Science.gov

Sample records for real-time holographic interferometry

  1. Real-time laser holographic Interferometry for aerodynamics

    NASA Technical Reports Server (NTRS)

    Lee, George

    1987-01-01

    Recent developments in thermoplastic recording holograms and advancements in automated image digitalization and analysis make real-time laser holographic interferometry feasible for two-dimensional flows such as airfoil flows. Typical airfoil measurements would include airfoil presssure distributions, wake and boundary layer profiles, and flow field density contours. This paper addresses some of the problems and requirements of a real-time laser holographic interferometer.

  2. Real-time laser holographic interferometry for aerodynamics

    NASA Technical Reports Server (NTRS)

    Lee, George

    1987-01-01

    Recent developments in thermoplastic recording holograms and advancements in automated image digitalization and analysis make real-time laser holographic interferometry feasible for two-dimensional flows such as airfoil flows. Typical airfoil measurements would include airfoil pressure distributions, wake and boundary layer profiles, and flow field density contours. This paper addresses some of the problems and requirements of a real-time laser holographic interferometer.

  3. A simplified holographic-interferometry technique for real-time flow visualization and analysis

    NASA Technical Reports Server (NTRS)

    Long, S. A.; Spencer, R. C.

    1974-01-01

    A holographic-interferometry technique for flow visualization and analysis that produces real-time moire fringes is described from both experimental and application considerations. It has three chief advantages: real-time data for continuous observation and photography, ease of optical adjustment, and capability of using ordinary-glass test-section windows without affecting the results. A theoretical discussion is presented describing the formation of the fringes in holographic terms and then comparing this result to that which is obtained from a conventional moire approach. A discussion on obtaining density information from the fringe pattern is also included.

  4. Coupling for capturing an displaying hologram systems for real-time digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Porras-Aguilar, Rosario; Zaperty, Weronika; Kujawinska, Malgorzata

    2013-11-01

    Conventional (analog) holographic interferometry (HI) has been used as a powerful technique in optical metrology since sixties of XX century. However, its practical applications have been constrained because of the cumbersome procedures required for holographic material development. Digital holography has brought significant simplifications due to digital capture of holograms and their further numerical reconstruction and manipulation of reconstructed phases and amplitudes. These features are the fundamentals of double exposure digital holographic interferometry which nowadays is used in such applications as industrial inspection, medical imaging, microscopy and metrology. However another very popular HI technique, namely real time holographic interferometry has not been demonstrated in its digital version. In this paper we propose the experimental-numerical method which allows for real-time DHI implementation. In the first stage a set of digital phase shifted holograms of an object in an initial condition is captured and the phase of an object wavefront in the hologram plane is calculated. This phase is used to address a spatial light modulator, which generates the initial object wavefront. This wavefront (after proper SLM calibration) propagates toward an object and interfere with an actual object wavefront giving real-time interference fringes. The procedure works correctly in the case when CCD camera and SLM LCOS pixel sizes are the same. Usually it is not the case. Therefore we had proposed two different methods which allow the overcome of this mismatch pixel problem. The first one compensates for lateral magnification and the second one is based on re-sampling of a captured phase. The methods are compared through numerical simulations and with experimental data. Finally, the implications of setting up the experiment with the object reference phase compensated by the two approaches are analyzed and the changes in an object are monitored in real time by DHI.

  5. Real-time holographic interferometry to measure displacement of the facial bone

    NASA Astrophysics Data System (ADS)

    Matsumoto, Toshiro; Tamamura, Kentaro; Tsuchida, Masahisa; Hashimoto, Seiichi; Yabuuchi, Hisashi; Uemura, Kazuyoshi; Sugimura, Masahito

    1998-01-01

    The deformation of the facial bone made up of many complex- formed bones was measured and the role of suture considered with the mechanical response. The displacement of human dried facial bone was measured and considered under static loads by real time holographic interferometry. Materials were dried human skulls. Various loads were applied to the zygomatic, maxillary and the other facial bones by means of a loading apparatus. As the experimental result obtained from the load to the neighborhood of the temporo-zygomatic suture on the temporal bone, density of interference fringes increased on the temporal bone more than on the zygomatic and other facial bones and parallel interference fringes were observed on the temporal bone. The buffer effect on the temporo-zygomatic suture to the load was greater than the sutures of other facial bones. When the amount of load was increased on the same bone, it was expected that the zygomatic arch was broken independently as the type II of the fracture patterns by Knight and NOrth. When the neighborhood of the median suture on the maxillary bone was loaded, fine interference fringes were observed horizontally on the maxillary and zygomatic bones, while coarse interference fringes occurred on the frontal bone and the bilateral fracture pattern by LeFort was expected.

  6. Measurement of displacement on facial bone by real-time holographic interferometry

    NASA Astrophysics Data System (ADS)

    Matsumoto, Toshiro; Taga, Masao; Tsuchida, Masahisa; Yoshioka, Minoru; Uemura, Kazuyoshi; Sugimura, Masahito

    1996-01-01

    The displacement of human dried facial bone was measured and considered under static loads by real time holographic interferometry. Materials were dried human skulls. Various loads were applied to the zygomatic, maxillary and other facial bones by means of a loading apparatus. As the experimental result obtained from the load to the neighborhood of the fronto-malar suture on the zygomatic bone, density of interference fringes increased on the zygomatic bone more than on the other facial bones and parallel interference fringes were observed on the zygomatic bone. Densities of orbital maxillary and zygomatic bones were greater, when the load was applied to the center of infraorbital margin than when it was applied to the other facial bones. When the neighborhood of the front-malar suture on the frontal bone was loaded, coarse interference fringes occurred on the zygomatic, maxillary and orbital bones, while fine interference fringes appeared on the frontal bone. When the maxillary bone near infraorbital margin was loaded, concentric circular fringes were observed. The result shows that the displacement depends on the loading point. When the load applied to the zygomatic bone, parallel fringes appeared on the bone. This means that the bone deformed almost as a body.

  7. Holographic interferometry applied to real-time dynamic modal analysis of an advanced exotic metal alloy airfoil structure

    NASA Astrophysics Data System (ADS)

    Fein, Howard

    1999-07-01

    Holographic Interferometry has been successfully employed to characterize the materials and behavior of diverse types of structures under stress. Specialized variations of this technology have also been applied to define dynamic and vibration related structural behavior. Such applications of holographic technique offer some of the most effective methods of modal and dynamic analysis available. Real-time dynamic testing of the structural behavior of aerodynamic control and airfoil structures for advanced aircraft and missile systems has traditionally required advanced instrumentation for data collection in either actual flight test or wind-tunnel simulations. Advanced optical holography techniques are alternate methods which result in full-field behavioral data on the ground in a nondestructive hardware- in-the-loop environment. These methods offer significant insight in both the development and subsequent operational test and modeling of advanced control and airfoil structures and their integration with total vehicle system dynamics. Aerodynamic control structures and components can be analyzed in place with very low amplitude excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural and behavioral models as well actual performance.

  8. Temporal averaging of phase measurements in the presence of spurious phase drift - Application to phase-stepped real-time holographic interferometry

    NASA Technical Reports Server (NTRS)

    Ovryn, B.; Haacke, E. M.

    1993-01-01

    A technique that compensates for low spatial frequency spurious phase changes during an interference experiment is developed; it permits temporal averaging of multiple-phase measurements, made before and after object displacement. The method is tested with phase-stepped real-time holographic interferometry applied to cantilever bending of a piezoelectric bimorph ceramic. Results indicate that temporal averaging of the corrected data significantly reduces the white noise in a phase measurement without incurring systematic errors or sacrificing spatial resolution. White noise is reduced from 3 deg to less than 1 deg using these methods.

  9. Real-time holographic camera system

    NASA Astrophysics Data System (ADS)

    Bazhenov, Mikhail Y.; Grabovski, Vitaly V.; Stolyarenko, Alexandr V.; Zahaykevich, George A.

    1997-04-01

    The holographic camera system for surface-relief hologram multiple reversible registration is presented. Photosensitive media is a single-layer photothermoplastic polymer on a glass substrate with conductive layer. This exclude a charges accumulation in the polymer volume and permits to realize an efficient enhancement of latent electrostatic image and its fast pulse heating development. The processes of charging, photogeneration, carriers transport, fast development and erasing, image enhancement were studied in detail and optimized. In order to improve some defects of photothermoplastic recording, originating from influences of circumstances and recording conditions, some new processes were developed: (1) fast charging with pulses corona in closed dielectric volume, (2) optoelectronic enhancement of electrostatic image, and (3) fast pulsed development with automatically controlled temperature rate. The dust-proof recording camera with built-in highvoltage power supply, thermo- and photosensors was designed to meet the needs of real-time or multiple- exposure interferometry, holographic training recording, holographic storage systems, correlation investigations and pattern recognition.

  10. Real-time holographic surveillance system

    DOEpatents

    Collins, H.D.; McMakin, D.L.; Hall, T.E.; Gribble, R.P.

    1995-10-03

    A holographic surveillance system is disclosed including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm. 21 figs.

  11. Real-time holographic surveillance system

    DOEpatents

    Collins, H. Dale; McMakin, Douglas L.; Hall, Thomas E.; Gribble, R. Parks

    1995-01-01

    A holographic surveillance system including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm.

  12. Real-time wideband holographic surveillance system

    DOEpatents

    Sheen, D.M.; Collins, H.D.; Hall, T.E.; McMakin, D.L.; Gribble, R.P.; Severtsen, R.H.; Prince, J.M.; Reid, L.D.

    1996-09-17

    A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm. 28 figs.

  13. Real-time wideband holographic surveillance system

    DOEpatents

    Sheen, David M.; Collins, H. Dale; Hall, Thomas E.; McMakin, Douglas L.; Gribble, R. Parks; Severtsen, Ronald H.; Prince, James M.; Reid, Larry D.

    1996-01-01

    A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm.

  14. Real-time and postprocessing holographic effects in dichromated pullulan.

    PubMed

    Savić, Svetlana; Pantelić, Dejan; Jakovijević, Dragica

    2002-08-01

    Experimental results concerning both real-time and postprocessing (after-development) behavior of a novel photosensitive material, dichromate-sensitized pullulan (DCP), are investigated. The exposure mechanism and possibilities for controlling holographic grating properties are discussed. We have shown that it is possible to maximize the diffraction efficiency of interference gratings after development by controlling diffraction efficiency in real time. Stronger real-time effects of DCP compared with those of dichromated gelatin are achieved. PMID:12153075

  15. Intellectual property in holographic interferometry

    NASA Astrophysics Data System (ADS)

    Reingand, Nadya; Hunt, David

    2006-08-01

    This paper presents an overview of patents and patent applications on holographic interferometry, and highlights the possibilities offered by patent searching and analysis. Thousands of patent documents relevant to holographic interferometry were uncovered by the study. The search was performed in the following databases: U.S. Patent Office, European Patent Office, Japanese Patent Office and Korean Patent Office for the time frame from 1971 through May 2006. The patent analysis unveils trends in patent temporal distribution, patent families formation, significant technological coverage within the market of system that employ holographic interferometry and other interesting insights.

  16. Real time moving scene holographic camera system

    NASA Technical Reports Server (NTRS)

    Kurtz, R. L. (Inventor)

    1973-01-01

    A holographic motion picture camera system producing resolution of front surface detail is described. The system utilizes a beam of coherent light and means for dividing the beam into a reference beam for direct transmission to a conventional movie camera and two reflection signal beams for transmission to the movie camera by reflection from the front side of a moving scene. The system is arranged so that critical parts of the system are positioned on the foci of a pair of interrelated, mathematically derived ellipses. The camera has the theoretical capability of producing motion picture holograms of projectiles moving at speeds as high as 900,000 cm/sec (about 21,450 mph).

  17. Real-Time Holographic Image Correction Using Bacteriorhodopsin

    NASA Technical Reports Server (NTRS)

    Downie, John D.

    1994-01-01

    We present experimental results of one-way coherent imaging through a thin phase-aberrating medium using a holographic technique with bacteriorhodopsin as a real-time holographic material. Bacteriorhodopsin is well suited for the application when the aberration is time varying because of its real-time writing and erasing characteristics, sensitivity, and spatial resolution. We show results with final image resolution of greater than 20 line pairs/mm and high signal-to-noise ratio using a polarization-holography approach.

  18. Processing system for real-time holographic video computation

    NASA Astrophysics Data System (ADS)

    Nwodoh, Thomas A.; Bove, V. Michael, Jr.; Watlington, John A.; Benton, Stephen A.

    1999-08-01

    This paper discusses the Chidi holographic video processing system (called Holo-Chidi) used for real-time computation of computer generated holograms and the subsequent display of the holograms at video frame rates. Chidi is a reconfigurable multimedia processing system designed at the MIT Media Laboratory for real-time synthesis and analysis of multimedia data in general and digital video frames in particular. Holo-Chidi which is an adaptation of Chidi, comprises two main components: the sets of processor cards and the display interface cards.

  19. Holograph and Interferometry.

    ERIC Educational Resources Information Center

    Altman, Thomas C.

    1992-01-01

    Describes a method to create holograms for use in different interferometry techniques. Students utilize these techniques in experiments to study the structural integrity of a clarinet reed and the effects of temperature on objects. (MDH)

  20. Aberration-free holographic reverse-shearing interferometry

    SciTech Connect

    Lyalikov, A M

    2005-02-28

    The peculiarities of holographic reverse-shearing interferometry, which make it possible to obtain two simultaneous real-time interferograms of the phase object free from aberrations of the optical system are studied. The behaviour of fringes in the interferograms is identical to their behaviour in the conventional two-beam interferometry with a standard reference wave. The peculiarities of fringe alignment in the interferograms are considered. The real-time interferograms of a glass test plate with various fringe alignments are obtained, confirming the practical prospects of this technique. (laser applications and other topics in quantum electronics)

  1. Real-time dynamic holographic image storage device

    NASA Technical Reports Server (NTRS)

    Lafleur, Sharon S. (Inventor); Montgomery, Raymond C. (Inventor)

    1990-01-01

    A real-time dynamic holographic image storage device uses four-wave mixing in a pair of photorefractive crystals. An oscillation is produced between the crystals which can be maintained indefinitely after the initial object beam is discontinued. The object beam produces an interference pattern in a first crystal to produce phase-conjugated object beam which is directed towards the second crystal. In the second crystal another interference pattern is created which produces a reconstructed object beam. The reconstructed object beam is directed back towards the first crystal. The interference patterns are produced by interaction of the object and phase-conjugated object beam with a read and write beam in each of the crystals. By manipulation of the ratio of the read and write beam intensities in at least one of the crystals, the phase-conjugate or reconstructed object beam output therefrom can be amplified to maintain stable oscillation between the two crystals.

  2. Nondestructive testing of composite materials by holographic interferometry

    NASA Astrophysics Data System (ADS)

    Ebbeni, J.; de Smet, M.-A.

    Techniques for the nondestructive testing of composites by holographic interferometry are discussed, and results from tests analyzing carbon/epoxy composites for two types of defects, resulting from the impact of steel rods and the introduction of mylar inhomogeneities, are presented. Holographic techniques for the interferometric real-time observation of the superposition of the object and the holographic image, and for the recording on two photosensitively different plates of holographic images of the object in the neutral and deformed states, are discussed. Results show that a defect of 0.02 mm, situated at less than three layers below the observed surface, could be precisely characterized, and that for certain cases of 3-12 layers, defects could be detected by a fringe deviation. Better definition of the zone of impact was obtained by the holographic method than by an ultrasound method.

  3. 50 years of holographic interferometry

    NASA Astrophysics Data System (ADS)

    Stetson, Karl A.

    2015-01-01

    Fifty years ago, Robert L. Powell and I discovered holographic interferometry while working at the Radar Laboratory of the University of Michigan's Institute of Science and Technology. I have worked in this field for this entire time span, watched it grow from an unexplored technology to become a widespread industrial testing method, and I have contributed to these developments. In this paper, I will trace my history in this field from our discovery to my involvement in its theory and applications. I will conclude with a discussion of digital holography, which is currently replacing photographic holography for most research and industrial applications.

  4. Polarization interferometry for real-time spectroscopic plasmonic sensing.

    PubMed

    Otto, Lauren M; Mohr, Daniel A; Johnson, Timothy W; Oh, Sang-Hyun; Lindquist, Nathan C

    2015-03-01

    We present quantitative, spectroscopic polarization interferometry phase measurements on plasmonic surfaces for sensing applications. By adding a liquid crystal variable wave plate in our beam path, we are able to measure phase shifts due to small refractive index changes on the sensor surface. By scanning in a quick sequence, our technique is extended to demonstrate real-time measurements. While this optical technique is applicable to different sensor geometries-e.g., nanoparticles, nanogratings, or nanoapertures-the plasmonic sensors we use here consist of an ultrasmooth gold layer with buried linear gratings. Using these devices and our phase measurement technique, we calculate a figure of merit that shows improvement over measuring only surface plasmon resonance shifts from a reflected intensity spectrum. To demonstrate the general-purpose versatility of our phase-resolved measurements, we also show numerical simulations with another common device architecture: periodic plasmonic slits. Since our technique inherently measures both the intensity and phase of the reflected or transmitted light simultaneously, quantitative sensor device characterization is possible. PMID:25672889

  5. Some applications of holographic interferometry in biomechanics

    NASA Astrophysics Data System (ADS)

    Ebbeni, Jean P. L.

    1992-03-01

    Holographic interferometry is well adapted for the determination of 2D strain fields in osseous structures. The knowledge of those strain fields is important for the understanding of structure behavior such as arthrosis.

  6. Shrinkage during holographic recording in photopolymer films determined by holographic interferometry.

    PubMed

    Moothanchery, Mohesh; Bavigadda, Viswanath; Toal, Vincent; Naydenova, Izabela

    2013-12-10

    Shrinkage of photopolymer materials is an important factor for their use in holographic data storage and for fabrication of holographic optical elements. Dimensional change in the holographic element leads to a requirement for compensation in the reading angle and/or wavelength. Normally, shrinkage is studied at the end of the polymerization process and no information about the dynamics is obtained. The aim of this study was to use holographic interferometry to measure the shrinkage that occurs during holographic recording of transmission diffraction gratings in acrylamide photopolymer layers. Shrinkage in photopolymer layers can be measured over the whole recorded area by real-time capture of holographic interferograms at regular intervals during holographic recording using a complimentary metal-oxide-semiconductor camera. The optical path length change, and hence the shrinkage, are determined from the captured fringe patterns. Through analysis of the real-time shrinkage curves, it is possible to distinguish two processes that determine the value of shrinkage in the photopolymer layer. These processes are ascribed to monomer polymerization and crosslinking of polymer chains. The dependence of shrinkage of the layers on the conditions of recording such as recording intensity, single or double beam exposure, and the physical properties of the layers, such as thickness, were studied. Higher shrinkage was observed with recordings at lower intensities and in thinner layers. Increased shrinkage was also observed in the case of single beam polymerization in comparison to the case of double beam holographic exposure. PMID:24513896

  7. Vibration Analysis Of Automotive Structures Using Holographic Interferometry

    NASA Astrophysics Data System (ADS)

    Brown, G. M.; Wales, R. R.

    1983-10-01

    Since 1979, Ford Motor Company has been developing holographic interferometry to supplement more conventional test methods to measure vehicle component vibrations. An Apollo PHK-1 Double Pulse Holographic Laser System was employed to visualize a variety of complex vibration modes, primarily on current production and prototype powertrain components. Design improvements to reduce powertrain response to problem excitations have been deter-mined through pulsed laser holography, and have, in several cases, been put into production in Ford vehicles. Whole-field definition of vibration related deflections provide continuity of information missed by accelerometer/modal analysis techniaues. Certain opera-tional problems, common among pulsed ruby holographic lasers, have reauired ongoing hardware and electronics improvements to minimize system downtime. Real-time, time-averaged and stroboscopic C. W. laser holographic techniques are being developed at Ford to complement the double pulse capabilities and provide rapid identification of modal frequencies and nodal lines for analysis of powertrain structures. Methods for mounting and exciting powertrains to minimize rigid body motions are discussed. Work at Ford will continue toward development of C. W. holographic techniques to provide refined test methodology dedicated to noise and vibration diagnostics with particular emphasis on semi-automated methods for quantifying displacement and relative phase using high resolution digitized video and computers. Continued use of refined pulsed and CW laser holographic interferometry for the analysis of complex structure vibrations seems assured.

  8. Real-Time, Holographic, Dynamic Image-Storage Device

    NASA Technical Reports Server (NTRS)

    Montgomery, Raymond C.; Lafleur, Sharon S.

    1995-01-01

    Solid-state device developed for high-speed acquisition, dynamic storage, and amplification of three-dimensional holographic images. Holograms generated via four-wave mixing in two or more photorefractive crystals (or subelements of single crystal) to create single-crystal or multicrystal oscillator. Apparatus provides dynamic storage of holographic image of object after electronic shutter closed to turn off object beam. Provides capability to store, amplify, process, and transmit time-varying, two-dimensional, spatial information. Developments include sensors, actuators, and optical computers operating at speeds on order of speed of light. Potential in applications in which need for high-speed acquisition and storage of three-dimensional holographic images.

  9. Holographic interferometry: A user`s guide

    SciTech Connect

    Griggs, D.

    1993-10-01

    This manual describes the procedures and components necessary to produce a holographic interferogram of a flow field in the Sandia National Laboratories hypersonic wind tunnel. In contrast to classical interferometry, holographic interferometry records the amplitude and phase distribution of a lightwave passing through the flow field at some instant of time. This information can then be reconstructed outside the wind tunnel for visual analysis and digital processing, yielding precise characterizations of aerodynamic phenomena. The reconstruction and subsequent hologram image storage process is discussed, with particular attention paid to the digital image processor and the data reduction technique.

  10. A near-real-time full-parallax holographic display for remote operations

    NASA Technical Reports Server (NTRS)

    Iavecchia, Helene P.; Huff, Lloyd; Marzwell, Neville I.

    1991-01-01

    A near real-time, full parallax holographic display system was developed that has the potential to provide a 3-D display for remote handling operations in hazardous environments. The major components of the system consist of a stack of three spatial light modulators which serves as the object source of the hologram; a near real-time holographic recording material (such as thermoplastic and photopolymer); and an optical system for relaying SLM images to the holographic recording material and to the observer for viewing.

  11. Real-time wideband cylindrical holographic surveillance system

    DOEpatents

    Sheen, D.M.; McMakin, D.L.; Hall, T.E.; Severtsen, R.H.

    1999-01-12

    A wideband holographic cylindrical surveillance system is disclosed including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply Fast Fourier Transforms and obtain a three dimensional cylindrical image. 13 figs.

  12. Real-time wideband cylindrical holographic surveillance system

    DOEpatents

    Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.; Severtsen, Ronald H.

    1999-01-01

    A wideband holographic cylindrical surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply Fast Fourier Transforms and obtain a three dimensional cylindrical image.

  13. Real-time optical holographic tracking of multiple objects

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Liu, Hua-Kuang

    1989-01-01

    A coherent optical correlation technique for real-time simultaneous tracking of several different objects making independent movements is described, and experimental results are presented. An evaluation of this system compared with digital computing systems is made. The real-time processing capability is obtained through the use of a liquid crystal television spatial light modulator and a dichromated gelatin multifocus hololens. A coded reference beam is utilized in the separation of the output correlation plane associated with each input target so that independent tracking can be achieved.

  14. Fast photochromism in polymer matrix with plasticizer and real-time dynamic holographic properties

    NASA Astrophysics Data System (ADS)

    Ishii, Norihito; Abe, Jiro

    2013-04-01

    We have developed a photochromic polymer film for the use of real-time dynamic hologram, fabricated by the plasticized polymer doped with the fast photochromic molecule. The addition of a plasticizer into the conventional polymer is proved to be effective to improve the photochromic performances for the polymer film doped with the fast photochromic molecule that shows instantaneous coloration upon exposure to UV light and rapid fading in the dark. The plasticized photochromic polymers enable the real-time control of the writing and erasing of a holographic grating and show a higher recording sensitivity compared with other organic holographic materials.

  15. Two color holographic interferometry for microgravity application

    NASA Technical Reports Server (NTRS)

    Trolinger, James D.; Weber, David C.

    1995-01-01

    Holographic interferometry is a primary candidate for determining temperature and concentration in crystal growth experiments designed for space. The method measures refractive index changes within the fluid of an experimental test cell resulting from temperature and/or concentration changes. When the refractive index changes are caused by simultaneous temperature and concentration changes, the contributions of the two effects cannot be separated by single wavelength interferometry. By using two wavelengths, however, two independent interferograms can provide the additional independent equation required to determine the two unknowns. There is no other technique available that provides this type of information. The primary objectives of this effort were to experimentally verify the mathematical theory of two color holographic interferometry (TCHI) and to determine the practical value of this technique for space application. In the foregoing study, the theory of TCHI has been tested experimentally over a range of interest for materials processing in space where measurements of temperature and concentration in a solution are required. New techniques were developed and applied to stretch the limits beyond what could be done with existing procedures. The study resulted in the production of one of the most advanced, enhanced sensitivity holographic interferometers in existence. The interferometric measurements made at MSFC represent what is believed to be the most accurate holographic interferometric measurements made in a fluid to date. The tests have provided an understanding of the limitations of the technique in practical use.

  16. Multi-channel holographic birfurcative neural network system for real-time adaptive EOS data analysis

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang; Diep, J.; Huang, K.

    1991-01-01

    Viewgraphs on multi-channel holographic bifurcative neural network system for real-time adaptive Earth Observing System (EOS) data analysis are presented. The objective is to research and develop an optical bifurcating neuromorphic pattern recognition system for making optical data array comparisons and to evaluate the use of the system for EOS data classification, reduction, analysis, and other applications.

  17. Two color holographic interferometry for microgravity application

    NASA Technical Reports Server (NTRS)

    Trolinger, James D.

    1993-01-01

    Holographic interferometry is a primary candidate for the measurement of temperature and concentration in various crystal growth experiments destined for space. The method measures refractive index changes in the experiment test cell. A refractive index change can be caused by concentration changes, temperature changes, or a combination of temperature and concentration changes. If the refractive index changes are caused by temperature and concentration changes occurring simultaneously in the experiment test cell, the contributions by the two effects cannot be separated by conventional measurement methods. By using two wavelengths, two independent interferograms can be produced from the reconstruction of the hologram. The two interferograms will be different due to dispersion properties of fluid materials. These differences provide the additional information that allows the separation of simultaneously occurring temperature and concentration gradients. There is no other technique available that can provide this type of information. The primary objectives of this effort are to experimentally verify the mathematical theory of two color holographic interferometry and to determine the practical value of this technique for space application. To achieve these objectives, the accuracy and sensitivity of the technique must be determined for geometry's and materials that are relevant to the Materials Processing in the Space program of NASA. This will be achieved through the use of a specially designed two-color holographic interferometry breadboard optical system. In addition to experiments to achieve the primary goals, the breadboard will also provide inputs to the design of an optimum space flight system.

  18. A real-time dynamic holographic material using a fast photochromic molecule

    NASA Astrophysics Data System (ADS)

    Ishii, Norihito; Kato, Tetsuya; Abe, Jiro

    2012-11-01

    We have developed a real-time, dynamic holographic material that exhibits rapid colouration upon irradiation with UV light and successive fast thermal bleaching within tens of milliseconds at room temperature. Photochromic polymer films were prepared by a simple solution-casting method from the benzene solution of the mixture of the photochromic molecule, poly(ethyl acrylate), and poly(phenoxyethyl acrylate). The real-time control of holographic images using the photochromic polymer film yields a speed equivalent to the time resolution of the human eye. This new type of dynamic holographic material based on fast photochromism opens up an exciting new area of research in the future development of a large dynamic 3D display.

  19. A real-time dynamic holographic material using a fast photochromic molecule

    PubMed Central

    Ishii, Norihito; Kato, Tetsuya; Abe, Jiro

    2012-01-01

    We have developed a real-time, dynamic holographic material that exhibits rapid colouration upon irradiation with UV light and successive fast thermal bleaching within tens of milliseconds at room temperature. Photochromic polymer films were prepared by a simple solution-casting method from the benzene solution of the mixture of the photochromic molecule, poly(ethyl acrylate), and poly(phenoxyethyl acrylate). The real-time control of holographic images using the photochromic polymer film yields a speed equivalent to the time resolution of the human eye. This new type of dynamic holographic material based on fast photochromism opens up an exciting new area of research in the future development of a large dynamic 3D display. PMID:23139865

  20. Deformation measurement of the bone fixed with external fixator using holographic interferometry

    NASA Astrophysics Data System (ADS)

    Kojima, Arata; Ogawa, Ryokei; Izuchi, N.; Yamamoto, Manabu; Nishimoto, T.; Matsumoto, Toshiro

    1991-08-01

    Mechanical properties of tibia fixed with an external fixative device (external fixator) were investigated under some simulated loading conditions. Deformation measurements were performed using double exposure holographic interferometry and real-time holographic interferometry. According to the results of the holographic interferometry, strains on the fixation pins and rods were also measured using strain gauges. The results showed that, with most types of external fixator, dislocations of both fractured ends were mainly caused by decrease in strength of the fixation pins. With increase in strength of fixation pins, angular deformation of the rod was more obvious. Increase in the strength of the rod was not always effective in decreasing dislocation of both fractured ends. Changes in bracing technique with marked change in rigidity of external fixator were useful to decrease dislocation of both fractured ends.

  1. Comparison of real-time phase-reconstruction methods in temporal speckle-pattern interferometry.

    PubMed

    Etchepareborda, Pablo; Bianchetti, Arturo; Veiras, Francisco E; Vadnjal, Ana Laura; Federico, Alejandro; Kaufmann, Guillermo H

    2015-09-01

    Three real-time methods for object-phase recovery are implemented and compared in temporal speckle-pattern interferometry. Empirical mode and intrinsic time-scale decompositions are used and compared as real-time nonstationary and nonlinear filtering techniques for the extraction of the spatio-temporal evolution of the object phase. The proposed real-time methods avoid the application of the Hilbert transform and improve the accuracy of the measurement by filtering under-modulated pixels using Delaunay triangulation. The performance of the proposed methods is evaluated by comparing phase-recovery accuracy and computation time by means of numerical simulations and experimental data obtained from common and simultaneous π/2 phase-shifting heterodyne interferometry. PMID:26368890

  2. The Compact and Inexpensive "Arrowhead" Setup for Holographic Interferometry

    ERIC Educational Resources Information Center

    Ladera, Celso L.; Donoso, Guillermo

    2011-01-01

    Hologram recording and holographic interferometry are intrinsically sensitive to phase changes, and therefore both are easily perturbed by minuscule optical path perturbations. It is therefore very convenient to bank on holographic setups with a reduced number of optical components. Here we present a compact off-axis holographic setup that…

  3. Transonic flow visualization using holographic interferometry

    NASA Technical Reports Server (NTRS)

    Bryanston-Cross, Peter J.

    1987-01-01

    An account is made of some of the applications of holographic interferometry to the visualization of transonic flows. In the case of the compressor shock visualization, the method is used regularly and has moved from being a research department invention to a design test tool. With the implementation of automatic processing and simple digitization systems, holographic vibrational analysis has also moved into routine nondestructive testing. The code verification interferograms were instructive, but the main turbomachinery interest is now in 3 dimensional flows. A major data interpretation effort will be required to compute tomographically the 3 dimensional flow around the leading or the trailing edges of a rotating blade row. The bolt on approach shows the potential application to current unsteady flows of interest. In particular that of the rotor passing and vortex interaction effects is experienced by the new generation of unducted fans. The turbocharger tests presents a new area for the application of holography.

  4. Study on basic problems in real-time 3D holographic display

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Liu, Juan; Wang, Yongtian; Pan, Yijie; Li, Xin

    2013-05-01

    In recent years, real-time three-dimensional (3D) holographic display has attracted more and more attentions. Since a holographic display can entirely reconstruct the wavefront of an actual 3D scene, it can provide all the depth cues for human eye's observation and perception, and it is believed to be the most promising technology for future 3D display. However, there are several unsolved basic problems for realizing large-size real-time 3D holographic display with a wide field of view. For examples, commercial pixelated spatial light modulators (SLM) always lead to zero-order intensity distortion; 3D holographic display needs a huge number of sampling points for the actual objects or scenes, resulting in enormous computational time; The size and the viewing zone of the reconstructed 3D optical image are limited by the space bandwidth product of the SLM; Noise from the coherent light source as well as from the system severely degrades the quality of the 3D image; and so on. Our work is focused on these basic problems, and some initial results are presented, including a technique derived theoretically and verified experimentally to eliminate the zero-order beam caused by a pixelated phase-only SLM; a method to enlarge the reconstructed 3D image and shorten the reconstruction distance using a concave reflecting mirror; and several algorithms to speed up the calculation of computer generated holograms (CGH) for the display.

  5. Digital three-color holographic interferometry devoted to fluid mechanics

    NASA Astrophysics Data System (ADS)

    Desse, J. M.; Picart, P.; Tankam, P.

    2010-09-01

    This paper presents work and results performed with LAUM collaboration in digital three-color holographic interferometry applied to Fluid Mechanics. In this method, three different wavelengths are used as luminous light source of the interferometer and the optical setup generates three micro interferences fringes which constitute three spatial carrier frequencies. When these images are recorded with a color sensor, the resolution of reconstructed hologram depends on the pixel size and pixel number of the sensor used for recording and also, the shape and the overlapping of three filters of color sensor influence strongly the three reconstructed images. This problem can be directly visualized in 2D Fourier planes on red, green and blue channels. To better understand this problem and to avoid parasitic images generated at the reconstruction, three different sensors have been tested : a CCD sensor equipped with a Bayer filter, a Foveon sensor and a 3CCD sensor. The best results have been obtained with the last one. In the recording principle, interference micro fringes produced by the superimposition of three reference waves and three measurement waves can be simultaneously recorded on the three spectral bands (red, green, and blue). Phase and amplitude images are computed using 2D Fourier transform in delayed time. Spectral filtering is applied on each Fourier plane in order to eliminate the parasitic diffraction orders. Then, phase differences are obtained by subtracting the reference phase to the probe phase. Several optical setups were tested and the best configuration allows the visualization of field about 70mm and increases the sensitivity since the measurement wave crosses twice the test section. Interferences induced by the wake flow have been recorded and intensities have been computed from the phase differences. Finally, one shows that fringes obtained with this process are those found with real-time color holographic interferometry using classical

  6. Status of holographic interferometry at Wright Patterson Air Force Base

    NASA Technical Reports Server (NTRS)

    Seibert, George

    1987-01-01

    At Wright Patterson AFB, holographic interferometry has been used for nearly 15 years in a variety of supersonic and hypersonic wind tunnels. Specifically, holographic interferometry was used to study boundary layers, shock boundary layer interaction, and general flow diagnostics. Although a considerable amount of quantitative work was done, the difficulty of reducing data severely restricted this. In the future, it is of interest to use holographic interferometry in conjunction with laser Doppler velocimetry to do more complete diagnostics. Also, there is an interest to do particle field diagnostics in the combustion research facility. Finally, there are efforts in nondestructive testing where automated fringe readout and analysis would be extremely helpful.

  7. Real-time contrast-enhanced holographic imaging using phase coherent photorefractive quantum wells.

    PubMed

    Dongol, A; Thompson, J; Schmitzer, H; Tierney, D; Wagner, H P

    2015-05-18

    We demonstrate wide-field real-time and depth-resolved contrast enhanced holographic imaging (CEHI) using the all-optical phase coherent photorefractive effect in ZnSe quantum wells. Moving objects are imaged at large depth-of-field by the local enhancement of a static reference hologram. The high refresh rate of the holographic films enables direct-to-video monitoring of floating glass beads and of living Paramecium and Euglena cells moving in water. Depth resolution is achieved by tilting the incident laser beam with respect to the normal of the cuvette. This creates double images of the objects, which are analyzed geometrically and with Fresnel diffraction theory. A two-color CEHI set-up further enables the visualization of a concealed 95 µm thick wire behind a thin layer of chicken skin. PMID:26074534

  8. Adaptive, spatially-varying aberration correction for real-time holographic projectors.

    PubMed

    Kaczorowski, Andrzej; Gordon, George S D; Wilkinson, Timothy D

    2016-07-11

    A method of generating an aberration- and distortion-free wide-angle holographically projected image in real time is presented. The target projector is first calibrated using an automated adaptive-optical mechanism. The calibration parameters are then fed into the hologram generation program, which applies a novel piece-wise aberration correction algorithm. The method is found to offer hologram generation times up to three orders of magnitude faster than the standard method. A projection of an aberration- and distortion-free image with a field of view of 90x45 degrees is demonstrated. The implementation on a mid-range GPU achieves high resolution at a frame rate up to 12fps. The presented methods are automated and can be performed on any holographic projector. PMID:27410846

  9. Holographic interferometry techniques using photorefractive crystals of sillenite family Bi12SiO20 (BSO) and their applications in analysis of surfaces

    NASA Astrophysics Data System (ADS)

    Gesualdi, M. R. R.; Soga, Diogo; Muramatsu, Mikiya

    2001-08-01

    The Holographic interferometry is a non-destructive testing of analysis on surfaces in basic research, technological and biomedical fields. However, the holographic interferometry techniques in real-time with conventional materials present serious difficulties. The photorefractives crystal are present as an attractive holographic recording medium. The phenomenon that characterizes these crystals in the photorefractive effect, consists of the refractive index modulation through photo-induced and linear electro-optic effect, allows the register of holograms of phase. Also it presents advantages as in situ self-proceeding of the recording medium and its indefinite reusability, i.e. it does not present fatigue. Thus, the objective of this work is the development of a holographic interferometer that uses the photorefractive crystal of the selenite family Bi12SiO20 as holographic recording medium. In this direction, we search to characterize BSO crystal determining some figures of merit in diffusive regime and drift regime. The holographic techniques of metrology are presented in three methods: real time holographic interferometry, double- exposure holographic interferometry, and time-average holographic interferometry had been studied with some applications in analysis of statics and dynamics processes on surfaces.

  10. Multi-layer holographic bifurcative neural network system for real-time adaptive EOS data analysis

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang; Huang, K.; Diep, J.

    1992-01-01

    Optical data processing techniques have the inherent advantage of high data throughout, low weight and low power requirements. These features are particularly desirable for onboard spacecraft in-situ real-time data analysis and data compression applications. The proposed multi-layer optical holographic neural net pattern recognition technique will utilize the nonlinear photorefractive devices for real-time adaptive learning to classify input data content and recognize unexpected features. Information can be stored either in analog or digital form in a nonlinear photorefractive device. The recording can be accomplished in time scales ranging from milliseconds to microseconds. When a system consisting of these devices is organized in a multi-layer structure, a feed forward neural net with bifurcating data classification capability is formed. The interdisciplinary research will involve the collaboration with top digital computer architecture experts at the University of Southern California.

  11. Multi-layer holographic bifurcative neural network system for real-time adaptive EOS data analysis

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang; Huang, K. S.; Diep, J.

    1993-01-01

    Optical data processing techniques have the inherent advantage of high data throughout, low weight and low power requirements. These features are particularly desirable for onboard spacecraft in-situ real-time data analysis and data compression applications. the proposed multi-layer optical holographic neural net pattern recognition technique will utilize the nonlinear photorefractive devices for real-time adaptive learning to classify input data content and recognize unexpected features. Information can be stored either in analog or digital form in a nonlinear photofractive device. The recording can be accomplished in time scales ranging from milliseconds to microseconds. When a system consisting of these devices is organized in a multi-layer structure, a feedforward neural net with bifurcating data classification capability is formed. The interdisciplinary research will involve the collaboration with top digital computer architecture experts at the University of Southern California.

  12. Shell deformation studies using holographic interferometry

    NASA Technical Reports Server (NTRS)

    Parmerter, R. R.

    1974-01-01

    The buckling of shallow spherical shells under pressure has been the subject of many theoretical and experimental papers. Experimental data above the theoretical buckling load of Huang have given rise to speculation that shallow shell theory may not adequately predict the stability of nonsymmetric modes in higher-rise shells which are normally classified as shallow by the Reissner criterion. This article considers holographic interferometry as a noncontact, high-resolution method of measuring prebuckling deformations. Prebuckling deformations of a lambda = 9, h/b = 0.038 shell are Fourier-analyzed. Buckling is found to occur in an N = 5 mode as predicted by Huang's theory. The N = 4 mode was unusually stable, suggesting that even at this low value of h/b, stabilizing effects may be at work.

  13. Real time chemical detection using species selective thin films and waveguide Zeeman interferometry

    SciTech Connect

    Grace, K.M.; Shrouf, K.; Honkanen, S.

    1998-12-01

    The authors present a chemical sensor scheme based on selective sensing surfaces and highly sensitive integrated optical transduction methods. Using self-assembly techniques, species selective thin-films are covalently attached to the surface of Si{sub 3}N{sub 4} channel waveguides to produce robust sensor elements. Exposure to targeted analytes results in the selective absorption of these molecules onto the waveguide surface causing a change in the effective index of the guided modes. These relative changes in effective index between TE and TM modes are precisely measured using Zeeman interferometry. Measurements demonstrate reversible, real time sensing of volatile organic compounds at ppm levels.

  14. Detection of breast lesions by holographic interferometry

    NASA Astrophysics Data System (ADS)

    Hong, HyunDae; Sheffer, Daniel B.; Loughry, C. William

    1999-07-01

    The holographic interferometry (HI) technique commonly used for nondestructive testing of laminate materials was applied to create fringe contour distortion near the site of indwelling breast lesions. For this medical imaging application, the HI technique was successful in demonstrating abnormal mechanical properties of living tissue. Adequate density and contrast of fringes, crucial factors necessary for analysis of surface deformation of an object, can be made only with an appropriate stressing method. We have applied vibration and mild pressure to the surface of female breasts for the purpose of detecting localized densities and mass alterations of the tissue, which may be indicative of an abnormality of that tissue. Even though each stressing method had both positive and negative aspects, pneumatic pressure was adopted for the present study because it was more suitable for a noninvasive and noncontact breast examination. We also developed a computer based holographic imaging system to precisely control the stressing phase for the pressure and laser triggering so the resultant holograms had manageable fringe density and repeatability.

  15. Holographic entropy and real-time dynamics of quarkonium dissociation in non-Abelian plasma

    DOE PAGESBeta

    Iatrakis, Ioannis; Kharzeev, Dmitri E.

    2016-04-26

    The peak of the heavy quark pair entropy at the deconfinement transition, observed in lattice QCD, suggests that the transition is effectively driven by the increase of the entropy of bound states. The growth of the entropy with the interquark distance leads to the emergent entropic force that induces dissociation of quarkonium states. Since the quark-gluon plasma around the transition point is a strongly coupled system, we use the gauge-gravity duality to study the entropy of heavy quarkonium and the real-time dynamics of its dissociation. In particular, we employ the improved holographic QCD model as a dual description of largemore » Nc Yang-Mills theory. Studying the dynamics of the fundamental string between the quarks placed on the boundary, we find that the entropy peaks at the transition point. We also study the real-time dynamics of the system by considering the holographic string falling in the black hole horizon where it equilibrates. As a result, in the vicinity of the deconfinement transition, the dissociation time is found to be less than a fermi, suggesting that the entropic destruction is the dominant dissociation mechanism in this temperature region.« less

  16. Holographic entropy and real-time dynamics of quarkonium dissociation in non-Abelian plasma

    NASA Astrophysics Data System (ADS)

    Iatrakis, Ioannis; Kharzeev, Dmitri E.

    2016-04-01

    The peak of the heavy quark pair entropy at the deconfinement transition, observed in lattice QCD, suggests that the transition is effectively driven by the increase of the entropy of bound states. The growth of the entropy with the interquark distance leads to the emergent entropic force that induces dissociation of quarkonium states. Since the quark-gluon plasma around the transition point is a strongly coupled system, we use the gauge-gravity duality to study the entropy of heavy quarkonium and the real-time dynamics of its dissociation. In particular, we employ the improved holographic QCD model as a dual description of large Nc Yang-Mills theory. Studying the dynamics of the fundamental string between the quarks placed on the boundary, we find that the entropy peaks at the transition point. We also study the real-time dynamics of the system by considering the holographic string falling in the black hole horizon where it equilibrates. In the vicinity of the deconfinement transition, the dissociation time is found to be less than a fermi, suggesting that the entropic destruction is the dominant dissociation mechanism in this temperature region.

  17. Demonstration of a real-time implementation of the ICVision holographic stereogram display

    NASA Astrophysics Data System (ADS)

    Kulick, Jeffrey H.; Jones, Michael W.; Nordin, Gregory P.; Lindquist, Robert G.; Kowel, Stephen T.; Thomsen, Axel

    1995-07-01

    There is increasing interest in real-time autostereoscopic 3D displays. Such systems allow 3D objects or scenes to be viewed by one or more observers with correct motion parallax without the need for glasses or other viewing aids. Potential applications of such systems include mechanical design, training and simulation, medical imaging, virtual reality, and architectural design. One approach to the development of real-time autostereoscopic display systems has been to develop real-time holographic display systems. The approach taken by most of the systems is to compute and display a number of holographic lines at one time, and then use a scanning system to replicate the images throughout the display region. The approach taken in the ICVision system being developed at the University of Alabama in Huntsville is very different. In the ICVision display, a set of discrete viewing regions called virtual viewing slits are created by the display. Each pixel is required fill every viewing slit with different image data. When the images presented in two virtual viewing slits separated by an interoccular distance are filled with stereoscopic pair images, the observer sees a 3D image. The images are computed so that a different stereo pair is presented each time the viewer moves 1 eye pupil diameter (approximately mm), thus providing a series of stereo views. Each pixel is subdivided into smaller regions, called partial pixels. Each partial pixel is filled with a diffraction grating that is just that required to fill an individual virtual viewing slit. The sum of all the partial pixels in a pixel then fill all the virtual viewing slits. The final version of the ICVision system will form diffraction gratings in a liquid crystal layer on the surface of VLSI chips in real time. Processors embedded in the VLSI chips will compute the display in real- time. In the current version of the system, a commercial AMLCD is sandwiched with a diffraction grating array. This paper will discuss

  18. Speckle reference beam holographic and speckle photographic interferometry in non-destructive test systems

    NASA Technical Reports Server (NTRS)

    Liu, H. K.

    1976-01-01

    The techniques of speckle beam holographic interferometry and speckle photographic interferometry are described. In particular, their practical limitations and their applications to the existing holographic nondestructive test system are discussed.

  19. Evaluation by holographic interferometry of impact damage in composite aeronautical structures

    NASA Astrophysics Data System (ADS)

    Ferraro, Pietro

    1992-01-01

    The results of an experimental study of holographic interferometry for impact damage detection and evaluation, in composite aeronautical sandwich structures is presented. The results show that holographic interferometry using thermal loading can accurately estimate delaminated areas on test samples in respect to ultrasonic inspection. The capability of holographic interferometry for detection of such damages in large composite components is shown also.

  20. Digital holographic microscopy real-time monitoring of cytoarchitectural alterations during simulated microgravity

    NASA Astrophysics Data System (ADS)

    Pache, Christophe; Kühn, Jonas; Westphal, Kriss; Toy, M. Fatih; Parent, Jérôme; Büchi, Oralea; Franco-Obregón, Alfredo; Depeursinge, Christian; Egli, Marcel

    2010-03-01

    Previous investigations on mammalian cells have shown that microgravity, either that experienced in space, or simulated on earth, causes severe cellular modifications that compromise tissue determination and function. The aim of this study is to investigate, in real time, the morphological changes undergone by cells experiencing simulated microgravity by using digital holographic microscopy (DHM). DHM analysis of living mouse myoblasts (C2C12) is undertaken under simulated microgravity with a random positioning machine. The DHM analysis reveals cytoskeletal alterations similar to those previously reported with conventional methods, and in agreement with conventional brightfield fluorescence microscopy a posteriori investigation. Indeed, DHM is shown to be able to noninvasively and quantitatively detect changes in actin reticular formation, as well as actin distribution, in living unstained samples. Such results were previously only obtainable with the use of labeled probes in conjunction with conventional fluorescence microscopy, with all the classically described limitations in terms of bias, bleaching, and temporal resolution.

  1. Instrument Development of Real Time Holographic Water Drop Size Measurement System

    SciTech Connect

    Springston, Stephen

    2007-02-09

    BNL participated with multiple correspondences with Physical Optics Corporation (POC) on the design considerations of an airbome instrument. A pod for extemal deployment ofthe POC unit on the DOE Research Aircraft Facility (RAF), an instrumented, Grumman G-1 aircraft was loaned to POC. BNL proposed evaluation flight tests between the POC unit and the BNL Cloud Aerosol Probe Spectrometer (CAPS) as a reference method. BNL's involvement is described in the semi-annual report ofPOC to DOE. Because of unanticipated technical and engineering difficulties, POC was unable to fit their instrument into an aircraft pod. As a result they are now focusing on a ground-based version first. A prototype laboratory version of the Real-Time Holographic Water Drop Size Measurement (WDSM) System has been constructed.

  2. Digital holographic microscopy real-time monitoring of cytoarchitectural alterations during simulated microgravity.

    PubMed

    Pache, Christophe; Kühn, Jonas; Westphal, Kriss; Toy, M Fatih; Parent, Jéro Me; Büchi, Oralea; Franco-Obregón, Alfredo; Depeursinge, Christian; Egli, Marcel

    2010-01-01

    Previous investigations on mammalian cells have shown that microgravity, either that experienced in space, or simulated on earth, causes severe cellular modifications that compromise tissue determination and function. The aim of this study is to investigate, in real time, the morphological changes undergone by cells experiencing simulated microgravity by using digital holographic microscopy (DHM). DHM analysis of living mouse myoblasts (C2C12) is undertaken under simulated microgravity with a random positioning machine. The DHM analysis reveals cytoskeletal alterations similar to those previously reported with conventional methods, and in agreement with conventional brightfield fluorescence microscopy a posteriori investigation. Indeed, DHM is shown to be able to noninvasively and quantitatively detect changes in actin reticular formation, as well as actin distribution, in living unstained samples. Such results were previously only obtainable with the use of labeled probes in conjunction with conventional fluorescence microscopy, with all the classically described limitations in terms of bias, bleaching, and temporal resolution. PMID:20459266

  3. A Phase Locked High Speed Real-Time Interferometry System for Large Amplitude Unsteady Flows

    NASA Technical Reports Server (NTRS)

    Chandrasekhara, M. S.; Squires, D. D.; Wilder, M. C.; Carr, L. W.; Kutler, Paul (Technical Monitor)

    1994-01-01

    A high speed phase locked interferometry system has been designed and developed for real-time measurements of the dynamic stall flow over a pitching airfoil. Point diffraction interferograms of incipient flow separation over a sinusoidally oscillating airfoil have been obtained at rates of up to 20 KHz and for free stream Mach numbers of 0.3 and 0.45. The images were recorded on ASA 125 and ASA 400 film using a drum camera. Special electronic timing and synchronizing circuits were developed to trigger the laser light source from the camera, and to initiate acquisition of the interferogram sequence from any desired phase angle of oscillation. The airfoil instantaneous angle of attack data provided by an optical encoder was recorded via a FIFO and in EPROM into a microcomputer. The interferograms have been analyzed using software developed in-house to get quantitative flow density and pressure distributions.

  4. Real-time, auto-focusing digital holographic microscope using graphics processors.

    PubMed

    Doğar, Mert; İlhan, Hazar A; Özcan, Meriç

    2013-08-01

    The most significant advantage of holographic imaging is that one does not need to do focusing alignment for the scene or objects while capturing their images. To focus on a particular object recorded in a digital hologram, a post-processing on the recorded image must be performed. This post-processing, so called the reconstruction, is essentially the calculation of wave propagation in free space. If the object's optical distance to the recording plane is not known a priori, focusing methods are used to estimate this distance. However, these operations can be quite time consuming as the hologram sizes increase. When there is a time constraint on these procedures and the image resolution is high, traditional central processing units (CPUs) can no longer satisfy the desired reconstruction speeds. Then, especially for real-time operations, additional hardware accelerators are required for reconstructing high resolution holograms. To this extend, today's commercial graphic cards offer a viable solution, as the holograms can be reconstructed tens of times faster with a graphics processing unit than with the state-of-the-art CPUs. Here we present an auto-focusing megapixel-resolution digital holographic microscope (DHM) that uses a graphics processing unit (GPU) as the calculation engine. The computational power of the GPU allows the DHM to work in real-time such that the reconstruction distance is estimated unsupervised, and the post-processing of the holograms are made completely transparent to the user. We compare DHM with GPU and CPU and present experimental results showing a maximum of 70 focused reconstructions per second (frps) with 1024 × 1024 pixel holograms. PMID:24007070

  5. Real-time, auto-focusing digital holographic microscope using graphics processors

    NASA Astrophysics Data System (ADS)

    Doğar, Mert; İlhan, Hazar A.; Özcan, Meriç

    2013-08-01

    The most significant advantage of holographic imaging is that one does not need to do focusing alignment for the scene or objects while capturing their images. To focus on a particular object recorded in a digital hologram, a post-processing on the recorded image must be performed. This post-processing, so called the reconstruction, is essentially the calculation of wave propagation in free space. If the object's optical distance to the recording plane is not known a priori, focusing methods are used to estimate this distance. However, these operations can be quite time consuming as the hologram sizes increase. When there is a time constraint on these procedures and the image resolution is high, traditional central processing units (CPUs) can no longer satisfy the desired reconstruction speeds. Then, especially for real-time operations, additional hardware accelerators are required for reconstructing high resolution holograms. To this extend, today's commercial graphic cards offer a viable solution, as the holograms can be reconstructed tens of times faster with a graphics processing unit than with the state-of-the-art CPUs. Here we present an auto-focusing megapixel-resolution digital holographic microscope (DHM) that uses a graphics processing unit (GPU) as the calculation engine. The computational power of the GPU allows the DHM to work in real-time such that the reconstruction distance is estimated unsupervised, and the post-processing of the holograms are made completely transparent to the user. We compare DHM with GPU and CPU and present experimental results showing a maximum of 70 focused reconstructions per second (frps) with 1024 × 1024 pixel holograms.

  6. Real-time photodisplacement imaging using parallel excitation and parallel heterodyne interferometry

    NASA Astrophysics Data System (ADS)

    Nakata, Toshihiko; Ninomiya, Takanori

    2005-05-01

    A parallel photodisplacement technique that achieves real-time imaging of subsurface structures is presented. In this technique, a linear region of photothermal displacement is excited by a line-focused intensity-modulated laser beam and detected with a parallel heterodyne interferometer using a charge-coupled device linear image sensor as a detector. Because of integration and sampling effects of the sensor, the interference light is spatiotemporally multiplexed. To extract the spatially resolved photodisplacement component from the sensor signal, a scheme of phase-shifting light integration combined with a Fourier analysis technique is developed for parallel interferometry. The frequencies of several control signals, including the heterodyne beat signal, modulation signal, and sensor gate signal, are optimized so as to eliminate undesirable components, allowing only the displacement component to be extracted. Two-dimensional subsurface lattice defects in silicon are clearly imaged at a remarkable speed of only 0.26s for an area of 256×256pixels. Thus, the proposed technique allows for real-time imaging more than 10 000 times faster than conventional photoacoustic microscopy.

  7. Determination of Young's modulus of silica aerogels using holographic interferometry

    NASA Astrophysics Data System (ADS)

    Chikode, Prashant P.; Sabale, Sandip R.; Vhatkar, Rajiv S.

    2016-05-01

    Digital holographic interferometry technique is used to determine elastic modulus of silica aerogels. Tetramethoxysilane precursor based Silica aerogels were prepared by the sol-gel process followed by supercritical methanol drying. The alcogels were prepared by keeping the molar ratio of tetramethoxysilane: methyltrimethoxysilane: H2O constant at 1:0.6:4 while the methanol / tetramethoxysilane molar ratio (M) was varied systematically from 12 to 18. Holograms of translucent aerogel samples have been successfully recorded using the digital holographic interferometry technique. Stimulated digital interferograms gives localization of interference fringes on the aerogel surface and these fringes are used to determine the surface deformation and Young's modulus (Y) of the aerogels.

  8. Monitoring of residual stresses in injection-molded plastics with holographic interferometry

    NASA Astrophysics Data System (ADS)

    Sanchez, Lilia A.; Hornberger, Lee E.

    2002-01-01

    Residual stresses are often trapped in injection-molded plastic parts due to the rapid cooling of the material in this manufacturing process. These stresses are a common source of failure in plastic components in automobiles, appliances and computers and are difficult to measure with conventional residual-stress experimental methods. Real-time holographic interferometry appears to be a viable technique to identify and monitor these stresses in plastic parts. In this investigation, holographic interferometry was used to monitor the relaxation of residual stresses in the plastic-molded actuator arm of a computer hard drive. In the first phase of this study, the relaxation of these residual stresses as a function of temperature was observed. In the second phase, the time to completely relax the residual stresses in the plastic part at an elevated temperature, the annealing temperature, was determined. In the third phase of this investigation, the rate of relaxation of these residual stresses as a function of time at various operating temperatures, was studied. Based on the results of this study, holographic interferometry appears to be a powerful research tool in the study of residual stresses in plastic parts. It also has the potential to be a practical tool for the inspection of manufactured plastic parts for the presence of residual stress.

  9. Application of holographic interferometry for dynamic vibration analysis of a jet engine turbine compressor rotor

    NASA Astrophysics Data System (ADS)

    Fein, Howard

    2003-05-01

    Holographic Interferometry has been successfully employed to characterize the materials and behavior of diverse types of structures under dynamic stress 1,2,3,4. Specialized variations of this technology have also been applied to define dynamic and vibration related structural behavior 5. Such applications of holographic technique offer some of the most effective methods of modal and dynamic analysis available. Real-time dynamic testing of the modal and mechanical behavior of jet engine turbine, rotor, vane, and compressor structures has always required advanced instrumentation for data collection in either simulated flight operation test or computer-based modeling and simulations. Advanced optical holography techniques are alternate methods which result in actual full-field behavioral data in a noninvasive, noncontact environment 6. These methods offer significant insight in both the development and subsequent operational test and modeling of advanced jet engine turbine and compressor rotor structures and their integration with total vehicle system dynamics. Structures and materials can be analyzed with very low amplitude excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural and behavioral models. Holographic Interferometry offers a powerful tool to aid in the developmental engineering of turbine rotor and compressor structures for high stress applications. Aircraft engine applications in particular must consider operational environments where extremes in vibration and impulsive as well as continuous mechanical stress can affect both operation and structural stability. These considerations present ideal requisites for analysis using advanced holographic methods in the initial design and test of turbine rotor components. Holographic techniques are nondestructive, real-time, and definitive in allowing the identification of vibrational modes, displacements, and motion geometries. Such information can be crucial to

  10. An application of holographic interferometry for dynamic vibration analysis of a jet engine turbine compressor rotor

    NASA Astrophysics Data System (ADS)

    Fein, Howard

    2003-09-01

    Holographic Interferometry has been successfully employed to characterize the materials and behavior of diverse types of structures under dynamic stress. Specialized variations of this technology have also been applied to define dynamic and vibration related structural behavior. Such applications of holographic technique offer some of the most effective methods of modal and dynamic analysis available. Real-time dynamic testing of the modal and mechanical behavior of jet engine turbine, rotor, vane, and compressor structures has always required advanced instrumentation for data collection in either simulated flight operation test or computer-based modeling and simulations. Advanced optical holography techniques are alternate methods which result in actual full-field behavioral data in a noninvasive, noncontact environment. These methods offer significant insight in both the development and subsequent operational test and modeling of advanced jet engine turbine and compressor rotor structures and their integration with total vehicle system dynamics. Structures and materials can be analyzed with very low amplitude excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural and behavioral models. Holographic Interferometry offers a powerful tool to aid in the developmental engineering of turbine rotor and compressor structures for high stress applications. Aircraft engine applications in particular most consider operational environments where extremes in vibration and impulsive as well as continuous mechanical stress can affect both operation and structural stability. These considerations present ideal requisites for analysis using advanced holographic methods in the initial design and test of turbine rotor components. Holographic techniques are nondestructive, real-time, and definitive in allowing the identification of vibrational modes, displacements, and motion geometries. Such information can be crucial to the

  11. Digital holographic interferometry for measurement of temperature in axisymmetric flames.

    PubMed

    Sharma, Shobhna; Sheoran, Gyanendra; Shakher, Chandra

    2012-06-01

    In this paper, experimental investigations and analysis is presented to measure the temperature and temperature profile of gaseous flames using lensless Fourier transform digital holographic interferometry. The evaluations of the experimental results give the accuracy, sensitivity, spatial resolution, and range of measurements to be well within the experimental limits. Details of the experimental results and analysis are presented. PMID:22695554

  12. Determination of use of a real time tone tracker to obtain same beam interferometry data

    NASA Technical Reports Server (NTRS)

    Nandi, S.; Border, J. S.; Folkner, W. M.

    1993-01-01

    The radio metric tracking technique known as Same-Beam Interferometry (SBI) has been shown to improve orbit determination accuracy for the Magellan and Pioneer 12 orbiter. Previous efforts to explore the technique were carried out by making open loop recordings of the carrier signals from the two spacecraft and extracting their phases through post processing. This paper reports on the use of a closed loop receiver to simultaneously measure the carrier signals from two spacecraft in order to produce SBI data in near real time. The Experiment Tone Tracker is a digital closed loop receiver installed in two of NASA's Deep Space Network stations which can simultaneously extract the phase of up to eight tones. The receivers were used in late September and October of 1992 to collect Doppler and SBI data from Pioneer 12 and Magellan. The demise of the Pionner 12 on October 8th during the start-up phase of our tests precluded the collection of an extensive set of SBI data, however two passes of SBI and several arcs of single spacecraft Doppler data were recorded. The SBI data were analyzed and determined to have statistical errors consistent with error models and similar to open loop data.

  13. Holographic Interferometry--A Laboratory Experiment.

    ERIC Educational Resources Information Center

    de Frutos, A. M.; de la Rosa, M. I.

    1988-01-01

    Explains the problem of analyzing a phase object, separating the contribution due to thickness variations and that due to refractive index variations. Discusses the design of an interferometer and some applications. Provides diagrams and pictures of holographic images. (YP)

  14. Level of holographic noise in interferometry

    NASA Astrophysics Data System (ADS)

    Smolyaninov, Igor I.

    2009-04-01

    The level of holographic noise expected to be observed in interferometric gravitational wave detectors such as GEO600 is reexamined. It is demonstrated that earlier estimates are based on assumed linear diffractive behavior of Planck radiation. Since nonlinear effects, such as self-focusing, are expected to appear at much lower energies, the expected level of holographic noise must be reduced by many orders of magnitude.

  15. Holographic Interferometry Applied At Subfreezing Temperatures: Study Of Damage In Concrete Exposed To Frost Action

    NASA Astrophysics Data System (ADS)

    Rastogi, Pramod K.; Jacquot, Pierre; Pflug, Leopold

    1988-02-01

    The aim of this research is to use holographic interferometry to evaluate the frost susceptibility of concrete. Concrete specimens are subjected to subzero temperatures inside a freezing cabinet. A holographic system is implanted astride both the interior and exterior of the cabinet. Problems related to the implementation of such a measurement system are discussed, and ways to overcome them are described. A fringe control capability eliminates the influence of rigid-body movements and controls the fringe density. The developed system enables one to monitor in real time the evolution of the deformation of concrete specimens exposed to freezing cycles. Besides demonstrating the existence of stresses arising from the thermal incompatibility between the components of the concrete, the method provides an accurate measurement of the temperature at which this thermal incompatibility leads to the impairment of the hardened concrete paste. Results computed from the application of a mathematical model are compared with those obtained by holographic interferometry. Close agreement between the numerically computed and the experimentally observed behavior is obtained.

  16. Development of real time digital holographic microscope for cell flow interactions using a High Performance Computing (HPC) cluster

    NASA Astrophysics Data System (ADS)

    Hojjati, Avesta; Molaei, Mehdi; Sheng, Jian

    2013-11-01

    Real-time imaging and analysis of 3D cell migration and locomotion is crucial to understand the underlying physics of cell environment interactions. In addition, such a microscopy would provide vital diagnostic capability in cell detection, particle sorting and drug screening with large throughput. However, 3D holographic imaging and subsequent analysis are computational intensive and up-to-date prohibitive for real-time applications. With the advances in high performance computing, we are developing a real-time digital holographic microscope (DHM) that includes an in-line DHM, a large format CCD camera, and a 24-node windows-based HPC cluster. The cluster is organized as the master-slave parallel computing paradigm with Message Passing Interface (MPI) as its communication protocol. The holograms are recorded, streamed and analyzed by the HPC cluster in real time, the 3D distributions and in focus images are rendered back on the data acquisition computer. The system will be applied to study marine protest interacting with oil droplets. Supports from GoMRI are acknowledged.

  17. Thermal stress studies using optical holographic interferometry

    NASA Technical Reports Server (NTRS)

    Harris, W. J.; Woods, D. C.

    1974-01-01

    The application of holography to thermal stress studies is discussed. Interference fringes as produced by holograms and their interpretation are reviewed in relation to workpiece displacement. Three potential mechanisms are given to explain thermal displacement as detected by holographic methods. Results of some thermal stressing studies are reported, including tests on a live rocket motor.

  18. Magnetostriction Measured by Holographic Interferometry with the Simple and Inexpensive "Arrowhead" Setup

    ERIC Educational Resources Information Center

    Ladera, Celso L.; Donoso, Guillermo; Contreras, Johnny H.

    2012-01-01

    Double-exposure holographic interferometry is applied to measure the "linear" or "longitudinal" magnetostriction constant of a soft-ferrite rod. This high-accuracy measurement is done indirectly, by measuring the small rotations of a lever in contact with the rod using double-exposure holographic interferometry implemented with a robust…

  19. Electronic speckle pattern interferometry and digital holographic interferometry with microbolometer arrays at 10.6 {mu}m

    SciTech Connect

    Vandenrijt, Jean-Francois; Georges, Marc P.

    2010-09-20

    Electronic speckle pattern interferometry and digital holographic interferometry are investigated at long infrared wavelengths. Using such wavelengths allows one to extend the measurement range and decrease the sensitivity of the techniques to external perturbations. We discuss the behavior of reflection by the object surfaces due to the long wavelength. We have developed different experimental configurations associating a CO2 laser emitting at 10.6{mu}m and microbolometer arrays. Phase-shifting in-plane and out-of-plane electronic speckle pattern interferometry and lensless digital holographic interferometry are demonstrated on rotation measurements of a solid object.

  20. Real-time holographic gratings modulate with voltage by different thickness film

    NASA Astrophysics Data System (ADS)

    Fontanilla-Urdaneta, Rosangela C.; Olivares-Pérez, Arturo; Fuentes-Tapia, Israel

    2011-04-01

    The holographic gratings on photopolymer films are studied by three different thicknesses for samples A, B, and C. The photopolymer emulsion is prepared with potassium dichromate and nickel (II) chloride hexahydrate in polyvinyl alcohol matrix. The evolution of diffraction efficiency is evaluated during holographic recording with and without voltage as a function of energy exposure by changing the thickness. The curves of diffraction efficiency reach a peak when the films are continuously exposed to energy for a period of time. Sample B obtains the highest diffraction efficiency

  1. Holographic interferometry with additional shadowgraph visualization

    NASA Astrophysics Data System (ADS)

    Kleine, Harald; Takayama, Kazuyoshi

    2001-05-01

    This paper describes the development of an optical system that can simultaneously generate an interferogram and a shadowgraph of a refractive index field (in this case, a compressible fluid flow). Such a combination allows one to record both the density and its second derivative OF THE SAME OBJECT AT THE SAME TIME. This can be achieved by splitting the object beam of a holographic interferometer before superimposing it with the reference beam. One half of this beam forms the hologram together with the reference beam, while the other is led into an imaging unit that generates an image of a plane that is located either before or behind the test object (the so-called shadow plane). This arrangement allows one to generate simultaneously two pictures, which provide more reliable quantitative and qualitative data about the investigated flow than each of the visualizations alone.

  2. Phenol adsorption using holographic interferometry in photorefractive crystals

    NASA Astrophysics Data System (ADS)

    Kurzeluk, Mona; Guzun, Anicuta; Petris, Adrian; Vlad, Valentin I.

    2001-06-01

    Phenol is a major pollutant under strict effluent restriction. Its toxicity is well known, both in aquatic environment and human health. Among the purification technologies, adsorption is widely used in ecological procedures for chemical industry, for water and air purification. In order to check up the adsorbent properties of different adsorbent materials, it is necessary to determine some modeling parameters as the diffusion constants and concentration profiles in the vicinity of the adsorbent. The visualization and measuring method used in this work is double-exposure holographic interferometry using a Bi12TiO20 (BTO) photorefractive crystal (PRC) as reusable recording material and a low cost laser diode, as coherent light source. By holographic methods, we are studying phenol adsorption on granulated active coal and active coal powder. The visualization of the diffusion layer and measurements of its dynamics have been performed.

  3. Computational hologram synthesis and representation on spatial light modulators for real-time 3D holographic imaging

    NASA Astrophysics Data System (ADS)

    Reichelt, Stephan; Leister, Norbert

    2013-02-01

    In dynamic computer-generated holography that utilizes spatial light modulators, both hologram synthesis and hologram representation are essential in terms of fast computation and high reconstruction quality. For hologram synthesis, i.e. the computation step, Fresnel transform based or point-source based raytracing methods can be applied. In the encoding step, the complex wave-field has to be optimally represented by the SLM with its given modulation capability. For proper hologram reconstruction that implies a simultaneous and independent amplitude and phase modulation of the input wave-field by the SLM. In this paper, we discuss full complex hologram representation methods on SLMs by considering inherent SLM parameter such as modulation type and bit depth on their reconstruction performance such as diffraction efficiency and SNR. We review the three implementation schemes of Burckhardt amplitude-only representation, phase-only macro-pixel representation, and two-phase interference representation. Besides the optical performance we address their hardware complexity and required computational load. Finally, we experimentally demonstrate holographic reconstructions of different representation schemes as obtained by functional prototypes utilizing SeeReal's viewing-window holographic display technology. The proposed hardware implementations enable a fast encoding of complex-valued hologram data and thus will pave the way for commercial real-time holographic 3D imaging in the near future.

  4. Real-time slope mapping and defect detection in bent plates using Talbot interferometry

    SciTech Connect

    Trivedi, Satya Prakash; Prakash, Shashi; Rana, Santosh; Sasaki, Osami

    2010-02-10

    We demonstrate a simple method for obtaining slope contours of bent plates using Talbot interferometry. The technique has been used to map slope contours of polymethyl methacrylate specimens of different shapes. The Talbot image of a coarse grating is projected onto a specimen such that the self-image is backreflected onto the same grating again. As a Talbot interferometer is basically a grating shearing interferometer, it results in the generation of characteristic slope maps of the specimen under test. Results of the investigation match well with other slope-mapping techniques. Validation of experimental results with theoretical predictions in the case of a cantilever beam specimen has been undertaken. Accuracy of about 4.7% with respect to theoretical predictions is obtained.

  5. Real-time characterization of the neuronal response to osmotic shock by digital holographic microscopy

    NASA Astrophysics Data System (ADS)

    Gomariz, Maria; Garcia, Isabel; Soto-Sánchez, Cristina; Martínez-Navarrete, Gema; Fernández, Eduardo; Fimia, Antonio

    2015-05-01

    Digital holographic microscopy has numerous applications in biology for visualizing living cells and 3D tissues. This technique allows for the direct visualization of biological structures avoiding invasive and phototoxic procedures such as fixation and dying processing. In this study we have characterized the morphometry changes of neurons subject to osmolarity changes. For this purpose, we have measured the variations of the amplitude and the oscillation frequency of the plasmatic membrane, as well as the volume changes of the cells before the osmotic shock. There was a relation between the neural culture ageing and its behavioral changes. "Long-term" cultures that had not previously been studied were used to analyze the behavioral changes in aged cells.

  6. Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration.

    PubMed

    Brandi, F; Giammanco, F; Conti, F; Sylla, F; Lambert, G; Gizzi, L A

    2016-08-01

    The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 10(19) cm(-3) range well suited for LWFA. PMID:27587174

  7. Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Brandi, F.; Giammanco, F.; Conti, F.; Sylla, F.; Lambert, G.; Gizzi, L. A.

    2016-08-01

    The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 1019 cm-3 range well suited for LWFA.

  8. Beam-modulation methods in quantitative and flow visualization holographic interferometry

    NASA Technical Reports Server (NTRS)

    Decker, A.

    1986-01-01

    This report discusses heterodyne holographic interferometry and time-average holography with a frequency shifted reference beam. Both methods will be used for the measurement and visualization of internal transonic flows, where the target facility is a flutter cascade. The background and experimental requirements for both methods are reviewed. Measurements using heterodyne holographic interferometry are presented. The performance of the laser required for time-average holography of time-varying transonic flows is discussed.

  9. Beam-modulation methods in quantitative and flow-visualization holographic interferometry

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.

    1986-01-01

    Heterodyne holographic interferometry and time-average holography with a frequency shifted reference beam are discussed. Both methods will be used for the measurement and visualization of internal transonic flows where the target facility is a flutter cascade. The background and experimental requirements for both methods are reviewed. Measurements using heterodyne holographic interferometry are presented. The performance of the laser required for time-average holography of time-varying transonic flows is discussed.

  10. Real-time optical fiber digital speckle pattern interferometry for industrial applications

    NASA Astrophysics Data System (ADS)

    Chan, Robert K.; Cheung, Y. M.; Lo, C. H.; Tam, T. K.

    1997-03-01

    There is current interest, especially in the industrial sector, to use the digital speckle pattern interferometry (DSPI) technique to measure surface stress. Indeed, many publications in the subject are evident of the growing interests in the field. However, to bring the technology to industrial use requires the integration of several emerging technologies, viz. optics, feedback control, electronics, imaging processing and digital signal processing. Due to the highly interdisciplinary nature of the technique, successful implementation and development require expertise in all of the fields. At Baptist University, under the funding of a major industrial grant, we are developing the technology for the industrial sector. Our system fully exploits optical fibers and diode lasers in the design to enable practical and rugged systems suited for industrial applications. Besides the development in optics, we have broken away from the reliance of a microcomputer PC platform for both image capture and processing, and have developed a digital signal processing array system that can handle simultaneous and independent image capture/processing with feedback control. The system, named CASPA for 'cascadable architecture signal processing array,' is a third generation development system that utilizes up to 7 digital signal processors has proved to be a very powerful system. With our CASPA we are now in a better position to developing novel optical measurement systems for industrial application that may require different measurement systems to operate concurrently and requiring information exchange between the systems. Applications in mind such as simultaneous in-plane and out-of-plane DSPI image capture/process, vibrational analysis with interactive DSPI and phase shifting control of optical systems are a few good examples of the potentials.

  11. Visualization of thermal behavior of fluid by laser holographic interferometry

    NASA Astrophysics Data System (ADS)

    Kurosaki, Y.; Kashiwagi, T.

    1990-01-01

    Visualization of four phenomena associated with thermal and fluid flow fields effectively using laser holographic interferometry are reviewed: airflow in a narrow passage between louver arrays, steam absorption into an aqueous solution of LiBr, Marangoni convection effect of steam absorption into a solution with the addition of high molecular weight alcohol, and pressure distribution on a plate induced by air-jet impingement. The observation result obtained in the first case is useful for designing louvered fins used in a heat exchanger. In the second case, the mass diffusivity of water into a solution of LiBr is shown to be measurable. In the third case, the effect of Marangoni convection on steam absorption is both qualitatively and quantitatively elucidated. The last case is a new visualization method of fluctuating pressure on a wall that can be used to resolve eddy-motion behavior near a wall.

  12. A real-time interferometer technique for compressible flow research

    NASA Technical Reports Server (NTRS)

    Bachalo, W. D.; Houser, M. J.

    1984-01-01

    Strengths and shortcomings in the application of interferometric techniques to transonic flow fields are examined and an improved method is elaborated. Such applications have demonstrated the value of interferometry in obtaining data for compressible flow research. With holographic techniques, interferometry may be applied in large scale facilities without the use of expensive optics or elaborate vibration isolation equipment. Results obtained using holographic interferometry and other methods demonstrate that reliable qualitative and quantitative data can be acquired. Nevertheless, the conventional method can be difficult to set up and apply, and it cannot produce real-time data. A new interferometry technique is investigated that promises to be easier to apply and can provide real-time information. This single-beam technique has the necessary insensitivity to vibration for large scale wind tunnel operations. Capabilities of the method and preliminary tests on some laboratory scale flow fluids are described.

  13. Measurements of the tympanic membrane with digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Muñoz Solís, S.; Mendoza Santoyo, F.; Del Socorro Hernández-Montes, M.

    2011-08-01

    In this paper a digital holographic interferometry (DHI) system with three object-illumination beams is used for the first time to detect and measure micrometer deformations on the surface of a tympanic membrane. Using this optical setup allows all three object displacement components x, y, and z, to be independently calculated. The corresponding deformations are registered using a cw laser in stroboscopic mode and a CCD camera synchronized to the excitation acoustic wave that produces a resonant vibration mode on the tympanic membrane surface. A series of digital holographic interferograms record the displacements undergone by the tympanic membrane and from them full field deformation phase maps are obtained. From the latter it is possible to observe the displacement of the tympanic membrane in response to the sound pressure. The study was performed on the tympanic membrane taken from a post-mortem cat. The results show the feasibility to apply a similar optomechanical arrangement for the study in humans, representing an alternative technique for the study of pathologies in the tympanic membrane.

  14. Digital holographic microscopy long-term and real-time monitoring of cell division and changes under simulated zero gravity.

    PubMed

    Pan, Feng; Liu, Shuo; Wang, Zhe; Shang, Peng; Xiao, Wen

    2012-05-01

    The long-term and real-time monitoring the cell division and changes of osteoblasts under simulated zero gravity condition were succeed by combing a digital holographic microscopy (DHM) with a superconducting magnet (SM). The SM could generate different magnetic force fields in a cylindrical cavity, where the gravitational force of biological samples could be canceled at a special gravity position by a high magnetic force. Therefore the specimens were levitated and in a simulated zero gravity environment. The DHM was modified to fit with SM by using single mode optical fibers and a vertically-configured jig designed to hold specimens and integrate optical device in the magnet's bore. The results presented the first-phase images of living cells undergoing dynamic divisions and changes under simulated zero gravity environment for a period of 10 hours. The experiments demonstrated that the SM-compatible DHM setup could provide a highly efficient and versatile method for research on the effects of microgravity on biological samples. PMID:22565769

  15. Panoramic Imaging and Holographic Interferometry Using a Panoramic Annular Lens.

    NASA Astrophysics Data System (ADS)

    Puliparambil, Joseph Thomas

    1992-01-01

    Ideally, a device for making measurements of the inner surface of a cavity should be rugged, compact, and capable of obtaining an unobstructed, complete, and comprehensive image of the cavity space in every direction. The first attempt to patent a system for panoramic imaging was made by Mangin in 1878 and since that time several other devices have been patented. Most of these devices depend on a scanning system or on a complex set of lenses and mirrors and as such they are not very practical for use. However, in 1984 Dr. Pal Greguss invented a simple lens known as a Panoramic Annular Lens (PAL) capable of giving a full 360 degree surround image of the area around the lens. This lens can be utilized along with digital cameras and computer programs to inspect and measure the interior walls of cavities. If a cavity can be regarded as a cylindrical rather than a spherical volume, the image information can be transformed, using stretching methods, onto a flat surface creating a two-dimensional representation of a three-dimensional cylindrical surface. This phenomenon called Flat Cylindrical Perspective (FCP) forms the basis for the image produced by a PAL. To apply standard methods of analysis on an image and also for visual interpretation, image processing algorithms were developed to linearize a PAL image. These programs can be used for endoscopy which is a technique for imaging the inner part of a volume or cavity. Such techniques have applications in the fields of medicine, civil engineering and aerospace; indeed, anywhere tubes and pipes are involved. Holographic interferometry has become an important diagnostic tool in non-destructive testing, but due to lack of panoramic imaging systems this work could not be effectively used for the analysis of cavities. Now, the PAL can be used for panoramic holographic interferometry which can be used to measure submicron deformations of cavity walls caused by small perturbations in temperature, pressured and mechanical loads

  16. Signal tracking approach for phase estimation in digital holographic interferometry.

    PubMed

    Waghmare, Rahul G; Mishra, Deepak; Sai Subrahmanyam, G R K; Banoth, Earu; Gorthi, Sai Siva

    2014-07-01

    In this research work, we introduce a novel approach for phase estimation from noisy reconstructed interference fields in digital holographic interferometry using an unscented Kalman filter. Unlike conventionally used unwrapping algorithms and piecewise polynomial approximation approaches, this paper proposes, for the first time to the best of our knowledge, a signal tracking approach for phase estimation. The state space model derived in this approach is inspired from the Taylor series expansion of the phase function as the process model, and polar to Cartesian conversion as the measurement model. We have characterized our approach by simulations and validated the performance on experimental data (holograms) recorded under various practical conditions. Our study reveals that the proposed approach, when compared with various phase estimation methods available in the literature, outperforms at lower SNR values (i.e., especially in the range 0-20 dB). It is demonstrated with experimental data as well that the proposed approach is a better choice for estimating rapidly varying phase with high dynamic range and noise. PMID:25089973

  17. Feasibility study of three-dimensional holographic interferometry for aerodynamics

    NASA Technical Reports Server (NTRS)

    Craig, J. E.

    1983-01-01

    Laser holographic interferometry was tried as a nonintrusive diagnostic tool for studying unsteady two dimensional flows. A NACA 0012 airfoil was tested, while undergoing dynamic stall, over a range of Mach numbers of 0.3 to 0.5, Reynolds number of 0.5 x 10 to the 6th power to 2 x 10 to the 6th power, and at reduced frequencies of 0.015 to 0.15. It was found that both quantitative and qualitative data could be obtained by the technique. Surface pressures on the airfoil can be measured to within 1% of those measured with orifices and pressure transducers when the flow is attached. Velocity profiles were measured near the wake region, and they compared very well with laser velocimeter data for attached flows. For separated flows with large scale vortices, densities can be measured, but pressures and velocities cannot be deduced with the assumption of constant pressure gradient in the normal direction. The sensitivity of the interferograms was good at a Mach number of 0.4 and a Reynolds number of 4 x 10 to the 6th power/ft; the sensitivity worsened at smaller Mach numbers and Reynolds numbers, and improved at larger ones.

  18. Modulated photoactivation of composite restoration: measurement of cuspal movement using holographic interferometry.

    PubMed

    Blažić, Larisa; Pantelić, Dejan; Savić-Šević, Svetlana; Murić, Branka; Belić, Ilija; Panić, Bratimir

    2011-03-01

    The purpose of this research was to investigate the influence of modulated photoactivation on cuspal movement. Eight class II MOD composite restorations were analyzed under various photoactivation protocols in a real-time manner using holographic interferometry. During the first photoactivation protocol, the composite restoration was illuminated for 200 s continuously. In the second protocol, the polymerization lamp was first turned on for 5 s, then turned off for 120 s, and again turned on for a final 195 s. In both protocols, radiant exposure was the same. A significant decrease (p < 0.05) in cuspal deflection was found for two-step irradiation (average value of total cuspal deflection was 5.03 ± 0.62 µm) compared to continuous irradiation (average value of total cuspal deflection was 5.95 ± 0.65 µm). The two-step photoactivation protocol was found preferable, since it resulted in a significantly lower cuspal deflection (11% lower, compared to the continuous illumination). PMID:20309595

  19. Holographic Laser Interferometry For Detection Of Tumors In The Rabbit Urinary Bladder

    NASA Astrophysics Data System (ADS)

    Bowering, R.; Hofstetter, A.; Keiditsch, E.; Grunewald, K.

    1980-05-01

    Holographic interferometric investigations were performed in male giant rabbits (n=10) with and without bladder tumors. Double impulse ruby laser technique was able to detect elasticity changes of the bladder wall caused by tumors. The reproducibility of the experimental results was tested in vivo and in vitro. Healthy and tumorous changed regions of the bladder show a different stretch behavior in response to alterations of internal pressure.The method was found applicable to organic tissue without destruction of the tissue. Holographic interferometry was found to be sensitive method for distinction between normal and tumorous regions of the bladder wall. The results encourage the construction of a designed endoscope for holographic medical diagnostics.

  20. Measurement of fluid properties using rapid-double-exposure and time-average holographic interferometry

    SciTech Connect

    Decker, A.J.

    1984-06-01

    The holographic recording of the time history of a flow feature in three dimensions is discussed. The use of diffuse illumination holographic interferometry or the three dimensional visualization of flow features such as shock waves and turbulent eddies is described. The double-exposure and time-average methods are compared using the characteristic function and the results from a flow simulator. A time history requires a large hologram recording rate. Results of holographic cinematography of the shock waves in a flutter cascade are presented as an example. Future directions of this effort, including the availability and development of suitable lasers, are discussed.

  1. Measurement of fluid properties using rapid-double-exposure and time-average holographic interferometry

    NASA Technical Reports Server (NTRS)

    Decker, A. J.

    1984-01-01

    The holographic recording of the time history of a flow feature in three dimensions is discussed. The use of diffuse illumination holographic interferometry or the three dimensional visualization of flow features such as shock waves and turbulent eddies is described. The double-exposure and time-average methods are compared using the characteristic function and the results from a flow simulator. A time history requires a large hologram recording rate. Results of holographic cinematography of the shock waves in a flutter cascade are presented as an example. Future directions of this effort, including the availability and development of suitable lasers, are discussed.

  2. Measurement of fluid properties using rapid-double-exposure and time-average holographic interferometry

    NASA Technical Reports Server (NTRS)

    Decker, A. J.

    1984-01-01

    The holographic recording of the time history of a flow feature in three dimensions is discussed. The use of diffuse illumination holographic interferometry or the three-dimensional visualization of flow features such as shock waves and turbulent eddies is described. The double-exposure and time-average methods are compared using the characteristic function and the results from a flow simulator. A time history requires a large hologram recording rate. Results of holographic cinematography of the shock waves in a flutter cascade are presented as an example. Future directions of this effort, including the availability and development of suitable lasers, are discussed. Previously announced in STAR as N84-21849

  3. Holographic And Speckle Interferometry In The UK A Review Of Recent Developments

    NASA Astrophysics Data System (ADS)

    Robinson, D. W.

    1987-02-01

    From its inception, the technique of holographic interferometry has been continuously developed within the UK. Non-destructive testing (NDT) and metrological applications of holography have grown over the last 20 years, with major contributions coming from NPL, Loughborough University, Rolls Royce Advanced Research Laboratory and many others. More recently the technique of Electronic Speckle Pattern Interferometry (Electro-Optic Holography) has added to the list of available methods and given a spur to holographic metrology in industry. This paper will review recent developments within the UK, in optical systems and data analysis techniques (for both holographic and speckle interferometry). These are promising to provide the mechanical engineer with commercial products based on automated non-contacting optical measurement systems, for applications in industrial design and testing. Important developments include the use of fibre optics, CCD cameras, speckle averaging, heterodyning, 3-D deformation and strain measurement, together with a range of fringe analysis techniques. These will be discussed within the context of typical applications of holographic interferometry in the UK. Finally a view to the future will be given.

  4. Object tracking mask-based NLUT on GPUs for real-time generation of holographic videos of three-dimensional scenes.

    PubMed

    Kwon, M-W; Kim, S-C; Yoon, S-E; Ho, Y-S; Kim, E-S

    2015-02-01

    A new object tracking mask-based novel-look-up-table (OTM-NLUT) method is proposed and implemented on graphics-processing-units (GPUs) for real-time generation of holographic videos of three-dimensional (3-D) scenes. Since the proposed method is designed to be matched with software and memory structures of the GPU, the number of compute-unified-device-architecture (CUDA) kernel function calls and the computer-generated hologram (CGH) buffer size of the proposed method have been significantly reduced. It therefore results in a great increase of the computational speed of the proposed method and enables real-time generation of CGH patterns of 3-D scenes. Experimental results show that the proposed method can generate 31.1 frames of Fresnel CGH patterns with 1,920 × 1,080 pixels per second, on average, for three test 3-D video scenarios with 12,666 object points on three GPU boards of NVIDIA GTX TITAN, and confirm the feasibility of the proposed method in the practical application of electro-holographic 3-D displays. PMID:25836082

  5. Digital holographic interferometry for simultaneous orthogonal radial vibration measurements along rotating shafts

    SciTech Connect

    Tatar, Kourosh; Gren, Per; Lycksam, Henrik

    2008-06-20

    A digital holographic interferometry setup used to measure radial vibrations along a rotating shaft is presented. A continuous Nd:YAG laser and a high-speed digital camera are used for recording the holograms. The shaft was polished optically smooth to avoid speckle noise from the rotating surface. The light reflected from the shaft was directed onto a diffuser which in turn was imaged by the holographic system. Simultaneous measurements with a laser vibrometer were performed at one point and comparisons between the signals showed good agreement. It is shown that different vibration components of a rotating shaft can be simultaneously measured with this technique.

  6. The use of holographic interferometry and electron speckle pattern interferometry for diffusion measurement in biochemical and pharmaceutical engineering applications

    NASA Astrophysics Data System (ADS)

    Axelsson, Anders; Marucci, Mariagrazia

    2008-12-01

    In this review holographic interferometry and electron speckle pattern interferometry are discussed as efficient techniques for diffusion measurements in biochemical and pharmaceutical applications. Transport phenomena can be studied, quantitatively and qualitatively, in gels, liquids and membranes. Detailed information on these phenomena is required to design effective chromatography bioseparation processes using gel beads or ultrafiltration membranes, and in the design of controlled-release pharmaceuticals using membrane-coated pellets or tablets. The influence of gel concentration, ion strength in the liquid and the size of diffusing protein molecules can easily be studied with good accuracy. When studying membranes, the resistance can be quantified, and it is also possible to discriminate between permeable and semi-permeable membranes. In this review the influence of temperature, natural convection and light deflection on the accuracy of the diffusion measurements is also discussed.

  7. Characterization of drying paint coatings by dynamic speckle and holographic interferometry measurements.

    PubMed

    Budini, N; Mulone, C; Balducci, N; Vincitorio, F M; López, A J; Ramil, A

    2016-06-10

    In this work we implemented dynamic speckle and holographic interferometry techniques to characterize the drying process of solvent-based paint coatings. We propose a simple way to estimate drying time by measuring speckle activity and incrementally fitting experimental data through standard regression algorithms. This allowed us to predict drying time after about 20-30 min of paint application, which is fast compared to usual times required to reach the so-called tack-free state (≈2  h). In turn, we used holographic interferometry to map small thickness variations in the coating surface during drying. We also demonstrate that results obtained from both techniques correlate with each other, which allows us to improve the accuracy of the drying time estimation. PMID:27409029

  8. Dynamical measurement of refractive index distribution using digital holographic interferometry based on total internal reflection.

    PubMed

    Zhang, Jiwei; Di, Jianglei; Li, Ying; Xi, Teli; Zhao, Jianlin

    2015-10-19

    We present a method for dynamically measuring the refractive index distribution in a large range based on the combination of digital holographic interferometry and total internal reflection. A series of holograms, carrying the index information of mixed liquids adhered on a total reflection prism surface, are recorded with CCD during the diffusion process. Phase shift differences of the reflected light are reconstructed exploiting the principle of double-exposure holographic interferometry. According to the relationship between the reflection phase shift difference and the liquid index, two dimensional index distributions can be directly figured out, assuming that the index of air near the prism surface is constant. The proposed method can also be applied to measure the index of solid media and monitor the index variation during some chemical reaction processes. PMID:26480394

  9. Unusual applications of holographic interferometry in a semi-industrial environment

    NASA Astrophysics Data System (ADS)

    Boone, Pierre M.

    1996-03-01

    This paper presents two rather specific applications of holographic interferometry. The first is related to the study of displacements and strains associated with the rapid (200 meter/second) crack propagation in pressurized polymer pipes. Denisyuk type holography using a double pulsed Ruby laser was found to yield practical results; due to the rather explosive nature, experiments were carried out at night, outside of the classical buildings. The other series of tests is concerned with the localization of most stressed zones in prototypes manufactured from steel castings. As the use of brittle lacquers is now prohibited, holographic interferometry was used to find the locations for putting the strain gauges. Relatively large (up to 1 X 1 m) and heavy (about 700 kgs) castings were tested, resting on an unisolated concrete slab, using a semi-professional ESPI system and a small argon laser.

  10. A comparison of electronic heterodyne moire deflectometry and electronic heterodyne holographic interferometry for flow measurements

    NASA Technical Reports Server (NTRS)

    Decker, A. J.; Stricker, J.

    1985-01-01

    Electronic heterodyne moire deflectometry and electronic heterodyne holographic interferometry are compared as methods for the accurate measurement of refractive index and density change distributions of phase objects. Experimental results are presented to show that the two methods have comparable accuracy for measuring the first derivative of the interferometric fringe shift. The phase object for the measurements is a large crystal of KD*P, whose refractive index distribution can be changed accurately and repeatably for the comparison. Although the refractive index change causes only about one interferometric fringe shift over the entire crystal, the derivative shows considerable detail for the comparison. As electronic phase measurement methods, both methods are very accurate and are intrinsically compatible with computer controlled readout and data processing. Heterodyne moire is relatively inexpensive and has high variable sensitivity. Heterodyne holographic interferometry is better developed, and can be used with poor quality optical access to the experiment.

  11. A comparison of electronic heterodyne moire deflectometry and electronic heterodyne holographic interferometry for flow measurements

    NASA Technical Reports Server (NTRS)

    Decker, A. J.; Stricker, J.

    1985-01-01

    Electronic heterodyne moire deflectometry and electronic heterodyne holographic interferometry are compared as methods for the accurate measurement of refractive index and density change distributions of phase objects. Experimental results are presented to show that the two methods have comparable accuracy for measuring the first derivative of the interferometric fringe shift. The phase object for the measurements is a large crystal of KD P, whose refractive index distribution can be changed accurately and repeatably for the comparison. Although the refractive index change causes only about one interferometric fringe shift over the entire crystal, the derivative shows considerable detail for the comparison. As electronic phase measurement methods, both methods are very accurate and are intrinsically compatible with computer controlled readout and data processing. Heterodyne moire is relatively inexpensive and has high variable sensitivity. Heterodyne holographic interferometry is better developed, and can be used with poor quality optical access to the experiment.

  12. Dynamic measurement by digital holographic interferometry based on complex phasor method

    NASA Astrophysics Data System (ADS)

    Tay, C. J.; Quan, C.; Chen, W.

    2009-03-01

    In this paper, complex phasor (CP) method is employed in digital holographic interferometry. Unlike commonly used digital phase subtraction (DPS), the proposed technique processes a CP instead of phase. It is shown that the results obtained by directly filtering the phase produce large errors. It is demonstrated that the phase is not a signal but rather a property of a signal. In addition, the results obtained by the CP method are also compared with those obtained by conventional sine/cosine transformation method.

  13. Combined implementation of holographic and speckle interferometry for comparative local stress analysis at different vibration modes

    NASA Astrophysics Data System (ADS)

    Novikov, Sergey A.; Pisarev, Vladimir S.; Dzuba, Alexander S.; Grigoriev, Vladimir D.

    1998-09-01

    New capability of combined application of time-averaged holographic interferometry and defocused speckle photography, allowing us a comparative analysis of local stresses corresponding to different vibration modes, is considered. The main aspects of the technique developed are illustrated by using as an example bending oscillations of thin square plate with a large central circular hole. Experimental results are compared with corresponding numerical data obtained by means of the MSC/NASTRAN software.

  14. Critical needs of fringe-order accuracies in two-color holographic interferometry

    NASA Technical Reports Server (NTRS)

    Vikram, C. S.; Witherow, W. K.

    1992-01-01

    Requirements for the fringe order accuracy in two-color holographic interferometry are discussed with reference to crystal growth. A simple test cell (rectangular parallelepiped) containing a fluid is considered. The temperature and concentration variations are related to the fringe orders from the two interference patterns, and the uncertainties in the fringe orders are related to errors in the temperature and concentration determination. The formulation developed here is applied to the particular case of an aqueous solution of triglycerine sulfate as an example.

  15. High-resolution moiré interferometry for quantitative low-cost, real-time surface profilometry.

    PubMed

    Steckenrider, J Josiah; Steckenrider, J Scott

    2015-10-01

    A two-dimensional optical profilometry system has been developed in which fringe projection and image processing methods allow for image acquisition and analysis at video frame rates with μm-scale precision in an inexpensive portable device. The device presented can be used to interrogate any uniformly reflective surface, imaging an area of approximately 10 square centimeters and providing a real-time digital display of the surface's contours. The presented system has the ability to resolve surface features with a lateral resolution of <50  μm and <15  μm in height. PMID:26479600

  16. Lens-free digital in-line holographic imaging for wide field-of-view, high-resolution and real-time monitoring of complex microscopic objects

    NASA Astrophysics Data System (ADS)

    Stahl, Richard; Vanmeerbeeck, Geert; Lafruit, Gauthier; Huys, Roeland; Reumers, Veerle; Lambrechts, Andy; Liao, Chao-Kang; Hsiao, Chin-Chun; Yashiro, Masayuki; Takemoto, Masashi; Nagata, Tomohisa; Gomi, Shinichi; Hatabayashi, Kunitada; Oshima, Yasuhiro; Ozaki, Shigenori; Nishishita, Naoki; Kawamata, Shin

    2014-03-01

    Lens-free inline Holographic Microscopy (LHM) holds great promise for biomedical and industrial applications thanks to its conceptual simplicity. However, the challenge lies in achieving an image quality comparable to conventional microscopes. We demonstrate a high-throughput LHM system that is able to resolve 1.23μm-thin lines on a standard USAF 1951 test target with 1.67μm pixels at the full field-of-view (>29mm2). The system is based on a unique multiwavelength iterative-phase-retrieval method, using customized hardware and real-time post-processing software. We have evaluated our system in experiments ranging from single-cell inspection to in-vitro imaging of stem-cell colonies.

  17. Real-time displacement measurement system using phase-shifted optical pulse interferometry: Application to a seismic observation system

    NASA Astrophysics Data System (ADS)

    Yoshida, Minoru; Hirayama, Yoshiharu; Takahara, Atsushi; Kashi, Motofumi; Takeuchi, Keiji; Ikeda, Toshiharu; Hirai, Fumio; Mizuno, Yosuke; Nakamura, Kentaro; Kimura, Hitoshi; Ino, Norio; Inoue, Wataru

    2016-02-01

    We developed a method of detecting incident light levels on the oscillator surfaces and light pulses that include two interfering pulses with a phase shift of π/2 (phase-shifted optical pulse interferometry). This system enables the measurement of displacements greatly exceeding the half wavelength of the laser. Moreover, it allows measurements at multiple locations with a single optical fiber for using optical pulses. In this study, we conducted an interference experiment using 30 ns optical pulses and transmitted them at 1 µs intervals. We confirmed that the above two measurements are possible. Furthermore, from the data of the oscillator used for verification, we showed that measurements on the order of nanometers are possible. Since this method does not require a power supply to the oscillator, its widespread applications in physical exploration can be expected.

  18. Real-time optical correlator using computer-generated holographic filter on a liquid crystal light valve

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Yu, Jeffrey

    1990-01-01

    Limitations associated with the binary phase-only filter often used in optical correlators are presently circumvented in the writing of complex-valued data on a gray-scale spatial light modulator through the use of a computer-generated hologram (CGH) algorithm. The CGH encodes complex-valued data into nonnegative real CGH data in such a way that it may be encoded in any of the available gray-scale spatial light modulators. A CdS liquid-crystal light valve is used for the complex-valued CGH encoding; computer simulations and experimental results are compared, and the use of such a CGH filter as the synapse hologram in a holographic optical neural net is discussed.

  19. Holographically recorded photopolymer diffractive optical element for holographic and electronic speckle-pattern interferometry

    NASA Astrophysics Data System (ADS)

    Guntaka, Sridhar Reddy; Toal, Vincent; Martin, Suzanne

    2002-12-01

    A diffractive optical element is described that can be used to implement a very simple self-aligning electronic speckle-pattern interferometer and holographic interferometer that requires only a laser source and a camera in the optical setup.

  20. Real-Time Detection and Tracking of Vital Signs with an Ambulatory Subject Using Millimeter-Wave Interferometry

    NASA Astrophysics Data System (ADS)

    Mikhelson, Ilya V.

    Finding a subject's heart rate from a distance without any contact is a difficult and very practical problem. This kind of technology would allow more comfortable patient monitoring in hospitals or in home settings. It would also allow another level of security screening, as a person's heart rate increases in stressful situations, such as when lying or hiding malicious intent. In addition, the fact that the heart rate is obtained remotely means that the subject would not have to know he/she is being monitored at all, adding to the efficacy of the measurement. Using millimeter-wave interferometry, a signal can be obtained that contains composite chest wall motion made up of component motions due to cardiac activity, respiration, and interference. To be of use, these components have to be separated from each other by signal processing. To do this, the quadrature and in-phase components of the received signal are analyzed to get a displacement waveform. After that, processing can be done on that waveform in either the time or frequency domains to find the individual heartbeats. The first method is to find the power spectrum of the displacement waveform and to look for peaks corresponding to heartbeats and respiration. Another approach is to examine the signal in the time domain using wavelets for multiresolution analysis. One more method involves studying the statistics of the wavelet-processed signal. The final method uses a heartbeat model along with probabilistic processing to find heartbeats. For any of the above methods to work, the millimeter-wave sensor has to be accurately pointed at the subject's chest. However, even small subject motions can render the rest of the gathered data useless as the antenna may have lost its aim. To combat this, a color and a depth camera are used with a servo-pan/tilt base. My program finds a face in the image and subsequently tracks that face through upcoming frames. The pan/tilt base adjusts the aim of the antenna depending on

  1. Measurement of Poisson's ratio of nonmetallic materials by laser holographic interferometry

    NASA Astrophysics Data System (ADS)

    Zhu, Jian T.

    1991-12-01

    By means of the off-axis collimated plane wave coherent light arrangement and a loading device by pure bending, Poisson's ratio values of CFRP (carbon fiber-reinforced plactics plates, lay-up 0 degree(s), 90 degree(s)), GFRP (glass fiber-reinforced plactics plates, radial direction) and PMMA (polymethyl methacrylate, x, y direction) have been measured. In virtue of this study, the ministry standard for the Ministry of Aeronautical Industry (Testing method for the measurement of Poisson's ratio of non-metallic by laser holographic interferometry) has been published. The measurement process is fast and simple. The measuring results are reliable and accurate.

  2. Visualisation and analysis of three dimensional transonic flows by holographic interferometry

    NASA Astrophysics Data System (ADS)

    Towers, D. P.; Towers, C. E.; Bryanston-Cross, P. J.; Fry, K.; Harris, A. E.

    1992-01-01

    Holographic interferometry has been used in a large scale transonic wind tunnel to produce a 3D flow visualization. The experiments have been carried out on a model civil transport aircraft wing and turbine powered engine simulator combination. This study is significant industrially as the method forms a diagnostic for turbofan installations. The holograms show many relevant flow features including shock waves, flow interactions between the engine simulator flow and the freestream flow, secondary flows, and acoustic waves. Quantitative 3D position information has also been obtained for some of these features. A comparison to other flow diagnostic methods has been made in this paper.

  3. Flow-field measurements on an airfoil with an oscillating trailing-edge using holographic interferometry

    NASA Technical Reports Server (NTRS)

    Bachalo, W. D.

    1984-01-01

    Holographic interferometry data were acquired on an NACA 64A010 airfoil with an oscillating flap. The airfoil was installed in the Ames 11-Foot Transonic Wind Tunnel between splitter plates. Recordings were made at discrete phase angles of the oscillation. The interferometry results provided detailed flow visualization of the shock boundary-layer interaction and the separated flow. Quantitative results were extracted from the interferograms to produce pressure data. These results were compared to the surface pressures obtained with the surface pressure taps. Excellent agreement was found for low angles of incidence. At larger angles of incidence, the flow had greater three-dimensionality, and the results were not in good agreement in some regions of the flow field. Mach contours were traced for representative flow conditions. Wake profiles were also obtained using the assumption of constant pressure across the wake and the Crocco relationship.

  4. Particle-filter-based phase estimation in digital holographic interferometry.

    PubMed

    Waghmare, Rahul G; Ram Sukumar, P; Subrahmanyam, G R K S; Singh, Rakesh Kumar; Mishra, Deepak

    2016-03-01

    In this paper, we propose a particle-filter-based technique for the analysis of a reconstructed interference field. The particle filter and its variants are well proven as tracking filters in non-Gaussian and nonlinear situations. We propose to apply the particle filter for direct estimation of phase and its derivatives from digital holographic interferometric fringes via a signal-tracking approach on a Taylor series expanded state model and a polar-to-Cartesian-conversion-based measurement model. Computation of sample weights through non-Gaussian likelihood forms the major contribution of the proposed particle-filter-based approach compared to the existing unscented-Kalman-filter-based approach. It is observed that the proposed approach is highly robust to noise and outperforms the state-of-the-art especially at very low signal-to-noise ratios (i.e., especially in the range of -5 to 20 dB). The proposed approach, to the best of our knowledge, is the only method available for phase estimation from severely noisy fringe patterns even when the underlying phase pattern is rapidly varying and has a larger dynamic range. Simulation results and experimental data demonstrate the fact that the proposed approach is a better choice for direct phase estimation. PMID:26974901

  5. Comparative measurements of natural convection heat transfer in channels by holographic interferometry and schlieren

    NASA Astrophysics Data System (ADS)

    Ambrosini, Dario; Tanda, Giovanni

    2006-01-01

    In this work, natural convection heat transfer in vertical channels is experimentally investigated by applying different optical techniques, namely holographic interferometry and schlieren. Both these techniques are based on the temperature dependence of the air refractive index but they detect different optical quantities and their use involves different instrumentation and optical components. Optical methods, non-intrusive in nature, are particularly suitable for the visualization of flow and thermal fields as witnessed by their increasing use in a range of scientific and engineering disciplines; for this reason, the introduction of these experimental tools into a laboratory course can be of high value. Physics and engineering students can get familiarized with optical techniques, grasp the basics of thermal phenomena, usually elusive, which can be more easily understood if they are made visible, and begin to master digital image analysis, a key skill in laboratory activities. A didactic description of holographic interferometry and schlieren is provided and experimental results obtained for vertical, smooth and rib-roughened channels with asymmetrical heating are presented. A comparison between distributions of the local heat transfer coefficient (or its dimensionless counterpart, the Nusselt number) revealed good agreement between the results separately obtained by the two techniques, thus proving their suitability for investigating free convection heat transfer in channels.

  6. Visual investigation on the heat dissipation process of a heat sink by using digital holographic interferometry

    SciTech Connect

    Wu, Bingjing; Zhao, Jianlin Wang, Jun; Di, Jianglei; Chen, Xin; Liu, Junjiang

    2013-11-21

    We present a method for visually and quantitatively investigating the heat dissipation process of plate-fin heat sinks by using digital holographic interferometry. A series of phase change maps reflecting the temperature distribution and variation trend of the air field surrounding heat sink during the heat dissipation process are numerically reconstructed based on double-exposure holographic interferometry. According to the phase unwrapping algorithm and the derived relationship between temperature and phase change of the detection beam, the full-field temperature distributions are quantitatively obtained with a reasonably high measurement accuracy. And then the impact of heat sink's channel width on the heat dissipation performance in the case of natural convection is analyzed. In addition, a comparison between simulation and experiment results is given to verify the reliability of this method. The experiment results certify the feasibility and validity of the presented method in full-field, dynamical, and quantitative measurement of the air field temperature distribution, which provides a basis for analyzing the heat dissipation performance of plate-fin heat sinks.

  7. The use of holographic interferometry for measurements of temperature in a rectangular heat pipe. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Marn, Jure

    1989-01-01

    Holographic interferometry is a nonintrusive method and as such possesses considerable advantages such as not disturbing the velocity and temperature field by creating obstacles which would alter the flow field. These optical methods have disadvantages as well. Holography, as one of the interferometry methods, retains the accuracy of older methods, and at the same time eliminates the system error of participating components. The holographic interferometry consists of comparing the objective beam with the reference beam and observing the difference in lengths of optical paths, which can be observed during the propagation of the light through a medium with locally varying refractive index. Thus, change in refractive index can be observed as a family of nonintersecting surfaces in space (wave fronts). The object of the investigation was a rectangular heat pipe. The goal was to measure temperatures in the heat pipe, which yields data for computer code or model assessment. The results were obtained by calculating the temperatures by means of finite fringes.

  8. A comparative investigation for the nondestructive testing of honeycomb structures by holographic interferometry and infrared thermography

    NASA Astrophysics Data System (ADS)

    Sfarra, S.; Ibarra-Castanedo, C.; Avdelidis, N. P.; Genest, M.; Bouchagier, L.; Kourousis, D.; Tsimogiannis, A.; Anastassopoulous, A.; Bendada, A.; Maldague, X.; Ambrosini, D.; Paoletti, D.

    2010-03-01

    The nondestructive testing (NDT) of honeycomb sandwich structures has been the subject of several studies. Classical techniques such as ultrasound testing and x-rays are commonly used to inspect these structures. Holographic interferometry (HI) and infrared thermography (IT) have shown to be interesting alternatives. Holography has been successfully used to detect debonding between the skin and the honeycomb core on honeycomb panels under a controlled environment. Active thermography has proven to effectively identify the most common types of defects (water ingress, debonding, crushed core, surface impacts) normally present in aeronautical honeycomb parts while inspecting large surfaces in a fast manner. This is very attractive for both the inspection during the manufacturing process and for in situ regular NDT assessment. A comparative experimental investigation is discussed herein to evaluate the performance of HI and IT for the NDT on a honeycomb panel with fabricated defects. The main advantages and limitations of both techniques are enumerated and discussed.

  9. An experimental investigation of circulation control flow fields using holographic interferometry

    NASA Technical Reports Server (NTRS)

    Bachalo, William D.

    1982-01-01

    Experiments are presented which were conducted on flow fields produced by a circulation control airfoil utilizing the Coanda effect at the trailing edge. The application of holographic interferometry to obtain both visualization and quantitative data on the flow field about a circulation control airfoil at transonic flow speed is covered. A brief description of the flow model and measurement techniques is given. The data reduction procedure, results, and interpretation are presented. The results have provided a good deal of information on the character of the flow field, particularly in the neighborhood of the trailing edge. As to the airfoil design, it is apparent that improved performance can be achieved if jet detachment is delayed. Another design improvement would involve the development of an optimum trailing-edge shape for the expected operating Mach and Reynolds number ranges.

  10. Study of heat dissipation process from heat sink using lensless Fourier transform digital holographic interferometry.

    PubMed

    Kumar, Varun; Shakher, Chandra

    2015-02-20

    This paper presents the results of experimental investigations about the heat dissipation process of plate fin heat sink using digital holographic interferometry. Visual inspection of reconstructed phase difference maps of the air field around the heat sink with and without electric power in the load resistor provides qualitative information about the variation of temperature and the heat dissipation process. Quantitative information about the temperature distribution is obtained from the relationship between the digitally reconstructed phase difference map of ambient air and heated air. Experimental results are presented for different current and voltage in the load resistor to investigate the heat dissipation process. The effect of fin spacing on the heat dissipation performance of the heat sink is also investigated in the case of natural heat convection. From experimental data, heat transfer parameters, such as local heat flux and convective heat transfer coefficients, are also calculated. PMID:25968185

  11. Synthetic aperture double exposure digital holographic interferometry for wide angle measurement and monitoring of mechanical displacements

    NASA Astrophysics Data System (ADS)

    Kujawinska, M.; Makowski, P.; Finke, G.; Zak, J.; Józwik, M.; Kozacki, T.

    2015-08-01

    A novel approach for wide angle registration and display of double exposure digital holograms of 3D objects under static or step-wise load is presented. The registration setup concept combines digital Fourier holography with synthetic aperture (SA) technique, which is equivalent to usage of a wide angle, spherically curved detector. The coherent object wavefields extracted from a pair of acquisitions collected in the synthetic aperture double exposure digital holographic interferometry scheme (SA DEDH) are utilized as the input for two different scenarios of investigation, which include (i) numerical determination of 2D phase difference fringes representing deformation of an object and (ii) physical displaying of a 3D image resulting from interference of two object (slightly different) wavefronts registered at the SA double exposure hologram. The capture and display processes are analyzed and implemented. The applicability of both numerical and experimental approach to SA DEDH for testing engineering objects is discussed.

  12. Holographic-interferometry methods employed for vibration-strength testing of aviation-engine workpieces

    NASA Astrophysics Data System (ADS)

    Elenevskii, D. S.; Krainiukov, N. I.; Shaposhnikov, Iu. N.; Khramov, A. G.

    The vibroshifting fields generated by turbine blades and aerospace engines are calculated numerically with a mathematical system incorporating holographic-interferometry data. The vibroshift field is computed directly from the interferogram pattern, whereas the deformation and strain of the object are obtained experimentally on the basis of the resulting data. The experimental installation is shown diagrammatically, and algorithms are presented which permit the analysis of brightness distributions of interferogram-pattern points, fringe centers, and the geometrical parameters of the image. Interferogram processing conducted on a PC with 512 x 512-pixel capacity is conducted for a compressor blade by means of the time-averaging and with the proposed local approximation by a second-order surface. The vibroshift vector field and corresponding projection demonstrate the results of detection of dark fringes and filtered skeletons facilitated by the method.

  13. Iterative signal separation based multiple phase estimation in digital holographic interferometry.

    PubMed

    Kulkarni, Rishikesh; Rastogi, Pramod

    2015-10-01

    We propose a new method for signal separation from a multicomponent interference field recorded in a digital holographic interferometry setup. The setup consisting of multiple object illuminating beams results in an interference field containing multiple signal components. The proposed method utilizes an amplitude discrimination criteria established by setting different intensities to the object illuminating beams in order to separate the signal components iteratively. The signal separation is performed in a small block of the interference field at a time. The augmentation of the block matrix with its own rows and columns is performed which has an effect of noise subspace inflation. This operation offers an improved noise robustness to the signal separation capability of the proposed method. The simulation and experimental results are provided to substantiate the applicability of the proposed method in multidimensional deformation measurement. PMID:26480195

  14. Visualization of marginal integrity of resin-enamel interface by holographic interferometry.

    PubMed

    Panduric, Vlatko; Demoli, Nazif; Tarle, Zrinka; Sariri, Kristina; Mandic, Visnja Negovetic; Knezevic, Alena; Sutalo, Jozo

    2007-01-01

    This study determined whether it was possible to detect deformations and fractures in dental hard tissues or in composite material from internal stresses using double-exposure holographic interferometry. On the proximal side of eight intact human permanent premolars, a direct Class II cavity was prepared and restored with a self-etching adhesive (Clearfil SE Bond) and Tetric Ceram, a resin composite. In five of the specimens, Tetric Flow was used as an elastic layer. The samples were illuminated using a helium-neon laser beam, and the holograms of samples were recorded using Agfa 10E75 photographic plates. Hologram reconstructions were captured with an 8-bit monochrome CCD camera and qualitatively analyzed. Deformations and fractures appeared as fringe patterns on all interferograms, where the distribution of fringes provided location information, while the density of fringes gave the amplitude information. Greater fringe densities were observed in samples treated without a flowable composite. PMID:17555178

  15. Holographic interferometry study of the dissolution and diffusion of gypsum in water

    NASA Astrophysics Data System (ADS)

    Colombani, Jean; Bert, Jacques

    2007-04-01

    We have performed holographic interferometry measurements of the dissolution of the (0 1 0) plane of a cleaved gypsum single crystal in pure water. These experiments have provided the value of the dissolution rate constant k of gypsum in water and the value of the interdiffusion coefficient D of its aqueous species in water. D is 1.0 × 10 -9 m 2 s -1, a value close to the theoretical value generally used in dissolution studies. k is 4 × 10 -5 mol m -2 s -1. It directly characterizes the microscopic transfer rate at the solid-liquid interface, and is not an averaged value deduced from quantities measured far from the surface as in macroscopic dissolution experiments. It is found to be two times lower than the value obtained from macroscopic experiments.

  16. Optical examination of load transfer in riveted lap joints using portable holographic interferometry

    NASA Astrophysics Data System (ADS)

    Shankar, Krishnakumar; Baird, John P.; Clark, Robert K.; Williamson, Hugh M.

    1997-03-01

    In mechanically fastened single lap joints, such as those employed on aircraft fuselage skin splices, there are two distinct mechanisms of load transfer. At low values of load the transfer occurs primarily through friction between the component sheets while at higher loads the load is transferred by friction as well as through bearing at the fasteners. The load level at which the bearing mode of load transfer comes into action significantly affects the fatigue life of the joint, since the fasteners are stressed only at loads above this threshold load value. The portable holographic interferometry testing system (PHITS) is a robust, portable and sensitive non-destructive inspection system which produces contours of relative out of plane displacement by the method of superposition. PHITS is applied here to monitor the load transfer mechanism and identify the threshold at which the bearing mode comes into effect. In the friction mode there is no relative displacement between the fasteners and the skin panels. In the bearing mode the fasteners are loaded, causing a distinct tipping of the rivets, which is readily observable in the fringe pattern of deflection contours recorded by the holographic system.

  17. Measurement of temperature and temperature distribution in gaseous flames by digital speckle pattern shearing interferometry using holographic optical element

    NASA Astrophysics Data System (ADS)

    Kumar, Manoj; Shakher, Chandra

    2015-10-01

    Digital speckle pattern lateral shear interferometry (DSPSI) based on volume phase holographic grating for the measurement of temperature and temperature distribution in candle flames is presented. The DSPSI setup uses the volume phase holographic grating combined with ground glass to shear the wavefronts. The shear of the two wavefronts is controlled by the distance between volume phase holographic grating and the ground glass. The sheared wavefronts on the ground glass are imaged onto the CMOS detector by an imaging lens. Two specklegrams are recorded corresponding to the absence of the flame and the presence of the flame. The fringe pattern is observed by subtracting these two specklegrams. A single fringe pattern was used to extract phase by the application of Riesz transform and the monogenic signal. The measured values of the temperature of the candle flame by DSPSI is compared with that of R-type Platinum-Platinum Rhodium thermocouple and the results are well within experimental limits.

  18. Towards the real-time monitoring of glucose in tear fluid: holographic glucose sensors with reduced interference from lactate and pH.

    PubMed

    Yang, Xiaoping; Pan, Xiaohan; Blyth, Jeff; Lowe, Christopher R

    2008-01-18

    Glucose-selective holographic sensors were fabricated from unique tetrahedral 2-acrylamidophenylboronic acid (2-APB) incorporated with co-monomers poly(ethylene glycol) acrylate (PEG), (3-acrylamidopropyl)trimethylammonium chloride (ATMA) and [2-(acryloyloxy)ethyl]-trimethylammonium chloride (AETA) into thin hydrogel films which were transformed into volume holograms using a diffusion method coupled with holographic recording using a frequency-doubled Nd:YAG laser (532 nm). The results showed that the 2-APB-based holographic sensors contracted upon addition of glucose due to the formation of a 2:1 complex between the tetrahedral 2-APB and glucose. More significantly, the 2-APB-based holographic sensors had greatly reduced lactate dependence and a hugely reduced pH effect over the physiological range of pH. These features are vital for development of contact lens-based glucose sensor, where the pH variability is greater (pH 5.8-7.8) and the lactate concentration is substantially higher than in blood. Furthermore, the 2-APB-based holographic sensors also displayed fast response to glucose. The successful union of holograms and the tetrahedral 2-APB receptor for glucose detection in artificial tear fluid is also demonstrated. This new type of holographic sensors responding to glucose with features of minor pH effect and negligible interference from lactate is applicable to the detection of glucose concentrations in tear fluid for the management of diabetes. PMID:18060763

  19. Modal analysis by holographic interferometry of a turbine blade for aircraft engines

    NASA Astrophysics Data System (ADS)

    Caponero, Michele A.; De Angelis, Alberto; Filetti, V. R.; Gammella, S.

    1994-11-01

    Within the planning stage devoted to realize an innovative turbine for an aircraft engine, an experimental prototype has been made. Several measurements have been carried out to experimentally verify the expected structural and dynamic features of such a prototype. Expected properties were worked out by finite elements method, using the well-known Nastran software package. Natural frequencies and vibration modes of the designed prototype were computed assuming the turbine being in both `dynamic condition' (rotating turbine at running speed and temperature), and in `static condition' (still turbine at room temperature). We present the experimental modal analysis carried out by time average holographic interferometry, being the prototype in `static condition;' results show the modal behavior of the prototype. Experimental and computed modal features are compared to evaluate the reliability of the finite elements model of the turbine used for computation by the Nastran package; reliability of the finite elements model must be checked to validate results computed assuming the turbine blade is in hostile environments, such as `dynamic condition,' which could hardly be tested by experimental measurements. A piezoelectric transducer was used to excite the turbine blade by sine variable pressure. To better estimate the natural vibration modes, two holographic interferograms have been made for each identified natural frequency, being the sensitivity vector directions of the two interferograms perpendicular to each other. The first ten lower natural frequencies and vibration modes of the blade have been analyzed; experimental and computed results are compared and discussed. Experimental and computed values of natural frequencies are in good agrement between each other. Several differences are present between experimental and computed modal patterns; a possible cause of such discrepancies is identified in wrong structural constraints imposed at nodes of the finite elements

  20. Experimental Study of Heat Transfer of Parallel Louvered Fins through Laser Holographic Interferometry

    NASA Astrophysics Data System (ADS)

    Kurosaki, Yasuo; Kashiwagi, Takao; Kobayashi, Hiroki; Uzuhashi, Hideo; Tang, Xue-Zhong

    The objectives of this paper are experimentally to study the detail of heat transfer in louver-array and to propose the preferable geometrical arrangement of louver from the point of view of improving the performance of heat exchanger. Our approach toward that goal was made via the following steps. The first step in the present study is optically to visualize the temperature field around louvers by employing the primitive heated flat louver model consisting of thin bakelite plate and thin Nichrome foil as a heater, and to measure the heat transfer coefficients of the louvers. Our experiment achieved to visualize the isotherms through the Laser holographic interferometry. The clear isotherms for various louver arrangements were successfully obtained. The thermal boundary layer and wake generated by an upstream louver were clearly observed to extend toward downstream ones ; the heat transfer coefficients obtained by the experiment were virtually affected by those boundary layers and wakes. The second step is to examine the plausible arrangement of louver for enhancing heat transfer. The slight position shift of downstream louvers toward the direction avoiding the influence of heated air wake was proposed from both the observation of isotherms and the measurement of heat transfer coefficients in staggered louver array ; its effectiveness was varified by the experiment. The improvement of the performance of heat exchanger is expected by applying the proposed minor rearrangement of louver array for enhanced fins.

  1. Holographic interferometry as a method to detect welding failures on ribbed iron structures

    NASA Astrophysics Data System (ADS)

    Vincitorio, F. M.; Budini, N.; Mulone, C.; Freyre, C.; Spector, M.; López Díaz, A. J.; Ramil Rego, A.; Yañez Casal, A.

    2013-11-01

    Metallic structures made of ribbed iron bars (ADN-420) are of common use in sheds and supporting structures. Usually, trusses are constructed with many pieces of ribbed iron bars, combined together through a welding process. Although ribbed iron manufacturers do not recommend this type of structure it is still frequently used. The main weakness of these trusses is the welding point because ribbed iron is not a material suitable for welding. This work presents results obtained from an analysis of welding points between ribbed iron bars extracted from a collapsed truss, by means of conventional (optical) and digital holographic interferometry (HI and DHI, respectively). The experiments were divided in two different series of studies. The first series were performed by HI on metallographic samples while the second series were done by DHI on different welding points. These results were complemented by metallographic analysis made in an external laboratory. DHI indicated that the bars did not have important failures but evidenced defects in one of the welding points under analysis. This information together with metallographic results allowed inferring that the collapse was probably due to an error in the design of the structure, since the iron bars were out of standard compliance.

  2. Experimental characterization of the hygroscopic properties of wood during convective drying using digital holographic interferometry.

    PubMed

    Kumar, Manoj; Shakher, Chandra

    2016-02-10

    In this paper, an application of digital holography for the measurement of surface deformations and the strain field to understand the shrinkage behavior of wood during convective drying is presented. Moisture absorption and desorption induce the dimensional changes and deformations in wood that leads to failure of certain components made of wood. The knowledge of the dimensional changes in wood, deformations, strain distribution and their causes are important for the best utilization of wood. For the study, lensless Fourier transform digital holographic interferometry is used to measure moisture- induced deformation, strain distribution, and the coefficient of hygroscopic shrinkage in different samples of wood. The technique is highly sensitive and enables the observation of deformation and strain distribution during the variations of moisture content in the wood. The wet wood sample was exposed to convective drying, which leads to changes in the moisture content and the associated deformations. The deformation/strain in each step of drying process is used to evaluate the coefficient of hygroscopic shrinkage in different wood samples. The experiments were repeated for differently treated woods. The experimental results show that the strain and coefficient of hygroscopic shrinkage can be minimized if the wood is dried in the presence of the proper moisture content. PMID:26906359

  3. Surface strain-field determination of tympanic membrane using 3D-digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Hernandez-Montes, María del S.; Mendoza Santoyo, Fernando; Muñoz, Silvino; Perez, Carlos; de la Torre, Manuel; Flores, Mauricio; Alvarez, Luis

    2015-08-01

    In order to increase the understanding of soft tissues mechanical properties, 3D Digital Holographic Interferometry (3D-DHI) was used to quantify the strain-field on a cat tympanic membrane (TM) surface. The experiments were carried out applying a constant sound-stimuli pressure of 90 dB SPL (0.632 Pa) on the TM at 1.2 kHz. The technique allows the accurate acquisition of the micro-displacement data along the x, y and z directions, which is a must for a full characterization of the tissue mechanical behavior under load, and for the calculation of the strain-field in situ. The displacements repeatability in z direction shows a standard deviation of 0.062 μm at 95% confidence level. In order to realize the full 3D characterization correctly the contour of the TM surface was measured employing the optically non-contact two-illumination positions contouring method. The x, y and z displacements combined with the TM contour data allow the evaluation its strain-field by spatially differentiating the u(m,n), v(m,n), and w(m,n) deformation components. The accurate and correct determination of the TM strain-field leads to describing its elasticity, which is an important parameter needed to improve ear biomechanics studies, audition processes and TM mobility in both experimental measurements and theoretical analysis of ear functionality and its modeling.

  4. Comparison on different insects' wing displacements using high speed digital holographic interferometry.

    PubMed

    Aguayo, Daniel D; Santoyo, Fernando Mendoza; De la Torre-I, Manuel H; Salas-Araiza, Manuel D; Caloca-Mendez, Cristian

    2011-06-01

    In-flight insect wing motion behavior depends on a wide variety of conditions. They have a complex structural system and what seems to be a rather complicated motion. Researchers in many fields have endeavoured to study and reproduce these wing movements with the aim to apply the gained knowledge in their fields and for the benefit of avionic technological improvements and insect migration studies, among many other themes. The study of in-flight insect wing motion and its measurement is a relevant issue to understand and reproduce its functionality. Being capable of measuring the wing flapping using optical noninvasive methods adds scientific and technological value to the fundamental research in the area. Four different types of butterflies found widely in Mexico's forests are used to compare their wing flapping mechanisms. An out-of-plane digital holographic interferometry system is used to detect and measure its wingmicro deformations. Displacement changes from in vivo flapping wings are registered with a CMOS high speed camera yielding full field of view images depicting these insects' wing motion. The results have a resolution in the scale of hundreds of nanometers over the entire wing surface. PMID:21721806

  5. Comparison on different insects' wing displacements using high speed digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Aguayo, Daniel D.; Santoyo, Fernando Mendoza; de La Torre-I, Manuel H.; Salas-Araiza, Manuel D.; Caloca-Mendez, Cristian

    2011-06-01

    In-flight insect wing motion behavior depends on a wide variety of conditions. They have a complex structural system and what seems to be a rather complicated motion. Researchers in many fields have endeavoured to study and reproduce these wing movements with the aim to apply the gained knowledge in their fields and for the benefit of avionic technological improvements and insect migration studies, among many other themes. The study of in-flight insect wing motion and its measurement is a relevant issue to understand and reproduce its functionality. Being capable of measuring the wing flapping using optical noninvasive methods adds scientific and technological value to the fundamental research in the area. Four different types of butterflies found widely in Mexico's forests are used to compare their wing flapping mechanisms. An out-of-plane digital holographic interferometry system is used to detect and measure its wingmicro deformations. Displacement changes from in vivo flapping wings are registered with a CMOS high speed camera yielding full field of view images depicting these insects' wing motion. The results have a resolution in the scale of hundreds of nanometers over the entire wing surface.

  6. Determination of curvature and twist of deformed object by digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Quan, C.; Chen, W.; Tay, C. J.

    2008-11-01

    This paper describes a feasibility study of digital holographic interferometry for the measurement of curvature and twist of a deformed object. Measurement of curvature and twist is an important aspect in experimental mechanics. Numerous methods have been proposed to determine the curvature and twist by using digital shearography. We proposed a novel method to determine curvature and twist based on digital holography (DH) and complex phasor (CP). In the conventional methods, phase difference between the first and second states is obtained directly by digital phase subtraction (DPS) and Fourier transform is then employed to extract phase maps. In this study, CP method is proposed to improve the quality of phase maps corresponding to second-order derivatives. Subsequently, sine/cosine transformation and short time Fourier transform (STFT) are employed to process the wrapped phase maps. An experiment is conducted on a clamped circular plate under a point load at centre. The experimental results show that the proposed method is valid and able to obtain high quality phase maps corresponding to curvature and twist of a deformed object.

  7. Grading of wooden plates for musical instrument making by means of holographic interferometry

    NASA Astrophysics Data System (ADS)

    Urgela, Stanislav

    1998-07-01

    Wood selection for musical instrument making is usually based on visual estimation and on manual mechanical and vibrational subjective testing. The method proposed uses TV holography and holographic interferometry with a double- pulsed laser to visualize the standing acoustic waves and the impact generated by transient waves as inspection testing tools. The theory of bending waves in orthotropic plates is used to interpret the experimental results. This enables us to estimate Young's moduli parallel to and perpendicular to the grain and the in-plane shear modulus in wood. The testing is nondestructive, so the expensive wooden plates can be used in production. Properly modified, the test can be applied to the judgement of any wooden and wooden composite plates. The 3D charts for a set of the physioacoustical characteristics--density, modulus of elasticity, and acoustic constant on the axes--are confirmed as a useful procedure that can help to provide more objective results in wood grading for materials selection in the design of musical instruments, mainly bowed string instruments and pianos.

  8. Binary Diffusion Coefficient Data of Various Gas Systems Determined Using a Loschmidt Cell and Holographic Interferometry

    NASA Astrophysics Data System (ADS)

    Kugler, T.; Rausch, M. H.; Fröba, A. P.

    2015-11-01

    The paper reports on binary diffusion coefficient data for the gaseous systems argon-neon, krypton-helium, ammonia-helium, nitrous oxide-nitrogen, and propane-helium measured using a Loschmidt cell combined with holographic interferometry between (293.15 and 353.15) K as well as between (1 and 10) bar. The investigations on the noble gas systems aimed to validate the measurement apparatus by comparing the binary diffusion coefficients measured as a function of temperature and pressure with theoretical data. In previous studies, it was already shown that the raw concentration-dependent data measured with the applied setup are affected by systematic effects if pure gases are used prior to the diffusion process. Hence, the concentration-dependent measurement data were processed to obtain averaged binary diffusion coefficients at a mean mole fraction of 0.5. The data for the molecular gas systems complete literature data on little investigated systems of technical interest and point out the capabilities of the applied measurement apparatus. Further experimental data are reported for the systems argon-helium, krypton-argon, krypton-neon, xenon-helium, xenon-krypton, nitrous oxide-carbon dioxide, and propane-carbon dioxide at 293.15 K, 2 bar, and a mean mole fraction of 0.5.

  9. Tympanic membrane contour measurement with two source positions in digital holographic interferometry.

    PubMed

    Solís, Silvino M; Hernández-Montes, María Del S; Santoyo, Fernando M

    2012-12-01

    The data acquisition from the shape of an object is a must to complete its quantitative displacement measurement analysis. Over the past years whole field of view optical non-invasive testing has been widely used in many areas, from industrial ones to, for instance, biomedical research topics. To measure the surface contour from the tympanic membrane (TM) of ex-vivo cats digital holographic interferometry (DHI) is used in combination with a two-illumination positions method: the shape is directly measured from the phase change between two source positions by means of a digital Fourier transform method. The TM shape data in conjunction with its displacement data renders a complete and accurate description of the TM deformation, a feature that no doubt will serve to better comprehend the hearing process. Acquiring knowledge from the tissue shape indicates a mechanical behavior and, indirectly, an alteration in the physiological structure due to middle ear diseases or damages in the tissue that can deteriorate sound transmission. The TM shape contour was successfully measured by using two source positions within DHI showing that the TM has a conical shape. Its maximum depth was found to be 2 mm, considering the umbo as the reference point with respect to the TM annulus plane, where the setup is arranged in such a manner that it is capable of measuring a height of up to 7 mm. PMID:23243570

  10. Comparison of digital holographic interferometry and constant temperature anemometry for measurement of temperature field in fluid

    NASA Astrophysics Data System (ADS)

    Doleček, Roman; Psota, Pavel; Lédl, Vít.; Vít, Tomáś; Dančová, Petra; Kopecký, Václav

    2015-05-01

    The presented paper shows possibility of using digital holographic interferometry (DHI) for temperature field measurement in moving fluids. This method uses a modified Twymann-Green setup having double sensitivity instead of commonly used Mach-Zehnder type of interferometer in order to obtain sufficient phases change of the field. On the other hand this setup is not light efficient as Mach-Zehnder interferometer. For measurement of the fast periodical phenomenon is not necessary to use always the high speed camera. One can consider this field to coherent phenomenon. With employing one digital camera synchronized to periodic field and external triggered one can capture whole period of the phenomenon. However the projections form one viewing direction of asymmetrical temperature field maybe misguided. Hence for sufficient examination of the asymmetrical field one should capture a large number of the phenomenon's projections from different viewing directions. This projections are later used for 3D tomographic reconstruction of the whole temperature field and its time evolution. One of the commonly used method for temperature field measurement in moving fluids is hot wire method - constant temperature anemometry (CTA). In contrast to whole field measurement of DHI it is an invasive point temperature measurement method. One of the limiting factor of using CTA in moving fluids is frequency of temperature changes. This changes should not exceed 1 kHz. This limitation could be overcome by using of optical methods such as DHI. The results of temperature field measurement achieved by both method are compared in the paper.

  11. Tympanic membrane contour measurement with two source positions in digital holographic interferometry

    PubMed Central

    Solís, Silvino M.; Hernández-Montes, María del S.; Santoyo, Fernando M.

    2012-01-01

    The data acquisition from the shape of an object is a must to complete its quantitative displacement measurement analysis. Over the past years whole field of view optical non-invasive testing has been widely used in many areas, from industrial ones to, for instance, biomedical research topics. To measure the surface contour from the tympanic membrane (TM) of ex-vivo cats digital holographic interferometry (DHI) is used in combination with a two-illumination positions method: the shape is directly measured from the phase change between two source positions by means of a digital Fourier transform method. The TM shape data in conjunction with its displacement data renders a complete and accurate description of the TM deformation, a feature that no doubt will serve to better comprehend the hearing process. Acquiring knowledge from the tissue shape indicates a mechanical behavior and, indirectly, an alteration in the physiological structure due to middle ear diseases or damages in the tissue that can deteriorate sound transmission. The TM shape contour was successfully measured by using two source positions within DHI showing that the TM has a conical shape. Its maximum depth was found to be 2 mm, considering the umbo as the reference point with respect to the TM annulus plane, where the setup is arranged in such a manner that it is capable of measuring a height of up to 7 mm. PMID:23243570

  12. A scheme for recording a fast process at nanosecond scale by using digital holographic interferometry with continuous wave laser

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Zhao, Jianlin; Di, Jianglei; Jiang, Biqiang

    2015-04-01

    A scheme for recording fast process at nanosecond scale by using digital holographic interferometry with continuous wave (CW) laser is described and demonstrated experimentally, which employs delayed-time fibers and angular multiplexing technique and can realize the variable temporal resolution at nanosecond scale and different measured depths of object field at certain temporal resolution. The actual delay-time is controlled by two delayed-time fibers with different lengths. The object field information in two different states can be simultaneously recorded in a composite hologram. This scheme is also suitable for recording fast process at picosecond scale, by using an electro-optic modulator.

  13. Systematic approach based on holographic interferometry measurements to characterize the flame structure of partially premixed flames.

    PubMed

    Xiao, X; Puri, I K

    2001-02-20

    Partially premixed flames (PPF's) represent a class of hybrid flames that contain multiple reaction zones. A detailed understanding of the temperature distribution in PPF's is important from both practical and scientific considerations. Path-integrated or line-of-sight measurement techniques, such as holographic interferometry (HI), that are based on the change in the optical phase of a light beam can be used to reconstruct the refractive index n in flames and thereafter to infer the temperature distribution. Therefore to describe the flame structure in the context of these measurements requires that a systematic approach be developed that relates the density, the temperature, and the composition to the refractive index. We demonstrate that a conserved scalar xi that transforms the flame structure from a spatial to a generic distribution can be inferred from the refractive-index distribution. Thereafter measurements of the density, the temperature, and the composition in two-dimensional PPF's become feasible. We report the first application, to our knowledge, of this method to HI. Specifically, we used HI to measure the refractive-index distributions in methane-air PPF's. One PPF is a double flame that has two reaction zones, and the other is a triple flame that contains three reaction zones. We have applied the procedure to infer the distribution of the modified mixture fraction and thereafter the local temperature and the local mass fractions. We find the local temperature differences, DT(x, y) = |T[n(x, y)] - T?[xi(x, y)]|, to be relatively small. We conclude that it is possible to use HI to infer the mixture-fraction distribution and thereafter the flame structures by the application of state relations in the case of PPF's. PMID:18357052

  14. SU-E-T-196: Heat Diffusion Modeling for Digital Holographic Interferometry Dosimetry

    SciTech Connect

    Cavan, A; Meyer, J

    2014-06-01

    Purpose: We have previously demonstrated that with Digital Holographic Interferometry (DHI) 2D spatial calorimetric measurements of high dose rate radiation sources can be obtained. The impact of heat transfer must be considered when undertaking any form of calorimetric measurement, as the radiation induced temperature distributions are subject to degradation due to heat diffusion. Unaccounted for, this limits the accuracy of the approach especially for long delivery times. Methods: 3D modelling of the heat diffusion in water was undertaken, and two different approaches developed to account for this effect. The mathematical framework to describe heat diffusion in 3D was applied, with the differential equations solved numerically using an implicit method. The first approach involved the comparison of the DHI measurements to an independent dose model of the source. The model was forward modeled to account for the heat diffusion during irradiation, allowing a direct comparison to validate the measured results. The second approach involved the correction of the measured data directly, by comparing the temperature distribution of two instances and subtracting the effects of heat diffusion of the first distribution from the second instance. This required the use of the Abel transform to approximate the 3D dose distribution from the 2D DHI results, thus limiting the approach to radiation applications possessing cylindrical symmetry. Results: The first approach resulted in higher accuracy and was more straightforward, but has a major limitation in that the measured results are only able to be utilized in comparison with an independent dose model. The applicability of the second approach is affected by noise in the measurement data and introduces higher uncertainties, but results in higher usability of the final data. Conclusion: Both approaches were implemented, and if used in conjunction would provide the most utility for the interpretation and use of DHI measurements.

  15. Digital holographic interferometry: A novel optical calorimetry technique for radiation dosimetry

    SciTech Connect

    Cavan, Alicia; Meyer, Juergen

    2014-02-15

    Purpose: To develop and demonstrate the proof-of-principle of a novel optical calorimetry method to determine radiation absorbed dose in a transparent medium. Methods: The calorimetric property of water is measured during irradiation by means of an interferometer, which detects temperature-induced changes in the refractive index that can be mathematically related to absorbed dose. The proposed method uses a technique called digital holographic interferometry (DHI), which comprises an optical laser interferometer setup and consecutive physical reconstruction of the recorded wave fronts by means of the Fresnel transform. This paper describes the conceptual framework and provides the mathematical basis for DHI dosimetry. Dose distributions from a high dose rate Brachytherapy source were measured by a prototype optical setup to demonstrate the feasibility of the approach. Results: The developed DHI dosimeter successfully determined absorbed dose distributions in water in the region adjacent to a high dose rate Brachytherapy source. A temperature change of 0.0381 K across a distance of 6.8 mm near the source was measured, corresponding to a dose of 159.3 Gy. The standard deviation in a typical measurement set was ±3.45 Gy (corresponding to an uncertainty in the temperature value of ±8.3 × 10{sup −4} K). The relative dose fall off was in agreement with treatment planning system modeled data. Conclusions: First results with a prototype optical setup and a Brachytherapy source demonstrate the proof-of-principle of the approach. The prototype achieves high spatial resolution of approximately 3 × 10{sup −5} m. The general approach is fundamentally independent of the radiation type and energy. The sensitivity range determined indicates that the method is predominantly suitable for high dose rate applications. Further work is required to determine absolute dose in all three dimensions.

  16. Experimental research on thermocapillary migration of drops by using digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Zhang, Shuoting; Duan, Li; Kang, Qi

    2016-07-01

    The thermocapillary migration of drops in a rectangular cell, with a heated top wall and a cooled bottom wall, was investigated experimentally on the ground. The rectangular test cell was 70 mm high, with a horizontal cross section of 40 mm × 40 mm. In the present experiment, 30 cSt silicon oil was used as the continuous phase, and a water-ethanol mixture was used as the drop phase, respectively. The drops ranged in size from 1.87 to 6.94 mm in diameter and were injected into the continuous phase, where the temperature gradients ranged from 0.193 to 0.484 °C mm-1. In order to measure the temperature distribution of the liquid, a digital holographic interferometry was used, which was non-contact, full-field, and in-situ. The holograms were recorded, and then the corresponding wrapped phase distributions images were numerically reconstructed. The temperature distribution of the continuous phase liquid in the cell had been obtained following the unwrapping. Also, through an algebra layer analysis, the temperature distribution around the drop during the thermocapillary migration was obtained. As a result, the drop was colder than the continuous phase liquid, and a thermal wake existed behind the drop. The influence of convective transport on the drop migration was also investigated for the Marangoni number in the range of 7-174. With the increasing of the Marangoni number, the dimensionless interface temperature difference decreased, which was caused by the convective transport enhanced results in the drop thermocapillary migration velocity becoming decreased. The data were compared with previous space experiments to explain the phenomena of the drop migration. Finally, with the increasing Marangoni numbers, the length of the thermal wake region increased, and the thermal wake region became extended.

  17. Laser-ablation-induced refractive index fields studied using pulsed digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Amer, Eynas; Gren, Per; Sjödahl, Mikael

    2009-07-01

    Pulsed digital holographic interferometry has been used to investigate the plume and the shock wave generated in the ablation process of a Q-switched Nd-YAG ( λ=1064 nm and pulse duration=12 ns) laser pulse on a polycrystalline boron nitride (PCBN) target under atmospheric air pressure. A special setup based on two synchronised wavelengths from the same laser for simultaneous processing and measurement has been used. Digital holograms were recorded for different time delays using collimated laser light ( λ=532 nm) passed through the volume along the target. Numerical data of the integrated refractive index field were calculated and presented as phase maps showing the propagation of the shock wave and the plume generated by the process. Radon inversion has been used to estimate the 3D refractive index fields measured from the projections assuming rotational symmetry. The shock wave density has been calculated using the point explosion model and the shock wave condition equation and its behaviour with time at different power densities ranging from 1.4 to 9.1 GW/cm 2 is presented. Shock front densities have been calculated from the reconstructed refractive index fields using the Gladstone-Dale equation. A comparison of the shock front density calculated from the reconstructed data and that calculated using the point explosion model at different time delays has been done. The comparison shows quite good agreement between the model and the experimental data. Finally the reconstructed refractive index field has been used to estimate the electron number density distribution within the laser-induced plasma. The electron number density behaviour with distance from the target at different power densities and its behaviour with time are shown. The electron number densities are found to be in the order of 10 18 cm -3 and decay at a rate of 3×10 15 electrons/cm 3 ns.

  18. Application_Of_Holographic_Interferometry To Problems In Geophysics And Detonics

    NASA Astrophysics Data System (ADS)

    Holloway, D. C.; Wilson, W. H.

    1985-02-01

    Holographic interferometry, with a Q-switched Ruby laser, has been used for laboratory study of dynamic problems in geophysics and detonics. The holograms provided not only the images of transient phenomena not visible in ordinary high speed photography, but also the data needed to analyze wave speeds and particle motions in solids, or density and pressure in gasses. Explosively driven cracks in rock plates have been studied dynamically by a modification to the usual timing sequence, in which both laser pulses occur after the explosive loading, and within less than a microsecond of each other. Changes in surface displacements, due to the stress wave motion in the model between exposures, cause interferometric fringes which are discontinuous along crack boundaries in the material. This method has successfully located cracks which would not be visible by normal optical methods. Surface and near-surface disturbances propagating in the earth from blasting sites were studied. Three-dimensional models were explosively loaded at points on the model surfaces. Holograms made at various delay times after loading showed the model's surface motions due to waves propagating from the source. Interactions of waves from two neighboring sources and wave interactions with steps and trenches in the model surface have been analyzed. Rayleigh waves crossing trenches were shown to undergo significant reductions in total particle displacement, particle velocity, and frequency content. It was also shown that as the diltational wave crosses steps or trenches, a substantial new Rayleigh wave is generated and propagates ahead of the source Rayleigh wave. Air shock due to explosive detonations has also been studied. Transmission holograms were made of the shock wave at the open end of a fine tube internally lined with an explosive coating.

  19. NDT testing by holographic interferometry applied to the structural diagnostic of artwork conservations by means of sound wave excitation

    NASA Astrophysics Data System (ADS)

    Vincitorio, Fabio; Ramil, Alberto; López, Ana J.; Saavedra, Emilio; Yáñez, Armando

    2008-06-01

    Techniques based on holographic interferometry have achieved a mature state of non destructive testing applications in industry and nowadays they are rising as interesting and promising tools in the field of conservation practices; giving information about the condition of structural integration of artworks. In the practice of these techniques it is necessary to generate a relative deformation in the object under study. Depending of the characteristics of the artwork, different methods may be used to achieve the desired displacement; being thermal excitation by means of filament lamps and wave sounds generated by speakers the most common. By applying these methods the deformation process usually involves a large area of the object, which limits the information obtained of a finite region. However, the use of a wave sound emitter of small dimensions, like a low power monotone buzzer, allows to decrease the affected area and to obtain information about the structural integrity of localized points of the surface. In the present study conventional double exposure double way holographic technique based on holographic films was used to obtain an out of plain deformation pattern caused by a sound emitter in an oil painting which has suffered heavy structural damage. Optimization of the excitation sound wave characteristics (frequency and amplitude) and the adjustment and calibration of the experimental set up, in order to obtain precise information about the physical and mechanical integrity of localized points of the painting are reported.

  20. Dual-polarization interferometry: an analytical technique to measure changes in protein structure in real time, to determine the stoichiometry of binding events, and to differentiate between specific and nonspecific interactions.

    PubMed

    Swann, Marcus J; Peel, Louise L; Carrington, Simon; Freeman, Neville J

    2004-06-15

    The study of solution-phase interactions between small molecules and immobilized proteins is of intense interest, especially to the pharmaceutical industry. An optical sensing technique, dual polarization interferometry, has been employed for the detailed study of a model protein system, namely, d-biotin interactions with streptavidin immobilized on a solid surface. Changes in thickness and density of an immobilized streptavidin layer as a result of the binding of d-biotin have been directly measured in solution and in real time. The results obtained from this approach are in excellent agreement with X-ray crystallographic data for the structural changes expected in the streptavidin-D-biotin system. The mass changes measured on binding d-biotin also agree closely with anticipated binding capacity values. Determination of the density changes occurring in the protein adlayer provides a means for differentiation between specific and nonspecific interactions. PMID:15158477

  1. Application of holographic interferometric studies of underwater shock-wave focusing to medicine

    NASA Astrophysics Data System (ADS)

    Takayama, Kazuyoshi; Nagoya, H.; Obara, Tetsuro; Kuwahara, M.

    1993-01-01

    Holographic interferometric flow visualization was successfully applied to underwater shock wave focusing and its application to extracorporeal shock wave lithotripsy (ESWL). Real time diffuse holograms revealed the shock wave focusing process in an ellipsoidal reflector made from PMMA and double exposure holographic interferometry also clarified quantitatively the shock focusing process. Disintegration of urinary tract stones and gallbladder stones was observed by high speed photogrammetry. Tissue damage associated with the ESWL treatment is discussed in some detail.

  2. Digital holographic Michelson interferometer for nanometrology

    NASA Astrophysics Data System (ADS)

    Sevrygin, Alexander A.; Korotkov, V. I.; Pulkin, S. A.; Tursunov, I. M.; Venediktov, D. V.; Venediktov, V. Yu.; Volkov, O. V.

    2014-11-01

    The paper considers the dynamic holographic interferometry schemes with amplification (multiplication) of holographic fringes and with correction for distortions, imposed by the interferometer scheme elements. The use of digital microscope and of the matrix light modulator with direct addressing provides the completely digital closed-loop performance of the overall system for real-time evaluation of nano-scale objects size. Considered schemes were verified in the laboratory experiment, using the Michelson micro-interferometer, equipped by the USB-microscope and digital holography stage, equipped by the Holoeye spatial light modulator.

  3. Holographic analysis as an inspection method for welded thin-wall tubing

    NASA Technical Reports Server (NTRS)

    Brooks, Lawrence; Mulholland, John; Genin, Joseph; Matthews, Larryl

    1990-01-01

    The feasibility of using holographic interferometry for locating flaws in welded tubing is explored. Two holographic techniques are considered: traditional holographic interferometry and electronic speckle pattern interferometry. Several flaws including cold laps, discontinuities, and tube misalignments are detected.

  4. Application of holographic interferometry to flow pattern visualization in a RTCVD reactor

    SciTech Connect

    Rainova, Yu.P.; Antonenko, K.I.; Pezoldt, J.; Eichhorn, G.

    1996-12-01

    This paper presents the development of an experimental technique for the reception of holographic interferograms of H{sub 2} and Ar flows in a RTCVD reactor with a complex geometry. The obtained holographic patterns were analyzed for the reconstruction of the gas flow in the RTCVD reactor. The fringe patterns showing the gas density distributions were recalculated into temperature distributions. Experimental results were compared with the predicted flow field.

  5. On-line surveillance of a dynamic process by a moving system based on pulsed digital holographic interferometry.

    PubMed

    Pedrini, Giancarlo; Alexeenko, Igor; Osten, Wolfgang; Schnars, Ulf

    2006-02-10

    A method based on pulsed digital holographic interferometry for the measurement of dynamic deformations of a surface by using a moving system is presented. The measuring system may move with a speed of several meters per minute and can measure deformation of the surface with an accuracy of better than 50 nm. The deformation is obtained by comparison of the wavefronts recorded at different times with different laser pulses produced by a Nd:YAG laser. The effect due to the movement of the measuring system is compensated for by digital processing of the different holograms. The system is well suited for on-line surveillance of a dynamic process such as laser welding and friction stir welding. Experimental results are presented, and the advantages of the method are discussed. PMID:16512536

  6. On-line surveillance of a dynamic process by a moving system based on pulsed digital holographic interferometry

    SciTech Connect

    Pedrini, Giancarlo; Alexeenko, Igor; Osten, Wolfgang; Schnars, Ulf

    2006-02-10

    A method based on pulsed digital holographic interferometry for the measurement of dynamic deformations of a surface by using a moving system is presented. The measuring system may move with a speed of several meters per minute and can measure deformation of the surface with an accuracy of better than 50 nm. The deformation is obtained by comparison of the wavefronts recorded at different times with different laser pulses produced by a Nd:YAG laser. The effect due to the movement of the measuring system is compensated for by digital processing of the different holograms. The system is well suited for on-line surveillance of a dynamic process such as laser welding and friction stir welding. Experimental results are presented, and the advantages of the method are discussed.

  7. Evaluation of the uncertainty of phase-difference measurements in (quasi-)Fourier transform digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Doval, Ángel F.; Trillo, Cristina; López Vázquez, José Carlos; Fernández, José L.

    2015-08-01

    Estimation of the uncertainty is an essential requisite for high-end measurement systems. In this communication we derive an expression to evaluate the standard uncertainty of the phase-difference measurements resulting from Fourier and quasi-Fourier transform digital holographic interferometry. We apply the law of propagation of uncertainty, as defined in the "Guide to the expression of uncertainty in measurement" (GUM), to the digital reconstruction of two holograms by Fourier transformation and to the subsequent calculation of the phase change between the holographic reconstructions. The resulting expression allows the evaluation of the uncertainty of the phase difference at every pixel in the reconstruction plane in terms of the measured hologram brightness values and their uncertainty at the whole of the pixels of the original digital holograms. This expression is simplified by assuming a linear dependence between the uncertainty and the local value of the original holograms; in that case, the local uncertainty of the phase difference can be evaluated from the local complex values of the reconstructed holograms. We assess the behavior of the method by comparing the predicted standard uncertainty with the sample variance obtained from experiments conducted under repeatability conditions, and found a good correlation between both quantities. This experimental procedure can be also used to calibrate the parameters of the linear function relating the uncertainty with the local value of the digital holograms, for a given set of operational conditions of the acquisition device.

  8. Fringe localization requirements for three-dimensional flow visualization of shock waves in diffuse-illumination double-pulse holographic interferometry

    NASA Technical Reports Server (NTRS)

    Decker, A. J.

    1982-01-01

    A theory of fringe localization in rapid-double-exposure, diffuse-illumination holographic interferometry was developed. The theory was then applied to compare holographic measurements with laser anemometer measurements of shock locations in a transonic axial-flow compressor rotor. The computed fringe localization error was found to agree well with the measured localization error. It is shown how the view orientation and the curvature and positional variation of the strength of a shock wave are used to determine the localization error and to minimize it. In particular, it is suggested that the view direction not deviate from tangency at the shock surface by more than 30 degrees.

  9. VERSE - Virtual Equivalent Real-time Simulation

    NASA Technical Reports Server (NTRS)

    Zheng, Yang; Martin, Bryan J.; Villaume, Nathaniel

    2005-01-01

    Distributed real-time simulations provide important timing validation and hardware in the- loop results for the spacecraft flight software development cycle. Occasionally, the need for higher fidelity modeling and more comprehensive debugging capabilities - combined with a limited amount of computational resources - calls for a non real-time simulation environment that mimics the real-time environment. By creating a non real-time environment that accommodates simulations and flight software designed for a multi-CPU real-time system, we can save development time, cut mission costs, and reduce the likelihood of errors. This paper presents such a solution: Virtual Equivalent Real-time Simulation Environment (VERSE). VERSE turns the real-time operating system RTAI (Real-time Application Interface) into an event driven simulator that runs in virtual real time. Designed to keep the original RTAI architecture as intact as possible, and therefore inheriting RTAI's many capabilities, VERSE was implemented with remarkably little change to the RTAI source code. This small footprint together with use of the same API allows users to easily run the same application in both real-time and virtual time environments. VERSE has been used to build a workstation testbed for NASA's Space Interferometry Mission (SIM PlanetQuest) instrument flight software. With its flexible simulation controls and inexpensive setup and replication costs, VERSE will become an invaluable tool in future mission development.

  10. Comparison between holographic interferometry and high-speed videography techniques in the study of the reflection of plane shock waves

    NASA Astrophysics Data System (ADS)

    Barbosa, Filipe J.; Skews, Beric W.

    1997-05-01

    Double exposure holographic interferometry and high speed laser shadowgraph photography and videography are used to investigate the mutual reflection of two plane shock waves. Normally research on the transition from regular to Mach reflection is undertaken by allowing a plane shock wave to impinge on a wedge. However due to the boundary layer growth on the wedge, regular reflection persists at wedge angles higher than that allowed for by inviscid shock wave theory. Several bifurcated shock tubes have been constructed, wherein an initially planar shock wave is split symmetrically into two and then recombined at the trailing edge of a wedge. The plane of symmetry acts as an ideal rigid wall eliminating thermal and viscous boundary layer effects. The flow visualization system used needs to provide high resolution information on the shockwave, slipstream, triple point and vortex positions and angles. Initially shadowgraph and schlieren methods, with a Xenon light source, were used. These results, while proving useful, are not of a sufficient resolution to measure the Mach stem and slipstream lengths accurately enough in order to determine the transition point between regular and Mach reflection. To obtain the required image resolution a 2 joule double pulse ruby laser, with a 30 ns pulse duration, was used to make holographic interferograms. The combined advantages of holographic interferometry and the 30 ns pulse laser allows one to obtain much sharper definition, and more qualitative as well as quantitative information on the flow field. The disadvantages of this system are: the long time taken to develop holograms, the difficulty of aligning the pulse laser and the fact that only one image per test is obtained. Direct contact shadowgraphs were also obtained using the pulse ruby laser to help determine triple point trajectory angles. In order to provide further information a one million frames per second CCD camera, which can take up to 10 superimposed images, was

  11. Operating manual holographic interferometry system for 2 x 2 foot transonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Craig, J. E.

    1981-01-01

    A holographic interferometer system was installed in a 2X2 foot transonic wind tunnel. The system incorporates a modern, 10 pps, Nd:YAG pulsed laser which provides reliable operation and is easy to align. The spatial filtering requirements of the unstable resonator beam are described as well as the integration of the system into the existing Schieren system. A two plate holographic interferometer is used to reconstruct flow field data. For static wind tunnel models the single exposure holograms are recorded in the usual manner; however, for dynamic models such as oscillating airfoils, synchronous laser hologram recording is used.

  12. Interferometry

    NASA Technical Reports Server (NTRS)

    Ridgway, Stephen; Wilson, Robert W.; Begelman, Mitchell C.; Bender, Peter; Burke, Bernard F.; Cornwell, Tim; Drever, Ronald; Dyck, H. Melvin; Johnston, Kenneth J.; Kibblewhite, Edward

    1991-01-01

    The following recommended programs are reviewed: (1) infrared and optical interferometry (a ground-based and space programs); (2) compensation for the atmosphere with adaptive optics (a program for development and implementation of adaptive optics); and (3) gravitational waves (high frequency gravitational wave sources (LIGO), low frequency gravitational wave sources (LAGOS), a gravitational wave observatory program, laser gravitational wave observatory in space, and technology development during the 1990's). Prospects for international collaboration and related issues are also discussed.

  13. Strain, curvature, and twist measurements in digital holographic interferometry using pseudo-Wigner-Ville distribution based method

    SciTech Connect

    Rajshekhar, G.; Gorthi, Sai Siva; Rastogi, Pramod

    2009-09-15

    Measurement of strain, curvature, and twist of a deformed object play an important role in deformation analysis. Strain depends on the first order displacement derivative, whereas curvature and twist are determined by second order displacement derivatives. This paper proposes a pseudo-Wigner-Ville distribution based method for measurement of strain, curvature, and twist in digital holographic interferometry where the object deformation or displacement is encoded as interference phase. In the proposed method, the phase derivative is estimated by peak detection of pseudo-Wigner-Ville distribution evaluated along each row/column of the reconstructed interference field. A complex exponential signal with unit amplitude and the phase derivative estimate as the argument is then generated and the pseudo-Wigner-Ville distribution along each row/column of this signal is evaluated. The curvature is estimated by using peak tracking strategy for the new distribution. For estimation of twist, the pseudo-Wigner-Ville distribution is evaluated along each column/row (i.e., in alternate direction with respect to the previous one) for the generated complex exponential signal and the corresponding peak detection gives the twist estimate.

  14. Real-Time Gauge/Gravity Duality

    SciTech Connect

    Skenderis, Kostas; Rees, Balt C. van

    2008-08-22

    We present a general prescription for the holographic computation of real-time n-point functions in nontrivial states. In quantum field theory such real-time computations involve a choice of a time contour in the complex time plane. The holographic prescription amounts to 'filling in' this contour with bulk solutions: real segments of the contour are filled in with Lorentzian solutions while imaginary segments are filled in with Riemannian solutions and appropriate matching conditions are imposed at the corners of the contour. We illustrate the general discussion by computing the 2-point function of a scalar operator using this prescription and by showing that this leads to an unambiguous answer with the correct i{epsilon} insertions.

  15. Strain determination in bone sections with simultaneous 3D digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Alvarez, Araceli Sánchez; De la Torre Ibarra, Manuel H.; Santoyo, Fernando Mendoza; Anaya, Tonatiuh-Saucedo

    2014-06-01

    A 3D digital holographic interferometer was used to measure the surface strain components in two different bovine's bone sections. The applied force on the sample was induced by a precisely controlled lateral micro compression. The simultaneous acquisition capability of the system helps to record a fast sequence of images, each one containing three independent holograms that result in three orthogonal displacement components u, v and w from which the surface strain components ɛx, ɛy and γxy over the bone's field of view were calculated. This research study was carried out in two different bone sections: the cortical bone and the medullary cavity/yellow marrow section. The resulting strain concentrators are of great importance to better understand the mechanical response of complex biological structures such as this bovine femoral bone.

  16. The use of holographic interferometry for turbomachinery fan evaluation during rotating tests

    NASA Astrophysics Data System (ADS)

    Parker, R. J.; Jones, D. G.

    1988-07-01

    Holography has been developed by Rolls-Royce as a technique for routine use in the evaluation of fan designs for aeroengines. It is used to investigate both aerodynamic and mechanical behavior of the rotating fan. Holographic flow visualization provides clear, three-dimensional images of the transonic flow region between the fan blades. Flow features such as shocks, shock/boundary layer interaction, and over-tip leakage vortices can be observed and measured. Holograms taken through an optical derotator allow vibration modes of the rotating fan to be mapped during resonance or flutter. Examples are given of the use of both techniques at rotational speeds up to and in excess of 10,000 rpm. Holography has provided valuable information used to verify and improve numerical modeling of the fan behavior and has been successful in evaluating the achievement of design intent.

  17. Real-time radiography

    SciTech Connect

    Bossi, R.H.; Oien, C.T.

    1981-02-26

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components.

  18. Optical interferometry in fluid dynamics research

    NASA Technical Reports Server (NTRS)

    Bachalo, W. D.; Houser, M. J.

    1987-01-01

    Optical interferometry techniques were applied to the investigation of transonic airfoil flow fields in large wind tunnels. Holographic interferometry techniques were used to study 2 dimensional symmetric NACA 64A010 and Douglas Aircraft Co. DSMA671 supercritical airfoil performance in the NASA Ames 2 x 2 ft transonic wind tunnel. Quantitative data obtained from the interferograms were compared to the surface pressure data. The agreement obtained verified the accuracy of the flow visualization and demonstrated the potential for acquiring quantitative scalar results. Measurements of the inviscid flow speed and the boundary layer and wake velocity profiles were extracted from the interferograms and compared to laser Doppler velocimeter measurements. These results were also in good agreement. A method for acquiring real time interferometric data in large scale facilities was developed. This method, based on the point diffraction interferometer, was successfully tested in the 2 x 2 ft transonic wind tunnel. The holographic and real time interferometry methods were applied to the investigations of circulation control airfoils utilizing the Coanda effect. These results reveals the details of the jet interacting with the trailing edge boundary layer and the other parameters affecting the lift augmentation.

  19. Optical interferometry in fluid dynamics research

    NASA Technical Reports Server (NTRS)

    Bachalo, W. D.; Houser, M. J.

    1985-01-01

    Optical interferometry techniques have been applied to the investigation of transonic airfoil flow fields in large-scale wind tunnels. Holographic interferometry techniques were used in the study of two-dimensional symmetric NACA 64A010 and Douglas Aircraft Company DSMA671 supercritical airfoil performance in the NASA Ames 2 ft x 2 ft transonic wind tunnel. Quantitative data obtained from the interferograms were compared to the surface pressure data. The excellent agreement obtained verified the accuracy of the flow visualization and demonstrated the potential for acquiring quantitative scalar results. Measurements of the inviscid flow speed and the boundary layer and wake velocity profiles were extracted from the interferograms and compared to laser Doppler velocimeter measurements. These results were also in good agreement. A method for acquiring real-time interferometric data in large-scale facilities was developed. This method, based on the point diffraction interferometer, was successfully tested in the Ames 2 ft x 2 ft transonic wind tunnel. The holographic and real-time interferometry methods were applied to the investigations of circulation control airfoils utilizing the Coanda effect. These results revealed the details of the jet interaction with the trailing edge boundary layer and the other parameters affecting the lift augmentation.

  20. Optical phase analysis in drilled cortical porcine bones using digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Tavera R., César G.; De la Torre I., Manuel H.; Flores M., J. Mauricio; Luna H., Juan M.; Briones R., Manuel de J.; Mendoza S., Fernando

    2016-03-01

    A study in porcine femoral bones with and without the presence of cortical drilling is presented. An out of plane digital holographic interferometer is used to retrieve the optical phase during the controlled compression tests. These tests try to simulate physiological deformations in postmortem healthy bones and compare their mechanical response with those having a cortical hole. The cortical drilling technique is widely used in medical procedures to fix plaques and metallic frames to a bone recovering from a fracture. Several materials and drilling techniques are used for this purpose. In this work we analyze the superficial variations of the bone when different drilling diameters are used. By means of the optical phase it is possible to recover the superficial deformation of the tissue during a controlled deformation with high resolution. This information could give a better understand about the micro structural variations of the bone instead of a bulk response. As proof of principle, several tests were performed to register the modes and ranges of the displacements for compressive loads. From these tests notorious differences are observed between both groups of bones, having less structural stiffness the drilled ones as expected. However, the bone's characteristic to absorb and adjust itself due the load is also highly affected according to the number of holes. Results from different kind of samples (undrilled and drilled) are presented and discussed in this work.

  1. Real-Time Simulation

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Coryphaeus Software, founded in 1989 by former NASA electronic engineer Steve Lakowske, creates real-time 3D software. Designer's Workbench, the company flagship product, is a modeling and simulation tool for the development of both static and dynamic 3D databases. Other products soon followed. Activation, specifically designed for game developers, allows developers to play and test the 3D games before they commit to a target platform. Game publishers can shorten development time and prove the "playability" of the title, maximizing their chances of introducing a smash hit. Another product, EasyT, lets users create massive, realistic representation of Earth terrains that can be viewed and traversed in real time. Finally, EasyScene software control the actions among interactive objects within a virtual world. Coryphaeus products are used on Silican Graphics workstation and supercomputers to simulate real-world performance in synthetic environments. Customers include aerospace, aviation, architectural and engineering firms, game developers, and the entertainment industry.

  2. Real-Time PCR

    NASA Astrophysics Data System (ADS)

    Evrard, A.; Boulle, N.; Lutfalla, G. S.

    Over the past few years there has been a considerable development of DNA amplification by polymerase chain reaction (PCR), and real-time PCR has now superseded conventional PCR techniques in many areas, e.g., the quantification of nucleic acids and genotyping. This new approach is based on the detection and quantification of a fluorescent signal proportional to the amount of amplicons generated by PCR. Real-time detection is achieved by coupling a thermocycler with a fluorimeter. This chapter discusses the general principles of quantitative real-time PCR, the different steps involved in implementing the technique, and some examples of applications in medicine. The polymerase chain reaction (PCR) provides a way of obtaining a large number of copies of a double-stranded DNA fragment of known sequence. This DNA amplification technique, developed in 1985 by K. Mullis (Cetus Corporation), saw a spectacular development over the space of a few years, revolutionising the methods used up to then in molecular biology. Indeed, PCR has many applications, such as the detection of small amounts of DNA, cloning, and quantitative analysis (assaying), each of which will be discussed further below.

  3. Interferometer real time control development for SIM

    NASA Astrophysics Data System (ADS)

    Bell, Charles E.

    2003-02-01

    Real Time Control (RTC) for the Space Interferometry Mission will build on the real time core interferometer control technology under development at JPL since the mid 1990s, with heritage from the ground based MKII and Palomar Testbed Interferometer projects developed in the late '80s and early '90s. The core software and electronics technology for SIM interferometer real time control is successfully operating on several SIM technology demonstration testbeds, including the Real-time Interferometer Control System Testbed, System Testbed-3, and the Microarcsecond Metrology testbed. This paper provides an overview of the architecture, design, integration, and test of the SIM flight interferometer real time control to meet challenging flight system requirements for the high processor throughput, low-latency interconnect, and precise synchronization to support microarcsecond-level astrometric measurements for greater than five years at 1 AU in Earth-trailing orbit. The electronics and software architecture of the interferometer real time control core and its adaptation to a flight design concept are described. Control loops for pointing and pathlength control within each of four flight interferometers and for coordination of control and data across interferometers are illustrated. The nature of onboard data processing to fit average downlink rates while retaining post-processed astrometric measurement precision and accuracy is also addressed. Interferometer flight software will be developed using a software simulation environment incorporating models of the metrology and starlight sensors and actuators to close the real time control loops. RTC flight software and instrument flight electronics will in turn be integrated utilizing the same simulation architecture for metrology and starlight component models to close real time control loops and verify RTC functionality and performance prior to delivery to flight interferometer system integration at Lockheed Martin

  4. Temperature measurement of axi- symmetric butane diffusion flame under the influence of upward decreasing gradient magnetic field using digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Kumar, Varun; Kumar, Manoj; Shakher, Chandra

    2015-08-01

    In this paper, digital holographic interferometry (DHI) is implemented to investigate the effect of upward decreasing gradient magnetic field on the temperature and temperature profile of diffusion flame created by butane torch burner. In the experiment double exposure digital holographic interferometry is used to calculate the temperature distribution inside the flame. First a digital hologram is recorded in the absence of flame and second hologram is recorded in the presence of flame. Phases in two different states of air (i.e. in absence of flame and presence of flame) are reconstructed individually by numerical method. The phase difference map is obtained by subtracting the reconstructed phase of air in presence and absence of flame. Refractive index inside the flame is obtained from the axi-symmetric phase difference data using the Abel inversion integral. Temperature distribution inside the flame is calculated from the refractive index data using Lorentz - Lorentz equation. Experiment is conducted on a diffusion flame created by butane torch burner in the absence of magnetic field and in presence of upward decreasing gradient magnetic field. Experimental investigations reveal that the maximum temperature inside the flame increases under the influence of upward decreasing magnetic field.

  5. Real time Faraday spectrometer

    DOEpatents

    Smith, Jr., Tommy E.; Struve, Kenneth W.; Colella, Nicholas J.

    1991-01-01

    This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

  6. Real-Time Optical Correlator Based On GaAs

    NASA Technical Reports Server (NTRS)

    Liu, Tsuen-Hsi; Cheng, Li-Jen

    1992-01-01

    Apparatus performs correlation between input image and reference image in real time by means of degenerate four-wave mixing in photorefractive crystal, which serves as real-time holographic medium. Gallium arsenide chosen to be photorefractive material in this application because at frame rate and level of illumination used in experiments, offers adequate diffraction efficiency. Frame rates as high as 1,000 s to negative 1st power achievable.

  7. Real time automated inspection

    DOEpatents

    Fant, Karl M.; Fundakowski, Richard A.; Levitt, Tod S.; Overland, John E.; Suresh, Bindinganavle R.; Ulrich, Franz W.

    1985-01-01

    A method and apparatus relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges are segmented out by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections.

  8. Real time automated inspection

    DOEpatents

    Fant, K.M.; Fundakowski, R.A.; Levitt, T.S.; Overland, J.E.; Suresh, B.R.; Ulrich, F.W.

    1985-05-21

    A method and apparatus are described relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections. 43 figs.

  9. Real time polarimetric dehazing.

    PubMed

    Mudge, Jason; Virgen, Miguel

    2013-03-20

    Remote sensing is a rich topic due to its utility in gathering detailed accurate information from locations that are not economically feasible traveling destinations or are physically inaccessible. However, poor visibility over long path lengths is problematic for a variety of reasons. Haze induced by light scatter is one cause for poor visibility and is the focus of this article. Image haze comes about as a result of light scattering off particles and into the imaging path causing a haziness to appear on the image. Image processing using polarimetric information of light scatter can be used to mitigate image haze. An imaging polarimeter which provides the Stokes values in real time combined with a "dehazing" algorithm can automate image haze removal for instant applications. Example uses are to improve visual display providing on-the-spot detection or imbedding in an active control loop to improve viewing and tracking while on a moving platform. In addition, removing haze in this manner allows the trade space for a system operational waveband to be opened up to bands which are object matched and not necessarily restricted by scatter effects. PMID:23518739

  10. One-shot and aberration-tolerable homodyne detection for holographic storage readout through double-frequency grating-based lateral shearing interferometry.

    PubMed

    Yu, Yeh-Wei; Xiao, Shuai; Cheng, Chih-Yuan; Sun, Ching-Cherng

    2016-05-16

    A simple method to decode the stored phase signal of volume holographic data storage with adequate wave aberration tolerance is highly demanded. We proposed and demonstrated a one-shot scheme to decode a binary-phase encoding signal through double-frequency-grating based shearing interferometry (DFGSI). The lateral shearing amount is dependent on the focal length of the collimated lens and the frequency difference between the gratings. Diffracted waves with phase encoding were successfully decoded through experimentation. An optical model for the DFGSI was built to analyze phase-error induction and phase-difference control by shifting the double-frequency grating longitudinally and laterally, respectively. The optical model was demonstrated experimentally. Finally, a high aberration tolerance of the DFGSI was demonstrated using the optical model. PMID:27409865

  11. Combination of temporal phase unwrapping and long-wave infrared digital holographic interferometry for metrology of mosaic detector under space simulated conditions

    NASA Astrophysics Data System (ADS)

    Vandenrijt, Jean-François; Thizy, Cédric; Beaumont, Florent; Garcia, José; Martin, Laurent; Fabron, Christophe; Prieto, Eric; Maciaszek, Thierry; Georges, Marc P.

    2015-08-01

    We present digital holographic interferometry (DHI) in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array to be used in a space mission. The long wavelength was chosen for its ability to allow measurement of displacements 20 times larger than DHI in the visible and which were foreseen with the test object under such temperature changes. The specimen consists of 4x4 mosaic of detectors assembled on a frame. It was required to assess the global deformation of the ensemble, the deformation of each detector, and piston movements of each of them with respect to their neighbors. For that reason we incorporated the temporal phase unwrapping by capturing a sufficiently high number of holograms between which the phase does not suffer strong variations. At last since the specimen exhibit specular reflectivity at that wavelength, it is illuminated through a reflective diffuser.

  12. Quasi-Heterodyne Hologram Interferometry

    NASA Astrophysics Data System (ADS)

    Hariharan, P.

    1985-08-01

    Wider use of hologram interferometry for quantitative measure-ments has been delayed by the fact that interpolation between the fringe maxima and minima to obtain the optical path difference at a particular point in the field is laborious and inaccurate. A solution to this problem is quasi-hetero-dyne interferometry, which permits rapid and accurate measurements simultaneously at a number of points distributed over the interference pattern. In this technique a television camera is used in conjunction with digital electronics to measure and store the irradiance values at points on a rectangular sampling grid covering the real-time interference fringes. The phase difference between the interfering wavefronts at each point is then calculated from the irradiance values obtained from successive scans of the camera made while the phase of one of the wavefronts is shifted either continuously or in steps. A practical system is described with which values of the optical path difference for 10,000 data points can be obtained with an accuracy of +/- A/200 in less than 10 s. The application of quasi-heterodyne hologram interferometry to the measurement of vector displacements and to holographic contouring is discussed.

  13. Real-Time Benchmark Suite

    Energy Science and Technology Software Center (ESTSC)

    1992-01-17

    This software provides a portable benchmark suite for real time kernels. It tests the performance of many of the system calls, as well as the interrupt response time and task response time to interrupts. These numbers provide a baseline for comparing various real-time kernels and hardware platforms.

  14. Experimental investigation of solid hydrogen pellet ablation in high-temperature plasmas using holographic interferometry and other diagnostics

    SciTech Connect

    Thomas, Jr., C. E.

    1981-03-01

    The technology currently most favored for the refueling of fusion reactors is the high-velocity injection of solid hydrogen pellets. Design details are presented for a holographic interferometer/shadowgraph used to study the microscopic characteristics of a solid hydrogen pellet ablating in an approx. 1-keV plasma. Experimental data are presented for two sets of experiments in which the interferometer/shadowgraph was used to study approx. 1-mm-diam solid hydrogen pellets injected into the Impurity Study Experiment (ISX-B) tokamak at Oak Ridge National Laboratory (ORNL) at velocities of 1000 m/s. In addition to the use of the holographic interferometer, the pellet ablation process is diagnosed by studying the emission of Balmer-alpha photons and by using the available tokamak diagnostics (Thomson scattering, microwave/far-infrared interferometer, pyroelectric radiometer, hard x-ray detector).

  15. Real-time flutter identification

    NASA Technical Reports Server (NTRS)

    Roy, R.; Walker, R.

    1985-01-01

    The techniques and a FORTRAN 77 MOdal Parameter IDentification (MOPID) computer program developed for identification of the frequencies and damping ratios of multiple flutter modes in real time are documented. Physically meaningful model parameterization was combined with state of the art recursive identification techniques and applied to the problem of real time flutter mode monitoring. The performance of the algorithm in terms of convergence speed and parameter estimation error is demonstrated for several simulated data cases, and the results of actual flight data analysis from two different vehicles are presented. It is indicated that the algorithm is capable of real time monitoring of aircraft flutter characteristics with a high degree of reliability.

  16. Real-time software receiver

    NASA Technical Reports Server (NTRS)

    Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

    2007-01-01

    A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

  17. Real-time refinery optimization

    SciTech Connect

    Kennedy, J.P.

    1989-05-01

    This article discusses refinery operation with specific consideration of the topics of: gasoline; control projects; catalytic reforming control; hydrocracker control packages; blending optimization; real-time data acquisition; and other plant automation packages.

  18. Real-time software receiver

    NASA Technical Reports Server (NTRS)

    Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

    2006-01-01

    A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

  19. Holographic interferometric tomography for reconstructing flow fields

    NASA Technical Reports Server (NTRS)

    Cha, Soyoung S.

    1994-01-01

    Holographic interferometric tomography is a technique for instantaneously capturing and quantitatively reconstructing three-dimensional flow fields. It has a very useful application potential for high-speed aerodynamics. However, three major challenging tasks need to be accomplished before its practical applications. First, fluid flows are mostly unsteady or at least non repeatable. Consequently, a means for Instantaneously recording three-dimensional flow fields, that is, a simple holographic technique for simultaneously recording multi-directional projections, needs to be developed. Second, while holographic interferometry provides enormous data storage capabilities, expeditious data extraction from complicated interferograms is very important for timely near real-time applications. Third, unlike medical applications, flow tomography does not provide complete data sets but instead involves ill-posed reconstruction problems of incomplete projection and limited angular scanning. During this summer research period, new experimental techniques and corresponding hardware were developed and tested to address the above mentioned tasks. The first task was achieved by diffuser illumination. This concept allows instantaneous capture of many projections with a conventional setup for single-projection recording. For the second task, a phase-shifting technique was incorporated. This technique allows one to acquire multiple phase-stepped interferograms for a single projection and thus to extract phase information from intensity data almost at real-time. For the third task, the research that has been extensively conducted previously was utilized. In this research period, a complete experimental setup that provides the above three major capabilities was designed, built, and tested by integrating all the techniques. A simple laboratory experiment for simulating wind-tunnel testing was then conducted. A test flow was produced by employing a relatively simple device that generated

  20. Real Time Data System (RTDS)

    NASA Technical Reports Server (NTRS)

    Muratore, John F.

    1991-01-01

    Lessons learned from operational real time expert systems are examined. The basic system architecture is discussed. An expert system is any software that performs tasks to a standard that would normally require a human expert. An expert system implies knowledge contained in data rather than code. And an expert system implies the use of heuristics as well as algorithms. The 15 top lessons learned by the operation of a real time data system are presented.

  1. Real-time vision systems

    SciTech Connect

    Johnson, R.; Hernandez, J.E.; Lu, Shin-yee

    1994-11-15

    Many industrial and defence applications require an ability to make instantaneous decisions based on sensor input of a time varying process. Such systems are referred to as `real-time systems` because they process and act on data as it occurs in time. When a vision sensor is used in a real-time system, the processing demands can be quite substantial, with typical data rates of 10-20 million samples per second. A real-time Machine Vision Laboratory (MVL) was established in FY94 to extend our years of experience in developing computer vision algorithms to include the development and implementation of real-time vision systems. The laboratory is equipped with a variety of hardware components, including Datacube image acquisition and processing boards, a Sun workstation, and several different types of CCD cameras, including monochrome and color area cameras and analog and digital line-scan cameras. The equipment is reconfigurable for prototyping different applications. This facility has been used to support several programs at LLNL, including O Division`s Peacemaker and Deadeye Projects as well as the CRADA with the U.S. Textile Industry, CAFE (Computer Aided Fabric Inspection). To date, we have successfully demonstrated several real-time applications: bullet tracking, stereo tracking and ranging, and web inspection. This work has been documented in the ongoing development of a real-time software library.

  2. High-density FPGAs for real-time video processing

    NASA Astrophysics Data System (ADS)

    Nordhauser, Steven; Beckstead, Jeffrey A.; Castracane, James; Koltai, Peter J.; Mouzakes, Jason; Simkulet, Michelle D.

    1997-04-01

    The use of an off-the-shelf general purpose processing system supplied by Giga Operations as applied to real-time video applications is described. The system is modular enough to be used in many scientific and industrial applications and powerful enough to maintain the throughput required for real-time video processing. This hardware and the associated programming environment has enabled InterScience to pursue research in real-time data compression, real-time Electronic Speckle Pattern Interferometry (ESPI) image processing, and industrial quality control and manufacturing. The system is based on Xilinx 4000 series field programmable gate arrays with associated static and dynamic random access memory in an architecture optimized for video processing on either the VL-Bus or PCI. This paper will focus on the design and development of a real-time frame subtractor for ESPI using this technology. Examples of the improvement in research capability provided by real-time frame subtraction are shown, including images from biomedical experiments. Further applications, based on this system are described. These include real-time data compression, quality control for production lines as part of an automated inspection system and a multi-camera security system allowing motion estimation to automatically prioritize camera selection.

  3. Simplest holographic technique: unsurpassed features very friendly to practical applications

    NASA Astrophysics Data System (ADS)

    Petrov, Valery

    1996-12-01

    Holography and holographic interferometry in spite of their attractive features are rather rarely used for industrial inspections of products and components or in medical practice due to relative complexity, costs, lengthy multi- stage procedures, need of dark rooms and vibration insulation. But the most of these drawbacks might be avoided if momental holography on silver halide (SH) media is involved. Momental technique simplifies drastically the holographic process and ensures quasi real time or real time (in situ) bright reconstructions from holograms, real time or double exposure holographic interferograms. This technique permits the user to avoid dark rooms and to work with standard office or industrial illumination of 0.5 klx or even much more. Moreover, very bright holograms and holographic interferograms might be obtained also in the street in a diffused daylight or even under strong direct sunlight illumination. High quality off-axis and reflection holograms, interferograms, HOE were obtained utilizing ruby, semiconductor, He-Ne and Ar laser sources. Agfa-Gevaert 8 E 75 HD films and plates, Russian PFG-03 and PFG-03 C (color) plates were used as recording media. Different levels of external polychromatic illumination were applied to holograms and holographic interferograms during production. Extremely high levels (more than 50 klx) were also tested. Bright holographic reconstructions were obtained even in such unpromising environment. Photographic images from such holograms are presented. One of the holograms was momentally photoprocessed in the light of projector (a few klx) during presentation of this paper at the conference 'Holographic and Diffractive Techniques' in Berlin. Another unique feature of the technique: extremely long-term storage of holographic data on SH media in latent form is shown. It relates both to holograms recorded with cw lasers and to those recorded with pulsed laser sources. The latter case is the most interesting because it was

  4. Real Time Sonic Boom Display

    NASA Technical Reports Server (NTRS)

    Haering, Ed

    2014-01-01

    This presentation will provide general information about sonic boom mitigation technology to the public in order to supply information to potential partners and licensees. The technology is a combination of flight data, atmospheric data and terrain information implemented into a control room real time display for flight planning. This research is currently being performed and as such, any results and conclusions are ongoing.

  5. Real Time Data System (RTDS)

    NASA Technical Reports Server (NTRS)

    Heindel, Troy A.

    1991-01-01

    Information is given in viewgraph form on the Real Time Data System (RTDS). Topics covered include applications to the Space Station Freedom, the Space Shuttle flight controllers, the Mission Control Center workstations, and the Remote Manipulator Systems (RMS). Also covered are the technology gap, pacing factors, and lessons learned during research.

  6. Holographic Interferometry (HI), Infrared Vision and X-Ray Fluorescence (XRF) spectroscopy for the assessment of painted wooden statues: a new integrated approach

    NASA Astrophysics Data System (ADS)

    Sfarra, Stefano; Ibarra-Castanedo, Clemente; Ridolfi, Stefano; Cerichelli, Giorgio; Ambrosini, Dario; Paoletti, Domenica; Maldague, Xavier

    2014-06-01

    Wood has been routinely employed in decorative arts, as well as in sculptures and paintings (support) during the Middle Ages, because of its unique aesthetic virtues. It may safely be assumed that wood, as a material for monumental sculpture, was much more commonly employed in the mediaeval period than existing examples would seem to indicate (Bulletin of the metropolitan Museum of Art, 2013). Wood is easily obtainable; it could be carved and put in place with less difficulty than stone, it is chemically stable when dry, and its surface offers a compatible substrate for paint application. However, the use of wood is not without pitfalls, and requires an understanding of its anisotropic and hygroscopic nature. It is also dimensionally unstable and subject to deterioration by fungi and insects. Moisture-related dimensional changes are certainly among the most challenging problems in painting conservation. With the purpose of preventing important damages, the use of non-or microdestructive testing (NDT) techniques is undoubtedly of paramount interest for painted wooden statues of great value. This work has a threefold purpose: (1) to validate the effectiveness of an integrated approach using near-infrared (NIR) reflectography, square pulse thermography (SPT), and holographic interferometry (HI) techniques for discovering old repairs and/or inclusions of foreign materials in a wooden structure, (2) to confirm and approximately date the restoration carried out by x-ray fluorescence (XRF) spectroscopy and energy-dispersive x-ray spectroscopy (EDS) (that is assembled with a scanning electron microscopy—SEM) techniques, and (3) to combine into a multidisciplinary approach two quantitative NDT results coming from optical and thermographic methods. The subject of the present study was a statue named "Virgin with her Child" (XIV century), whose origins are mysterious and not properly documented.

  7. Digital Holographic Logic

    NASA Technical Reports Server (NTRS)

    Preston, K., Jr.

    1972-01-01

    The characteristics of the holographic logic computer are discussed. The holographic operation is reviewed from the Fourier transform viewpoint, and the formation of holograms for use in performing digital logic are described. The operation of the computer with an experiment in which the binary identity function is calculated is discussed along with devices for achieving real-time performance. An application in pattern recognition using neighborhood logic is presented.

  8. Holography and the virtual patient: the holographic medical image

    NASA Astrophysics Data System (ADS)

    Ko, Kathryn; Erickson, Ronald R.; Webster, John M.

    1996-12-01

    Practical holographic systems utilizing the pulsed laser are finding potential applications in medicine. Exploiting both the hologram's true 3D image and holographic interferometry these techniques enhance the physician's vision beyond the 2D radiological imaging of even the best CT and MRI. The authors describe the use of pulsed laser holography as applied to the morphological specialties: anatomy, pathology, and surgery. The authors report on the Holographic Brain Anatomy Atlas for medical education; pathologic documentation with holography, and the use of holographic interferometry in surgical planning. The techniques are outlined and a discussion on the interpretation of holographic interferometry with living subjects is provided.

  9. Real-time tritium imaging

    SciTech Connect

    Malinowski, M.E.

    1981-09-15

    A real-time image of a tritium-containing titanium film has been made by detecting the secondary electrons produced by tritium ..beta.. decay with a simple two-element electrostatic lens and microchannel plate image intensifier. The obtained image indicates that a resolution of better than 100 ..mu..m is currently obtainable and suggests that image magnification to enhance resolution should be possible.

  10. Real Time Data System (RTDS)

    NASA Technical Reports Server (NTRS)

    Heindel, Troy A.

    1991-01-01

    Information is given in viewgraph form on the Real Time Data System (RTDS). The goals are to increase the quality of flight decision making, reduce and enhance flight controller training time, and serve as a near-operations technology test-bed. Information is given on the growth of RTDS; flight control disciplines; RTDS technology deployment in 1987-1989 and 1990-91; a functionality comparison of mainframes and workstations; and technology transfer activities.

  11. Real-time ultrasound elastography

    NASA Astrophysics Data System (ADS)

    Bae, Unmin; Kim, Yongmin

    2007-03-01

    Ultrasound elastography can provide tissue stiffness information that is complementary to the anatomy and blood flow information offered by conventional ultrasound machines, but it is computationally challenging due to many time-consuming modules and a large amount of data. To facilitate real-time implementations of ultrasound elastography, we have developed new methods that can significantly reduce the computational burden of common processing components in ultrasound elastography, such as the crosscorrelation analysis and spatial filtering applied to displacement and strain estimates. Using the new correlation-based search algorithm, the computational requirement of correlation-based search does not increase with the correlation window size. For typical parameters used in ultrasound elastography, the computation in correlation-based search can be reduced by a factor of more than 30. Median filtering is often performed to suppress the spike-like noise that results from correlation-based search. For fast median filtering, we have developed a method that efficiently finds a new median value utilizing the sort result of the previous pixel. With careful mapping of the new algorithms on digital signal processors, our work has led to development of a clinical ultrasound machine supporting real-time elastography. Our methods can help real-time implementations of various applications including ultrasound elastography, which could lead to increased use of ultrasound elastography in the clinic.

  12. [Real time 3D echocardiography].

    PubMed

    Bauer, F; Shiota, T; Thomas, J D

    2001-07-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients. PMID:11494630

  13. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  14. Real-time flutter analysis

    NASA Technical Reports Server (NTRS)

    Walker, R.; Gupta, N.

    1984-01-01

    The important algorithm issues necessary to achieve a real time flutter monitoring system; namely, the guidelines for choosing appropriate model forms, reduction of the parameter convergence transient, handling multiple modes, the effect of over parameterization, and estimate accuracy predictions, both online and for experiment design are addressed. An approach for efficiently computing continuous-time flutter parameter Cramer-Rao estimate error bounds were developed. This enables a convincing comparison of theoretical and simulation results, as well as offline studies in preparation for a flight test. Theoretical predictions, simulation and flight test results from the NASA Drones for Aerodynamic and Structural Test (DAST) Program are compared.

  15. Real-time streamflow conditions

    USGS Publications Warehouse

    Graczyk, David J.; Gebert, Warren A.

    1996-01-01

    Would you like to know streamflow conditions before you go fishing in Wisconsin or in more distant locations? Real-time streamflow data throughout Wisconsin and the United States are available on the Internet from the U.S. Geological Survey. You can see if the stream you are interested in fishing is high due to recent rain or low because of an extended dry spell. Flow conditions at more than 100 stream-gaging stations located throughout Wisconsin can be viewed by accessing the Wisconsin District Home Page at: http://wwwdwimdn.er.usgs.gov

  16. Real time infrared aerosol analyzer

    DOEpatents

    Johnson, Stanley A.; Reedy, Gerald T.; Kumar, Romesh

    1990-01-01

    Apparatus for analyzing aerosols in essentially real time includes a virtual impactor which separates coarse particles from fine and ultrafine particles in an aerosol sample. The coarse and ultrafine particles are captured in PTFE filters, and the fine particles impact onto an internal light reflection element. The composition and quantity of the particles on the PTFE filter and on the internal reflection element are measured by alternately passing infrared light through the filter and the internal light reflection element, and analyzing the light through infrared spectrophotometry to identify the particles in the sample.

  17. Real-time analysis keratometer

    NASA Technical Reports Server (NTRS)

    Adachi, Iwao P. (Inventor); Adachi, Yoshifumi (Inventor); Frazer, Robert E. (Inventor)

    1987-01-01

    A computer assisted keratometer in which a fiducial line pattern reticle illuminated by CW or pulsed laser light is projected on a corneal surface through lenses, a prismoidal beamsplitter quarterwave plate, and objective optics. The reticle surface is curved as a conjugate of an ideal corneal curvature. The fiducial image reflected from the cornea undergoes a polarization shift through the quarterwave plate and beamsplitter whereby the projected and reflected beams are separated and directed orthogonally. The reflected beam fiducial pattern forms a moire pattern with a replica of the first recticle. This moire pattern contains transverse aberration due to differences in curvature between the cornea and the ideal corneal curvature. The moire pattern is analyzed in real time by computer which displays either the CW moire pattern or a pulsed mode analysis of the transverse aberration of the cornea under observation, in real time. With the eye focused on a plurality of fixation points in succession, a survey of the entire corneal topography is made and a contour map or three dimensional plot of the cornea can be made as a computer readout in addition to corneal radius and refractive power analysis.

  18. Real-time face tracking

    NASA Astrophysics Data System (ADS)

    Liang, Yufeng; Wilder, Joseph

    1998-10-01

    A real-time face tracker is presented in this paper. The system has achieved 15 frames/second tracking using a Pentium 200 PC with a Datacube MaxPCI image processing board and a Panasonic RGB color camera. It tracks human faces in the camera's field of view while people move freely. A stochastic model to characterize the skin color distribution of human skin is used to segment the face and other skin areas from the background. Median filtering is then used to clean up the background noise. Geometric constraints are applied to the segmented image to extract the face from the background. To reduce computation and achieve real-time tracking, 1D projections (horizontal and vertical) of the image are analyzed instead of the 2D image. Run-length- encoding and frequency domain analysis algorithms are used to separate faces from other skin-like blobs. The system is robust to illumination intensity variations and different skin colors. It can be applied to many human-computer interaction applications such as sound locating, lip- reading, gaze tracking and face recognition.

  19. Autonomous Real Time Requirements Tracing

    NASA Technical Reports Server (NTRS)

    Plattsmier, George; Stetson, Howard

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto- Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner-TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  20. Autonomous Real Time Requirements Tracing

    NASA Technical Reports Server (NTRS)

    Plattsmier, George I.; Stetson, Howard K.

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto-Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner- TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  1. Real-time tomographic holography for augmented reality

    PubMed Central

    Galeotti, John M.; Siegel, Mel; Stetten, George

    2011-01-01

    The concept and instantiation of Real-Time Tomographic Holography (RTTH) for augmented reality is presented. RTTH enables natural hand-eye coordination to guide invasive medical procedures without requiring tracking or a head-mounted device. It places a real-time virtual image of an object's cross-section into its actual location, without noticeable viewpoint dependence (e.g. parallax error). The virtual image is viewed through a flat narrow-band Holographic Optical Element with optical power that generates an in-situ virtual image (within 1 m of the HOE) from a small SLM display without obscuring a direct view of the physical world. Rigidly fixed upon a medical ultrasound probe, an RTTH device could show the scan in its actual location inside the patient, even as the probe was moved relative to the patient. PMID:20634827

  2. Real-time flood forecasting

    USGS Publications Warehouse

    Lai, C.; Tsay, T.-K.; Chien, C.-H.; Wu, I.-L.

    2009-01-01

    Researchers at the Hydroinformatic Research and Development Team (HIRDT) of the National Taiwan University undertook a project to create a real time flood forecasting model, with an aim to predict the current in the Tamsui River Basin. The model was designed based on deterministic approach with mathematic modeling of complex phenomenon, and specific parameter values operated to produce a discrete result. The project also devised a rainfall-stage model that relates the rate of rainfall upland directly to the change of the state of river, and is further related to another typhoon-rainfall model. The geographic information system (GIS) data, based on precise contour model of the terrain, estimate the regions that were perilous to flooding. The HIRDT, in response to the project's progress, also devoted their application of a deterministic model to unsteady flow of thermodynamics to help predict river authorities issue timely warnings and take other emergency measures.

  3. Holographic Characteristics of an Acrylamide/Bisacrylamide Photopolymer in 40 1000 µm Thick Layers

    NASA Astrophysics Data System (ADS)

    Ortuño, M.; Gallego, S.; García, C.; Pascual, I.; Neipp, C.; Beléndez, A.

    2005-01-01

    In this study we analyze the holographic behaviour of an acrylamide/bisacrylamide photopolymer in layers that range in thickness from 40 to 1000 µm. The photopolymer is composed of acrylamide as polymerizable monomer, N,N' methylene-bis-acrylamide as crosslinker, triethanolamine as radical generator, yellowish eosin as sensitizer and polyvinyl alcohol as binder. The composition and method of depositing the solution varies depending on the desired thickness of the final layer. For each thickness we analyze the holographic behaviour of the material during recording of unslanted diffraction gratings using a continuous argon laser (514 nm) at an intensity of 5 mW/cm2. The response of the material is monitored in real time with an He-Ne laser. The results obtained for the different parameters evaluated vary considerably depends on the layer thickness. Therefore, the different potential applications of the material (fabrication of holographic optical elements, use as recording material in holographic interferometry, or manufacture of holographic memories) depends on its thickness.

  4. Biomechanical model produced from light-activated dental composite resins: a holographic analysis

    NASA Astrophysics Data System (ADS)

    Pantelić, Dejan; Vasiljević, Darko; Blažić, Larisa; Savić-Šević, Svetlana; Murić, Branka; Nikolić, Marko

    2013-11-01

    Light-activated dental composites, commonly applied in dentistry, can be used as excellent material for producing biomechanical models. They can be cast in almost any shape in an appropriate silicone mold and quickly solidified by irradiation with light in the blue part of the spectrum. In that way, it is possible to obtain any number of nearly identical casts. The models can be used to study the behavior of arbitrary structure under mechanical loads. To test the technique, a simple mechanical model of the tooth with a mesio-occluso-distal cavity was manufactured. Composite resin restoration was placed inside the cavity and light cured. Real-time holographic interferometry was used to analyze the contraction of the composite resin and its effect on the surrounding material. The results obtained in the holographic experiment were in good agreement with those obtained using the finite element method.

  5. Qualitative holographic study of hemi-pelvic deformation caused by loading different hip prostheses.

    PubMed

    Spirakis, A; Learmonth, I D; Gryzagoridis, J; Davis, B L

    1992-03-01

    The dynamic biological response of bone can materially influence the longevity of artificial implants. This paper presents a series of in vitro experiments conducted on epoxy resin models of human hemi-pelves. Different commercially available acetabular components were implanted and used for the construction of simplified three-dimensional models of the artificial hip joint. Boundary conditions included simulation of muscle groups and femoral loading. Real-time holographic interferometry, a stress analysis technique permitting whole-field simultaneous inspection of deformation patterns, was used as the experimental method. The holographic interferograms were interpreted qualitatively rather than quantitatively. High stresses were identified in the hemi-pelvis and it is postulated that these stresses may be implicated in the mechanical pathogenesis of loosening. The observed changes in the detected stress levels could influence both future design of acetabular prostheses and surgical techniques. PMID:1306037

  6. Phase-shifting real-time holography with photorefractive crystals

    NASA Astrophysics Data System (ADS)

    Gesualdi, M. R. R.; Soga, D.; Muramatsu, M.

    2006-01-01

    The phase-shifting interferometry techniques is a well-known technique which has been used with great success in optical profilers, micro-displacements, micro-deformations and others applications in Non-Destructive Test in basic research, engineering and biotechnology areas. This work presents our Advances in Phase-Shifting Real-Time Holography using Photorefractive Sillenite. And we have obtained quantitative results in many applications in measurements of micro-rotation, micro-displacements, deformation, surface contouring and whole lens wave-optics. The real-time holography process is doing using the photorefractive Bi 12SiO 20 crystal recording medium, where the phase-shifting 4-frames method for obtained the phase map, this was filtered by sin/cos filter and was applied the unwrapping process. The experimental results agree with the expected one in these applications and with promises potentialities of this method for studies with in situ visualization, monitoring and analysis.

  7. Real-time extended dynamic range imaging in shearography

    SciTech Connect

    Groves, Roger M.; Pedrini, Giancarlo; Osten, Wolfgang

    2008-10-20

    Extended dynamic range (EDR) imaging is a postprocessing technique commonly associated with photography. Multiple images of a scene are recorded by the camera using different shutter settings and are merged into a single higher dynamic range image. Speckle interferometry and holography techniques require a well-modulated intensity signal to extract the phase information, and of these techniques shearography is most sensitive to different object surface reflectivities as it uses self-referencing from a sheared image. In this paper the authors demonstrate real-time EDR imaging in shearography and present experimental results from a difficult surface reflectivity sample: a wooden panel painting containing gold and dark earth color paint.

  8. Real-time extended dynamic range imaging in shearography.

    PubMed

    Groves, Roger M; Pedrini, Giancarlo; Osten, Wolfgang

    2008-10-20

    Extended dynamic range (EDR) imaging is a postprocessing technique commonly associated with photography. Multiple images of a scene are recorded by the camera using different shutter settings and are merged into a single higher dynamic range image. Speckle interferometry and holography techniques require a well-modulated intensity signal to extract the phase information, and of these techniques shearography is most sensitive to different object surface reflectivities as it uses self-referencing from a sheared image. In this paper the authors demonstrate real-time EDR imaging in shearography and present experimental results from a difficult surface reflectivity sample: a wooden panel painting containing gold and dark earth color paint. PMID:18936802

  9. Real-time Control and Modeling of Plasma Etching

    NASA Astrophysics Data System (ADS)

    Sarfaty, M.; Baum, C.; Harper, M.; Hershkowitz, N.; Shohet, J. L.

    1997-10-01

    The relatively high process rates in high density plasma tools as well as the shrinking thickness of the films, require fast estimate of the process state in order to implement real-time advanced process control. The fast etch rate estimate, within one second, in a single spot size of 1-2 mm and the time averaged rates across the wafer are obtained by a combined use of an in-situ two-color laser interferometer and a full wafer image interferometer, respectively. The gas phase state is monitored by optical emission spectroscopy and a residual gas analyzer. The magnetically confined ICP tool state, including gas flow, pressure, and RF power to the antenna and the electrostatic chuck, is computer controlled and monitored. The absolute thickness of the film is determined during the process, thus providing an end-point prediction. The advantages of two-color laser interferometry for real-time process monitoring, development and control will be described. Langmuir kinetics modeling of the measured etch rates of polysilicon and SiO2 films in Cl2 and CF4 discharges using tool state parameters will be described. The etch rate model enabled us to develop a model-based real-time control algorithm. The achieved real-time control of plasma etch rates of un-patterned SiO2 and polysilicon films will be described. This work is funded by NSF grant No. EEC-8721545.

  10. MISR Level 1 Near Real Time Products

    Atmospheric Science Data Center

    2014-09-15

    Level 1 Near Real Time The MISR Near Real Time Level 1 data products consist of radiance measurements organized in 10-50 minute ... (off-nadir) cameras. The remaining channels are sampled at 1.1 km. ...

  11. Mobile real time radiography system

    SciTech Connect

    Vigil, J.; Taggart, D.; Betts, S.

    1997-11-01

    A 450-keV Mobile Real Time Radiography (RTR) System was delivered to Los Alamos National Laboratory (LANL) in January 1996. It was purchased to inspect containers of radioactive waste produced at (LANL). Since its delivery it has been used to radiograph more than 600 drums of radioactive waste at various LANL sites. It has the capability of inspecting waste containers of various sizes from <1-gal. buckets up to standard waste boxes (SWB, dimensions 54.5 in. x 71 in. x 37 in.). It has three independent x-ray acquisition formats. The primary system used is a 12- in. image intensifier, the second is a 36-in. linear diode array (LDA) and the last is an open system. It is fully self contained with on board generator, HVAC, and a fire suppression system. It is on a 53-ft long x 8-ft. wide x 14-ft. high trailer that can be moved over any highway requiring only an easily obtainable overweight permit because it weights {approximately}38 tons. It was built to conform to industry standards for a cabinet system which does not require an exclusion zone. The fact that this unit is mobile has allowed us to operate where the waste is stored, rather than having to move the waste to a fixed facility.

  12. Students Collecting Real time Data

    NASA Astrophysics Data System (ADS)

    Miller, P.

    2006-05-01

    Students Collecting Real-Time Data The Hawaiian Islands Humpback Whale National Marine Sanctuary has created opportunities for middle and high school students to become Student Researchers and to be involved in real-time marine data collection. It is important that we expose students to different fields of science and encourage them to enter scientific fields of study. The Humpback Whale Sanctuary has an education visitor center in Kihei, Maui. Located right on the beach, the site has become a living classroom facility. There is a traditional Hawaiian fishpond fronting the property. The fishpond wall is being restored, using traditional methods. The site has the incredible opportunity of incorporating Hawaiian cultural practices with scientific studies. The Sanctuary offers opportunities for students to get involved in monitoring and data collection studies. Invasive Seaweed Study: Students are collecting data on invasive seaweed for the University of Hawaii. They pull a large net through the shallow waters. Seaweed is sorted, identified and weighed. The invasive seaweeds are removed. The data is recorded and sent to UH. Remote controlled monitoring boats: The sanctuary has 6 boogie board sized remote controlled boats used to monitor reefs. Boats have a camera with lights on the underside. The boats have water quality monitoring devices and GPS units. The video from the underwater camera is transmitted via a wireless transmission. Students are able to monitor the fish, limu and invertebrate populations on the reef and collect water quality data via television monitors or computers. The boat can also pull a small plankton tow net. Data is being compiled into data bases. Artificial Reef Modules: The Sanctuary has a scientific permit from the state to build and deploy artificial reef modules. High school students are designing and building modules. These are deployed out in the Fishpond fronting the Sanctuary site and students are monitoring them on a weekly basis

  13. Real-Time Data Display

    NASA Technical Reports Server (NTRS)

    Pedings, Marc

    2007-01-01

    RT-Display is a MATLAB-based data acquisition environment designed to use a variety of commercial off-the-shelf (COTS) hardware to digitize analog signals to a standard data format usable by other post-acquisition data analysis tools. This software presents the acquired data in real time using a variety of signal-processing algorithms. The acquired data is stored in a standard Operator Interactive Signal Processing Software (OISPS) data-formatted file. RT-Display is primarily configured to use the Agilent VXI (or equivalent) data acquisition boards used in such systems as MIDDAS (Multi-channel Integrated Dynamic Data Acquisition System). The software is generalized and deployable in almost any testing environment, without limitations or proprietary configuration for a specific test program or project. With the Agilent hardware configured and in place, users can start the program and, in one step, immediately begin digitizing multiple channels of data. Once the acquisition is completed, data is converted into a common binary format that also can be translated to specific formats used by external analysis software, such as OISPS and PC-Signal (product of AI Signal Research Inc.). RT-Display at the time of this reporting was certified on Agilent hardware capable of acquisition up to 196,608 samples per second. Data signals are presented to the user on-screen simultaneously for 16 channels. Each channel can be viewed individually, with a maximum capability of 160 signal channels (depending on hardware configuration). Current signal presentations include: time data, fast Fourier transforms (FFT), and power spectral density plots (PSD). Additional processing algorithms can be easily incorporated into this environment.

  14. Etch rate Modeling and Real-time Control

    NASA Astrophysics Data System (ADS)

    Hershkowitz, N.; Sarfaty, M.; Baum, C.; Harper, M.; Shohet, J. L.

    1997-11-01

    The relatively high process rates in high density plasma tools as well as the shrinking thickness of the films, require fast estimate of the process state in order to implement real-time advanced process control. The fast etch rate estimate, within one second, in a spot size of 1-2 mm and the time averaged rates across the wafer are obtained by a combined use of an in-situ two-color laser interferometer and a full wafer image interferometer, respectively. The gas phase state is monitored by optical emission spectroscopy and a residual gas analyzer. The magnetically confined ICP tool state, including gas flow, pressure, and RF power to the antenna and the electrostatic chuck, is computer controlled and monitored. The absolute thickness of the film is determined during the process, thus providing an end-point prediction. Splitting the two-color laser beam to two spots on the wafer that are coated with different films provides real-time etch selectivity. The advantages of two-color laser interferometry for real-time process monitoring, development and control will be described. Langmuir kinetics modeling of the measured etch rates of polysilicon and SiO2 films in Cl2 and CF4 discharges using tool state parameters will be described. The etch rate model enabled us to develop a model-based real-time control algorithm. The achieved real-time control of plasma etch rates of un-patterned SiO2 and polysilicon films will be described. This work is funded by NSF grant No. EEC-8721545.

  15. The goldstone real-time connected element interferometer

    NASA Technical Reports Server (NTRS)

    Edwards, C., Jr.; Rogstad, D.; Fort, D.; White, L.; Iijima, B.

    1992-01-01

    Connected element interferometry (CEI) is a technique of observing a celestial radio source at two spatially separated antennas and then interfering the received signals to extract the relative phase of the signal at the two antennas. The high precision of the resulting phase delay data type can provide an accurate determination of the angular position of the radio source relative to the baseline vector between the two stations. This article describes a recently developed connected element interferometer on a 21-km baseline between two antennas at the Deep Space Network's Goldstone, California, tracking complex. Fiber-optic links are used to transmit the data to a common site for processing. The system incorporates a real-time correlator to process these data in real time. The architecture of the system is described, and observational data are presented to characterize the potential performance of such a system. The real-time processing capability offers potential advantages in terms of increased reliability and improved delivery of navigational data for time-critical operations. Angular accuracies of 50-100 nrad are achievable on this baseline.

  16. Research in Distributed Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.

    1997-01-01

    This document summarizes the progress we have made on our study of issues concerning the schedulability of real-time systems. Our study has produced several results in the scalability issues of distributed real-time systems. In particular, we have used our techniques to resolve schedulability issues in distributed systems with end-to-end requirements. During the next year (1997-98), we propose to extend the current work to address the modeling and workload characterization issues in distributed real-time systems. In particular, we propose to investigate the effect of different workload models and component models on the design and the subsequent performance of distributed real-time systems.

  17. Real time programming environment for Windows

    SciTech Connect

    LaBelle, D.R.

    1998-04-01

    This document provides a description of the Real Time Programming Environment (RTProE). RTProE tools allow a programmer to create soft real time projects under general, multi-purpose operating systems. The basic features necessary for real time applications are provided by RTProE, leaving the programmer free to concentrate efforts on his specific project. The current version supports Microsoft Windows{trademark} 95 and NT. The tasks of real time synchronization and communication with other programs are handled by RTProE. RTProE includes a generic method for connecting a graphical user interface (GUI) to allow real time control and interaction with the programmer`s product. Topics covered in this paper include real time performance issues, portability, details of shared memory management, code scheduling, application control, Operating System specific concerns and the use of Computer Aided Software Engineering (CASE) tools. The development of RTProE is an important step in the expansion of the real time programming community. The financial costs associated with using the system are minimal. All source code for RTProE has been made publicly available. Any person with access to a personal computer, Windows 95 or NT, and C or FORTRAN compilers can quickly enter the world of real time modeling and simulation.

  18. CDDIS Near Real Time Data for Geodesy Based Applications

    NASA Astrophysics Data System (ADS)

    Michael, B. P.; Noll, C. E.; Roark, J.

    2014-12-01

    The Crustal Dynamics Data Information System (CDDIS) is one of NASA's Earth Observing System Data and Information System (EOSDIS) distributed data centers and as such is tasked to provide facilities for search and access of science data and products for a diverse user community. The archive consists of Global Navigation Satellite Systems (GNSS), laser ranging, Very Long Baseline Interferometry (VLBI), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) data sets and products derived from these data. With these data sets and products the CDDIS and its archive are a key component in several of the operational services within the International Association of Geodesy (IAG) and its project the Global Geodetic Observing System (GGOS) and the International GNSS Service (IGS). In the spring of 2013, the IGS officially launched its Real Time Service (RTS) to provide support for applications requiring real time access to IGS products. The IGS RTS is a GNSS orbit and clock correction service that enables precise point positioning (PPP) and related applications, such as time synchronization and disaster monitoring. The service is based on a global infrastructure of network stations, data centers and analysis centers that provide high precision GNSS products and is operated as a public service. The CDDIS has decided to join the RTS infrastructure and take part in disseminating GNSS data and products through the RTS. This poster will include information about the CDDIS real time implementation, how it fits into the RTS infrastructure, the user registration process, and computation and conversion of data feeds into high-rate data files for both near real time and offline usage.

  19. Large-memory real-time multichannel multiplexed pattern recognition

    NASA Technical Reports Server (NTRS)

    Gregory, D. A.; Liu, H. K.

    1984-01-01

    The principle and experimental design of a real-time multichannel multiplexed optical pattern recognition system via use of a 25-focus dichromated gelatin holographic lens (hololens) are described. Each of the 25 foci of the hololens may have a storage and matched filtering capability approaching that of a single-lens correlator. If the space-bandwidth product of an input image is limited, as is true in most practical cases, the 25-focus hololens system has 25 times the capability of a single lens. Experimental results have shown that the interfilter noise is not serious. The system has already demonstrated the storage and recognition of over 70 matched filters - which is a larger capacity than any optical pattern recognition system reported to date.

  20. Real-time measurement of internal stress of dental tissue using holography

    NASA Astrophysics Data System (ADS)

    Pantelic, Dejan; Blazic, Larisa; Savic-Sevic, Svetlana; Muric, Branka; Vasiljevic, Darko; Panic, Bratimir; Belic, Ilija

    2007-05-01

    We describe a real-time holographic technique used to observe dental contraction due to photo-polymerization of dental filling during LED lamp illumination. An off-axis setup was used, with wet in-situ processing of the holographic plate, and consequent recording of interference fringes using CCD camera. Finite elements method was used to calculate internal stress of dental tissue, corresponding to experimentally measured deformation. A technique enables selection of preferred illumination method with reduced polymerization contraction. As a consequence, durability of dental filling might be significantly improved.

  1. Making real-time reactive systems reliable

    NASA Technical Reports Server (NTRS)

    Marzullo, Keith; Wood, Mark

    1990-01-01

    A reactive system is characterized by a control program that interacts with an environment (or controlled program). The control program monitors the environment and reacts to significant events by sending commands to the environment. This structure is quite general. Not only are most embedded real time systems reactive systems, but so are monitoring and debugging systems and distributed application management systems. Since reactive systems are usually long running and may control physical equipment, fault tolerance is vital. The research tries to understand the principal issues of fault tolerance in real time reactive systems and to build tools that allow a programmer to design reliable, real time reactive systems. In order to make real time reactive systems reliable, several issues must be addressed: (1) How can a control program be built to tolerate failures of sensors and actuators. To achieve this, a methodology was developed for transforming a control program that references physical value into one that tolerates sensors that can fail and can return inaccurate values; (2) How can the real time reactive system be built to tolerate failures of the control program. Towards this goal, whether the techniques presented can be extended to real time reactive systems is investigated; and (3) How can the environment be specified in a way that is useful for writing a control program. Towards this goal, whether a system with real time constraints can be expressed as an equivalent system without such constraints is also investigated.

  2. The ALMA Real Time Control System

    NASA Astrophysics Data System (ADS)

    Kern, Jeffrey S.; Juerges, Thomas A.; Marson, Ralph G.

    2009-01-01

    The Atacama Large Millimeter Array (ALMA) is a revolutionary millimeter and submillimeter array being developed on the Atacama plateau of northern Chile. An international partnership lead by NRAO, ESO, and NAOJ this powerful and flexible telescope will provide unprecedented observations of this relatively unexplored frequency range. The control subsystem for the Atacama Large Millimeter Array must coordinate the monitor and control of at least sixty six antennas (in four different styles), two correlators, and all of the ancillary equipment (samplers, local oscillators, front ends, etc.). This equipment will be spread over tens of kilometers and operated remotely. Operation of the array requires a robust, scalable, and maintainable real time control system. The real time control system is responsible for monitoring and control of any devices where there are fixed deadlines. Examples in the ALMA context are antenna pointing and fringe tracking. Traditionally the real time portion of a large software system is an intricate and error prone portion of the software. As a result the real time portion is very expensive in terms of effort expended both during construction and during maintenance phases of a project. The ALMA real time control system uses a Linux based real time operating system to interact with the hardware and the CORBA based ALMA Common Software to communicate in the distributed computing environment. Mixing the requirements of real time computing and the non-deterministic CORBA middleware has produced an interesting design. We discuss the architecture, design, and implementation of the ALMA real time control system. Highlight some lessons learned along the way, and justify our assertion that this should be the last large scale real time control system in radio astronomy.

  3. Chidi holographic video system

    NASA Astrophysics Data System (ADS)

    Nwodoh, Thomas A.; Benton, Stephen A.

    2000-03-01

    Holo-Chidi is a holographic video processing system designed at the MIT Media Laboratory for real-time computation of Computer Generated Holograms and the subsequent display of the holograms at video frame rates. It's processing engine is adapted from Chidi which is reconfigurable multimedia processing system used for real-time synthesis and analysis of digital video frames. Holo-Chidi is made of two main components: the sets of Chidi processor cards and the display video concentrator card. The processor cards are used for hologram computation while the display video concentrator card acts as frame buffer for the system. The display video concentrator also formats the computed holographic data and converts them to analog form for feeding the acousto-optic modulators of the Media Lab's Mark-II holographic display system. The display video concentrator card can display the computed holograms from the Chidi cards loaded from its high-speed I/O interface port or precomputed holograms loaded from a PC through the United Serial Bus port of its communications processor at above video refresh rates. This paper discusses the design of the display video concentrator used to display holographic video in the Mark-II system.

  4. Real-time monitoring of landslides

    USGS Publications Warehouse

    Reid, Mark E.; LaHusen, Richard G.; Baum, Rex L.; Kean, Jason W.; Schulz, William H.; Highland, Lynn M.

    2012-01-01

    Landslides cause fatalities and property damage throughout the Nation. To reduce the impact from hazardous landslides, the U.S. Geological Survey develops and uses real-time and near-real-time landslide monitoring systems. Monitoring can detect when hillslopes are primed for sliding and can provide early indications of rapid, catastrophic movement. Continuous information from up-to-the-minute or real-time monitoring provides prompt notification of landslide activity, advances our understanding of landslide behavior, and enables more effective engineering and planning efforts.

  5. Real-Time Monitoring of Active Landslides

    USGS Publications Warehouse

    Reid, Mark E.; LaHusen, Richard G.; Ellis, William L.

    1999-01-01

    Landslides threaten lives and property in every State in the Nation. To reduce the risk from active landslides, the U.S. Geological Survey (USGS) develops and uses real-time landslide monitoring systems. Monitoring can detect early indications of rapid, catastrophic movement. Up-to-the-minute or real-time monitoring provides immediate notification of landslide activity, potentially saving lives and property. Continuous information from real-time monitoring also provides a better understanding of landslide behavior, enabling engineers to create more effective designs for halting landslide movement.

  6. Real time sensor for therapeutic radiation delivery

    DOEpatents

    Bliss, Mary; Craig, Richard A.; Reeder, Paul L.

    1998-01-01

    The invention is a real time sensor for therapeutic radiation. A probe is placed in or near the patient that senses in real time the dose at the location of the probe. The strength of the dose is determined by either an insertion or an exit probe. The location is determined by a series of vertical and horizontal sensing elements that gives the operator a real time read out dose location relative to placement of the patient. The increased accuracy prevents serious tissue damage to the patient by preventing overdose or delivery of a dose to a wrong location within the body.

  7. Real time sensor for therapeutic radiation delivery

    DOEpatents

    Bliss, M.; Craig, R.A.; Reeder, P.L.

    1998-01-06

    The invention is a real time sensor for therapeutic radiation. A probe is placed in or near the patient that senses in real time the dose at the location of the probe. The strength of the dose is determined by either an insertion or an exit probe. The location is determined by a series of vertical and horizontal sensing elements that gives the operator a real time read out dose location relative to placement of the patient. The increased accuracy prevents serious tissue damage to the patient by preventing overdose or delivery of a dose to a wrong location within the body. 14 figs.

  8. NTT's ultra-high-speed networking experiment: a real-time VLBI project

    NASA Astrophysics Data System (ADS)

    Uose, Hisao; Irie, Kazunari; Iwamura, Sotetsu

    2002-11-01

    Since 1995 Nippon Telegraph and Telephone Corporation (NTT) has been conducting experiments on real-time VLBI (very long baseline interferometry) using a large scale network testbed having the maximum speed of 2.4Gb/s. With the real-time data transmission using high-speed communications network, the bottleneck resulted from the limited data rates with the conventional magnetic tape based VLBI system can be removed. Two applications of VLBI, geodesy and radio astronomy, are being pursued with our trial and extensive research items regarding the real-time VLBI technology are being conducted. So far, through the experiments using the developed real-time VLBI system, great improvement in observation performance has been achieved. Now we are concentrated in developing an economical VLBI data transfer system using advanced IP (Internet Protocol) technologies to achieve greater connectivity to other research organizations.

  9. Real-time smart fluorescence sensor platform

    NASA Astrophysics Data System (ADS)

    Dickens, Jason E.; Vaughn, Mike S.; Taylor, Mervin; Ponstingl, Mike

    2011-06-01

    A novel compact LED array based light induced fluorescence (LIF) sensor has been developed for real-time in-line monitoring of intrinsic fluorophores in the solid and liquid state. The sensor is essential for on-the-spot, routine, and cost effective real-time analysis. The sensor is designed to provide real-time emission response along with various smart sensing parameters to ensure real-time measurement quality that is required for regulated GMP process monitoring applications. This work describes a LIF sensor tailored for solid-phase fluorometry. Fundamental figures of merit, excitation overexposure and smart sensing features required for modern process monitoring and control are discussed within the context of pharmaceutical solid-phase manufacturing and similar applications.

  10. Processing PCM Data in Real Time

    NASA Technical Reports Server (NTRS)

    Wissink, T. L.

    1982-01-01

    Novel hardware configuration makes it possible for Space Shuttle launch processing system to monitor pulse-code-modulated data in real time. Using two microprogramable "option planes," incoming PCM data are monitored for changes at rate of one frame of data (80 16-bit words) every 10 milliseconds. Real-time PCM processor utilizes CPU in mini-computer and CPU's in two option planes.