Showing papers in "Optics and Lasers in Engineering in 2008"

TL;DR: In this article, the effect of out-of-plane motion on 2D and 3D digital image correlation measurements is demonstrated using basic theoretical pinhole image equations and experimentally through synchronized, multi-system measurements.

TL;DR: The aim of this work is to investigate the sources of errors related to digital image correlation (DIC) technique applied to strain measurements and to address a classification of the error related to the used equipment.

TL;DR: In this article, a new method for image encryption using fractional Fourier transform and chaos theory is proposed, where the input image is combined with the first random phase mask at the object plane and is then transformed using the FFT transform.

TL;DR: In this paper, a hybrid approach of Taguchi method (TM) and principal component analysis (PCA) has been applied for multi-objective optimization (MOO) of pulsed Nd:YAG laser beam cutting (LBC) of nickel-based superalloy (SUPERNI 718) sheet to achieve better cut qualities within existing resources.

TL;DR: In this paper, the authors defined the performances of eight different phase unwrapping algorithms applied to the Fourier transform profilometry (FTP) optical scan method and defined the best one.

TL;DR: In this paper, a non-destructive, highly precise optical metrology system for measuring the average refractive index of a liquid solution such that its glucose concentration can be derived is presented.

TL;DR: In this paper, the spectral properties and the resulting coherence length of an LED are investigated for application in digital holographic microscopy, and an analysis of dispersion effects and their influence on the hologram formation is carried out.

TL;DR: In this paper, laser ablation of magnesium in deionized water (DW), solutions of DW and sodium dodecyl sulfate (SDS) with different concentrations, acetone and 2-propanol has been conducted.

TL;DR: In this paper, a quality guided approach for isoclinic unwrapping is developed, which uses a ten-step phase shifting approach to obtain a smooth variation of the digital photoelastic parameters over the domain.

TL;DR: In this paper, a statistical design of experiment (DOE) was used to optimize selected laser beam welding (LBW) parameters (laser power, welding speed, and focus length).

TL;DR: Wavelet filtering is presented to improve SNR in the reconstructed images from digital holograms by reducing the presence of speckle noise in the reconstruction process.

TL;DR: A generalized temporal phase unwrapping algorithm (GTPU), which eliminates some limitations imposed on the fringe sequence for the classical TPU algorithms, leading to a flexible method for phase reconstruction.

TL;DR: An obstacle detection system using stereo vision sensors is developed that utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs.

TL;DR: In this article, an analytical formula for beam width of flat-topped beams propagating through turbulent atmosphere is derived which shows that higher order flat-top beams are less broadened.

TL;DR: In this paper, the authors presented a technique for coastal mapping from an airborne visible/infrared imaging spectrometer (AVIRIS) hyperspectral image and a light detection and ranging (LIDAR)-based digital elevation model (DEM).

TL;DR: In this paper, an overview of diffusion measurements using various optical methods is provided, including interferometry, holography, speckle techniques, moire and common-path shearing interferometers.

TL;DR: This paper presents a practical implementation of a binocular system for three-dimensional (3D) surface measurement by proposing the method of structured light calibration to obtain the parameters of the structured light sheets.

TL;DR: In this article, a self-referencing technique was proposed for the detection of phase singularities in optical fields, where the reference wave front required to form interference fringes is drawn from the test wave front itself.

TL;DR: In this paper, the microstructures, microhardness and wear resistance of the repair coating are investigated and compared with the substrate. And the results show that it is feasible to repair the near alpha titanium alloy structural members by pulse-laser cladding.

TL;DR: In this paper, the keyhole wall was observed in deep penetration laser welding, which provided an effective way to analyze both the Fresnel and inverse Bremsstrahlung absorption in CO2 laser welding.

TL;DR: In this article, a laser surface alloying of an electroless plating Ni-P coatings on an Al-356 aluminium alloy was carried out using a 1-kW pulsed Nd:YAG laser.

TL;DR: In this article, the influence of the operating factors on the laser texturing process has been studied using two experimental approaches: Taguchi methodology and response surface methodology (RSM), which allowed us to determine a correlation between process operating factors and performance indicators such as surface roughness and material removal rate.

TL;DR: In this article, the authors presented a portable device to measure residual stress fields outside the optical bench using a binary diffractive optical element (DOE) in order to generate double illumination and radial inplane sensitivity.

TL;DR: In this article, the authors used two Nd:YAG laser pulses with a pulse duration of 0.5 µm superposed by 17 µm pulses for deep drilling of stainless steel holes.

TL;DR: In this paper, the propagation of partially coherent flat-topped (PCFT) beams in a turbulent atmosphere was investigated and analytical formula for the average intensity was derived, which showed that beam width and power in bucket (PIB) of PCFT propagated through turbulence media are more affected by turbulence.

TL;DR: In this paper, a phase unwrapping software has been developed using discrete cosine transform (DCT) to generate the three-dimensional (3-D) profiles of the machined surface.

TL;DR: The different fractional orders and random phase masks used during the process of encryption and decryption are the keys to enhance the security of the proposed system.

TL;DR: In this paper, a reflective caustics method was used to resolve dynamic fracture problems in orthotropic composites by combining the fundamental principle of Caustics with the mechanical properties of orthotropic materials.

TL;DR: In this paper, a multiple laser system consisting of CO2 line-shaped and Nd-YAG pulsed lasers was applied to cleave a soda-lime glass substrate in high temperatures.