Showing papers in "Optics and Lasers in Engineering in 1993"

TL;DR: In this paper, a carrier fringe technique for photoelasticity stress analysis is described and verified experimentally, where linear carrier fringes generated by using a quartz wedge are superimposed on fringes formed by the stressed model and the resultant fringe pattern is captured using a charge coupled device camera and stored in a digital frame buffer.

TL;DR: In this paper, a mathematical model relating surface and bulk behaviors of metals in aqueous solution has been developed based on principles of holographic interferometry for measuring microsurface dissolution, and on those of electrochemistry for measuring the bulk electronic current, i.e. corrosion current.

TL;DR: In this work, the advantages of phase shifting have been applied to a conventional moire interferometer, yielding a system capable of recording phase shifted fringe patterns for both in-plane displacement components.

TL;DR: In this paper, the authors compared skeletonising, temporary heterodyning, phase shifting and Fourier transform evaluation with regard to experimental requirements, achievable resolution and precision, as well as inherent noise suppression and image enhancement.

TL;DR: In this article, computer aided moire methods (CAMM) use the versatility of the computer to manipulate gratings rapidly, the basis of all Moire methods, and application of CAMM to moire teaching, in-plane moire, shadow and projection moire and reflection moire are reviewed.

TL;DR: In this article, a general theory of in-line Fraunhofer holography is presented, along with practical and theoretical considerations for holographic reconstruction and non-image plane analysis.

TL;DR: In this article, the Fourier transform grid (FTGM) was used to analyze the 3D shape and the surface strain distributions of a moving object, using stereo vision, where a 2D cross grating is drawn on the surface of the object and it is recorded as images with two charge coupled device cameras.

TL;DR: In this paper, a non-destructive and noncontact extensometry technique was developed in order to study the behavior of different materials such as polycarbonate, araldite, urethane, etc.

TL;DR: In this paper, a method that uses pulsed laser light and coherent light interferometry in a fiber-optic-based system for noncontact generation and detection of ultrasound is described.

TL;DR: In this article, the authors present an introduction on the pure grid method for deformation measurements in experimental mechanics, which involves that the grid images are processed separately, and subsequently the results of these separate processings are substrated from each other in order to obtain a quantified deformation indication.

TL;DR: In this article, the effect of particle shape and surface roughness on intergranular load transfer, velocity and wavelength of a stress wave transmitted through granular media subjected to explosive loading was investigated.

TL;DR: In this paper, the Fourier transform was used to reduce the noise level of spatially filtered speckle interferograms, and correlation fringes formed by spatial filtering of the developed film were combined numerically.

TL;DR: In this paper, the authors review recent theoretical and experimental developments related to the investigation of dynamic and transient crack-tip deformations using a new coherent optical technique, coherent gradient sensing (CGS), which is a full-field, lateral-shearing interferometric technique with an online spatial filter.

TL;DR: The procedure has been successfully tested on noisy fringe patterns and is general, automatic and convenient for fringe analysis, and useful for processing other line patterns.

TL;DR: In this paper, an automated fringe pattern analysis enables the full-field of data to be used with the minimum of operator intervention, and is shown to be accurate to within 10%.

TL;DR: The architecture of the system which enables a proper choice between the Fourier transform method, temporal and spatial phase-shifting methods is described and the modular structure of the software gives the possibility of getting the results in the most efficient way.

TL;DR: The opportunity and challenge of the day is to closely couple CAE (FEM, EFA, etc.) methods and experimental methods to optimize structural performance in the upstream product development process where necessary tooling modifications can and will be made.

TL;DR: In this article, the mechanics of material removal in waterjet and abrasive waterjet (AWJ) piercing processes in a birefringent polymer material were investigated and a two-dimensional dynamic photoelasticity experimental set-up was developed and utilized to record the photo-elastic stress patterns associated with jet piercing.

TL;DR: In this paper, the emission behavior and application of sequential and phase synchronized pulsed laser diodes in a multi-component laser Doppler anemometer with only one receiver, one signal processing chain and identical wavelength for all components are outlined.

TL;DR: A series of experiments has been undertaken to investigate the feasibility of using a Nd:YAG laser to produce a highly random surface on steel, which could be used as a finished, textured surface itself, or as a master for a stamping process as discussed by the authors.

TL;DR: In this paper, an optical processor for generating a two-dimensional squared auto-correlation function is proposed, where incoherent-to-coherent conversion is performed by an optically-addressed spatial light modulator.

TL;DR: A survey of the status of laser safety in UK laser companies is reported in this paper, showing that nearly two-thirds of suppliers produce lasers in the Class IIIB and IV categories, i.e. those requiring the highest level of safety precautions.

TL;DR: In this paper, a method of in-situ monitoring of laser metal cutting and drilling using cladding power monitoring of an optical fiber beam delivery system is presented, which detects the light reflected or scattered from the workpiece.

TL;DR: In this paper, the power intensity distribution of a laser beam across the focal plane is examined for producing good hole geometry using a diffraction integral method, where lens aberration is accounted for by the intensity of appropriate phase changes.

TL;DR: In this article, it was shown that it is possible to obtain Young's fringes from the stored holographic data, and the particle velocity can be measured directly from the hologram.

TL;DR: In this article, the specular reflectance of rough nickel samples was studied using a fiber optic system based on the use of a semiconductor laser as a light source and a monomode fibre for light guiding.

TL;DR: The results obtained using a software code suitable for reading and analysing fringe patterns are presented, which uses two different approaches: the first semi-automatic with algorithms proper of fringe tracking and the second based on Fourier transform.

TL;DR: In this article, the influence of the relative refractive index on the efficiency of chromium diffraction gratings, working in total internal reflection with s-polarized light, is investigated.

TL;DR: In this paper, the principle of flowing metal and the distribution of strain and stress have also been obtained based on this information, and the results should help us to improve the metal forming processes.