon steel (EN8) was found to effect significant changes to the wettability characteristics of the metal.

TL;DR: In this paper, the authors deal with the determination of tensors of an elementary area of an object surface by means of an optical experimental method, which makes use of properties of the speckle field in an optically free space or in an image field.

TL;DR: In this article, an improved 3D vectorial model has been proposed to assess qualitatively and quantitatively what is actually measured throughout all the inspected surface using real ESPI instruments designed in the Joint Research Centre of Ispra (Italy).

TL;DR: In this article, a general introduction to the integrating sphere method is given, with emphasis on the current understanding of instrumental artefacts and ways of correcting the artificial losses from the sphere.

TL;DR: Two techniques to accelerate the Fourier fringe analysis technique are described, one of which proposes a reduction in the number of pixels calculated by the Fouriers transform, the other automates the filtering operation to avoid user interaction.

TL;DR: Using first order ray optics theory, a method has been developed and experimentally verified for measurement of surface strains on structures immersed in fluid environments as discussed by the authors, which utilizes an imaging system that is contained within an air environment and separated from the fluid media by an optical quality, transparent window.

TL;DR: In this paper, the use of shearing interferometry (shearography) for the quantitative measurement of gas temperatures in axisymmetric systems in which vibration and shock are substantial, and measurement time is limited.

TL;DR: In this paper, the authors reviewed the techniques of in-fiber grating sensors with an emphasis on interrogation approaches to reflecting wavelength shift induced by measurement quantities, and some suggestions are also made.

TL;DR: In this paper, an analytical model of the energy exchange between the light pulse and the target surface is proposed together with a finite element model of thermal and mechanical behaviour of the structure under excitation.

TL;DR: The concept of the hybrid numerical methods is clarified and features of each category of hybrid numerical method are presented with pertinent numerical results.

TL;DR: In this paper, a unique structure of microbend optical fiber sensor (MOFS) for measuring tensile and compressive strain is described, and the average measuring sensitivity for tensile strain is 35 μe using 3 MOFS arrays.

TL;DR: In this article, the application of ESPI to measure deformations induced by thermal load on lightweight honeycomb panels for space applications is reported. But the authors focus on the quantitative analysis of the deformation of this large object (0.8× 0.8m 2 ) viewed from a relatively short distance of 1.1m and illuminated sequentially from three non-orthogonal directions.