Showing papers in "Optics and Lasers in Engineering in 1982"

TL;DR: In this paper, the sensitivity of the photon counting method for the detection of extra-weak optical intensity was improved on the introduction of the enhanced single photoelectron counting technique incorporated with a selected photomultiplier operated under optimum conditions.

TL;DR: The history of the development of modern moire topography is reviewed and the practice of making quantitative measurements of the living human body is explained in this article, where the importance of compromising between the related factors is emphasised.

TL;DR: Three techniques for digital smoothing of fringe patterns when the intensity of such a pattern is digitised and fed into a computer are discussed here.

TL;DR: A novel type of sensing system is currently being developed, in which optical fibres are used as sensing elements or transmission lines, and the principles, performance, and problems of some typical fibre optic sensing systems are described in detail.

TL;DR: Two digital systems are developed for the automatic measurement of 3-D shapes using moire techniques—an automatic3-D shape measuring system using the scanning moire method and an interactive fringe analysing system for moire fringe photographs.

TL;DR: In this article, experiments on laser conduction seam welding with a 500 W CO 2 laser were carried out with low carbon and stainless steel samples and an accurate analysis of these results showed such excellent agreement with the theoretical models that an a priori method could be formulated to calculate the values of all the related parameters, even including the laser focal spot radius to ensure the best utilization of the beam energy.

TL;DR: In this paper, the statistical properties of the time-averaged speckle-reduced pattern at the image plane of a coherently illuminated uniform diffuse object are theoretically and experimentally studied.

TL;DR: In this article, the rays that form moire fringes in projection type moire topography are discussed and an alternative formula based on principal rays is proposed and compared with the conventional nodal ray formula.

TL;DR: In this paper, a simple optical method of measuring Poisson's ratio is reported, which relies on the use of microscopic investigations of Newton's rings to measure the radius of the Hertzian contact between the test sample and a flat glass plate.

TL;DR: In this paper, two real images of artificially generated speckle patterns are transmitted through a second bundle to a photographic film or a vidicon camera to measure surface displacement in the region of interest.

TL;DR: In this paper, the shape of a self-luminous object is recorded by using a laser scanning method with a slit camera, which is not affected by any diffraction effect caused by the grid and can be achieved with excellent image quality using the properties of the laser beam.

TL;DR: In this paper, a theory based on the geometric shadow of light can account for the spatial location of moire fringes in topographical applications, where the fringe location depends on the optical arrangement of the system and also on the surface slope of the specimen.

TL;DR: In this paper, an analytical method of predicting the intensity profile of the moire fringes formed by a three-dimensional grating is proposed, which is proved to be effective in determining the appropriate structure of the grating and the experimental conditions for directional moire topography.

TL;DR: In this article, an electro-optic device is described that effectively removes secondary speckle in Young's fringe speckles measurements, which can be used to remove the secondary specckle.

TL;DR: In this article, the aperture filtering of lenses for the purpose of moire topography is described, where the circular iris of a lens is replaced with a rectangular one whose long side is parallel with the bars of the grating, and both visibility of the fringes and the exposure condition are greatly enhanced.

TL;DR: In this paper, the pyroelectric response of a type II TGS detector at 118−8 μm is related to its FIR absorption in two perpendicular characteristic directions, and a so-called pyro-spectroscopic method could be derived from their observation.

TL;DR: In this article, the relationship between radiation flux and subsequent damage to the fibre waveguides is described and a procedure is given as an aid to predicting the "lifetime" of a fibre optics link when it is exposed to the damaging effects of radiation.

TL;DR: In this article, the flow of an oil film draining down a rough surface is studied, and it is shown that only the long wave components of the roughness give rise to corrugation of the film surface.

TL;DR: Two opto-electronic systems for seismic data information treatment are described and the possibilities of directional and frequency filtering and evaluation on the basis of the seismic section correlogram are discussed.