Quantitative and automatic analysis of interferometric fringe data using carrier fringe and FFT techniques

Computerised analysis of optical fringe pattern is a rapidly developing approach to extract quantitative data from phase encoded intensity distribution. This thesis describes results of investigations of quantitative and automatic analysis of interference fringe data using carrier fringe and FFT techniques. Several automatic and semiautomatic fringe analysis algorithms that enable the reduction of fringe patterns to quantitative data have been reviewed and illustrated with some examples. A fresh holographic contouring approach by the movement of object beams through fibre optics is described. The use of fibre optics provides a simple method for obtaining contouring fringes in the holographic system. A carrier fringe technique for measuring surface deformation is described and verified by experiments. A theoretical analysis of the carrier fringe technique is given. The effects of carrier frequency on holographic fringe data has been investigated with computer generated holograms. In contrast to conventional holography and fringe analysis, this holographic system based on fibre optics and automatic spatial carrier fringe analysis technique. The FFT approach is used to process the interferograms. An excellent correlation between the theoretical deformation profile and that suggested by the technique is given. The accuracy of the measurement for a centrally loaded aluminum disk is 0.05pm. The design and construction of a computerised photoelastic stress measurement system is discussed. This full field, fully automated photoelastic stress measurement system is a new approach to photoelastic fringe analysis. Linear carrier fringes generated using quartz wedge are superimposed on fringes formed by the stressed model. The resultant fringes pattern is then captured using a CCD camera and stored in a digital frame buffer. A FFT method has been used to process the complete photoelastic fringe image over the whole surface of the model. The whole principal stress difference field has been calculated and plotted from one single video frame

Quantitative digital image processing in fringe analysis and particle image velocimetry (PIV)

This thesis concerns the application of Quantitative Digital Image Pro­cessing to some problems in the domain of Optical Engineering. The applications addressed are those of automatic two dimensional phase unwrapping and the analysis of images from high speed particle image displacement velocimetry. The first application involves subdivision of the two dimensional image of a wrapped phase map into small two dimensional areas or tiles, which are unwrapped individually, in order that discontinuities may be localised to small areas. In this case the discontinuities have a contained effect on the unwrapped phase solution. The concept of minimum spanning trees, from Graph Theory, is employed to minimise the effect of such local discontinuities by computation of an un­wrapping path which avoids areas likely to be discontinuous in a probabilistic manner. This approach is implemented over two hierarchical levels, the first level identifying pixel level discontinuities such as spike noise, the second ad­dressing larger scale discontinuities which may not be detected by pixel level comparisons, but which can be detected by comparison of the local solutions of image areas larger than the pixel. The second application is in the area of Particle Image Displacement Velocimetry (PIDV). A digital processing method is developed for high speed PIDV. In high speed PIDV the seeding is sparsely distributed. This method attempts to pair individual particle images, rather than statistically average the positions of a large number of particle images as is the case with other analysis methods. The digital processing method is suitable for use with Video PIDV whose feasibility has recently been demonstrated

Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 272)

This bibliography lists 360 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1985

The 1995 Research Reports: NASA/ASEE Summer Faculty Fellowship Program

This document is a collection of technical reports on research conducted by the participants in the 1995 NASA/ASEE Summer Faculty Fellowship Program at the Kennedy Space Center (KSC). This was the eleventh year that a NASA/ASEE program has been conducted at KSC. The 1995 program was administered by the University of Central Florida in cooperation with KSC. The program was operated under the auspices of the American Society for Engineering Education (ASEE) with sponsorship and funding from the Office of Educational Affairs, NASA Headquarters, Washington, D.C. The KSC Program was one of nine such Aeronautics and Space Research Programs funded by NASA Headquarters in 1995. The NASA/ASEE Program is intended to be a two-year program to allow in-depth research by the University faculty member

Atom interferometry--dispersive index of refraction and rotation induced phase shifts for matter-waves

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1997.Includes bibliographical references (leaves 144-152).by Troy Douglas Hammond.Ph.D

Biology - Space Resources for Teachers

Aerospace biology curriculum for secondary schools including life support, physiological, and psychological aspects of manned space flight, and exobiolog

Aeronautical engineering: A continuing bibliography with indexes (supplement 296)

This bibliography lists 592 reports, articles, and other documents introduced into the NASA scientific and technical information system in Oct. 1993. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Pre-phase A: Development of a far-ultraviolet photometric- and spectroscopic-survey small-explorer experiment

We propose to perform a far ultraviolet photometric and spectroscopic survey covering the lambda lambda 1300-2000 band with a sensitivity comparable to that of the Palomar Sky Survey. This survey will proceed in three phases: an all-sky survey in three bands to 18-19.5(sup m), deep surveys of selected targets of interest in the same bands to 21-22(sup m), and a spectroscopic survey of 2 percent of the sky to 18(sup m) with a resolution of 3-20A. This mission, the Joint Ultraviolet Nightsky Observer (JUNO), can be performed by a Small-Explorer-class satellite

Cumulative index to NASA Tech Briefs, 1970-1975

Tech briefs of technology derived from the research and development activities of the National Aeronautics and Space Administration are presented. Abstracts and indexes of subject, personal author, originating center, and tech brief number for the 1970-1975 tech briefs are presented