The ESA mission to Comet Halley

NASA Technical Reports Server (NTRS)

Reinhard, R.

1981-01-01

The Europeon Space Agency's approximately Giotto mission plans for a launch in July 1985 with a Halley encounter in mid-March 1986 4 weeks after the comet's perihelion passage. Giotto carries 10 scientific experiments, a camera, neutral, ion and dust mass spectrometers, a dust impact detector system, various plasma analyzers, a magnetometer and an optical probe. The instruments are described, the principles on which they are based are described, and the experiment key performance data are summarized. The launch constraints the helicentric transfer trajectory, and the encounter scenario are analyzed. The Giotto spacecraft major design criteria, spacecraft subsystem and the ground system are described. The problem of hypervelocity dust particle impacts in the innermost part of the coma, the problem of spacecraft survival, and the adverse effects of impact-generated plasma aroung the spacecraft are considered.

Bleed-through correction for rendering and correlation analysis in multi-colour localization microscopy

PubMed Central

Kim, Dahan; Curthoys, Nikki M.; Parent, Matthew T.; Hess, Samuel T.

2015-01-01

Multi-colour localization microscopy has enabled sub-diffraction studies of colocalization between multiple biological species and quantification of their correlation at length scales previously inaccessible with conventional fluorescence microscopy. However, bleed-through, or misidentification of probe species, creates false colocalization and artificially increases certain types of correlation between two imaged species, affecting the reliability of information provided by colocalization and quantified correlation. Despite the potential risk of these artefacts of bleed-through, neither the effect of bleed-through on correlation nor methods of its correction in correlation analyses has been systematically studied at typical rates of bleed-through reported to affect multi-colour imaging. Here, we present a reliable method of bleed-through correction applicable to image rendering and correlation analysis of multi-colour localization microscopy. Application of our bleed-through correction shows our method accurately corrects the artificial increase in both types of correlations studied (Pearson coefficient and pair correlation), at all rates of bleed-through tested, in all types of correlations examined. In particular, anti-correlation could not be quantified without our bleed-through correction, even at rates of bleed-through as low as 2%. Demonstrated with dichroic-based multi-colour FPALM here, our presented method of bleed-through correction can be applied to all types of localization microscopy (PALM, STORM, dSTORM, GSDIM, etc.), including both simultaneous and sequential multi-colour modalities, provided the rate of bleed-through can be reliably determined. PMID:26185614

Bleed-through correction for rendering and correlation analysis in multi-colour localization microscopy.

PubMed

Kim, Dahan; Curthoys, Nikki M; Parent, Matthew T; Hess, Samuel T

2013-09-01

Multi-colour localization microscopy has enabled sub-diffraction studies of colocalization between multiple biological species and quantification of their correlation at length scales previously inaccessible with conventional fluorescence microscopy. However, bleed-through, or misidentification of probe species, creates false colocalization and artificially increases certain types of correlation between two imaged species, affecting the reliability of information provided by colocalization and quantified correlation. Despite the potential risk of these artefacts of bleed-through, neither the effect of bleed-through on correlation nor methods of its correction in correlation analyses has been systematically studied at typical rates of bleed-through reported to affect multi-colour imaging. Here, we present a reliable method of bleed-through correction applicable to image rendering and correlation analysis of multi-colour localization microscopy. Application of our bleed-through correction shows our method accurately corrects the artificial increase in both types of correlations studied (Pearson coefficient and pair correlation), at all rates of bleed-through tested, in all types of correlations examined. In particular, anti-correlation could not be quantified without our bleed-through correction, even at rates of bleed-through as low as 2%. Demonstrated with dichroic-based multi-colour FPALM here, our presented method of bleed-through correction can be applied to all types of localization microscopy (PALM, STORM, dSTORM, GSDIM, etc.), including both simultaneous and sequential multi-colour modalities, provided the rate of bleed-through can be reliably determined.

Electric field measurements from Halley, Antarctica

NASA Astrophysics Data System (ADS)

Nicoll, Keri; Harrison, R. Giles

2016-04-01

Antarctica is a unique location for the study of atmospheric electricity. Not only is it one of the most pollutant free places on Earth, but its proximity to the south magnetic pole means that it is an ideal location to study the effects of solar variability on the atmospheric electric field. This is due to the reduced shielding effect of the geomagnetic field at the poles which leads to a greater flux of incoming Galactic Cosmic Rays (GCRs) as well as an increased probability of energetic particle precipitation from SEPs and relativistic electrons. To investigate such effects, two electric field mills of different design were installed at the British Antarctic Survey Halley base in February 2015 (75. 58 degrees south, 26.66 degrees west). Halley is situated on the Brunt Ice Shelf in the south east of the Weddell Sea and has snow cover all year round. Preliminary analysis has focused on selection of fair weather criteria using wind speed and visibility measurements which are vital to assess the effects of falling snow, blowing snow and freezing fog on the electric field measurements. When the effects of such adverse weather conditions are removed clear evidence of the characteristic Carnegie Curve diurnal cycle exists in the Halley electric field measurements (with a mean value of 50V/m and showing a 40% peak to peak variation in comparison to the 34% variation in the Carnegie data). Since the Carnegie Curve represents the variation in thunderstorm activity across the Earth, its presence in the Halley data confirms the presence of the global atmospheric electric circuit signal at Halley. The work presented here will discuss the details of the Halley electric field dataset, including the variability in the fair weather measurements, with a particular focus on magnetic field fluctuations.

Finding Comet Halley.

ERIC Educational Resources Information Center

Glenn, William H.

1985-01-01

Provides background information and references on Comet Halley (which will be observable by telescope in October 1985 and reach its most brilliant appearance in March and April of 1986). Suggestions for equipment and maps of its path through the sky are included. (DH)

The natural history of Halley's comet

NASA Astrophysics Data System (ADS)

McLaughlin, W. I.

1981-07-01

The 1986 apparition of Halley's comet will be the subject of numerous space probes, planned to determine the chemical nature and physical structure of comet nuclei, atmospheres, and ionospheres, as well as comet tails. The problems of cometary origin remain inconclusive, with theories ranging from a purely interstellar origin to their being ejecta from the Galilean satellites of Jupiter. Comets can be grouped into one of two classes, depending on their periodicity, and statistical mechanics of the entire Jovian family of comets can be examined under the equilibrium hypothesis. Comet anatomy estimations have been determined, and there is speculation that comet chemistry may have been a factor in the origin of life on earth. Halley's comet was first noted using Newton's dynamical methods, and Brady (1972) attempted to use the comet as a gravitational probe in search of a trans-Plutonian planet. Halley's orbit is calculated by combination of ancient observations and modern scientific methods.

Fresh-slice multicolour X-ray free-electron lasers

DOE PAGES

Lutman, Alberto A.; Maxwell, Timothy J.; MacArthur, James P.; ...

2016-10-24

X-ray free-electron lasers (XFELs) provide femtosecond X-ray pulses with a narrow energy bandwidth and unprecedented brightness. Ultrafast physical and chemical dynamics, initiated with a site-specific X-ray pulse, can be explored using XFELs with a second ultrashort X-ray probe pulse. However, existing double-pulse schemes are complicated, difficult to customize or provide only low-intensity pulses. Here we present the novel fresh-slice technique for multicolour pulse production, wherein different temporal slices of an electron bunch lase to saturation in separate undulator sections. This method combines electron bunch tailoring from a passive wakefield device with trajectory control to provide multicolour pulses. The fresh-slice schememore » outperforms existing techniques at soft X-ray wavelengths. It produces femtosecond pulses with a power of tens of gigawatts and flexible colour separation. The pulse delay can be varied from temporal overlap to almost one picosecond. As a result, we also demonstrate the first three-colour XFEL and variably polarized two-colour pulses.« less

Pioneer Venus observations during Comet Halley's inferior conjunction

NASA Technical Reports Server (NTRS)

Russell, C. T.; Luhmann, J. G.; Scarf, F. L.

1985-01-01

On Feb. 4, 1986, Halley passed through inferior conjunction with Venus but was at high latitudes. Not all data for this time period have been received. However, the data that are available suggest that at most only weak effects associated with Halley were seen at Pioneer Venus. The data during this time, however, are useful for correlating with the behavior of the plasma tail.

Earth-return trajectory options for the 1985-86 Halley opportunity

NASA Technical Reports Server (NTRS)

Farquhar, R. W.; Dunham, D. W.

1982-01-01

A unique and useful family of ballistic trajectories to Halley's comet is described. The distinguishing feature of this family is that all of the trajectories return to the Earth's vicinity after the Halley intercept. It is shown that, in some cases, the original Earth-return path can be reshaped by Earth-swingby maneuvers to achieve additional small-body encounters. One mission profile includes flybys of the asteroid Geographos and comet Tempel-2 following the Halley intercept. Dual-flyby missions involving comets Encke and Borrelly and the asteroid Anteros are also discussed. Dust and gas samples are collected during the high-velocity (about 70 km/sec) flythrough of Halley, and then returned to a high-apogee Earth orbit. Aerobraking maneuvers are used to bring the sample-return spacecraft to a low-altitude circular orbit where it can be recovered by the Space Shuttle.

The Comet Halley dust and gas environment

NASA Technical Reports Server (NTRS)

Divine, N.; Hanner, M. S.; Newburn, R. L., Jr.; Sekanina, Z.; Yeomans, D. K.

1986-01-01

Quantitative descriptions of environments near the nucleus of comet P/Halley have been developed to support spacecraft and mission design for the flyby encounters in March, 1986. To summarize these models as they exist just before the encounters, the relevant data from prior Halley apparitions and from recent cometary research are reviewed. Orbital elements, visual magnitudes, and parameter values and analysis for the nucleus, gas and dust are combined to predict Halley's position, production rates, gas and dust distributions, and electromagnetic radiation field for the current perihelion passage. The predicted numerical results have been useful for estimating likely spacecraft effects, such as impact damage and attitude perturbations. Sample applications are cited, including design of a dust shield for spacecraft structure, and threshold and dynamic range selection for flight experiments. It is expected that the comet's activity may be more irregular than these smoothly varying models predict, and that comparison with the flyby data will be instructive.

Comet Halley passes the halfway mark. Very distant image obtained with the ESO NTT.

NASA Astrophysics Data System (ADS)

1994-02-01

Eight years after the passage of Comet Halley in early 1986, astronomers at the European Southern Observatory have succeeded in obtaining an image [1] of this famous object at a distance of no less than 2,820 million km from the Sun. The comet is now about as far away as giant planet Uranus. It recently passed the halfway mark towards the most distant point of its very elongated 76-year orbit. The image shows the 6 x 15 km avocado-shaped nucleus as an extremely faint point of light without any surrounding dust cloud. It appears that the surface is now completely frozen and the comet has ceased to emit dust and gas. This observation was made with the ESO 3.58 metre New Technology Telescope (NTT). It is by far the faintest and most distant image ever recorded of this comet. A DIFFICULT OBSERVATION The new Halley image was obtained in the course of an observational programme by a small group of astronomers [2], aimed at the investigation of distant solar system objects. The observation was difficult to perform and is close to the limit of what is possible, even with the NTT, one of the technologically most advanced astronomical telescopes. In fact, this observation may be compared to viewing a black golfball, used during a late evening game, from a distance of 12,000 km. At Halley's present, very large distance from the Sun, the intensity of the solar light is over 350 times fainter than here on Earth. The surface of the cometary nucleus is very dark; it reflects only 4 % of the infalling sunlight. The amount of light received from Halley is therefore extremely small: the recorded star-like image of the nucleus is about 160 million times fainter than the faintest star that can be seen with the unaided eye. A long exposure was needed to catch enough light to show the object; even with the very sensitive SuSI CCD camera at the NTT, the shutter had to be kept open for a total of 3 hours 45 minutes. During this time, of the order of 9000 photons from Comet Halley were

Colour, albedo and nucleus size of Halley's comet

NASA Technical Reports Server (NTRS)

Cruikshank, D. P.; Tholen, D. J.; Hartmann, W. K.

1985-01-01

Photometry of Halley's comet in the B, J, V, and K broadband filters during a time when the coma was very weak and presumed to contribute negligibly to the broadband photometry is reported. The V-J and J-K colors suggest that the color of the nucleus of Halley's comet is similar to that of the D-type asteroids, which in turn suggests that the surface of the nucleus has an albedo less than 0.1.

International Halley watch amateur observers' manual for scientific comet studies. Part 1: Methods

NASA Technical Reports Server (NTRS)

Edberg, S. J.

1983-01-01

The International Halley Watch is described as well as comets and observing techniques. Information on periodic Comet Halley's apparition for its 1986 perihelion passage is provided. Instructions are given for observation projects valuable to the International Halley Watch in six areas of study: (1) visual observations; (2) photography; (3) astrometry; (4) spectroscopic observations; (5) photoelectric photometry; and (6) meteor observations.

Halley's Comet: A Bibliography.

ERIC Educational Resources Information Center

Freitag, Ruth S., Comp.

Included in this bibliography are over 3,200 references to publications on Halley's Comet, its history, orbital motion, and physical characteristics, meteor streams associated with it, preparations for space missions to study it in 1986, and popular reaction to its appearances. Also cited are a few papers that, although they devote little…

The International VEGA "Venus-Halley" (1984-1986) Experiment: Description and Scientific Objectives

NASA Technical Reports Server (NTRS)

1985-01-01

The Venus-Halley (Vega) project will provide a unique opportunity to combine a mission over Venus with a transfer flight to Halley's comet. This project is based on three research goals: (1) to study the surface of Venus; (2) to study the air circulation on Venus and its meteorological parameters; and (3) to study Halley's comet. The objective of the study of Halley's comet is to: determine the physical characteristics of its nucleus; define the structure and dynamics of the coma around the nucleus; define the gas composition near the nucleus; investigate the dust particle distribution as a function of mass at various distances from the nucleus; and investigate the solar wind interaction with the atmosphere and ionosphere of the comet.

Charles Nordmann and Multicolour Stellar Photometry

NASA Astrophysics Data System (ADS)

Lequeux, James

2010-11-01

Charles Nordmann (1881-1940), an astronomer at the Paris Observatory, was the first to determine the effective temperature of stars with his photometre heterochrome, simultaneously and independently of Rosenberg, Wilsing and Scheiner in Germany. He is also the remote precursor of the multicolour photometry of Johnson and Morgan. In spite of the quality of his temperature determinations, which were as good or better than those made by spectrophotometry, he rapidly fell into oblivion because of some failures in his scientific work. We examine his activity in the international context of the time, and explain why he has been forgotten, to be rediscovered only recently.

Halley and the eternity of the world revisited

PubMed Central

Levitin, Dmitri

2013-01-01

Since the publication in Notes and Records of the Royal Society of an article by Simon Schaffer in 1977, it has been a historiographical commonplace that there was an ‘underlying unity’ to the religio-philosophical opinions of Edmond Halley, specifically on issues concerning the age of the world. This article (i) argues that the evidence adduced for this claim—specifically the account of a lecture given by Halley to the Royal Society in 1693—has been misinterpreted, and (ii) brings forward some new evidence concerning the mysterious events surrounding Halley's unsuccessful attempt to secure the Savilian Professorship in Astronomy in 1691 and the nature of his religious heterodoxy, both as it was developed by himself and as it was perceived by contemporaries. It thus functions as a full revisionist account of one of the key players in the destabilization of the relationship between natural philosophy and Genesis in the first decades of the Royal Society.

Chaotic dynamics of Comet 1P/Halley: Lyapunov exponent and survival time expectancy

NASA Astrophysics Data System (ADS)

Muñoz-Gutiérrez, M. A.; Reyes-Ruiz, M.; Pichardo, B.

2015-03-01

The orbital elements of Comet Halley are known to a very high precision, suggesting that the calculation of its future dynamical evolution is straightforward. In this paper we seek to characterize the chaotic nature of the present day orbit of Comet Halley and to quantify the time-scale over which its motion can be predicted confidently. In addition, we attempt to determine the time-scale over which its present day orbit will remain stable. Numerical simulations of the dynamics of test particles in orbits similar to that of Comet Halley are carried out with the MERCURY 6.2 code. On the basis of these we construct survival time maps to assess the absolute stability of Halley's orbit, frequency analysis maps to study the variability of the orbit, and we calculate the Lyapunov exponent for the orbit for variations in initial conditions at the level of the present day uncertainties in our knowledge of its orbital parameters. On the basis of our calculations of the Lyapunov exponent for Comet Halley, the chaotic nature of its motion is demonstrated. The e-folding time-scale for the divergence of initially very similar orbits is approximately 70 yr. The sensitivity of the dynamics on initial conditions is also evident in the self-similarity character of the survival time and frequency analysis maps in the vicinity of Halley's orbit, which indicates that, on average, it is unstable on a time-scale of hundreds of thousands of years. The chaotic nature of Halley's present day orbit implies that a precise determination of its motion, at the level of the present-day observational uncertainty, is difficult to predict on a time-scale of approximately 100 yr. Furthermore, we also find that the ejection of Halley from the Solar system or its collision with another body could occur on a time-scale as short as 10 000 yr.

The Photometric lightcurve of Comet 1P/Halley

NASA Astrophysics Data System (ADS)

Bair, Allison N.; Schleicher, David G.

2014-11-01

Comet 1P/Halley is considered an important object for a number of reasons. Not only is it the first-identified and brightest periodic comet, being the only periodic comet visible to the naked eye at every apparition, but in 1986 Halley became the first comet to be imaged by fly-by spacecraft. The NASA-funded International Halley Watch (IHW) directly supported the spacecraft by providing narrowband filters for groundbased photometric observations, and until the arrival of Hale-Bopp (1995 O1), Halley was the subject of the largest groundbased observational campaign in history. Following considerable controversy regarding its rotation period, it was eventually determined to be in complex rotation -- the first comet to be so identified. While the overall brightness variations of the coma repeated with a period of about 7.4 days, the detailed period and shape of the lightcurve constantly evolved. The determination of the specific characteristics of each of the two components of its non-principal axis rotational state has remained elusive.To resolve this situation we have now incorporated all of the narrowband photometry, taken by 21 telescopes from around the world and submitted to the IHW archive, to create the most complete homogeneous lightcurve possible. Using measurements of three gas species and the dust, the lightcurve was investigated and found to alternate between a double- and triple-peaked shape, with no single feature being present throughout the entire duration of our dataset (316 days). The apparent period as a function of time was extracted and seen to vary in a step-wise manner between 7.27 and 7.60 days. Taken together, these results were used to produce a synthetic lightcurve revealing Halley's behavior even when no data were available. Details of this and other results, to be used to constrain future detailed modeling, will be presented. This research is supported by NASA's Planetary Atmospheres Program.

International Halley Watch: Discipline specialists for spectroscopy and spectrophotometry

NASA Technical Reports Server (NTRS)

Wyckoff, S.; Feston, M. C.; Wehinger, P.

1986-01-01

Spectroscopic observations of Comets P/Crommelin, P/Giacobini-Zinner and P/Halley are coordinated, preliminary results are delivered to the astronomical community and the data collected from observers throughout the world are archived. The ASU IHW Center has the additional responsibility of maintaining the IHW Electronic Bulletin Board which reports real-time information on the status of Comet P/Halley. Access to this electronic bulletin board via telephone modem connection is available to any astronomer upon request.

The comet Halley meteoroid stream: just one more model

NASA Astrophysics Data System (ADS)

Ryabova, G. O.

2003-05-01

The present attempt to simulate the formation and evolution of the comet Halley meteoroid stream is based on a tentative physical model of dust ejection of large particles from comet Halley. Model streams consisting of 500-5000 test particles have been constructed according to the following ejection scheme. The particles are ejected from the nucleus along the cometary orbit (r < 9 au) within the sunward 70° cone, and the rate of ejection has been taken as proportional to r-4. Two kinds of spherical particles have been considered: 1 and 0.001 g with density equal to 0.25 g cm-3. Ejections have been simulated for 1404 BC, 141 AD and 837 AD. The equations of motion have been numerically integrated using the Everhart procedure. As a result, a complicated fine structure of the comet Halley meteoroid stream, consisting not of filaments but of layers, has been revealed.

New Image of Comet Halley in the Cold

NASA Astrophysics Data System (ADS)

2003-09-01

VLT Observes Famous Traveller at Record Distance Summary Seventeen years after the last passage of Comet Halley , the ESO Very Large Telescope at Paranal (Chile) has captured a unique image of this famous object as it cruises through the outer solar system. It is completely inactive in this cold environment. No other comet has ever been observed this far - 4200 million km from the Sun - or that faint - nearly 1000 million times fainter than what can be perceived with the unaided eye. This observation is a byproduct of a dedicated search [1] for small Trans-Neptunian Objects, a population of icy bodies of which more than 600 have been found during the past decade. PR Photo 27a/03 : VLT image (cleaned) of Comet Halley PR Photo 27b/03 : Sky field in which Comet Halley was observed PR Photo 27c/03 : Combined VLT image with star trails and Comet Halley The Halley image ESO PR Photo 27a/03 ESO PR Photo 27a/03 [Preview - JPEG: 546 x 400 pix - 207k] [Normal - JPEG: 1092 x 800 pix - 614k] [FullRes - JPEG: 1502 x 1100 pix - 1.1M] Caption : PR Photo 27a/03 shows the faint, star-like image of Comet Halley (centre), observed with the ESO Very Large Telescope (VLT) at the Paranal Observatory on March 6-8, 2003. 81 individual exposures from three of the four 8.2-m VLT telescopes with a total exposure time of about 9 hours were combined to show the magnitude 28.2 object. At this time, Comet Halley was about 4200 million km from the Sun (28.06 AU) and 4080 million km (27.26 AU) from the Earth. All images of stars and galaxies in the field were removed during the extensive image processing needed to produce this unique image. Due to the remaining, unavoidable "background noise", it is best to view the comet image from some distance. The field measures 60 x 40 arcsec 2 ; North is up and East is left. Remember Comet Halley - the famous "haired star" that has been observed with great regularity - about once every 76 years - during more than two millennia? Which was visited by an

Halley's Comet Makes a Comeback.

ERIC Educational Resources Information Center

Glenn, William H.

1984-01-01

Presents information on Halley's Comet including its discovery, impact on history, planned investigations related to its 1986 return, where and when to make observations, and predicted calendar of events. Gives general information on comets such as physical structure, theoretical origin, and paths and provides an annotated reference list. (JM)

Comet Halley and nongravitational forces

NASA Technical Reports Server (NTRS)

Yeomans, D. K.

1977-01-01

The motion of comet Halley is investigated over the 1607-1911 interval. The required nongravitational-force model was found to be most consistent with a rocket-type thrust from the vaporization of water ice in the comet's nucleus. The nongravitational effects are time-independent over the investigated interval.

Current status of the international Halley Watch infrared net archive

NASA Technical Reports Server (NTRS)

Mcguinness, Brian B.

1988-01-01

The primary purposes of the Halley Watch have been to promote Halley observations, coordinate and standardize the observing where useful, and to archive the results in a database readily accessible to cometary scientists. The intention of IHW is to store the observations themselves, along with any information necessary to allow users to understand and use the data, but to exclude interpretations of these data. Each of the archives produced by the IHW will appear in two versions: a printed archive and a digital archive on CD-ROMs. The archive is expected to have a very long lifetime. The IHW has already produced an archive for P/Crommelin. This consists of one printed volume and two 1600 bpi tapes. The Halley archive will contain at least twenty gigabytes of information.

Analysis of the Tail Structures of Comet 1P/Halley 1910 II

NASA Astrophysics Data System (ADS)

Voelzke, Marcos Rincon

2013-11-01

For the purpose of identifying, measuring, and correlating the morphological structures along the plasma tail of 1P/Halley, 886 images from September 1909 to May 1911 are analysed. These images are from the Atlas of Comet Halley 1910 II (DONN; RAHE; BRANDT, 1986).

On the past orbital history of Comet P/Halley

NASA Astrophysics Data System (ADS)

Carusi, A.; Valsecchi, G. B.; Kresak, L.; Perozzi, E.

The results of backward integration of the Comet P/Halley behavior over the time span from 1585 AD to 9367 BC (a total of 4 million days) are discussed. The integration was performed on the FPS 364, using the integrator described by Everhart (1985); planets from Venus to Neptune were included, and nongravitational forces were neglected. Graphs are presented for the temporal evolution of the orbital eccentricity (computed along the barycentric orbit at each aphelion passage), orbital inclination, the argument of perihelion of the orbit, perihelion distance, and the two nodal distances of P/Halley comet. A more or less continuous decrease of the orbital eccentricity and inclination were found, as well as of the argument of perihelion. It is suggested that Comet P/Halley may have undergone strong gravitational interactions with Jupiter about 11,000 years ago, and that the time span spent by the comet in a short period orbit may be as short as that.

Halley's Comet: A Bibliographic Essay.

ERIC Educational Resources Information Center

Gallant, Stephen L.

1985-01-01

This bibliographic essay evaluates six books on Halley's Comet as science writings that fall into three categories: middle school and junior high-level books; senior high to adult-level books; and advanced level. Author, number of pages, publication date, price, International Standard Book Number, and publisher information are provided. (EJS)

Dynamical and collisional evolution of Halley-type comets

NASA Astrophysics Data System (ADS)

van der Helm, E.; Jeffers, S. V.

2012-03-01

The number of observed Halley-type comets is hundreds of times less than predicted by models (Levison, H.F., Dones, L., Duncan, M.J. [2001]. Astron. J. 121, 2253-2267). In this paper we investigate the impact of collisions with planetesimals on the evolution of Halley-type comets. First we compute the dynamical evolution of a sub-set of 21 comets using the MERCURY integrator package over 100 Myr. The dynamical lifetime is determined to be of the order of 105-106 years in agreement with previous work. The collisional probability of Halley-type comets colliding with known asteroids, a simulated population of Kuiper-belt objects, and planets, is calculated using a modified, Öpik-based collision code. Our results show that the catastrophic disruption of the cometary nucleus has a very low probability of occurring, and disruption through cumulative minor impacts is concluded to be negligible. The dust mantle formed from ejected material falling back to the comet’s surface is calculated to be less than a few centimeters thick, which is insignificant compared to the mantle formed by volatile depletion, while planetary encounters were found to be a negligible disruption mechanism.

The Archive of the Amateur Observation Network of the International Halley Watch. Volume 1; Comet Giacobini-Zinner

NASA Technical Reports Server (NTRS)

Edberg, Stephen J. (Editor)

1996-01-01

The International Halley Watch (IHW) was organized for the purpose of gathering and archiving the most complete record of the apparition of a comet, Comet Halley (1982i = 1986 III = 1P/Halley), ever compiled. The redirection of the International Cometary Explorer (ICE), toward Comet Giacobini-Zinner (1984e = 1985 XIII = 21P/Giacobini-Zinner) prompted the initiation of a formal watch on that comet. All the data collected on P/Giacobini-Zinner and P/Halley have been published on CD-ROM in the Comet Halley Archive. This document contains a printed version of the archive data, collected by amateur astronomers, on these two comets. Volume 1 contains the Comet Giacobini-Zinner data archive and Volume 2 contains the Comet Halley archive. Both volumes include information on how to read the data in both archives, as well as a history of both comet watches (including the organizing of the network of astronomers and lessons learned from that experience).

The Archive of the Amateur Observation Network of the International Halley Watch. Volume 1; Comet Giacobini-Zinner

NASA Technical Reports Server (NTRS)

Edberg, Stephen J. (Editor)

1966-01-01

The International Halley Watch (IHW) was organized for the purpose of gathering and archiving the most complete record of the apparition of a comet, Halley's Comet (1982i = 1986 III = 1P/Halley), ever compiled. The redirection of the International Sun-Earth Explorer 3 (ISEE-3) spacecraft, subsequently renamed the International Cometary Explorer (ICE), toward Comet Giacobini-Zinner (1984e = 1985 XIII = 21P/Giacobini-Zinner) prompted the initiation of a formal watch on that comet. All the data collected on P/Giacobini-Zinner and P/Halley have been published on CD-ROM in the Comet Halley Archive. This document contains a printed version of the archive data, collected by amateur astronomers, on these two comets. Volume 1 contains the Comet Giacobini-Zinner data archive and Volume 2 contains the Comet Halley archive. Both volumes include information on how to read the data in both archives, as well as a history of both comet watches (including the organizing of the network of astronomers and lessons learned from that experience).

MOLECULAR OXYGEN IN OORT CLOUD COMET 1P/HALLEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubin, M.; Altwegg, K.; Dishoeck, E. F. van

2015-12-10

Recently, the ROSINA mass spectrometer suite on board the European Space Agency's Rosetta spacecraft discovered an abundant amount of molecular oxygen, O{sub 2}, in the coma of Jupiter family comet 67P/Churyumov–Gerasimenko of O{sub 2}/H{sub 2}O = 3.80 ± 0.85%. It could be shown that O{sub 2} is indeed a parent species and that the derived abundances point to a primordial origin. Crucial questions are whether the O{sub 2} abundance is peculiar to comet 67P/Churyumov–Gerasimenko or Jupiter family comets in general, and also whether Oort cloud comets such as comet 1P/Halley contain similar amounts of molecular oxygen. We investigated mass spectra obtained bymore » the Neutral Mass Spectrometer instrument during the flyby by the European Space Agency's Giotto probe of comet 1P/Halley. Our investigation indicates that a production rate of O{sub 2} of 3.7 ± 1.7% with respect to water is indeed compatible with the obtained Halley data and therefore that O{sub 2} might be a rather common and abundant parent species.« less

Make a Halley's Comet Orbit Model.

ERIC Educational Resources Information Center

Podmore, Francis; Fleet, Richard W.

1985-01-01

Describes a simple three-dimensional model of Halley's Comet orbit (which is much more informative than a two-dimensional drawing) to illustrate spatial relationships and visualize how the comet moves relative to the earth. Instructions for model assembly are given along with a template which can be photocopied and glued to cardboard. (JN)

Records of Halley's comet on Babylonian tablets

NASA Astrophysics Data System (ADS)

Stephenson, F. R.; Yau, K. K. C.; Hunger, H.

1985-04-01

The late Babylonian texts in the British Museum are shown to contain probable observations of Halley's comet at both its 164 BC and 87 BC apparitions. These texts have important bearing on the orbital motion of the comet in the ancient past.

In-vivo RGB marking and multicolour single-cell tracking in the adult brain

PubMed Central

Gomez-Nicola, Diego; Riecken, Kristoffer; Fehse, Boris; Perry, V. Hugh

2014-01-01

In neuroscience it is a technical challenge to identify and follow the temporal and spatial distribution of cells as they differentiate. We hypothesised that RGB marking, the tagging of individual cells with unique hues resulting from simultaneous expression of the three basic colours red, green and blue, provides a convenient toolbox for the study of the CNS anatomy at the single-cell level. Using γ-retroviral and lentiviral vector sets we describe for the first time the in-vivo multicolour RGB marking of neurons in the adult brain. RGB marking also enabled us to track the spatial and temporal fate of neural stem cells in the adult brain. The application of different viral envelopes and promoters provided a useful approach to track the generation of neurons vs. glial cells at the neurogenic niche, allowing the identification of the prominent generation of new astrocytes to the striatum. Multicolour RGB marking could serve as a universal and reproducible method to study and manipulate the CNS at the single-cell level, in both health and disease. PMID:25531807

Carbonaceous Components in the Comet Halley Dust

NASA Technical Reports Server (NTRS)

Fomenkova, M. N.; Chang, S.; Mukhin, L. M.

1994-01-01

Cometary grains containing large amounts of carbon and/or organic matter (CHON) were discovered by in situ measurements of comet Halley dust composition during VEGA and GIOTTO flyby missions. In this paper, we report the classification of these cometary, grains by means of cluster analysis, discuss the resulting compositional groups, and compare them with substances observed or hypothesized in meteorites, interplanetary dust particles, and the interstellar medium. Grains dominated by carbon and/or organic matter (CHON grains) represent approx. 22% of the total population of measured cometary dust particles. They, usually contain a minor abundance of rock-forming elements as well. Grains having organic material are relatively more abundant in the vicinity of the nucleus than in the outer regions of the coma, which suggests decomposition of the organics in the coma environment. The majority of comet Halley organic particles are multicomponent mixtures of carbon phases and organic compounds. Possibly, the cometary CHON grains may be related to kerogen material of an interstellar origin in carbonaceous meteorites. Pure carbon grains, hydrocarbons and polymers of cyanopolyynes, and multi-carbon monoxides are present in cometary dust as compositionally simple and distinctive components among a variety of others. There is no clear evidence of significant presence of pure formaldehyde or HCN polymers in Halley dust particles. The diversity of types of cometary organic compounds is consistent with the inter-stellar dust model of comets and probably reflects differences in composition of precursor dust. Preservation of this heterogeneity among submicron particles suggest the gentle formation of cometary, nucleus by aggregation of interstellar dust in the protosolar nebula without complete mixing or chemical homogenization at the submicron level.

The International Cometary Explorer (ICE) mission to Comets Giacobini-Zinner and Halley

NASA Technical Reports Server (NTRS)

Brandt, J. C.

1986-01-01

Use of the ISEE-3 satellite (renamed ICE) to study the interaction between the solar wind and a cometary atmosphere by passing through the plasma tail by intercepting Comet Giacobini-Zinner on 11 September 1985 is described. Details of the targeting strategy are discussed. Additional scientific objectives following the tail intercept of Comet Giacobini-Zinner include the support of Comet Halley studies through the measurement of solar-wind conditions upstream of P/Halley in October 1985 and March 1986.

The composition of heavy molecular ions inside the ionopause of Comet Halley

NASA Technical Reports Server (NTRS)

Mitchell, David L.; Lin, R. P.; Anderson, K. A.; Carlson, C. W.; Curtis, D. W.; Korth, A.; Reme, H.; Sauvaud, J. A.; Duston, C.; Mendis, D. A.

1989-01-01

The RPA2-PICCA instrument aboard the Giotto spacecraft obtained 10-210 amu mass spectral of cold thermal molecular ions in the coma of Comet Halley. The dissociation products of the long chain formaldehyde polymer polyoxymethylene (POM) have recently been proposed as the dominant complex molecules in the coma of Comet Halley; however, POM alone cannot account for all of the features of the high resolution spectrum. An important component of the dust at Comet Halley is particles highly enriched in carbon, hydrogen, oxygen, and nitrogen relative to the composition of carbonaceous chondrites. Since this dust could be a source for the heavy molecules observed by PICCA, a search was conducted for other chemical species by determining all the molecules with mass between 20 and 120 amu which can be made from the relatively abundant C, H, O, and N, without regard to chemical structure.

The 2.4 micron spectrum of Comet Halley - A search for H2 emission

NASA Astrophysics Data System (ADS)

Smith, W. H.; Wolstencroft, R. D.; Lutz, B. L.

1989-02-01

A 2.4-micron spectrum of Comet Halley was obtained on April 1, 1986 with the UKIRT scanning Fabry-Perot-CVF equipped with an InSb detector. From the ratio of the measured flux from comet Halley to Zeta Her in the 8.8 x 10 to the -4th micron bandwidth, Comet Halley produced a detected flux of about 1.3 x 10 to the 5th photons/sec with a 1-sigma variance of 385 photons. The flux detected in the same spectral region by Maillard et al. (1986) agrees with the measurements reported here to within a factor of two. The data obtained are examined from the standpoint of the possible mechanisms of H2 production.

Iron, magnesium, and silicon in dust from Comet Halley

NASA Technical Reports Server (NTRS)

Lawler, Mark E.; Brownlee, Donald E.; Temple, Scott; Wheelock, Maya M.

1989-01-01

The highest-quality impact mass spectrometer data from the Vega-1 and Giotto spacecraft are presently used to study the Mg, Si, and Fe composition of dust grains in Comet Halley. The results thus obtained are in general agreement with previously reported data, but differ with respect to ion ratio dispersions. A lack of sharp clustering in the data indicates that none of the detected particles can be characterized as single mineral grains; an abundant glass content in the solids may be indicated. The best match of the distribution of Fe/(Fe+Mg) is with interplanetary particles containing high temperature, Mg-rich silicates dominated by anhydrous minerals, so that Comet Halley may be a mixture of ice and high-temperature anhydrous minerals.

The digital archive of the International Halley Watch

NASA Technical Reports Server (NTRS)

Klinglesmith, D. A., III; Niedner, M. B.; Grayzeck, E.; Aronsson, M.; Newburn, R. L.; Warnock, A., III

1992-01-01

The International Halley Watch was established to coordinate, collect, archive, and distribute the scientific data from Comet P/Halley that would be obtained from both the ground and space. This paper describes one of the end products of that effort, namely the IHW Digital Archive. The IHW Digital Archive consists of 26 CD-ROM's containing over 32 gigabytes of data from the 9 IHW disciplines as well as data from the 5 spacecraft missions flown to comet P/Haley and P/Giacobini-Zinner. The total archive contains over 50,000 observations by 1,500 observers from at least 40 countries. The first 24 CD's, which are currently available, contain data from the 9 IHW disciplines. The two remaining CD's will have the spacecraft data and should be available within the next year. A test CD-ROM of these data has been created and is currently under review.

Nonlinear stability of Halley comethosheath with transverse plasma motion

NASA Technical Reports Server (NTRS)

Srivastava, Krishna M.; Tsurutani, Bruce T.

1994-01-01

Weakly nonlinear Magneto Hydrodynamic (MHD) stability of the Halley cometosheath determined by the balance between the outward ion-neutral drag force and the inward Lorentz force is investigated including the transverse plasma motion as observed in the flanks with the help of the method of multiple scales. The eigenvalues and the eigenfunctions are obtained for the linear problem and the time evolution of the amplitude is obtained using the solvability condition for the solution of the second order problem. The diamagnetic cavity boundary and the adjacent layer of about 100 km thickness is found unstable for the travelling waves of certain wave numbers. Halley ionopause has been observed to have strong ripples with a wavelength of several hundred kilometers. It is found that nonlinear effects have stabilizing effect.

Astronomical Resources: A Selected Halley's Comet Reading List.

ERIC Educational Resources Information Center

Fraknoi, Andrew

1985-01-01

Presents annotated lists of: (1) general introductory books about comets and Comet Halley; (2) books about comet history and lore; (3) introductory books for younger children; and (4) books for the serious amateur astronomer. A list of magazine and journal articles is included. (JN)

A worldwide photographic network for wide-field observations of Halley's Comet in 1985-1986

NASA Technical Reports Server (NTRS)

Niedner, M. B., Jr.; Brandt, J. C.; Rahe, J.

1982-01-01

A global network of ground-based observatories for the study of Halley's Comet in 1985/1986 is discussed. Recommendations are made with respect to improving coordination between reporting observatories, in order to ensure detailed imaging of such fast-generating cometary phenomena as plasma-tail knots, helices, disconnected tails, rays and condensations. A method for calibrating telescopes is considered by which well-studied objects will be photographed to provide references for images of Halley's Comet. This procedure is expected to reduce errors to approximately 0.05 mag. A coordinated study of Halley's Comet will provide important data on the physical properties of the Comet. Examples of the topics of study related to the plasma physics of the Comet's tail include: magnetic reconnection, rippling and tearing modes, kink instability, Kelvin-Helmholtz instability, and the flute instability.

Solar wind mass-loading at Comet Halley - A lesson from Venus?

NASA Astrophysics Data System (ADS)

Breus, T. K.; Krymskii, A. M.; Luhmann, J. G.

1987-05-01

Recent observations at comet Halley show that the region within which cometary ions become the dominant component lies outside of the magnetic field-free cavity. This behavior resembles that found at Venus under conditions where the incident solar wind dynamic pressure exceeds the ionospheric pressure. On these occasions the magnetosheath magnetic field is found well inside of the region where planetary ions are observed. Although scaling and the details of formation of the inner boundary of the magnetic field are different for these two objects, the processes by which the interplanetary magnetic field penetrates into the ionospheres at Venus and at comet Halley are in many ways analogous.

A ballistic mission to fly by Comet Halley

NASA Technical Reports Server (NTRS)

Boain, R. J.; Hastrup, R. C.

1980-01-01

The paper describes the available options, ballistic trajectory opportunities, and a preliminary reference trajectory that were selected as a basis for spacecraft design studies and programmatic planning for a Halley ballistic intercept mission in 1986. The paper also presents trajectory, performance, and navigation data which support the preliminary selection.

Comet Halley - The orbital motion

NASA Technical Reports Server (NTRS)

Yeomans, D. K.

1977-01-01

The orbital motion of Comet Halley is investigated over the interval from A.D. 837 to 2061. Using the observations from 1607 through 1911, least-squares differential orbit corrections were successfully computed using the existing model for the nongravitational forces. The nongravitational-force model was found to be consistent with the outgassing-rocket effect of a water-ice cometary nucleus and, prior to the 1910 return, these forces are time-independent for nearly a millennium. For the 1986 return, viewing conditions are outlined for the comet and the related Orionid and Eta Aquarid meteor showers.

The effects of electrostatic charging on the dust distribution at Halley's Comet

NASA Technical Reports Server (NTRS)

Horanyi, M.; Mendis, D. A.

1986-01-01

The distribution of fine dust near Comet Halley at its 1910 and 1986 apparitions is investigated by means of computer simulations, taking the effects of EM forces due to the dust electrostatic charge into account. It is found that the nucleus spin period and orbital obliquity estimated by Sekanina and Larson (1984) from the 1910 observations are unaffected by these EM forces because the 1910 dust morphology involved mainly large grains. For 1986, the orientation of the smaller dust is shown to depend on the interplanetary magnetic field, with implications for the dust distribution encountered by the Halley probes.

Electron plasma environment at comet Grigg-Skjellerup: General observations and comparison with the environment at comet Halley

NASA Technical Reports Server (NTRS)

Reme, H.; Mazelle, C.; Sauvaud, J. A.; D'Uston, C.; Froment, F.; Lin, R. P.; Anderson, K. A.; Carlson, C. W.; Larson, D. E.; Korth, A.

1993-01-01

The three-dimensional electron spectrometer of the Reme plasma analyzer-complete positive ion, electron and ram negative ion measurements near comet Halley (RPA-COPERNIC) experiment aboard the Giotto spacecraft, although damaged during the comet Halley encounter in March 1986, has provided very new results during the encounter on July 10, 1992, with the weakly active comet Grigg-Skjellerup (G-S). The main characteristic features of the highly structured interaction region extending from approximately 26,500 km inbound to approximately 37,200 km outbound are presented. These results are compared to the results obtained by the same instrument during the Giotto comet Halley fly-by. Despite the large difference in the size of the interaction regions (approximately 60,000 km for G-S, approximately 2000,000 km for Halley) due to 2 orders of magnitude difference in cometary neutral gas production rate, there are striking similarities in the solar wind interactions with the two comets.

Ground-base multicolour photometry of NGC 6811

NASA Astrophysics Data System (ADS)

Ocando, S.; Martín-Ruiz, S.; Rodríguez, E.

2017-03-01

NGC 6811 is one of the four open clusters in the field of view of the Kepler space mission. Among its members there are several known pulsating A-F stars of the δ Scuti, γ Doradus, and hybrid type, which makes this cluster a very interesting object to study its pulsational content. During the summers of 2013 and 2014 we performed an extensive observational campaign using the 1.5 m telescope at the Sierra Nevada Observatory and multicolour photometry. New pulsating variables candidates were detected in this work. We fulfilled a frequency analysis for the known variables, with very good agreement with previous results. By using Str ̈omgren photometry we were able to obtain the main physical parameters of the stars such as temperature, surface gravity, metallicity and luminosity. We have also determined the corresponding frequency phase-shifts and amplitude ratios between different filters as a first step to identify the pulsational modes of the variables.

Analysis of hydrogen H-alpha observations of the coma of Comet P/Halley

NASA Technical Reports Server (NTRS)

Smyth, William H.; Marconi, M. L.; Scherb, Frank; Roesler, Fred L.

1993-01-01

The Monte Carlo Particle Trajectory Model of Combi and Smyth (1988) is used here to analyze observations of the H-alpha coma of Comet Halley. The solar excitation mechanism for the H-alpha emissions line is described. The H2O production rates derived for the H-alpha brightness measurements are shown to be very consistent with the H2O production rates determined from other Comet Halley observations of the H, O, and OH comae. Revised H2O production rates determined from 6300 A brightness measurements are presented.

Comet Halley Returns. A Teacher's Guide, 1985-1986.

ERIC Educational Resources Information Center

Chapman, Robert D.; Bondurant, R. Lynn, Jr.

This booklet was designed as an aid for elementary and secondary school teachers. It is divided into two distinct parts. Part I is a brief tutorial which introduces some of the most important concepts about comets. Areas addressed include: the historical importance of Comet Halley; how comets are found and names; cometary orbits; what Comet Halley…

International Halley Watch: Discipline specialists for large scale phenomena

NASA Technical Reports Server (NTRS)

Brandt, J. C.; Niedner, M. B., Jr.

1986-01-01

The largest scale structures of comets, their tails, are extremely interesting from a physical point of view, and some of their properties are among the most spectacular displayed by comets. Because the tail(s) is an important component part of a comet, the Large-Scale Phenomena (L-SP) Discipline was created as one of eight different observational methods in which Halley data would be encouraged and collected from all around the world under the aspices of the International Halley Watch (IHW). The L-SP Discipline Specialist (DS) Team resides at NASA/Goddard Space Flight Center under the leadership of John C. Brandt, Malcolm B. Niedner, and their team of image-processing and computer specialists; Jurgan Rahe at NASA Headquarters completes the formal DS science staff. The team has adopted the study of disconnection events (DE) as its principal science target, and it is because of the rapid changes which occur in connection with DE's that such extensive global coverage was deemed necessary to assemble a complete record.

Halley's Comet - Canadian Observations and Reactions 1835-36 and 1910

NASA Astrophysics Data System (ADS)

Smith, J. A.

1986-02-01

The files of old newspapers provide a rich source of Canadian data about the past returns of Halley's comet. A description is presented of the 1835 - 36 and 1910 stories, editorials, advertisements, poems, and columns that are informative.

Organic Chemistry in Interstellar Ices: Connection to the Comet Halley Results

NASA Technical Reports Server (NTRS)

Schutte, W. A.; Agarwal, V. K.; deGroot, M. S.; Greenberg, J. M.; McCain, P.; Ferris, J. P.; Briggs, R.

1997-01-01

Mass spectroscopic measurements on the gas and dust in the coma of Comet Halley revealed the presence of considerable amounts of organic species. Greenberg (1973) proposed that prior to the formation of the comet UV processing of the ice mantles on grains in dense clouds could lead to the formation of complex organic molecules. Theoretical predictions of the internal UV field in dense clouds as well as the discovery in interstellar ices of species like OCS and OCN- which have been formed in simulation experiments by photoprocessing of interstellar ice analogues point to the importance of such processing. We undertook a laboratory simulation study of the formation of organic molecules in interstellar ices and their possible relevance to the Comet Halley results.

Early star catalogues of the southern sky. De Houtman, Kepler (second and third classes), and Halley

NASA Astrophysics Data System (ADS)

Verbunt, F.; van Gent, R. H.

2011-06-01

De Houtman in 1603, Kepler in 1627 and Halley in 1679 published the earliest modern catalogues of the southern sky. We provide machine-readable versions of these catalogues, make some comparisons between them, and briefly discuss their accuracy on the basis of comparison with data from the modern Hipparcos Catalogue. We also compare our results for De Houtman with those by Knobel in 1917 finding good overall agreement. About half of the ~ 200 new stars (with respect to Ptolemaios) added by De Houtman are in twelve new constellations, half in old constellations like Centaurus, Lupus and Argo. The right ascensions and declinations given by De Houtman have error distributions with widths of about 40', the longitudes and latitudes given by Kepler have error distributions with widths of about 45'. Halley improves on this by more than an order of magnitude to widths of about 3', and all entries in his catalogue can be identified. The measurement errors of Halley are due to a systematic deviation of his sextant (increasing with angle to 2' at 60°) and random errors of 0.7 arcmin. The position errors in the catalogue of Halley are dominated by the position errors in the reference stars, which he took from Brahe. The full Tables Houtman, Classis, Aliter and Halley (see Tables 6, 7, 8) are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/530/A93

Carbon-rich particles in Comet Halley

NASA Technical Reports Server (NTRS)

Clark, Benton C.

1990-01-01

The majority of particles detected in the coma of Comet Halley contain carbon atoms; many of these grains appear to consist preponderately or only of light elements. These light-element particles may be composed of organic compounds. Of the possible combinations of the elements hydrogen, carbon, nitrogen, and oxygen, numerous examples are found of particles containing the combinations (H,C,O,N), (H,C,N), (H,C,O), and (H,C). These results may bear on the recent detection of polyoxymethylene fragments, the observation of cyanojets (CN patterns consistent with release from solid particles), the possible presence of cyanopolyacetylenes or HCN polymer and the make-up of the CHON particles. If cometary matter could reach the surface of the earth without complete disruption, these diverse organic and mixed particles could create unique microenvironments, possibly with significant or even pivotal prebiotic chemical activity. Here a speculative insight into possible relationships between carbon in comets and carbon in life is given, as well as a brief overview of on-going analysis of data from the highly successful Particle Impact Analyzer (PIA) experiment flown on the Giotto spacecraft for the flyby of Comet Halley (development and implementation of PIA was under the direction of J. Kissel of the Max Planck Institute for Kernphysik, Heidelberg). PIA is a time-of-flight analyzer which obtains mass spectra of ions from individual particles impacting on a Pt-Ag foil target within the instrument.

3D CSEM data inversion using Newton and Halley class methods

NASA Astrophysics Data System (ADS)

Amaya, M.; Hansen, K. R.; Morten, J. P.

2016-05-01

For the first time in 3D controlled source electromagnetic data inversion, we explore the use of the Newton and the Halley optimization methods, which may show their potential when the cost function has a complex topology. The inversion is formulated as a constrained nonlinear least-squares problem which is solved by iterative optimization. These methods require the derivatives up to second order of the residuals with respect to model parameters. We show how Green's functions determine the high-order derivatives, and develop a diagrammatical representation of the residual derivatives. The Green's functions are efficiently calculated on-the-fly, making use of a finite-difference frequency-domain forward modelling code based on a multi-frontal sparse direct solver. This allow us to build the second-order derivatives of the residuals keeping the memory cost in the same order as in a Gauss-Newton (GN) scheme. Model updates are computed with a trust-region based conjugate-gradient solver which does not require the computation of a stabilizer. We present inversion results for a synthetic survey and compare the GN, Newton, and super-Halley optimization schemes, and consider two different approaches to set the initial trust-region radius. Our analysis shows that the Newton and super-Halley schemes, using the same regularization configuration, add significant information to the inversion so that the convergence is reached by different paths. In our simple resistivity model examples, the convergence speed of the Newton and the super-Halley schemes are either similar or slightly superior with respect to the convergence speed of the GN scheme, close to the minimum of the cost function. Due to the current noise levels and other measurement inaccuracies in geophysical investigations, this advantageous behaviour is at present of low consequence, but may, with the further improvement of geophysical data acquisition, be an argument for more accurate higher-order methods like those

Comet Science Working Group report on the Halley Intercept Mission

NASA Technical Reports Server (NTRS)

1980-01-01

The Halley Intercept Mission is described and the scientific benefits expected from the program are defined. One characteristic of the mission is the optical navigation and resulting accurate delivery of the spacecraft to a desired point near the nucleus. This accuracy of delivery has two important implications: (1) high probability that the mass spectrometers and other in situ measurement devices will reach the cometary ionosphere and the zone of parent molecules next to the nucleus; (2) high probability that sunlit, high resolution images of Halley's nucleus will be obtained under proper lighting conditions. In addition an observatory phase is included during which high quality images of the tail and coma structure will be obtained at progressively higher spatial resolutions as the spacecraft approaches the comet. Complete measurements of the comet/solar wind interaction can be made around the time of encounter. Specific recommendations are made concerning project implementation and spacecraft requirements.

A study of ion composition and dynamics at Comet Halley

NASA Technical Reports Server (NTRS)

Shelley, E. G.; Fuselier, S. A.

1991-01-01

This report details the participation by Lockheed co-investigators in the reduction, analysis, and interpretation of data obtained by the Ion Mass Spectrometer onboard the Giotto mission to Comet Halley. The data analysis activities and much of the scientific collaboration was shared by this team. One objective of the effort under this contract was to use data obtained by the Giotto Ion Mass Spectrometer (IMS) during the encounter with comet Halley for the purpose of advancing our understanding of the chemistry and physics of the interaction of the solar wind with comets and obtaining new information on the comet's composition. An additional objective was to make this unique data set available in a format which can be easily used by the reset of the cometary science community for other analysis in the future. The IMS has two sensors: the High Intensity Spectrometer (HIS) and the High Energy Range Spectrometer (HERS).

IUE observations of Comet Halley: Evolution of the UV spectrum between September 1985 and July 1986

NASA Technical Reports Server (NTRS)

Feldman, P. D.; Festou, Michael C.; Ahearn, M. F.; Arpigny, C.; Butterworth, P. S.; Cosmovici, C. B.; Danks, A. C.; Gilmozzi, R.; Jackson, W. M.; Mcfadden, L. A.

1986-01-01

The ultraviolet spectrum of comet P/Halley was monitored with the IUE between 12 September 1985 and 8 July 1986 (r <2.6 AU pre and post-perihelion) at regular time intervals except for a two-month period around the time of perihelion. A complete characterization of the UV spectrum of the comet was obtained to derive coma abundances and to study the light emission mechanisms of the observed species. The Fine Error Sensor (FES) camera of the IUE was used to photometrically investigate the coma brightness variation on time scales of the order of hours. Spectroscopic observations as well as FES measurements show that the activity of the nucleus is highly variable, particularly at the end of December 1985 and during March and April 1986. The production rates of OH, CS and dust are derived for the entire period of the observations. The total water loss rate for this period is estimated to be 150 million metric tons.

The hydrogen coma of Comet P/Halley observed in Lyman-alpha using sounding rockets

NASA Technical Reports Server (NTRS)

Mccoy, R. P.; Meier, R. R.; Keller, H. U.; Opal, C. B.; Carruthers, G. R.

1992-01-01

Hydrogen Lyman-alpha (121.6 nm) images of Comet P/Halley were obtained using sounding rockets launched from White Sands Missile Range on 24.5 February and 13.5 March 1986. The second rocket was launched 13 hours before the fly-by of the Giotto spacecraft. An electrographic camera on both flights provided Lyman-alpha images covering a 20 field of view with 3 arcmin resolution. The data from both flights have been compared with a time-dependent model of hydrogen kinetics. To match the measured isophote contours, hydrogen sources with velocity components of 8 km/s and 20 km/s (from OH and H2O respectively) as well as a low velocity component (about 2 km/s) are required. This low velocity component is thought to result from thermalization of fast hydrogen atoms within the collision zone, providing an important diagnostic of temperature and density near the nucleus. Hydrogen production rates of 3.8 x 10 exp 30/s and 1.7 x 10 exp 30/s have been obtained for the two observations.

Ion abundances and implications for photochemistry in Comets Halley (1986 III) and Bradfield (1987 XXIX)

NASA Astrophysics Data System (ADS)

Lutz, B. L.; Womack, M.; Wagner, R. M.

1993-04-01

The Ohio State University Image Dissector Scanner on the Perkins 1.8-m telescope at the Lowell Observatory was used to record spectra of the plasma tails of Comets P/Halley (1986 III) and P/Bradfield (1987 XXIX, also 1987s). The ionic species CO(+), N2(+), CH(+), and H2O(+) were identified in these spectra, and column densities for them were calculated from measured fluxes. The observed N2(+)/H2O(+) ratios are at least an order of magnitude lower and the observed CH(+)/H2O(+) ratios are a factor of 100 higher than theoretical results. The abundance ratio N2/CO was derived in the plasma tail of Bradfield from N2(+) and CO(+) data, and found to be an order of magnitude higher than a value measured in Halley. The relative ion abundances of CH(+), N2(+), CO(+), and H2O(+) in Halley are consistent with in situ measurements obtained from the Giotto spacecraft.

Multicolour Multilevel STED nanoscopy of Actin/Spectrin Organization at Synapses

PubMed Central

Sidenstein, Sven C.; D’Este, Elisa; Böhm, Marvin J.; Danzl, Johann G.; Belov, Vladimir N.; Hell, Stefan W.

2016-01-01

Superresolution fluorescence microscopy of multiple fluorophores still requires development. Here we present simultaneous three-colour stimulated emission depletion (STED) nanoscopy relying on a single STED beam at 620 nm. Toggling the STED beam between two or more power levels (“multilevelSTED”) optimizes resolution and contrast in all colour channels, which are intrinsically co-aligned and well separated. Three-colour recording is demonstrated by imaging the nanoscale cytoskeletal organization in cultured hippocampal neurons. The down to ~35 nm resolution identified periodic actin/betaII spectrin lattices along dendrites and spines; however, at presynaptic and postsynaptic sites, these patterns were found to be absent. Both our multicolour scheme and the 620 nm STED line should be attractive for routine STED microscopy applications. PMID:27220554

The International Halley Watch: A program of coordination, cooperation and advocacy

NASA Technical Reports Server (NTRS)

Friedman, L.; Newburn, R. L.

1981-01-01

To prevent a repetition of the lack of reporting and dissemination of the data obtained during the 1910 observations of Comet Halley, a mechanism is proposed for coordinating the work of scientists and amateurs, including government, industrials, and academic personnel during the 1985-86 apparition of Comet Halley. Specialists from each discipline, in consultation with other experts in the field, would recommend specific objectives, standards, data format, and priorities for observations in that discipline. Following time for individual publication, scientists would be invited to contribute results to a multivolume compilation containing as complete as possible a record of the apparition. It is suggested that the discipline specialists be selected jointly by the IHW leader an by an international steering group with members from COSPAR, the IAU, etc., perhaps in response to some form of international announcement of opportunity.

Radar observations of Comet Halley

NASA Technical Reports Server (NTRS)

Campbell, D. B.; Harmon, J. K.; Shapiro, I. I.

1989-01-01

Five nights of Arecibo radar observations of Comet Halley are reported which reveal a feature in the overall average spectrum which, though weak, seems consistent with being an echo from the comet. The large radar cross section and large bandwidth of the feature suggest that the echo is predominantly from large grains which have been ejected from the nucleus. Extrapolation of the dust particle size distribution to large grain sizes gives a sufficient number of grains to account for the echo. The lack of a detectable echo from the nucleus, combined with estimates of its size and rotation rate from spacecraft encounters and other data, indicate that the nucleus has a surface of relatively high porosity.

Mass spectra of heavy ions near comet Halley

NASA Astrophysics Data System (ADS)

Korth, A.; Richter, A. K.; Loidl, A.; Anderson, K. A.; Carlson, C. W.; Curtis, D. W.; Lin, R. P.; Reme, H.; Sauvaud, J. A.; D'Uston, C.; Cotin, F.; Cros, A.; Mendis, D. A.

1986-05-01

The heavy-ion analyser aboard the Giotto spacecraft, detected the first cometary ions at a distance of ≡1.05x106km from the nucleus of comet Halley. In the inner coma the major ions identified are associated with the H2O, CO and CO2 groups. Ions of larger atomic mass unit are also present, corresponding possibly to various hydrocarbons, heavy metals of the iron-group or to sulphur compounds.

Mass spectra of heavy ions near comet Halley

NASA Technical Reports Server (NTRS)

Korth, A.; Richter, A. K.; Loidl, A.; Anderson, K. A.; Carlson, C. W.

1986-01-01

The heavy-ion analyzer, RPA2-PICCA, aboard the Giotto spacecraft, detected the first cometary ions at a distance of about 1.05 million km from the nucleus of comet Halley. In the inner coma the major ions identified are associated with the H2O, CO and CO2 groups. Ions of larger atomic mass unit are also present, corresponding possibly to various hydrocarbons, heavy metals of the iron-group or to sulphur compounds.

Comet P/Halley 1910, 1986: An objective-prism study

NASA Technical Reports Server (NTRS)

Carsenty, U.; Bus, E. S.; Wyckoff, S.; Lutz, B.

1986-01-01

V. M. Slipher of the Lowell Obs. collected a large amount of spectroscopic data during the 1910 apparition of Halley's comet. Three of his post perihelion objective-prism plates were selected, digitized, and subjected to modern digital data reduction procedures. Some of the important steps in the analysis where: (1) Density to intensity conversion for which was used 1910 slit spectra of Fe-arc lamp on similar plates (Sigma) and derived an average characteristic curve; (2) Flux calibration using the fact that during the period June 2 to 7 1910 P/Halley was very close (angular distance) to the bright star Alpha Sex (A0III, V-4.49), and the spectra of both star and comet were recorded on the same plates. The flux distribution of Alpha Sex was assumed to be similar to that of the standard star 58 Aql and derived a sensitivity curve for the system; (3) Atmospheric extinction using the standard curve for the Lowell Obs.; (4) Solar continuum subtraction using the standard solar spectrum binned to the spectral resolution. An example of a flux-calibrated spectrum of the coma (integrated over 87,000km) before the subtraction of solar continuum is presented.

Modelling the neutral gas environment of comets with special application to P/Halley

NASA Technical Reports Server (NTRS)

Newburn, R. L., Jr.

1982-01-01

A technique has been developed which allows relatively accurate modelling of cometary gas production from nothing more than a visible light curve. Application to P/Halley suggests that the production rate of parent molecules will be about 2.6 x 10 to the 29th/second on March 10, 1986, for example. The uncertainties and intrinsic limitations in this approach are outlined. The theory is then extended to predictions of abundance of other gaseous species, and a photometric model of these gases is provided.Combined with the dust model of Divine (1981), preliminary predictions of the luminance of P/Halley, as seen in any direction from inside the coma or outside, can be provided for in the 3000-7000 A wavelength range.

The spacecraft encounters of Comet Halley

NASA Technical Reports Server (NTRS)

Asoka Mendis, D.; Tsurutani, Bruce T.

1986-01-01

The characteristics of the Comet Halley spacecraft 'fleet' (VEGA 1 and VEGA 2, Giotto, Suisei, and Sakigake) are presented. The major aims of these missions were (1) to discover and characterize the nucleus, (2) to characterize the atmosphere and ionosphere, (3) to characterize the dust, and (4) to characterize the nature of the large-scale comet-solar wind interaction. While the VEGA and Giotto missions were designed to study all four areas, Suisei addressed the second and fourth. Sakigake was designed to study the solar wind conditions upstream of the comet. It is noted that NASA's Deep Space Network played an important role in spacecraft tracking.

Temporal analysis of the morphological structures of comet 1P/Halley in the perihelion passages in 1910 and 1986

NASA Astrophysics Data System (ADS)

Voelzke, M. R.

2016-11-01

This work is based on a systematic analysis of images of 1P/Halley comet collected during its penultimate and ultimate approaches, i.e., in 1910 and in 1986. The present research basically characterised, identified, classified, measured and compared some of the tail structures of comet 1P/Halley like DEs, wavy structures and solitons. The images illustrated in the Atlas of Comet Halley 1910 II (Donn et al., 1986), which shows the comet in its 1910 passage, were compared with the images illustrated in The International Halley Watch Atlas of Large-Scale Phenomena (Brandt et al., 1992), which shows the comet in its 1986 passage. While two onsets of DEs were discovered after the perihelion passage in 1910, the average value of the corrected cometocentric velocity Vc was (57 ± 15) km/s; ten were discovered after the perihelion passage in 1986 with an average of corrected velocities equal to (130 ± 37) km/s. The mean value of the corrected wavelength of wavy structures, in 1910, is equal to (1.7 ± 0.1) x 10^6 km and in 1986 is (2.2 ± 0.2) x 10^6 km. The mean value of the amplitude A of the wave, in 1910, is equal to (1.4 ± 0.1) x 10^5 km and in 1986 it is equal to (2.8 ± 0.5) x 10^5 km. The goals of this research are to report the results obtained from the analysis of the P/Halleýs 1910 and 1986 images, to provide empirical data for comparison and to form the input for future physical/theoretical work. Referências [1] Brandt, J.C., Niedner Jr., M.B. & Rahe, J. 1992. International Halley Watch Atlas of Large-Scale Phenomena. University of Colorado-Boulder (printed by Johnson Printing Co., Boulder, CO) [2] Donn, B., Rahe, J. & Brandt, J.C. 1986. Atlas of Comet Halley 1910 II. NASA SP-488

Charge exchange of solar wind ions in the Comet Halley coma

NASA Technical Reports Server (NTRS)

Shelley, E. G.; Ing-H. afgoldstein, B. E. AGGOLDSTEIN, R.; Ing-H. afgoldstein, B. E. AGGOLDSTEIN, R.

1986-01-01

The He(2+) and He(+) radial profiles measured by the Giotto mass spectrometer on the inbound trajectory to comet Halley are compared to a simple 1-dimensional charge exchange model. Results indicate that charge exchange alone cannot account for the observed radial profiles of He(2+) and He(+).

Oxygen production rates for P/Halley over much of the 1985-1986 apparition

NASA Technical Reports Server (NTRS)

Spinrad, Hyron; Mccarthy, Patrick J.; Strauss, Michael A.

1986-01-01

Long slit CCD spectrophotometry of comet P/Halley in the visible region was used to measure the production rate of atomic oxygen during the 1985/86 apparition. The observations cover a large range of heliocentric distances, since the technique is applicable to apparently bright and faint comets. The cometary gas production rate for P/Halley increases rapidly with decreasing heliocentric distance toward perihelion and is systematicaly larger at a given heliocentric distance for the postperihelion observations. The average production rate for O1D on the day of the Giotto flyby is 4 times 10 to the 28th power atoms/sec giving an extrapolated total water production rate of 6 times 10 to the 29th power mols/sec. A method for comparing the absolute cometary gas production rates for different comets is discussed.

Analysis of the tail structures of comet P/Halley 1910 II

NASA Astrophysics Data System (ADS)

Voelzke, M. R.; Izaguirre, L. S.

Eight hundred and eighty six images from September 1909 to May 1911 are analysed for the purpose of identifying, measuring and correlating the morphological structures along the plasma tail of P/Halley. These images are from the Atlas of Comet Halley 1910 II (Donn et al. 1986). A systematic visual analysis revealed 304 wavy structures along the main tail and 164 along the secondary tails, 41 solitary waves (solitons), 13 Swan-like tails, 26 disconnection events (DEs), 166 knots and six shells. While the wavy structures denote undulations or a train of waves, the solitons refer to the formations usually denominated kinks. In general, it is possible to associate the occurrence of a DE and/or a Swan-Tail with the occurrence of a knot, but the last one may occur independently. It is also possible to say that the solitons occur in association with the wavy structures, but the reverse is not true. The 26 DEs documented in 26 different images allowed the derivation of two onsets of DEs, i.e., the time when the comet supposedly crossed a frontier between magnetic sectors of the solar wind. Both onsets of DEs were determined after the perihelion passage with an average of the corrected velocities Vc equal to (57 ± 15) km s-1. The mean value of the corrected wavelength λ c measured in 70 different wavy structures is equal to (1.7 ± 0.1) × 106 km and the mean amplitude A of the wave (measured in the same 70 wavy structures cited above) is equal to (1.4 ± 0.1) × 105 km. The mean value of the corrected cometocentric phase velocity Vpc measured in 20 different wavy structures is equal to (168 ± 28) km s-1. The average value of the corrected velocities Vkc of the knots measured in 36 different images is equal to (128 ± 12) km s-1. There is a tendency for A and λ c to increase with increasing cometocentric distance. The preliminary results of this work agree with the earlier research from Voelzke and Matsuura (1998), which analysed comet P/Halley's tail structures in its

3 micron spectrophotometry of Comet Halley - Evidence for water ice

NASA Technical Reports Server (NTRS)

Bregman, Jesse D.; Tielens, A. G. G. M.; Witteborn, Fred C.; Rank, David M.; Wooden, Diane

1988-01-01

Structure has been observed in the 3-3.6 micron preperihelion spectrum of Comet Halley consistent with either an absorption band near 3.1 microns or emission near 3.3 microns. The results suggest that a large fraction of the water molecules lost by the comet are initially ejected in the form of small ice particles rather than in the gas phase.

Analysis of the perihelic passages of the comet 1P/Halley in 1910 and in 1986

NASA Astrophysics Data System (ADS)

Voelzke, Marcos Rincon

2016-07-01

This work is based on a systematic analysis of images of 1P/Halley comet collected during its penultimate and ultimate approaches, i.e., in 1910 and in 1986. The present research basically characterised, identified, classified, measured and compared some of the tail structures of comet 1P/Halley like DEs, wavy structures and solitons. The images illustrated in the Atlas of Comet Halley 1910 II (Donn et al., 1986), which shows the comet in its 1910 passage, were compared with the images illustrated in The International Halley Watch Atlas of Large-Scale Phenomena (Brandt et al., 1992), which shows the comet in its 1986 passage. While two onsets of DEs were discovered after the perihelion passage in 1910, the average value of the corrected cometocentric velocity Vc was (57 ± 15) km/s; ten were discovered after the perihelion passage in 1986 with an average of corrected velocities equal to (130 ± 37) km/s. The mean value of the corrected wavelength of wavy structures, in 1910, is equal to (1.7 ± 0.1) x 10 ^{6} km and in 1986 is (2.2 ± 0.2) x 10 ^{6} km. The mean value of the amplitude A of the wave, in 1910, is equal to (1.4 ± 0.1) x 10 ^{5} km and in 1986 it is equal to (2.8 ± 0.5) x 10 ^{5} km. The goals of this research are to report the results obtained from the analysis of the P/Halleýs 1910 and 1986 images, to provide empirical data for comparison and to form the input for future physical/theoretical work.

The D/H ratio in water from Halley

NASA Technical Reports Server (NTRS)

Eberhardt, P.; Dolder, U.; Schulte, W.; Krankowsky, D.; Laemmerzahl, P.; Hoffman, J. H.; Hodges, R. R.; Berthelier, J. J.; Illiano, J. M.

1986-01-01

The neutral gas mass spectrometer on Giotto made neutral and ion composition measurements with a high mass resolution. Evaluation of the ion data within the contact surface gives a D/H ratio in water from Halley between 0.00006 and 0.00048. While this ratio is definitely not compatible with the D/H in molecular hydrogen of the protosolar nebula or the Jovian and Saturnian atmospheres, it is in the range observed for hydrogen in solar system objects which acquired their hydrogen as part of volatile molecules, e.g., as ices.

The cyanogen band of Comet Halley

NASA Astrophysics Data System (ADS)

Tatum, J. B.; Campbell, E. C.

The results of improved whole disk solar irradiance spectrum calculations performed for projected Halley's Comet heliocentric radial velocity and distance are provided. The computations were carried out to account for Doppler effects in the Fraunhofer lines of rotational excitation bands of violet CN emissions from the comet in its encounters with solar radiation. The calculations spanned every half-day for 200 days before and after perihelion. The 801 computer images of the expected intensities were photographed in sequence to form an animated film paced by background music from Liszt's Second Hungarian Rhapsody. The results are intended for accounting for spectral changes observed due to Doppler effects induced by changing velocity and distance, rather than physical mechanisms of the emitting processes.

The long-term motion of comet Halley

NASA Technical Reports Server (NTRS)

Yeomans, D. K.; Kiang, T.

1981-01-01

The orbital motion of comet Halley is numerically integrated back to 1404 BC. Starting with an orbit based on the 1759, 1682, and 1607 observations of the comet, the integration was run back in time with full planetary perturbations and nongravitational forces taken into account at each 0.5 day time-step. Small empirical corrections were made to the computed perihelion passage time in 837 and to the osculating orbital eccentricity in 800. In nine cases, the perihelion passage times calculated by Kiang (1971) from Chinese observations have been redetermined, and osculating orbital elements are given at each apparition from 1910 back to 1404 BC.

Chemical Heterogeneity and Mineralogy of Halley's Dust

NASA Astrophysics Data System (ADS)

Schulze, H.; Kissel, J.

1992-07-01

It is commonly assumed that comets are pristine bodies which still contain relatively unaltered material from the beginning of our solar system. Therefore, in March 1986 the chemical composition of Halley's dust particles was investigated by time- of-flight mass spectrometers on board the Vega 1 & 2 and Giotto spacecraft using the high relative velocity of 70-80 km/s between spacecraft and Halley for the generation of ions by dust impact ionization (see e.g. Kissel, 1986; Jessberger et al., 1988). This paper investigates the overall chemical variation among the dust particles with special emphasis on rock-forming elements to derive a mineralogical model of the dust and to give constraints to the evolution of cometary and preplanetary matter. The interpretation is based on 123 selected spectra obtained by the mass spectrometer PUMA 1 on Vega 1. Selection criteria, interpretation of raw data and examined instrumental effects are described in more detail elsewhere (Schulze and Kissel, 1992). The bulk composition of Halley's dust is characterized for the rock-forming elements by cosmic abundances within the experimental uncertainty of factor two (see also Jessberger et al., 1988). A small systematic deviation of the abundances can be used for a revision of the ion yields. The volatile elements carbon and nitrogen, however, are significantly enriched to CI-chondrites. A histogram of the Mg/(Mg+Fe)-ratios shows typical peaks at about 0 and 1 which indicate separated phases for Mg and Fe and an anhydrous nature of the dust (e.g. Brownlee et al., 1987; Bradley, 1988). However, also a broad peak occurs at 0.5. Mg-rich spectra are characterized by an excellent Mg-Si correlation with a narrow range of Mg/Si ratios at about 1. Also oxygen is correlated with Mg and Si. Fe-rich spectra partly show a good Fe-S correlation. However, several spectra are rich only in Fe or S. A cluster analysis of the spectra regarding Na, Mg, Al, Si, S, Ca, and Fe revealed seven groups. These

A spacecraft attitude and articulation control system design for the Comet Halley intercept mission

NASA Technical Reports Server (NTRS)

Key, R. W.

1981-01-01

An attitude and articulation control system design for the Comet Halley 1986 intercept mission is presented. A spacecraft dynamics model consisting of five hinge-connected rigid bodies is used to analyze the spacecraft attitude and articulation control system performance. Inertial and optical information are combined to generate scan platform pointing commands. The comprehensive spacecraft model has been developed into a digital computer simulation program, which provides performance characteristics and insight pertaining to the control and dynamics of a Halley Intercept spacecraft. It is shown that scan platform pointing error has a maximum value of 1.8 milliradians during the four minute closest approach interval. It is also shown that the jitter or scan platform pointing rate error would have a maximum value of 2.5 milliradians/second for the nominal 1000 km closest approach distance trajectory and associated environment model.

Comparative analysis of images of comet 1P/Halley in their perihelion passages in 1910 and 1986

NASA Astrophysics Data System (ADS)

Voelzke, Marcos Rincon

This work is based on a systematic analysis of images of 1P/Halley comet collected during its penultimate and ultimate approaches, i.e., in 1910 and in 1986. The present research basically characterised, identified, classified, measured and compared some of the tail structures of comet 1P/Halley like DEs, wavy structures and solitons. The images illustrated in the Atlas of Comet Halley 1910 II (Donn et al., 1986), which shows the comet in its 1910 passage, were compared with the images illustrated in The International Halley Watch Atlas of Large-Scale Phenomena (Brandt et al., 1992), which shows the comet in its 1986 passage. While two onsets of DEs were discovered after the perihelion passage in 1910, the average value of the corrected cometocentric velocity Vc was (57 ± 15) km s (-1) ; ten were discovered after the perihelion passage in 1986 with an average of corrected velocities equal to (130 ± 37) km s (-1) .The mean value of the corrected wavelength of wavy structures, in 1910, is equal to (1.7 ± 0.1) x 10 (6) km and in 1986 is (2.2 ± 0.2) x 10 (6) km. The mean value of the amplitude A of the wave, in 1910, is equal to (1.4 ± 0.1) x 10 (5) km and in 1986 it is equal to (2.8 ± 0.5) x 10 (5) km. The goals of this research are to report the results obtained from the analysis of the P/Halleýs 1910 and 1986 images, to provide empirical data for comparison and to form the input for future physical/theoretical work.

A mesoscale vortex over Halley Station, Antarctica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, J.; Lachlan-Cope, T.A.; Warren, D.E.

1993-05-01

A detailed analysis of the evolution and structure of a mesoscale vortex and associated cloud comma that developed at the eastern edge of the Weddell Sea, Antarctica, during the early part of January 1986 is presented. The system remained quasi-stationary for over three days close to the British research station Halley (75[degrees]36'S, 26'42[degrees]W) and gave severe weather with gale-force winds and prolonged snow. The formation and development of the system were investigated using conventional surface and upper-air meteorological observations taken at Halley, analyses from the U.K. Meteorological Office 15-level model, and satellite imagery and sounder data from the TIROS-N-NOAA seriesmore » of polar orbiting satellites. The thermal structure of the vortex was examined using atmospheric profiles derived from radiance measurements from the TIROS Operational Vertical Sounder. Details of the wind field were examined using cloud motion vectors derived from a sequence of Advanced Very High Resolution Radiometer images. The vortex developed inland of the Brunt Ice Shelf in a strong baroclinic zone separating warm air, which had been advected polewards down the eastern Weddell Sea, and cold air descending from the Antarctic Plateau. The system intensified when cold, continental air associated with an upper-level short-wave trough was advected into the vortex. A frontal cloud band developed when slantwise ascent of warm air took place at the leading edge of the cold-air outbreak. Most of the precipitation associated with the low occurred on this cloud band. The small sea surface-atmospheric temperature differences gave only limited heat fluxes and there was no indication of deep convection associated with the system. The vortex was driven by baroclinic forcing and had some features in common with the baroclinic type of polar lows that occur in the Northern Hemisphere. 25 refs., 14 figs.« less

Negative Ion Chemistry in the Coma of Comet 1P/Halley

NASA Technical Reports Server (NTRS)

Cordiner, M. A.; Charnley, S. B.

2012-01-01

Negative ions (anions) were identified in the coma of comet 1P/Halley from in-situ measurements performed by the Giotto spacecraft in 1986. These anions were detected with masses in the range 7-110 amu, but with insufficient mass resolution to permit unambiguous identification. We present details of a new chemical-hydrodynamic model for the coma of comet Halley that includes - for the first time - atomic and molecular anions, in addition to a comprehensive hydrocarbon chemistry. Anion number densities arc calculated as a function of radius in the coma, and compared with the Giotto results. Important anion production mechanisms arc found to include radiative electron attachment, polar photodissociation, dissociative electron attachment, and proton transfer. The polyyne anions C4H(-) and C6H(-) arc found to be likely candidates to explain the Giotto anion mass spectrum in the range 49-73 amu. Thc CN(-) anion probably makes a significant contribution to the mass spectrum at 26 amu. Larger carbon-chain anions such as C8H(1) can explain the peak near 100 amu provided there is a source of large carbon-chain-bearing molecules from the cometary nucleus.

Infrared Observations of Comets Halley and Wilson and Properties of the Grains

NASA Technical Reports Server (NTRS)

Hanner, Martha S. (Editor)

1988-01-01

The presented papers and discussions at a workshop held at Cornell Univ. are summarized. The infrared observations of Comet Halley and Comet Wilson are reviewed and they are related to optical properties and composition of cometary grains. Relevant laboratory studies are also discussed. Recommendations are made for future infrared comet observations and supporting laboratory investigations.

Observations of the Perseids 2012 using SPOSH cameras

NASA Astrophysics Data System (ADS)

Margonis, A.; Flohrer, J.; Christou, A.; Elgner, S.; Oberst, J.

2012-09-01

The Perseids are one of the most prominent annual meteor showers occurring every summer when the stream of dust particles, originating from Halley-type comet 109P/Swift-Tuttle, intersects the orbital path of the Earth. The dense core of this stream passes Earth's orbit on the 12th of August producing the maximum number of meteors. The Technical University of Berlin (TUB) and the German Aerospace Center (DLR) organize observing campaigns every summer monitoring the Perseids activity. The observations are carried out using the Smart Panoramic Optical Sensor Head (SPOSH) camera system [0]. The SPOSH camera has been developed by DLR and Jena-Optronik GmbH under an ESA/ESTEC contract and it is designed to image faint, short-lived phenomena on dark planetary hemispheres. The camera features a highly sensitive backilluminated 1024x1024 CCD chip and a high dynamic range of 14 bits. The custom-made fish-eye lens offers a 120°x120° field-of-view (168° over the diagonal). Figure 1: A meteor captured by the SPOSH cameras simultaneously during the last 2011 observing campaign in Greece. The horizon including surrounding mountains can be seen in the image corners as a result of the large FOV of the camera. The observations will be made on the Greek Peloponnese peninsula monitoring the post-peak activity of the Perseids during a one-week period around the August New Moon (14th to 21st). Two SPOSH cameras will be deployed in two remote sites in high altitudes for the triangulation of meteor trajectories captured at both stations simultaneously. The observations during this time interval will give us the possibility to study the poorly-observed postmaximum branch of the Perseid stream and compare the results with datasets from previous campaigns which covered different periods of this long-lived meteor shower. The acquired data will be processed using dedicated software for meteor data reduction developed at TUB and DLR. Assuming a successful campaign, statistics, trajectories

Primitive bodies - Molecular abundances in Comet Halley as probes of cometary formation environments

NASA Technical Reports Server (NTRS)

Lunine, Jonathan I.

1989-01-01

The most recent results on abundances of molecules in Halley's comet are examined in the context of various models for the environment in which comets formed. These environments include molecular clouds associated with star-forming regions, the solar nebula, gaseous disks around proto-planets, and combinations of these. Of all constituents in a cometary nucleus, the highly volatile molecules such as methane, ammonia, molecular nitrogen, and carbon monoxide are most sensitive to the final episode of cometary grain formation and incorporation in the comet's nucleus; hence they likely reflect at least some chemical processing in the solar nebula. Proper interpretation requires modeling of a number of physical processes including gas phase chemistry, chemistry on grain surfaces, and fractionation effects resulting from preferential incorporation of certain gases in proto-cometary grains. The abundance of methane in Halley's comet could be a key indicator of where that comet formed, provided the methane abundance on grains in star-forming regions can be observationally constrained.

Halley's comet exploration and the Japanese Usuda large antenna

NASA Technical Reports Server (NTRS)

Nomura, T.

1986-01-01

An overview of the Japanese PLANET-A project to investigate Halley's Comet is given. The objectives and scientific challenges involved in the project are given, and the nature of the contribution made by the large antenna array located at Usuda-Cho, Nagano Prefecture, Japan is discussed. The structural design of the MS-T5 and PLANET-A probes are given, as well as the tracking and control network for the probes. The construction, design, operating system and site selection for the Usuda antenna station are discussed.

Ammonia in comet P/Halley

NASA Technical Reports Server (NTRS)

Meier, R.; Eberhardt, P.; Krankowsky, D.; Hodges, R. R.

1994-01-01

In comet P/Halley the abundances of ammonia relative to water reported in the literature differ by about one order of magnitude from roughly 0.1% up to 2%. Different observational techniques seem to have inherent systematic errors. Using the ion mass channels m/q = 19 amu/e, 18 amu/e and 17 amu/e of the Neutral Mass Spectrometer experiment aboard the spacecraft Giotto, we derive a production rate of ammonia of (1.5(sub -0.7)(sup +0.5))% relative to water. Inside the contact surface we can explain our data by a nuclear source only. The uncertainty in our abundance of ammonia is primarily a result of uncertainties in some key reaction coefficients. We discuss in detail these reactions and the range of error indicated results from extreme assumptions in the rate coefficients. From our data, even in the worst case, we can exclude the ammonia abundance to be only of the order of a few per mill.

Ion flow at comet Halley

NASA Technical Reports Server (NTRS)

Johnstone, A.; Coates, A.; Kellock, S.; Wilken, B.; Jockers, K.

1986-01-01

The three-dimensional positive ion analyzer aboard the Giotto spacecraft has been used to study the interaction between protons and alpha-particles in the solar wind and positive ions from comet Halley. Although the first impression of the overall structure is that the plasma flow evolves smoothly as the nucleus is approached, three sharp transitions of relatively small amplitude can be identified on both the inbound and outbound legs of the trajectory. The outermost one, at about one million km from the nucleus, appears to be a multiple crossing of a weak bow shock. The innermost one, at 80,000 km, is the boundary where the flowing plasma becomes depleted. On a microscopic scale, the turbulence created by the interaction between the two ion populations extends to a distance of several million km from the nucleus. At Giotto's closest approach to the nucleus, the plasma produced around the spacecraft by dust and gas impacts was much more energetic than had been expected.

Water and dust production rates in comet P/Halley derived from ultraviolet and optical observations

NASA Technical Reports Server (NTRS)

Festou, Michel C.

1992-01-01

We evaluate whether the activity of comet P/Halley is due solely to the presence of discrete active areas. We preliminarily conclude that the dark areas of the nucleus contribute to the formation of the coma.

An interpretation of the ion pile-up region outside the ionospheric contact surface. [Halley's comet

NASA Technical Reports Server (NTRS)

Ip, WING-H.; Schwenn, R.; Rosenbauer, H.; Balsiger, H.; Neugebauer, M.; Shelley, E. G.

1986-01-01

The possibility that the formation of the plasma pile-up region at comet Halley as observed by Giotto could be the combined result of field-aligned transport and recombination process is discussed. Giotto measurements support the hypothesis.

Analysis of the morphological structures of comet 1P/Halley in their perihelion passages in 1910 and 1986

NASA Astrophysics Data System (ADS)

Voelzke, Marcos Rincon

2015-08-01

This work is based on a systematic analysis of images of 1P/Halley comet collected during its penultimate and ultimate approaches, i.e., in 1910 and in 1986. The present research basically characterised, identified, classified, measured and compared some of the tail structures of comet 1P/Halley like DEs, wavy structures and solitons. The images illustrated in the Atlas of Comet Halley 1910 II (Donn et al., 1986), which shows the comet in its 1910 passage, were compared with the images illustrated in The International Halley Watch Atlas of Large-Scale Phenomena (Brandt et al., 1992), which shows the comet in its 1986 passage. While two onsets of DEs were discovered after the perihelion passage in 1910, the average value of the corrected cometocentric velocity Vc was (57 ± 15) km/s ; ten were discovered after the perihelion passage in 1986 with an average of corrected velocities equal to (130 ± 37) km/s .The mean value of the corrected wavelength of wavy structures, in 1910, is equal to (1.7 ± 0.1) x 106 km and in 1986 is (2.2 ± 0.2) x 106 km. The mean value of the amplitude A of the wave, in 1910, is equal to (1.4 ± 0.1) x 105 km and in 1986 it is equal to (2.8 ± 0.5) x 105 km. The goals of this research are to report the results obtained from the analysis of the P/Halleýs 1910 and 1986 images, to provide empirical data for comparison and to form the input for future physical/theoretical work.

An extended source for CN jets in Comet P/Halley

NASA Technical Reports Server (NTRS)

Klavetter, James Jay; A'Hearn, Michael F.

1994-01-01

We examined radial intensity profiles of CN jets in comparison with the diffuse, isotropic component of the CN coma of Comet P/Halley. All images were bias-subtracted, flat-fielded, and continuum-subtracted. We calculated the diffuse profiles by finding the azimuthal mean of the coma least contaminated by jets yielding profiles similar to those of vectorial and Haser models of simple photodissociation. We found the jet profiles by calculating a mean around a Gaussian-fitted center in r-theta space. There is an unmistakable difference between the profiles of the CN jets and the profiles of the diffuse CN. Spatial derivatives of these profiles, corrected for geometrical expansion, show that the diffuse component is consistent with a simple photodissociation process, but the jet component is not. The peak production of the jet profile occurs 6000 km from the nucleus at a heliocentric distance of 1.4 AU. Modeling of both components of the coma indicate results that are consistent with the diffuse CN photochemically produced, but the CN jets need an additional extended source. We found that about one-half of the CN in the coma of Comet P/Halley originated from the jets, the rest from the diffuse component. These features, along with the width of the jet being approximately constant, are consistent with a CHON grain origin for the jets.

Espectroscopia del Cometa Halley

NASA Astrophysics Data System (ADS)

Naranjo, O.; Fuenmayor, F.; Ferrin, L.; Bulka, P.; Mendoza, C.

1987-05-01

Se reportan observaciones espectroscópicas del cometa Halley. Los espectros fueron tomados usando el espectrógrafo del telescopio reflector de 1 metro del Observatorio Nacional de Venezuela. Se utilizó óptica azul, con una red de difracción de 600 lineas/min, obteniéndose una dispersión de 74.2 A/mm y una resolución de 2.5 A, en el rango espectral de 3500 a 6500 A. Seis placas fueron tomadas con emulsión IIa-O y dos con IIa-D. Los tiempos de exposición fueron entre 10 y 150 minutos. El cometa se encontraba entre 0.70 y 1.04 UA del Sol, y entre 1.28 y 0.73 UA de la Tierra. Las emisiones más prominentes en el espectro, son las del CN, C2, y C3. Otras emisiones detectadas corresponden a CH, NH2 y Na. Los espectros muestran un fuerte continuo, indicando un contenido significativo de polvo. Se detectó mayor intensidad del contínuo, en la dirección anti solar, lo cual es evidencia de la cola de polvo.

The Evolution of the Multicoloured Face of Mandrills: Insights from the Perceptual Space of Colour Vision

PubMed Central

Renoult, Julien P.; Schaefer, H. Martin; Sallé, Bettina; Charpentier, Marie J. E.

2011-01-01

Multicomponent signals consist of several traits that are perceived as a whole. Although many animals rely on multicomponent signals to communicate, the selective pressures shaping these signals are still poorly understood. Previous work has mainly investigated the evolution of multicomponent signals by studying each trait individually, which may not accurately reflect the selective pressures exerted by the holistic perception of signal receivers. Here, we study the design of the multicoloured face of an Old World primate, the mandrill (Mandrillus sphinx), in relation to two aspects of signalling that are expected to be selected by receivers: conspicuousness and information. Using reflectance data on the blue and red colours of the faces of 34 males and a new method of hue vectorisation in a perceptual space of colour vision, we show that the blue hue maximises contrasts to both the red hue and the foliage background colouration, thereby increasing the conspicuousness of the whole display. We further show that although blue saturation, red saturation and the contrast between blue and red colours are all correlated with dominance, dominance is most accurately indicated by the blue-red contrast. Taken together our results suggest that the evolution of blue and red facial colours in male mandrills are not independent and are likely driven by the holistic perception of conspecifics. In this view, we propose that the multicoloured face of mandrills acts as a multicomponent signal. Last, we show that information accuracy increases with the conspicuousness of the whole display, indicating that both aspects of signalling can evolve in concert. PMID:22216180

Spectrophotometry of comets Giacobini-Zinner and Halley

NASA Technical Reports Server (NTRS)

Tegler, Stephen C.; O'Dell, C. R.

1987-01-01

Optical window spectrophotometry was performed on comets Giacobini-Zinner and Halley over the interval 300-1000 nm. Band and band-sequence fluxes were obtained for the brightest features of OH, CN, NH, and C2, special care having been given to determinations of extinction, instrumental sensitivities, and corrections for Fraunhofer lines. C2 Swan band-sequence flux ratios were determined with unprecedented accuracy and compared with the predictions of the detailed equilibrium models of Krishna Swamy et al. (1977, 1979, 1981, and 1987). It is found that these band sequences do not agree with the predictions, which calls into question the assumptions made in deriving the model, namely resonance fluorescence statistical equilibrium. Suggestions are made as to how to resolve this discrepancy.

A comparative study of the continuum and emission characteristics of comet dust. 1: Are the silicates in Comet Halley and Kohoutek amorphous or crystalline

NASA Technical Reports Server (NTRS)

Nansheng, Zhao; Greenberg, J. Mayo; Hage, J. I.

1989-01-01

A continuum emission was subtracted from the 10 micron emission observed towards comets Halley and Kohoutek. The 10 micron excess emissions were compared with BN absorption and laboratory amorphous silicates. The results show that cometary silicates are predominantly amorphous which is consistent with the interstellar dust model of comets. It is concluded that cometary silicates are predominantly similar to interstellar silicates. For a periodic comet like Comet Halley, it is to be expected that some of the silicate may have been heated enough to convert to crystalline form. But apparently, this is only a small fraction of the total. A comparison of Comet Halley silicates with a combination of the crystalline forms observed in interplanetary dust particles (IPDs) seemed reasonable at first sight (Walker 1988, Brownlee 1988). But, if true, it would imply that the total silicate mass in Comet Halley dust is lower than that given by mass spectrometry data of Kissel and Krueger (1987). They estimated m sub org/m sub sil = 0.5 while using crystalline silicate to produce the 10 micron emission would give m sub org/m sub sil = 5 (Greenberg et al. 1988). This is a factor of 10 too high.

A two component model for thermal emission from organic grains in Comet Halley

NASA Technical Reports Server (NTRS)

Chyba, Christopher; Sagan, Carl

1988-01-01

Observations of Comet Halley in the near infrared reveal a triple-peaked emission feature near 3.4 micrometer, characteristic of C-H stretching in hydrocarbons. A variety of plausible cometary materials exhibit these features, including the organic residue of irradiated candidate cometary ices (such as the residue of irradiated methane ice clathrate, and polycyclic aromatic hydrocarbons. Indeed, any molecule containing -CH3 and -CH2 alkanes will emit at 3.4 micrometer under suitable conditions. Therefore tentative identifications must rest on additional evidence, including a plausible account of the origins of the organic material, a plausible model for the infrared emission of this material, and a demonstration that this conjunction of material and model not only matches the 3 to 4 micrometer spectrum, but also does not yield additional emission features where none is observed. In the case of the residue of irradiated low occupancy methane ice clathrate, it is argued that the lab synthesis of the organic residue well simulates the radiation processing experienced by Comet Halley.

Electron distributions upstream of the Comet Halley bow shock - Evidence for adiabatic heating

NASA Technical Reports Server (NTRS)

Larson, D. E.; Anderson, K. A.; Lin, R. P.; Carlson, C. W.; Reme, H.; Glassmeier, K. H.; Neubauer, F. M.

1992-01-01

Three-dimensional plasma electron (22 eV to 30 keV) observations upstream of Comet Halley bow shock, obtained by the RPA-1 COPERNIC (Reme Plasma Analyzer - Complete Positive Ion, Electron and Ram Negative Ion Measurements near Comet Halley) experiment on the Giotto spacecraft are reported. Besides electron distributions typical of the undisturbed solar wind and backstreaming electrons observed when the magnetic field line intersects the cometary bow shock, a new type of distribution, characterized by enhanced low energy (less than 100 eV) flux which peaks at 90-deg pitch angles is found. These are most prominent when the spacecraft is on field lines which pass close to but are not connected to the bow shock. The 90-deg pitch angle electrons appear to have been adiabatically heated by the increase in the magnetic field strength resulting from the compression of the upstream solar wind plasma by the cometary mass loading. A model calculation of this effect which agrees qualitatively with the observed 90-deg flux enhancements is presented.

Plasma-tail activity and the interplanetary medium at Halley's Comet during Armada Week: 6-14 March 1986

NASA Technical Reports Server (NTRS)

Niedner, Malcolm B., Jr.; Schwingenschuh, Konrad; Hoeksema, J. Todd; Dryer, Murray; Mcintosh, Patrick S.

1987-01-01

The encounters of five spacecraft with Halley's Comet during 6-14 March 1986 offered a unique opportunity to calibrate the solar-wind interaction with cometary plasmas as recorded by remote wide-field and narrow-field/narrowband imaging. Perhaps not generally recognized in the comet community is the additional opportunity offered by the Halley Armada to study the structure of the solar-wind and interplanetary magnetic field (IMF) in three dimensions using five sets of data obtained over similar time intervals and heliocentric distances, but at somewhat different heliolatitudes. In fact, the two problems, i.e., comet physics and the structure of the interplanetary medium, are coupled if one wants to understand what conditions pertained at the comet between the encounters. This relationship is discussed.

Monte Carlo simulation of nonadiabatic expansion in cometary atmospheres - Halley

NASA Astrophysics Data System (ADS)

Hodges, R. R.

1990-02-01

Monte Carlo methods developed for the characterization of velocity-dependent collision processes and ballistic transports in planetary exospheres form the basis of the present computer simulation of icy comet atmospheres, which iteratively undertakes the simultaneous determination of velocity distribution for five neutral species (water, together with suprathermal OH, H2, O, and H) in a flow regime varying from the hydrodynamic to the ballistic. Experimental data from the neutral mass spectrometer carried by Giotto for its March, 1986 encounter with Halley are compared with a model atmosphere.

Airborne spectrophotometry of P/Halley from 16 to 30 microns

NASA Technical Reports Server (NTRS)

Herter, T.; Gull, G. E.; Campins, H.

1986-01-01

Comet Halley was observed in the 16 to 30 micron region using the Cornell University 7-channel spectrometer (resolution = 0.02) on board the Kuiper Airborne Observatory on 1985 Dec. 14.2. A 30-arcsec aperture (FWHM) was used. Measurements centered on the nuclear condensation micron indicate that if present, the 20 micron silicate feature is very weak, and that a relatively narrow strong feature centered at 28.4 microns possibly exists. However, this feature may be an artifact of incomplete correction for telluric water vapor absorption.

Analysis and interpretation of CCD data on P/Halley and physical parameters and activity status of cometary nuclei at large heliocentric distance

NASA Technical Reports Server (NTRS)

Belton, Michael J. S.; Mueller, Beatrice

1991-01-01

The scientific objectives were as follows: (1) to construct a well sampled photometric time series of comet Halley extending to large heliocentric distances both post and pre-perihelion passage and derive a precise ephemeris for the nuclear spin so that the physical and chemical characteristics of individual regions of activity on the nucleus can be determined; and (2) to extend the techniques in the study of Comet Halley to the study of other cometary nuclei and to obtain new observational data.

Analysis of the tail structures of comet P/Halley 1910 II

NASA Astrophysics Data System (ADS)

Voelzke, Marcos Rincon; Izaguirre, Liberdade

2012-07-01

Eight hundred and eighty six images from September 1909 to May 1911 are analysed for the purpose of identifying, measuring and correlating the morphological structures along the plasma tail of P/Halley. These images are from the Atlas of Comet Halley 1910 II (Donn et al., 1986). A systematic visual analysis revealed 304 wavy structures along the main tail and 164 along the secondary tails, 41 solitary waves (solitons), 13 Swan-like tails, 26 disconnection events (DEs), 166 knots (regions of higher density of matter) and six shells. While the wavy structures denote undulations or a train of waves, the solitons refer to the formations usually denominated kinks. In general, it is possible to associate the occurrence of a DE and/or a Swan-Tail with the occurrence of a knot, but the last one may occur independently. It is also possible to say that the solitons occur in association with the wavy structures, but the reverse is not true. The 26 DEs documented in 26 different images allowed the derivation of two onsets of DEs (Table 1), i.e., the time when the comet supposedly crossed a frontier between magnetic sectors of the solar wind (Brandt and Snow, 2000). Both onsets of DEs were determined after the perihelion passage with an average of the corrected velocities Vc equal to (57 ± 15) km/s. The mean value of the corrected wavelength c measured in 70 different wavy structures is equal to (1.7 ± 0.1) x 10^6 km and the mean amplitude A of the wave (measured in the same 70 wavy structures cited above) is equal to (1.4 ± 0.1) x 10^5 km. The mean value of the corrected cometocentric phase velocity Vpc measured in 20 different wavy structures is equal to (168 ± 28) km/s. The average value of the corrected velocities Vkc of the knots measured in 36 different images is equal to (128 ± 12) km/s. There is a tendancy for A and c to increase with increasing cometocentric distance. The results of this work agree with the earlier research from Voelzke and Matsuura (1998), which

Observations of Halley's Comet by the Solar Maximum Mission (SMM)

NASA Technical Reports Server (NTRS)

Niedner, M. B.

1986-01-01

Solar Maximum Mission coronagraph/polarimeter observations of large scale phenomena in Halley's Comet are discussed. Observations of the hydrogen coma with the UV spectrometer are considered. It is concluded that coronograph/polarimeter observations of the disconnection event, in which the entire plasma tail uproots itself from the head of the comet, is convected away in the solar wind at speeds in the 50 to 100 km/sec range (relative to the head), and is replaced by a plasma tail constructed from folding ion-tail rays, are the most interesting.

Photometry of the comet Halley : solar analogs selected along the path (November 1985 - Mat 1986)

NASA Astrophysics Data System (ADS)

Fracassini, M.; Pasinetti, L. E.

1985-11-01

108 solar analogs are selected within a strip along the path of the comet Halley (Δδ ≅ ±10°) for photometric observations of the comet from November 1985 to May 1986. Some criteria in the UBV and Geneva photometric systems were adopted for this selection.

On the global nature of the solar wind interaction with Comet Halley

NASA Technical Reports Server (NTRS)

Mendis, D. A.; Flammer, K. R.; Reme, H.; Sauvaud, J. A.; D'Uston, C.

1989-01-01

Data obtained by two instruments of the RPA-Copernic experiment aboard Giotto during its encounter with Comet Halley are used to determine the positions of several sharp boundaries delineating transitions from one flow state to another. Production rates of the neutrals are obtained, along with ion-neutral drag coefficients. It is suggested that the cometopause observed between the shock and the ionopause coincides with the expected position of a previously proposed collisionopause.

VEGA - EN route to Venus and comet Halley

NASA Astrophysics Data System (ADS)

Gombosi, T. I.

1985-01-01

In December 1984, the Soviet Union launched the two spacecraft Vega 1 and Vega 2. After reaching Venus and releasing entry probes for a study of the planet, the two modified Venera-class, three-axis stabilized spacecraft will continue their voyage toward an encounter with the comet Halley. The two spacecraft carry an international scientific payload. The instruments will be used in a study of the comet. Scientific objectives are related to the determination of the physical characteristics and chemical structure of the nucleus, the identification of the parent molecules of the coma, the characteristics of the dust particles at different distances from the nucleus, and the interaction between the solar wind and the comet. The various instruments are discussed in some detail.

Navigation and guidance of Japanese deepspace probes encountering Halley's comet

NASA Astrophysics Data System (ADS)

Nishimura, T.; Matsuo, H.; Takano, T.; Kawaguchi, J.

The techniques used by ISAS in the guidance of the Sakigake and Suisei probes, which encountered Comet Halley in March 1986, are reviewed. Consideration is given to the guidance of the last rocket stage in the direct ascent phase, midcourse maneuvers, tracking systems and communication links, the tracking strategy, trajectory-generation and orbit-determination software, and orbit-determination accuracy. Diagrams, drawings, graphs, photographs, and tables of numerical data are provided, and the ISAS positions of both probes during the first 10 days after launch are shown to be within 100 km in distance and 1 m/sec in velocity of NASA coordinate estimates.

Morphological analysis of the tail structures of comet P/Halley 1910 II

NASA Astrophysics Data System (ADS)

Voelzke, M. R.; Izaguirre, L. S.

2012-05-01

For the purpose of identifying, measuring and correlating the morphological structures along the plasma tail of P/Halley 886 images from September 1909 to May 1911 are analysed. These images are from the Atlas of Comet Halley 1910 II (Donn et al., 1986). A systematic visual analysis revealed 304 wavy structures along the main tail and 164 along the secondary tails, 41 solitary waves (solitons), 13 Swan-like tails, 26 disconnection events (DEs), 166 knots (regions of higher density of matter) and six shells. While the wavy structures denote undulations or a train of waves, the solitons refer to the formations usually denominated as kinks. In general, it is possible to associate the occurrence of a DE and/or a Swan-Tail with the occurrence of a knot, but the last one may occur independently. It is also possible to say that the solitons occur in association with the wavy structures, but the reverse is not true. The 26 DEs documented in 26 different images allowed the derivation of two onsets of DEs (Table 1), i.e., the time when the comet supposedly crossed a frontier between magnetic sectors of the solar wind (Brandt and Snow, 2000). Both onsets of DEs were determined after the perihelion passage with an average of the corrected velocities Vc equal to (57±15) km s-1. The mean value of the corrected wavelength λc measured in 70 different wavy structures is equal to (1.7±0.1)×106 km and the mean amplitude A of the wave (measured in the same 70 wavy structures cited above) is equal to (1.4±0.1)×105 km. The mean value of the corrected cometocentric phase velocity Vpc measured in 20 different wavy structures is equal to (168±28) km s-1. The average value of the corrected velocities Vkc of the knots measured in 36 different images is equal to (128±12) km s-1. There is a tendency for A and λc to increase with increasing cometocentric distance. The results of this work agree with the earlier research from Voelzke and Matsuura (1998), which analysed comet P/Halley

In situ gas and ion measurements at comet Halley

NASA Astrophysics Data System (ADS)

Krankowsky, D.; Lammerzahl, P.; Herrwerth, I.; Woweries, J.; Eberhardt, P.; Dolder, U.; Herrmann, U.; Schulte, W.; Berthelier, J. J.; Illiano, J. M.; Hodges, R. R.; Hoffman, J. H.

1986-05-01

The neutral mass spectrometer experiment carried by the Giotto spacecraft was designed to determine the abundances and the chemical, elemental and isotopic composition of the gases and low-energy ions in the coma of comet Halley. Its first results show the predominance of water vapour with an H2O density of 4.7x107molecules cm-3 at 1,000 km. Limits on the abundances of CO2, NH3 and CH4 relative to H2O are given. The water-group ions H3O+, H2O+ and OH+ have been unambiguously identified, along with the ions 12C+, 12CH+, 16O+, Na+, 12C2+, 32S+, 34S+ and 56Fe+.

Multicolour modelling of SN 2013dx associated with GRB 130702A★

NASA Astrophysics Data System (ADS)

Volnova, A. A.; Pruzhinskaya, M. V.; Pozanenko, A. S.; Blinnikov, S. I.; Minaev, P. Yu.; Burkhonov, O. A.; Chernenko, A. M.; Ehgamberdiev, Sh. A.; Inasaridze, R.; Jelinek, M.; Khorunzhev, G. A.; Klunko, E. V.; Krugly, Yu. N.; Mazaeva, E. D.; Rumyantsev, V. V.; Volvach, A. E.

2017-05-01

We present optical observations of SN 2013dx, related to the Fermi burst GRB 130702A, which occurred at red shift z = 0.145. It is the second-best sampled gamma-ray burst (GRB)/supernova (SN) after SN 1998bw. The observational light curves contain more than 280 data points in the uBgrRiz filters until 88 d after the burst, and the data were collected from our observational collaboration (Maidanak Observatory, Abastumani Observatory, Crimean Astrophysical Observatory, Mondy Observatory, National Observatory of Turkey and Observatorio del Roque de los Muchachos) and from the literature. We model numerically the multicolour light curves using the one-dimensional radiation hydrodynamical code stella, previously widely implemented for modelling typical non-GRB SNe. The best-fitting model has the following parameters: pre-SN star mass M = 25 M⊙; mass of the compact remnant MCR = 6 M⊙; total energy of the outburst Eoburst = 3.5 × 1052 erg; pre-supernova star radius R = 100 R⊙; M_^{56Ni} = 0.2 M_{⊙}, which is totally mixed through the ejecta; MO = 16.6 M⊙; MSi = 1.2 M⊙ and MFe = 1.2 M⊙, and the radiative efficiency of the SN is 0.1 per cent.

Comparison of Wave Energy Transport at the Comets p/Halley and p/Giacobini-Zinner

NASA Technical Reports Server (NTRS)

Sding, A.; Glassmeir, K. H.; Fuselier, S. A.; Neubauer, Fritz M.; Tsurutani, B. T.

1995-01-01

Using magnetic field, plasma density and flow observations from spacecraft flybys of two comets, Eler variables are determined in order to study wave propogation directions. We investigate the inbound path of the Giotto spacecraft flyby of comet p/Halley outside the bow shock, and the inbound and outbound path of the ICE spacecraft flyby of comet p/Giacobini-Zinner outsinde of the bow wave.

Spectrophotometry of 25 comets - Post-Halley updates for 17 comets plus new observations for eight additional comets

NASA Technical Reports Server (NTRS)

Newburn, Ray L., Jr.; Spinrad, Hyron

1989-01-01

The best possible production figures within the current post-Halley framework and available observations are given for H2O, O(1D), CN, C3, C2 and dust in 25 comets. Of these, the three objects with the smallest mixing ratios of all minor species have moderate to little or no dust and appear 'old'. Comets with large amounts of CN are very dusty, and there is a clear correlation of CN with dust, although comets with little or no dust still have some CN. Thus, CN appears to have at least two sources, dust and one or more parent gases. Also, the C2/CN production ratio changes continuously with heliocentric distance in every comet considered, suggesting that C2 production may be a function of coma density as well as parental abundance. Dust production ranges from essentially zero in Comet Sugano-Saigusa-Fujikawa up to 67,000 kg/s for Halley on March 14, 1986.

Outbursts of H2O in Comet P/Halley

NASA Astrophysics Data System (ADS)

Larson, H. P.; Hu, H.-Y.; Mumma, M. J.; Weaver, H. A.

1990-07-01

Comet Halley gas-production monitoring efforts in March 1986 with the NASA Kuiper Airborne Observatory's Fourier transform spectrometer have indicated rapid temporal variations in H2O emissions; a continuous record of an H2O outburst was thus obtained. The event, in which H2O brightness increased by a factor of 2.2 in less than 10 min, is ascribable to an energetic process in the nucleus whose character may have been that of amorphous H2O ice crystallization, chemical explosion, thermal stress, or a compressed gas pocket. The timing and energy of the event appear to require an internal energy source; amorphous ice crystallization is held to be most consistent with compositional and thermal models of cometary nuclei as well as the observations.

SEP ENCKE-87 and Halley rendezvous studies and improved S/C model implementation in HILTOP

NASA Technical Reports Server (NTRS)

Horsewood, J. L.; Mann, F. I.

1978-01-01

Studies were conducted to determine the performance requirements for projected state-of-the-art SEP spacecrafts boosted by the Shuttle/IUS to perform a rendezvous with the comet Halley and a rendezvous with the comet Encke during its 1977 apparition. The spacecraft model of the standard HILTOP computer program was assumed. Numerical and graphical results summarizing the studies are presented.

Comparison of the plasma tails of four comets: P/Halley, Okazaki-Levy-Rudenko, Austin, and Levy

NASA Technical Reports Server (NTRS)

Farnham, Tony L.; Meech, Karen J.

1994-01-01

Photographic and charge coupled device (CCD) plasma tail observations are compared for four comets: P/Halley (22 nights in 1985/1986), Okazaki-Levy-Rudenko 1989 XIX (1989 December 2), Austin 1990 V (nine nights in 1990), and Levy 1990 XX (two nights in 1991). We present a discussion of several image-processing techniques used to enhance the visibility of the plasma tail features in order to measure velocities, accelerations, and position angles. The data are used to assess the validity of various physical mechanisms proposed to explain plasma tail phenomena. Seven disconnection events were observed in the comet P/Halley data, two in the Austin data, and none for the other comets. Analysis of these data suggests that while the crossing of the solar neutral sheet (the sector boundary) is a prominent factor in the production of a disconnection event, it is likely that several mechanisms are at work. A sector boundary crossing has been ruled out as the cause of either the 1986 April 26 P/Halley disconnection or the 1990 May 5/6 Austin disconnection. The motions of the disconnection events, knots, and condensations in the tails were seen to increase from 30-60 km/s near the nucleus (within 10(exp 6) km) to 80-100 km/s at 10(exp 7) km, consistent with either bulk motion or Alfven waves. Distinguishing between the two cases is not possible with these data. It was found that although the tail ray rotation rate slows as the ray approaches the tail axis, it is not a good indicator of the solar wind speed. Historical plasma tail data are also used to look for clues as to why some comets form well-developed plasma tails and others do not.

A learning approach to the bandwidth multicolouring problem

NASA Astrophysics Data System (ADS)

Akbari Torkestani, Javad

2016-05-01

In this article, a generalisation of the vertex colouring problem known as bandwidth multicolouring problem (BMCP), in which a set of colours is assigned to each vertex such that the difference between the colours, assigned to each vertex and its neighbours, is by no means less than a predefined threshold, is considered. It is shown that the proposed method can be applied to solve the bandwidth colouring problem (BCP) as well. BMCP is known to be NP-hard in graph theory, and so a large number of approximation solutions, as well as exact algorithms, have been proposed to solve it. In this article, two learning automata-based approximation algorithms are proposed for estimating a near-optimal solution to the BMCP. We show, for the first proposed algorithm, that by choosing a proper learning rate, the algorithm finds the optimal solution with a probability close enough to unity. Moreover, we compute the worst-case time complexity of the first algorithm for finding a 1/(1-ɛ) optimal solution to the given problem. The main advantage of this method is that a trade-off between the running time of algorithm and the colour set size (colouring optimality) can be made, by a proper choice of the learning rate also. Finally, it is shown that the running time of the proposed algorithm is independent of the graph size, and so it is a scalable algorithm for large graphs. The second proposed algorithm is compared with some well-known colouring algorithms and the results show the efficiency of the proposed algorithm in terms of the colour set size and running time of algorithm.

The interactive astronomical data analysis facility - image enhancement techniques to Comet Halley

NASA Astrophysics Data System (ADS)

Klinglesmith, D. A.

1981-10-01

PDP 11/40 computer is at the heart of a general purpose interactive data analysis facility designed to permit easy access to data in both visual imagery and graphic representations. The major components consist of: the 11/40 CPU and 256 K bytes of 16-bit memory; two TU10 tape drives; 20 million bytes of disk storage; three user terminals; and the COMTAL image processing display system. The application of image enhancement techniques to two sequences of photographs of Comet Halley taken in Egypt in 1910 provides evidence for eruptions from the comet's nucleus.

The International Cometary Explorer mission to comets Giacobini-Zinner and Halley - An update

NASA Technical Reports Server (NTRS)

Brandt, J. C.

1986-01-01

Aspects of the International Cometary Explorer (ICE) flight to the comet Giacobini-Zinner (GZ) are discussed. The most important experiments to be performed by ICE are reviewed, and the orbital parameters of GZ are described. The dust characteristics of GZ that pose a hazard to the spacecraft are addressed, and the ICE targeting strategy toward the comet is discussed. Requested ground-based coverage of GZ is indicated, and the complementarity of the GZ coverage with that given to the Halley mission is shown.

Velocity-resolved observations of water in Comet Halley

NASA Technical Reports Server (NTRS)

Larson, Harold P.; Davis, D. Scott; Mumma, Michael J.; Weaver, Harold A.

1986-01-01

High resolution (lambda/delta lambda approx. = 3 x 10 to the 5th power) near-infrared observations of H2O emission from Comet Halley were acquired at the time of maximum post-perihelion geocentric Doppler shift. The observed widths and absolute positions of the H2O line profiles reveal characteristics of the molecular velocity field in the coma. These results support H2O outflow from a Sun-lit hemisphere or the entire nucleus, but not from a single, narrow jet emanating from the nucleus. The measured pre- and post-perihelion outflow velocities were 0.9 + or - 0.2 and 1.4 + or - 0.2 km/s, respectively. Temporal variations in the kinematic properties of the outflow were inferred from changes in the spectral line shapes. These results are consistent with the release of H2O into the coma from multiple jets.

Electron energetics in the inner coma of Comet Halley

NASA Astrophysics Data System (ADS)

Gan, L.; Cravens, T. E.

1990-05-01

A quasi-two-dimensional model of the spatial and energy distribution of electrons in the inner coma of Comet Halley has been constructed from a spherically symmetric ion density profile based on Giotto measurements, using the two-stream electron transport method and the time-dependent electron energy equation. A sharp jump in the electron temperature was found to be present at a cometocentric distance of about 15,000 km. This thermal boundary separates an inner region where cooling processes are dominant from an outer region where heat transport is more important. Both thermal and suprathermal electron populations exist inside the thermal boundary with comparable kinetic pressures. Outside the thermal boundary, a cloud electron population does not exist, and the electrons are almost isothermal along the magnetic field lines.

Observations of the Perseids 2013 using SPOSH cameras

NASA Astrophysics Data System (ADS)

Margonis, A.; Elgner, S.; Christou, A.; Oberst, J.; Flohrer, J.

2013-09-01

Earth is constantly bombard by debris, most of which disintegrates in the upper atmosphere. The collision of a dust particle, having a mass of approximately 1g or larger, with the Earth's atmosphere results into a visible streak of light in the night sky, called meteor. Comets produce new meteoroids each time they come close to the Sun due to sublimation processes. These fresh particles are moving around the Sun in orbits similar to their parent comet forming meteoroid streams. For this reason, the intersection of Earth's orbital path with different comets, gives rise to anumber of meteor showers throughout the year. The Perseids are one of the most prominent annual meteor showers occurring every summer, having its origin in Halley-type comet 109P/Swift-Tuttle. The dense core of this stream passes Earth's orbit on the 12th of August when more than 100 meteors per hour can been seen by a single observer under ideal conditions. The Technical University of Berlin (TUB) and the German Aerospace Center (DLR) together with the Armagh observatory organize meteor campaigns every summer observing the activity of the Perseids meteor shower. The observations are carried out using the Smart Panoramic Optical Sensor Head (SPOSH) camera system [2] which has been developed by DLR and Jena-Optronik GmbH under an ESA/ESTEC contract. The camera was designed to image faint, short-lived phenomena on dark planetary hemispheres. The camera is equipped with a highly sensitive back-illuminated CCD chip having a pixel resolution of 1024x1024. The custom-made fish-eye lens offers a 120°x120° field-of-view (168° over the diagonal) making the monitoring of nearly the whole night sky possible (Fig. 1). This year the observations will take place between 3rd and 10th of August to cover the meteor activity of the Perseids just before their maximum. The SPOSH cameras will be deployed at two remote sites located in high altitudes in the Greek Peloponnese peninsula. The baseline of ∼50km

ULF waves at comets Halley and Giacobini-Zinner - Comparison with simulations

NASA Astrophysics Data System (ADS)

Le, G.; Russell, C. T.; Gary, S. P.; Smith, E. J.; Riedler, W.; Schwingenschuh, K.

1989-09-01

A comparison is made between observations and numerical simulations of magnetic fluctuations near the proton and water group ion cyclotron frequencies as a function of distance from the comets Halley and Giacobini-Zinner. The amplitude of waves due to different cyclotron resonant instabilities is monitored by examining the amplitude of waves near the gyrofrequency of the respective ions, measured in by the ICE spacecraft. The results are compared with a one-dimensional electromagnetic hybrid simulation of two-ion pickup based on the predictions of Gary et al. (1989). The observations are consistent with the prediction that amplitudes are dependent on the properties of the injected beams and the local injection rate.

Dust density and mass distribution near comet Halley from Giotto observations

NASA Technical Reports Server (NTRS)

Mcdonnell, J. A. M.; Alexander, W. M.; Burton, W. M.; Bussoletti, E.; Clark, D. H.; Grard, J. L.; Gruen, E.; Hanner, M. S.; Sekanina, Z.; Hughes, D. W.

1986-01-01

The density and the mass spectrum of the dust near comet Halley have been measured by the Giotto space probe's dust impact detection system. The dust spectrum obtained at 291,000 km from the comet nucleus show depletion in small and intermediate masses; at about 600 km from the nucleus, however, the dust activity rises and the spectrum is dominated by larger masses. Most of the mass striking Giotto is noted to reside in the few large particles penetrating the dust shield. Momentum balances and energy considerations applied to an observed deceleration suggest that a large mass of the spacecraft was detached by an impact.

The status of the international Halley watch

NASA Technical Reports Server (NTRS)

Newburn, Ray L., Jr.; Rahe, Juergen

1987-01-01

More than 1000 professional astronomers worldwide actually observed Halley's comet from the ground. Preliminary logs from the observers indicate that 20-40 Gbytes of data were acquired in eight professional disciplines and as much as 5 Gbytes in the amateur network. The latter will be used to fill in gaps in the Archive and to provide a visual light curve. In addition roughly 400 Mbytes of data were taken on Comet Giacobini-Zinner. Data will be accepted for archiving until early 1989. The permanent archive will consist of a set of CD-ROMs and a set of books, publication of both to be completed by mid-1990. Data from the space missions will be included but only on the CDs. From every indication, the ground based effort and the space missions complimented each other beautifully, both directly in the solution of spacecraft navigation problems and indirectly in the solution of scientific problems. The major remaining concern is that scientists submit their data to the Archive before the 1989 deadline.

A comparison between VEGA 1, 2 and Giotto flybys of comet 1P/Halley: implications for Rosetta

NASA Astrophysics Data System (ADS)

Volwerk, M.; Glassmeier, K.-H.; Delva, M.; Schmid, D.; Koenders, C.; Richter, I.; Szegö, K.

2014-11-01

Three flybys of comet 1P/Halley, by VEGA 1, 2 and Giotto, are investigated with respect to the occurrence of mirror mode waves in the cometosheath and field line draping in the magnetic pile-up region around the nucleus. The time interval covered by these flybys is approximately 8 days, which is also the approximate length of an orbit or flyby of Rosetta around comet 67P/Churyumov-Gerasimenko. Thus any significant changes observed around Halley are changes that might occur for Rosetta during one pass of 67P/CG. It is found that the occurrence of mirror mode waves in the cometosheath is strongly influenced by the dynamical pressure of the solar wind and the outgassing rate of the comet. Field line draping happens in the magnetic pile-up region. Changes in nested draping regions (i.e. regions with different Bx directions) can occur within a few days, possibly influenced by changes in the outgassing rate of the comet and thereby the conductivity of the cometary ionosphere.

A comparison between VEGA 1, 2 and Giotto flybys of comet 1P/Halley: Implications for Rosetta

NASA Astrophysics Data System (ADS)

Volwerk, Martin; Glassmeier, Karl-Heinz; Delva, Magda; Schmid, Daniel; Koenders, Christoph; Richter, Ingo; Szegö, Karoly

2015-04-01

Three flybys of comet 1P/Halley, by VEGA 1, 2 and Giotto, are investigated with respect to the occurrence of mirror mode waves in the cometosheath and field line draping in the magnetic pile-up region around the nucleus. The time interval covered by these flybys is approximately 8 days, which is also the approximate length of an orbit or flyby of Rosetta around comet 67P/Churyumov-Gerasimenko. Thus any significant changes observed around Halley are changes that might occur for Rosetta during one pass of 67P/CG. It is found that the occurrence of mirror mode waves in the cometosheath is strongly influenced by the dynamical pressure of the solar wind and the outgassing rate of the comet. Field line draping happens in the magnetic pile-up region. Changes in nested draping regions (i.e. regions with different Bx-directions) can occur within a few days, possibly in fluenced by changes in the outgassing rate of the comet and thereby the conductivity of the cometary ionosphere.

VizieR Online Data Catalog: de Houtman, Kepler and Halley star catalogs (Verbunt+ 2011)

NASA Astrophysics Data System (ADS)

Verbunt, F.; van Gent, R. H.

2011-04-01

We present Machine-readable versions of the star catalogues of de Houtman (1602), Kepler (1627: Secunda Classis and Tertia Classis) and Halley (1679). In addition to the data from the Historical catalogue, the machine-readable version contains the modern identification with a Hipparcos star and the latter's magnitude, and based on this identification the positional accuracy. For Kepler's catalogues we also give cross references to the catalogue of Ptolemaios (in the edition by Toomer 1998). (4 data files).

Temporal Evolution of the Morphological Tail Structures of Comet P/Halley 1910 II

NASA Astrophysics Data System (ADS)

Izaguirre, L. S.; Voelzke, M. R.

2004-08-01

Eight hundred and eighty six images from September 1909 to May 1911 are analysed for the purpose of identifying, measuring and correlating the morphological structures along the plasma tail of P/Halley. These images are from the Atlas of Comet Halley 1910 II (Donn et al., 1986). A systematic visual analysis revealed 304 wavy structures (Yi et al., 1998) along the main tail and 164 along the secondary tails, 41 solitary waves (solitons) (Roberts, 1985), 13 Swan-like tails (Jockers, 1985), 26 disconnection events (DEs) (Voelzke, 2002a), 166 knots (Voelzke et al., 1997) and six shells (Schulz and Schlosser, 1989). While the wavy structures denote undulations or a train of waves, the solitons refer to the formations usually denominated kinks (Tomita et al., 1987). In general, it is possible to associate the occurrence of a DE and/or a Swan-Tail with the occurrence of a knot, but the last one may occur independently. It is also possible to say that the solitons occur in association with the wavy structures, but the reverse is not true. The 26 DEs documented in 26 different images allowed the derivation of two onsets of DEs, i.e., the time when the comet supposedly crossed a frontier between magnetic sectors of the solar wind (Brandt and Snow, 2000). Both onsets of DEs were determined after the perihelion passage with an average of the corrected velocities Vc equal to (57 ± 15) km s-1. The mean value of the corrected wavelength lc measured in 70 different wavy structures is equal to (1.7 ± 0.1) x 10^6 km and the mean amplitude A of the wave (measured in the same 70 wavy structures cited above) is equal to (1.4 ± 0.1) x 10^5 km. The mean value of the corrected cometocentric phase velocity Vpc measured in 20 different wavy structures is equal to (168 ± 28) km s-1. The average value of the corrected velocities Vkc of the knots measured in 36 different images is equal to (128 ± 12) km s-1. There is a tendency for A and lc to increase with increasing cometocentric

Far-ultraviolet spectral images of comet Halley from sounding rockets

NASA Technical Reports Server (NTRS)

Mccoy, R. P.; Carruthers, G. R.; Opal, C. B.

1986-01-01

Far-ultraviolet images of comet Halley obtained from sounding rockets launched from White Sands Missile Range, New Mexico, on 24 February and 13 March, 1986, are presented. Direct electrographic images of the hydrogen coma of the comet were obtained at the Lyman-alpha wavelength along with objective spectra containing images of the coma at the oxygen, carbon, and sulfur resonance multiplets. Analysis of the Lyman-alpha images yields hydrogen atom production rates of 1.9 x 10 to the 30th/s and 1.4 x 120 to the 30th/s for the two observations. Images of oxygen, carbon, and sulfur emissions obtained with the objective grating spectrograph are presented for the first set of observations and preliminary production rates are derived for these elements.

Eventos de Desconexao na Cauda de Plasma do Cometa P/Halley

NASA Astrophysics Data System (ADS)

Voelzke, M. R.; Fahr, H. J.

2001-08-01

Observacoes cometárias e de vento solar sao comparadas com o propósito de determinar-se as condicoes do vento solar associadas aos eventos de desconexao (DEs) observados em caudas de plasma cometárias. Os dados cometários sao provenientes do The International Halley Watch Atlas of Large-Scale Phenomena. A análise visual sistemática das imagens do atlas revelou, entre outras estruturas morfológicas, 47 DEs ao longo da cauda de plasma do P/Halley. Estes 47 DEs registrados em 47 imagens distintas permitiram a descoberta de 19 origens de DEs, ou seja, o tempo em que as desconexoes iniciaram foi calculado. Os dados do vento solar sao provenientes de medidas feitas in situ pela sonda espacial IMP-8, as quais foram usadas para elaborar a variacao da velocidade do vento solar, densidade e pressao dinâmica durante o intervalo analisado. O presente trabalho compara as atuais teorias conflitantes, baseadas nos mecanismos de formacao, com o intuito de explicar o fenômeno cíclico dos DEs, ou seja, os efeitos de producao iônica, os efeitos de pressao e os efeitos de reconexao magnética sao analisados. Para cada uma das 19 origens de DEs comparou-se a densidade com a respectiva velocidade do vento solar com o intuito de determinar-se uma possível correlacao entre estas origens e os efeitos de pressao dinâmica. Quando da ocorrência de 6 origens de DEs o IMP-8 nao realizou medidas, nos outros 13 casos 10 origens (77%) mostraram uma anticorrelacao entre velocidade e densidade e apenas 3 (23%) revelaram uma tendência similar entre velocidade e densidade. Portanto, a análise inicial demonstra uma fraca correlacao entre as origens dos DEs e os efeitos de pressao.

The Infrared Activity of Comet P/Halley 1986 III at Heliocentric Distances from 0.6 to 3.0 AU

NASA Astrophysics Data System (ADS)

Homich, A. A.; Gehrz, R. D.; Hanner, M. S.; Tokunaga, A. T.

2001-05-01

We present an analysis of the combined infrared data obtained on Comet P/Halley 1986 III acquired by Gehrz and Ney (1992), Hanner et al. (1987), Tokunaga et al. (1986, 1988), Green et al. (1986), Ryan and Campins (1991), Campins and Ryan (1989), and Bregman et al. (1987). This data base, the largest single body of infrared photometric data for any comet, spans a wavelength range from 0.7 to 23 μ m and describes the activity of P/Halley at heliocentric distances from 0.6 to 3.0 AU. The quantitative corrections and calibration procedures required to intercompare the individual data sets are described. Long-term trends in the heliocentric dependance of P/Halley's grain color temperature Tobs, silicate emission optical strength M10, grain albedo A, grain superheat S, apparent luminosity L, and infrared monochromatic fluxes are discussed. The infrared data sets are compared with data sets at other wavelengths for evidence of short-duration bursts associated with the activity of the comet's nucleus. We conclude that short duration outbursts at small heliocentric distances produce small grains whose thermal emission during the outburst dominates the normal background thermal emission from larger grains. These outbursts are not observed at heliocentric distances larger than 2.0 AU pre-perihelion, but cannot be ruled out for the post-perihelion data. We discuss the nuclear activity implied by both the long-term trends and the short period outburst behavior. This research was supported by NASA, the National Science Foundation, the U.S. Air Force, the University of Minnesota Institute of Technology Dean's Office and Graduate School, and the University of Wyoming.

Modeling the neutral gas and dust coma of Comet 1P/Halley

NASA Astrophysics Data System (ADS)

Rubin, Martin; Tenishev, Valeriy M.; Combi, Michael R.; Hansen, Kenneth C.; Gombosi, Tamas I.; Altwegg, Kathrin; Balsiger, Hans

2010-05-01

The neutral gas environment of a comet is largely influenced by dissociation of parent molecules created at the surface of the comet and collisions of all the involved species. We compare the results from a kinetic model of the neutral cometary environment with measurements from the Neutral Mass Spectrometer (NMS) and the Dust Impact Detection System (DIDSY) onboard the Giotto spacecraft which flew-by at comet 1P/Halley in 1986. We further show that our model is in good agreement to measurements obtained by the International Ultraviolet Explorer (IUE), sounding rocket experiments, and the International Halley Watch (IHW). The model solves the Boltzmann equation with a Direct Simulation Monte Carlo technique [Tenishev et al. (2008, Astrophys. J., 685, 659-677)] by tracking trajectories of gas molecules and dust grains under the influence of the comet's weak gravity field with momentum exchange among particles modeled in a probabilistic manner. The cometary nucleus is considered to be the source of dust and the parent species (in our model: H2O, CO, H2CO, CO2, CH3OH, C2H6, C2H4, C2H2, HCN, NH3, and CH4) in the coma. Subsequently our model also tracks the corresponding dissociation products (H, H2, O, OH, C, CH, CH2, CH3, N, NH, NH2, C2, C2H, C2H5, CN, and HCO). This work has been supported by JPL subcontract 1266313 under NASA grant NMO710889, NASA planetary atmospheres program grant NNX09AB59G, grant AST-0707283 from the NSF Planetary Astronomy program, and the Swiss National Science Foundation.

Airborne spectrophotometry of P/Halley from 20 to 65 microns

NASA Technical Reports Server (NTRS)

Glaccum, W.; Moseley, S. H.; Campins, H.; Loewenstein, R. F.

1986-01-01

Simultaneous 20 to 65 microns spectrometry and 100 microns photometry of P/Halley obtained on board the Kuiper Airborne Observatory (KAO) in 1985 Dec. and 1986 April are discussed. Spectra with resolution 30 to 50 were obtained with the NASA/Goddard 24 channel grating spectrometer. Measurements were made on the nucleus as well as 5 points along and perpendicular to the Sun-tail direction. The observations reveal the absence of any strong spectral features. The color temperature of the dust varies over time scales as short as 2 days, but is higher than that expected for a rapidly rotating blackbody at the same distance from the Sun. The color temperature does not vary within 1 arcmin of the nucleus, but the coma is brighter on the sunward side than on the antisunward side.

Airborne spectrophotometry of Comet Halley from 5 to 9 microns

NASA Technical Reports Server (NTRS)

Campins, H.; Bregman, J. D.; Witteborn, F. C.; Wooden, D. H.; Rank, D. M.; Cohen, M.; Allamandola, Louis J.; Tielens, Alexander G. G. M.

1986-01-01

Spectrophotometry from 5 to 9 microns (resolution = 0.02) of comet Halley was obtained from the Kuiper Airborne Observatory on 1985 Dec. 12.1 and 1986 April 8.6 and 10.5 UT. Two spectral features are apparent in all the observations, one from 5.24 to 5.6 microns, and the silicate emission feature which has an onset between 7 and 8 microns. There is no evidence for the 7.5 microns feature observed by the Vega 1 spacecraft; the large difference between the areal coverage viewed from the spacecraft and the airplane may explain the discrepancy. Color temperatures significantly higher than a blackbody indicate that small particles are abundant in the coma. Significant spatial and temporal variations in the spectrum show trends similar to those observed from the ground.

Dust impact effects recorded by the APV-N experiment during Comet Halley encounters

NASA Astrophysics Data System (ADS)

Oberc, P.; Orlowski, D.; Klimov, S.

1986-12-01

During the Vega 1 and 2 comet Halley encounters plasma wave instrument APV-N entered a region of impulsive noise 220,000 km from nucleus. The noise is attributed to dust grain impacts onto spacecraft body. Regression analysis of impact induced effects recorded during flyby shows that from 100,000 km from closest approach most plasma wave spectra measured by APV-N onboard Vega 1 and 2 are significantly influenced by dust impact effects. Signals associated with large dust impacts are directly recorded on the E2 0.1 to 25 Hz electric field waveform channel.

High precision low resolution spectrophotometry of Comets Giacobini-Zinner and Halley

NASA Technical Reports Server (NTRS)

Odell, C. R.; Tegler, Stephen C.

1986-01-01

Optical window (300 to 1000 nm) observations were made of Comet Halley during 12 to 14 Mar. 1986 by a scanning spectrometer. The results provide accurate spectrophotometric measurements of the principal molecular bands from the 308 nm OH through the 918 nm CN emissions. The observations can be used to tie space derived ultraviolet and groundbased infrared observations to the optical observations and to one another. Additional observations were made of comet Giacobini-Zinner on 30 September 1985 of the same OH band and the 388 nm band of CN. The Swan band sequence ratios are used to test the best models of C2, with different ratios favoring different models, calling into question the assumptions of these very complete models.

First results from the Giotto magnetometer experiment at comet Halley

NASA Technical Reports Server (NTRS)

Neubauer, F. M.; Glassmeier, K. H.; Pohl, M.; Raeder, J.; Acuna, M. H.; Burlaga, L. F.; Ness, N. F.

1986-01-01

The Giotto magnetometer experiment at comet Halley has for the first time provided magnetic field measurements in all the important spatial regions characterizing the front-side interaction between the solar-wind magnetoplasma and a cometary atmosphere. Upstream waves of cometary origin have been observed at distances greater than two million km from the comet, both inbound and outbound. A cometary bow shock has been identified at 1.15 million inbound on the dawn side and a thick quasi-parallel cometary bow shock outbound. A turbulent magnetosheath has been observed further inside. A magnetic pile-up region has been identified inside 135,000 km, inbound, and 263,000 km, outbound, with fields up to 57 and 65 nT, respectively. A cavity region with essentially zero magnetic field has been discovered, with a width of 8500 km along the trajectory around closest approach.

International Halley Watch: Discipline specialists for near-nucleus studies

NASA Technical Reports Server (NTRS)

Larson, S.; Sekanina, Z.; Rahe, J.

1986-01-01

The purpose of the Near-Nucleus Studies Net is to study the processes taking place in the near-nucleus environment as they relate to the nature of nucleus. This is accomplisghed by measuring the spatial and temporal distribution of dust, gases and ions in the coma on high resolution images taken from many observatories around the world. By modeling the motions of discrete dust features in Comet Halley, it is often possible to determine the locations of the emission sources on the surface and learn about the nucleus structure. In addition to the general goals shared by all IHW nets, the scientific goals of the net has been to determine (1)the gross surface structure of the nucleus, (2)the nucleus spin vector, (3)the distribution and evolution of jet sources and (4)the interrelationships between the gas, dust and ion components of the coma. An additional Comet Giacobini-Zinner watch was carried out by the NNSN in support of the NASA International Cometary Explorer flyby.

The trend of production rates with heliocentric distance for comet P/Halley

NASA Technical Reports Server (NTRS)

Fink, Uwe

1994-01-01

Comet P/Halley was observed spectroscopically in the wavelength range 5200-10,400 A during 10 observing runs, roughly a month apart from 1985 August 28 to 1986 June 6. The observations span a heliocentric distance from 0.73 to 2.52 AU. This data set is analyzed to determine the course of the production rate with heliocentric distance for C2, NH2, CN, and the continuum. The effect of changing the Haser scale lengths and their heliocentric distance dependence is examined. The production rate ratios to water change only in a minor way, but the absolute values of the production rates are more severely affected. Fluorescent efficiencies, or g-factors for the CN red system are calculated, and band intensity ratios for NH2 and CN are presented. Using presently available fluorescence efficiencies and Haser scale lengths, mixing ratios for the parents of C2, CN, and NH2 with respect to water are: 0.34 +/- 0.07%, 0.15 +/- 0.04%, and 0.13 +/- 0.05%. It is found that these mixing ratios are essentially constant over the heliocentric distance range of the observations, implying a rather uniform nucleus and uniform outgassing characteristics, although there are indications of smaller scale day-to-day variations. The results provide strong observational confirmation that water evaporation controls the activity of the comet over the distance range studied. Continuum values Af rho are determined, and their ratios to QH2O are found to have a clear dependence with heliocentric distance approximately r(exp -1.0) with a post-perihelion enhancement. No correlation of the production rate ratios with light curve of P/Halley were found, nor was there any correlation of the C2 or CN production with the dust.

Airborne and groundbased spectrophotometry of comet P/Halley from 5-13 micrometers

NASA Technical Reports Server (NTRS)

Bregman, J. D.; Witteborn, F. C.; Allamandola, L. J.; Campins, H.; Wooden, D. H.; Rank, D. M.; Cohen, M.; Tielens, A. G. G. M.

1987-01-01

Spectrophotometry of comet Halley from 5-13 microns was obtained from the Kuiper Airborne Observatory and from the Lick Observatory Nickel Telescope, revealing a strong broad emission band at 10 microns and a weak feature at 6.8 microns. The 10-micron band is identified with silicate materials, and the primary component of the silicate emission is suggested to be due to olivine. The 6.8 micron feature may be due either to carbonates or the C-H deformation mode in organic molecules. The data indicate that small particles are abundant in the coma and that the dust contains at least two physically separate components. Significant spatial and temporal variations are also noted in the spectrum.

Modeling of Pickup Ion Distributions in the Halley Cometo-Sheath: Empirical Rates of Ionization, Diffusion, Loss and Creation of Fast Neutral Atoms

NASA Technical Reports Server (NTRS)

Huddleston, D.; Neugebauer, M.; Goldstein, B.

1994-01-01

The shape of the velocity distribution of water-group ions observed by the Giotto ion mass spectrometer on its approach to comet Halley is modeled to derive empirical values for the rates on ionization, energy diffusion, and loss in the mid-cometosheath.

Exploring structural colour in uni- and multi-coloured butterfly wings and Ag+ uptake by scales

NASA Astrophysics Data System (ADS)

Aideo, Swati N.; Haloi, Rajib; Mohanta, Dambarudhar

2017-09-01

We discuss the origin of the structural colour of different butterfly wings in the light of the typical built-in microstructural arrangement of scales that are comprised of chitin-melanin layer and air-gaps. Three specimens of butterfly wings namely, Papilio Liomedon (black), Catopsilia Pyranthe (light green) and Vanessa Cardui (multi-coloured) were chosen and diffuse reflectance characteristics have been aquired for normal incidence of p-polarized light. Moreover, the time-dependent uptake of Ag+ into scales has led to swelling and spread of the chitinous ridges and ribs, with revelation of micro-beads in Catopsilia Pyranthe specimen. The reduction of the number of air-gaps between any two parallel ridges is attributed to the merging of adjacent gaps possessing a common boundary. The availability of Ag at the centre of a chosen ridge, for every wing type, follows an exponential growing trend, ∼e0.36t . Precise inclusion of nanoscale metals into natural photonic systems would provide new insight, while applying principles of photonics and plasmonics simultaneously.

Liverpool Telescope classification of ATLAS16bdg as a Type Ia supernova near maximum light

NASA Astrophysics Data System (ADS)

Mundell, C. G.; Smith, R. J.; Childress, M. J.

2016-06-01

On 2016 June 15 at approximately 21:03 UT, we performed multicolour optical imaging, spectroscopy and polarimetry with the 2-m robotic Liverpool Telescope IO:O camera of galaxy NGC4708 in which a bright optical transient was reported by Tonry et al. ATel #9151 (ATLAS16bdg).

Ultralow-mass solar-array designs for Halley's comet rendezvous mission

NASA Technical Reports Server (NTRS)

Costogue, E. N.; Rayl, G.

1978-01-01

This paper describes the conceptual design study results of photovoltaic arrays capable of powering a Halley's comet rendezvous mission. This mission would be Shuttle-launched, employ a unique form of propulsion (ion drive) which requires high power levels for operation, and operate at distances between 0.6 and 4.5 AU. These requirements make it necessary to develop arrays with extremely high power-to-mass ratio (200 W/kg). In addition, the dual requirements of providing ion thruster power as well as housekeeping power leads to the development of unique methods for mode switching. Both planar and variable-concentrator-enhanced array concepts using ultrathin (50 micron) high-efficiency (up to 12.5%) silicon solar cells coupled with thin (75 micron) plastic encapsulants are considered. In order to satisfy the Shuttle launch environment it was necessary to provide novel methods of both storing and deploying these arrays.

Airborne 20-65 micron spectrophotometry of Comet Halley

NASA Technical Reports Server (NTRS)

Glaccum, William; Moseley, S. H.; Campins, Humberto C.; Loewenstein, R. F.

1988-01-01

Observations of Comet Halley with a grating spectrometer on board the Kuiper Airborne Observatory on four nights in Dec. 1985 to Apr. 1986 are reported. Low resolution 20 to 65 micrometer spectra of the nucleus with a 40 arcsec FWHM beam was obtained on 17 Dec. 1985, and on 15 and 17 Apr. 1986. On 20 Dec. 1985, only a 20 to 35 micrometer spectrum was obtained. Most of the data have been discussed in a paper where the continuum was dealt with. In that paper, models were fit to the continuum that showed that more micron sized particles of grain similar to amorphous carbon were needed to fit the spectrum than were allowed by the Vega SP-2 mass distribution, or that a fraction of the grains had to be made out of a material whose absorption efficiency fell steeper than lambda sup -1 for lambda greater than 20 micrometers. Spectra was also presented taken at several points on the coma on 15 Apr. which showed that the overall shape to the spectrum is the same in the coma. Tabulated values of the data and calibration curves are available. The spectral features are discussed.

Cometary kilometric radio waves and plasma waves correlated with ion pick-up effect at Comet Halley

NASA Technical Reports Server (NTRS)

Oya, H.; Morioka, A.; Miyake, W.; Smith, E. J.; Tsurutani, B. T.

1985-01-01

Bow-shock movements at Comet Halley are inferred from the discrete spectra of the cometary kilometric radiation (30-195 kHz); the observed emissions can be interpreted as being generated and propagating from the moving shock. The shock motion is possibly associated with the time variation of the solar wind and cometary outgassing. It is concluded that these plasma wave phenomena are manifestations of ion pick-up processes, which occur even in a remote region 7 million to 10 million km from the cometary nucleus.

Comet Halleys Legacy: SUNA, Astronomy from Universidad Central de Venezuela (U.C.V.)

NASA Astrophysics Data System (ADS)

Romero, Gabriel; Fernandez, Nelson

2007-12-01

The Sociedad Universitaria de Astronomia (SUNA) is a group of astronomy amateurs which works inside the Universidad Central de Venezuela (Venezuelas Central University)s campus. The initiative is originated during the path through the perihelion of Comet Halley in 1986, and since then their goals are promotion of astronomical information to all the university community. Observational works are also carried out, such as: registration and investigation of astronomical events, with the purpose to offer the opportunity to all public, mostly students o the University, to enjoy a spectacle, and at the same time to motivate the students to continue professional studies of astronomy. Being this last goal one of the most gratifying in the society.

The variability of Halley's Comet during the Vega, Planet-A, and Giotto encounters

NASA Technical Reports Server (NTRS)

Schleicher, D. G.; Millis, R. L.; Tholen, D.; Lark, N.; Birch, Peter V.; Martin, Ralph; Ahearn, Michael F.

1986-01-01

Narrowband photometry of Halley obtained at Cerro Tololo Inter-American Observatory (CTIO), Mauna Kea Observatory (MKO), and Perth Observatory was combined to determine the relative level of activity during the interval spanning the spacecraft encounters. Measurements of the flux from the comet in emission bands of OH, NH, CN, C3, and C2, as well as at 2 continuum points, were obtained at CTIO on each night between 5 March and 17 March 1986. Observations were made on many of these same dates at MKO and Perth using comparable interference filters. The date clearly show variation of a factor of 2.5 in the production of all observed species with a characteristic time scale of a few days.

A new calibration of the semi-empirical photometric theory for Halley and other comets

NASA Technical Reports Server (NTRS)

Newburn, R. L., Jr.

1984-01-01

The semiempirical photometric theory of gas and dust production in comets (Newburn, 1979, 1981, and 1982) is recalibrated on the basis of the 17-comet compilation of spectrophotometric data of Newburn and Spinrad (1984). The results are presented in graphs and tables, and it is shown that no corrections are required for the constant R and the function delta, but that the mixing ratios (obtained as functions of heliocentric distance) can be improved, with implications for the visual-photometric comet model. Recently calculated light curves for comet Halley are compared, and the use of the nearly identical curves of Bortle and Morris (1984) and Marcus (1983) is recommended.

Human seasonal and circadian studies in Antarctica (Halley, 75°S).

PubMed

Arendt, Josephine; Middleton, Benita

2018-03-01

Living for extended periods in Antarctica exposes base personnel to extremes of daylength (photoperiod) and temperature. At the British Antarctic Survey base of Halley, 75°S, the sun does not rise for 110 d in the winter and does not set for 100 d in summer. Photoperiod is the major time cue governing the timing of seasonal events such as reproduction in many species. The neuroendocrine signal providing photoperiodic information to body physiology is the duration of melatonin secretion which reflects the length of the night: longer in the short days of winter and shorter in summer. Light of sufficient intensity and spectral composition serves to suppress production of melatonin and to set the circadian timing and the duration of the rhythm. In humans early observations suggested that bright (>2000 lux) white light was needed to suppress melatonin completely. Shortly thereafter winter depression (Seasonal Affective Disorder or SAD) was described, and its successful treatment by an artificial summer photoperiod of bright white light, sufficient to shorten melatonin production. At Halley dim artificial light intensity during winter was measured, until 2003, at a maximum of approximately 500 lux in winter. Thus a strong seasonal and circadian time cue was absent. It seemed likely that winter depression would be common in the extended period of winter darkness and could be treated with an artificial summer photoperiod. These observations, and predictions, inspired a long series of studies regarding human seasonal and circadian status, and the effects of light treatment, in a small overwintering, isolated community, living in the same conditions for many months at Halley. We found little evidence of SAD, or change in duration of melatonin production with season. However the timing of the melatonin rhythm itself, and/or that of its metabolite 6-sulphatoxymelatonin (aMT6s), was used as a primary marker of seasonal, circadian and treatment changes. A substantial phase

Comparison of picked-up protons and water group ions upstream of Comet Halley's bow shock

NASA Technical Reports Server (NTRS)

Neugebauer, M.; Coates, A. J.; Neubauer, F. M.

1990-01-01

The similarities and differences between the picked-up cometary protons and water-group (WG) ions upstream of the bow shock of Comet Halley are examined using measurements obtained by the ion mass spectrometer and plasma analyzer experiments on board Giotto. It was found that the dependencies of the pitch angle and the energy diffusion rates of the cometary protons and WG ions on the ion densities and on the angle alpha between the interplanetary field and the solar wind velocity vector were very different. This finding could not be explained in terms of presently available theories and models.

Produccion Gaseosa del Cometa Halley: Erupciones Y Fotodisociacion del Radical OH

NASA Astrophysics Data System (ADS)

Silva, A. M.; Mirabel, I. F.

1990-11-01

RESUMEN:En este trabajo informamos la detecci6n de 20 erupciones en la li'nea de =18cm (1667MHz) del radical OH en el Cometa Halley.Las observaciones incluyen todos los monitoreos existentes y se extienden desde 120 dias antes del perihelio hasta 90 dias despues.Se detectan bruscos crecimientos en el flujo medido,hasta un factor 1O,seguidos por decaimientos lentos asociados con la fotodisociaci6n del OH. Se obtuvieron valores para el tiempo de vida fotoquimico del OH y del H2O basandose en el modelo desarrollado previamente por Silva(1988). Esos tiempos de vida estan de acuerdo con predicciones teoricas y con las observaciones en el Ultravioleta, y los resultados, los que son fuertemente dependientes de la velocidad heliocentrica del Coineta (variando hasta un factor 6), han sido calculados para varios rangos de velocidad entre +28 y -28 km/seg. Key wo'L :

Automatic inference of geometric camera parameters and inter-camera topology in uncalibrated disjoint surveillance cameras

NASA Astrophysics Data System (ADS)

den Hollander, Richard J. M.; Bouma, Henri; Baan, Jan; Eendebak, Pieter T.; van Rest, Jeroen H. C.

2015-10-01

Person tracking across non-overlapping cameras and other types of video analytics benefit from spatial calibration information that allows an estimation of the distance between cameras and a relation between pixel coordinates and world coordinates within a camera. In a large environment with many cameras, or for frequent ad-hoc deployments of cameras, the cost of this calibration is high. This creates a barrier for the use of video analytics. Automating the calibration allows for a short configuration time, and the use of video analytics in a wider range of scenarios, including ad-hoc crisis situations and large scale surveillance systems. We show an autocalibration method entirely based on pedestrian detections in surveillance video in multiple non-overlapping cameras. In this paper, we show the two main components of automatic calibration. The first shows the intra-camera geometry estimation that leads to an estimate of the tilt angle, focal length and camera height, which is important for the conversion from pixels to meters and vice versa. The second component shows the inter-camera topology inference that leads to an estimate of the distance between cameras, which is important for spatio-temporal analysis of multi-camera tracking. This paper describes each of these methods and provides results on realistic video data.

From the Vega mission to comet Halley to the Rosetta mission to comet 67/P Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Zelenyi, L. M.; Ksanfomality, L. V.

2016-12-01

The data acquired by the Vega and Giotto spacecraft, while investigating comet 1P/Halley in 1986, are compared to the results of the first phase of exploration of the nucleus of comet 67P/Churyumov-Gerasimenko performed with the Rosetta and Philae modules. The course of the Rosetta mission activity and the status of the modules after the Philae probe landing on the comet's nucleus are overviewed. Since some elements of the touchdown equipment failed, a number of in-situ experiments on the comet's nucleus were not carried out.

Dual cameras acquisition and display system of retina-like sensor camera and rectangular sensor camera

NASA Astrophysics Data System (ADS)

Cao, Nan; Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Song, Shengyu

2015-04-01

For a new kind of retina-like senor camera and a traditional rectangular sensor camera, dual cameras acquisition and display system need to be built. We introduce the principle and the development of retina-like senor. Image coordinates transformation and interpolation based on sub-pixel interpolation need to be realized for our retina-like sensor's special pixels distribution. The hardware platform is composed of retina-like senor camera, rectangular sensor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes two cameras' acquisition and display.

A multicolour flow cytometric assay for c-MYC protein in B-cell lymphoma.

PubMed

Alayed, Khaled; Schweitzer, Karen; Awadallah, Amad; Shetty, Shashirekha; Turakhia, Samir; Meyerson, Howard

2018-05-16

Develop an objective assay to detect c-MYC protein expression using multiparametric flow cytometry (FCM) as an alternative to immunohistochemistry (IHC). 57 patient samples and 11 cell line samples were evaluated. Cell suspensions were obtained and c-MYC staining was performed in combination with CD45 and CD19 and, in some samples, CD10. The percentage of c-MYC+ cells by FCM was correlated with the percentage determined by IHC. The relationship between c-MYC protein expression and the presence of a c-MYC gene rearrangement in aggressive and high-grade lymphomas was also assessed. c-MYC expression by FCM and IHC demonstrated a high degree of correlation in a training set of 33 patient cases, r=0.92, 11 cell line samples, r=0.81 and in a validation set of 24 aggressive and high-grade B-cell lymphomas, r=0.85. c-MYC gene was rearranged by fluorescence in situ hybridisation in 6/9 samples with high c-MYC expression (>40%) by FCM and 6/14 by IHC. We have developed a reliable multicolour FCM assay to detect c-MYC expression suitable for clinical laboratories that should be helpful to accurately quantify c-MYC expression in B-cell lymphomas. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Systematics of the CHON and other light-element particle populations in Comet Halley

NASA Technical Reports Server (NTRS)

Clark, Benton; Mason, Larry W.; Kissel, Jochen

1986-01-01

Based on chemical signatures measured by the PIA experiment during the Giotto flyby of comet Halley, particle classifications were designated. In addition to silicate-like grains and particles of mixed (cosmic) composition, there appear to be several light-element rich populations, including the CHON, (H,C), (H,C,O), and (H,C,N) particle types. These compositional classes are further distinguished by differences in mass distributions, a density indicator, and variations in relative abundance within the coma. These particle populations are evidence for chemical heterogeneity in the surface of the cometary nucleus. Particles found mainly in the inner coma may be volatile icy grains. Most of the N of the comet may be found in up to three different populations of grains; one or more of these may be responsible for the observation of cyanojets.

Complete positive ion, electron, and ram negative ion measurements near Comet Halley (COPERNIC) plasma experiment for the European Giotto Mission

NASA Technical Reports Server (NTRS)

Lin, Robert P.

1988-01-01

Participation of U.S. scientists on the COPERNIC (COmplete Positive ions, Electrons and Ram Negative Ion measurements near Comet Halley) plasma experiment on the Giotto mission is described. The experiment consisted of two detectors: the EESA (electron electrostatic analyzer) which provided three-dimensional measurements of the distribution of electrons from 10 eV to 30 keV, and the PICCA (positive ion cluster composition analyzer) which provided mass analysis of positively charged cold cometary ions from mass 10 to 210 amu. In addition, a small 3 deg wide sector of the EESA looking in the ram direction was devoted to the detection of negatively charged cold cometary ions. Both detectors operated perfectly up to near closest approach (approx. 600 km) to Halley, but impacts of dust particles and neutral gas on the spacecraft contaminated parts of the data during the last few minutes. Although no flight hardware was fabricated in the U.S., The U.S. made very significant contributions to the hardware design, ground support equipment (GSE) design and fabrication, and flight and data reduction software required for the experiment, and also participated fully in the data reduction and analysis, and theoretical modeling and interpretation. Cometary data analysis is presented.

7. VAL CAMERA CAR, DETAIL OF 'FLARE' OR TRAJECTORY CAMERA ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. VAL CAMERA CAR, DETAIL OF 'FLARE' OR TRAJECTORY CAMERA INSIDE CAMERA CAR. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Infrared techniques for comet observations

NASA Technical Reports Server (NTRS)

Hanner, Martha S.; Tokunaga, Alan T.

1991-01-01

The infrared spectral region (1-1000 microns) is important for studies of both molecules and solid grains in comets. Infrared astronomy is in the midst of a technological revolution, with the development of sensitive 2D arrays leading to IR cameras and spectrometers with vastly improved sensitivity and resolution. The Halley campaign gave us tantalizing first glimpses of the comet science possible with this new technology, evidenced, for example, by the many new spectral features detected in the infrared. The techniques of photometry, imaging, and spectroscopy are reviewed in this chapter and their status at the time of the Halley observations is described.

Caught on Camera.

ERIC Educational Resources Information Center

Milshtein, Amy

2002-01-01

Describes the benefits of and rules to be followed when using surveillance cameras for school security. Discusses various camera models, including indoor and outdoor fixed position cameras, pan-tilt zoom cameras, and pinhole-lens cameras for covert surveillance. (EV)

6. VAL CAMERA CAR, DETAIL OF COMMUNICATION EQUIPMENT INSIDE CAMERA ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. VAL CAMERA CAR, DETAIL OF COMMUNICATION EQUIPMENT INSIDE CAMERA CAR WITH CAMERA MOUNT IN FOREGROUND. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Angular and energy distribution of low energy cometary ions measured in the outer coma of Comet Halley

NASA Technical Reports Server (NTRS)

Berthelier, J. J.; Illiano, J. M.; Hodges, R. R.; Krankowsky, D.; Eberhardt, P.; Laemmerzahl, P.; Hoffman, J. H.; Herrwerth, I.; Woweries, J.; Dolder, U.

1986-01-01

During the early phase of the Giotto encounter with comet Halley, at distances from the nucleus greater than 350,000 km, the neutral mass spectrometer was operated in a mode allowing the measurement of low energy ions. Data reveal two important features of the outer coma: the presence of a sharp discontinuity in the plasma flow at 550,000 km from the nucleus which results in a significant decrease of the plasma flow accompanied by an increase in temperature; and the detection of newly born ions identified as O(+) and CO(+), at distances from the comet greater than 800,000 km.

2. VAL CAMERA CAR, VIEW OF CAMERA CAR AND TRACK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. VAL CAMERA CAR, VIEW OF CAMERA CAR AND TRACK WITH CAMERA STATION ABOVE LOOKING WEST TAKEN FROM RESERVOIR. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Biodiversity of air-borne microorganisms at Halley Station, Antarctica.

PubMed

Pearce, David A; Hughes, K A; Lachlan-Cope, T; Harangozo, S A; Jones, A E

2010-03-01

A study of air-borne microbial biodiversity over an isolated scientific research station on an ice-shelf in continental Antarctica was undertaken to establish the potential source of microbial colonists. The study aimed to assess: (1) whether microorganisms were likely to have a local (research station) or distant (marine or terrestrial) origin, (2) the effect of changes in sea ice extent on microbial biodiversity and (3) the potential human impact on the environment. Air samples were taken above Halley Research Station during the austral summer and austral winter over a 2-week period. Overall, a low microbial biodiversity was detected, which included many sequence replicates. No significant patterns were detected in the aerial biodiversity between the austral summer and the austral winter. In common with other environmental studies, particularly in the polar regions, many of the sequences obtained were from as yet uncultivated organisms. Very few marine sequences were detected irrespective of the distance to open water, and around one-third of sequences detected were similar to those identified in human studies, though both of these might reflect prevailing wind conditions. The detected aerial microorganisms were markedly different from those obtained in earlier studies over the Antarctic Peninsula in the maritime Antarctic.

1. VARIABLEANGLE LAUNCHER CAMERA CAR, VIEW OF CAMERA CAR AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VARIABLE-ANGLE LAUNCHER CAMERA CAR, VIEW OF CAMERA CAR AND TRACK WITH CAMERA STATION ABOVE LOOKING NORTH TAKEN FROM RESERVOIR. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Pickup protons and water ions at Comet Halley - Comparisons with Giotto observations

NASA Astrophysics Data System (ADS)

Ye, G.; Cravens, T. E.; Gombosi, T. I.

1993-02-01

The cometary ion pickup process along the sun-comet line at Comet Halley is investigated using a quasi-linear diffusion model including both pitch angle and energy diffusion, adiabatic compression, and convective motion with the solar wind flow. The model results are compared with energetic ion distributions observed by instruments on board the Giotto spacecraft. The observed power spectrum index of magnetic turbulence (gamma) is 2-2.5. The present simulation shows that when gamma was 2, the calculated proton distributions were much more isotropic than the observed ones. The numerical solutions of the quasi-linear diffusion equations show that the isotropization of the pickup ion distribution, particularly at the pickup velocity, is not complete even close to the bow shock. Given the observed turbulence level, quasi-linear theory yields pickup ion energy distributions that agree with the observed ones quite well and easily produces energetic ions with energies up to hundreds of keV.

Infrared observations of an outburst of small dust grains from the nucleus of Comet P/Halley 1986 III at perihelion

NASA Technical Reports Server (NTRS)

Gehrz, R. D.; Johnson, C. H.; Magnuson, S. D.; Ney, E. P.; Hayward, T. L.

1995-01-01

A close examination of the 0.7- to 23-micron infrared data base acquired by Gehrz and Ney (1992), suggests that the nucleus of Comet P/Halley 1986 III emitted a burst of small dust grains during a 3-day period commencing within hours of perihelion passage on 1986 February 9.46 UT. The outburst was characterized by significant increases in the coma's grain color temperature T(sub obs), temperature excess (superheat: S = T(sub obs)/T(sub BB)), infrared luminosity, albedo, and 10-micron silicate emission feature strength. These changes are all consistent with the sudden ejection from the nucleus of a cloud of grains with radii of approximately 0.5 micron. This outburst may have produced the dust that was responsible for some of the tail streamers photographed on 1986 February 22 UT. The peak of the dust outburst occurred about 3 days before a pronounced increase in the water production rate measured by the Pioneer Venus Orbiter Ultraviolet Spectrometer. We suggest that jets that release large quantities of small particles may be largely responsible for some of the variable infrared behavior that has been reported for P/Halley and other comets during the past two decades. Such jets may also account for some of the differences IR Type I and IR Type II comets.

Halley's Legacy: The Selfless Genius Who Founded Geophysics, Led the Science Community to Solve the Problem of Finding Longitude at Sea, and Whose Work in Areas from Geomagnetism to Planetology Still Has Meaning For Today's Scientists

NASA Astrophysics Data System (ADS)

Wakefield, J.

2005-12-01

2005 marks the 300th anniversary of Edmond Halley's publication of his infamous synopsis predicting the accurate return of the comet that would come to bear his name. On this occasion, it is time to remember him not only as the founder of geophysics but for his contributions to the world of science beyond his comet work. Halley's comet-transformed by the first triumph of the Newtonian revolution from a dire supernatural omen to a predictable element of the universe's clockwork-remains a recurring symbol of the scientific age of the Enlightenment. His comet is hurtling through space at some 20,000 miles per hour and won't be back until 2061. But it can remind us of past epochs and everlastingly of Halley's contributions to geophysics and the world of science writ large. For a start, Halley completed a series of little known sea voyages in his effort to solve one of his life-long quests: the problem of determining longitude at sea. On the basis of his earlier theories on magnetism, his approach entailed mapping the magnetic deviation across the test-bed of the Atlantic Ocean. In this paper, his findings from the voyages, which technically comprised the first science mission funded by a government and stand as the forerunner of all big science projects, will be reconsidered and put into the context of today's notions about terrestrial magnetism, including the geodynamo. To this day, scientists remain perplexed about exactly how core's dynamo regenerates its energy. When Halley was sailing his vessel, the Paramore, across the North Atlantic and making the first charts of geomagnetism, little did he ever imagine magnetism would underpin today's stunning advances in information technology and electromagnetic engineering. Magnetism also offers ways to study phase transitions, random disorder, and physics in low dimensions, which looks at particle interactions at ever higher energies in order to essentially study matter at smaller and smaller size scales. The presentation

Camera Optics.

ERIC Educational Resources Information Center

Ruiz, Michael J.

1982-01-01

The camera presents an excellent way to illustrate principles of geometrical optics. Basic camera optics of the single-lens reflex camera are discussed, including interchangeable lenses and accessories available to most owners. Several experiments are described and results compared with theoretical predictions or manufacturer specifications.…

Observations of a Greenstein effect in the O I 1302A emission of Comet Halley

NASA Astrophysics Data System (ADS)

Dymond, K. F.; Feldman, P. D.; Woods, T. N.

1989-03-01

Far-ultraviolet spectra of Comet Halley (1986 III) were obtained on February 26, 1986, 17 days after perihelion, and on March 13, 1986, 13 hr before the Giotto encounter, using an imaging spectrograph aboard a sounding rocket. A sunward-antisunward asymmetry observed in the brightness distribution of the O I 1302A emission is a result of the differential Swings effect first discussed by Greenstein (1958) for Fraunhofer structure in the solar continuum. The mean velocity of the O atoms in the coma at cometocentric radii greater than 10,000 km was 2.2 + or - 0.8 km/s based on model calculations which incorporate the Greenstein effect. This velocity is consistent with H2O as the principal source of oxygen.

On charge exchange effect in the vicinity of the cometopause of Comet Halley

NASA Astrophysics Data System (ADS)

Ip, W.-H.

1989-08-01

In order to explore the physical nature of the cometopause observed at Comet Halley by the Vega spacecraft and by the Giotto probe, the chemical compositional changes and variations of the thermal-energy distributions of the water-group ions are examined, adopting a two-dimensional cometary-plasma flowfield model based on three-dimensional MHD simulations of Fedder et al. (1986). The charge-exchange loss of hot cometary ions and the solar-wind protons could be used to explain the observed number-density profiles quantitatively. The resulting exponential depletion of the hot-ion populations with a scale length of about 10,000 km occurs near 60,000-80,000 km along the trajectory of Giotto, as indicated by both theoretical computations and the ion-mass-spectrometer measurements. The formation of the cometopause located at about 140,000 km is therefore not necessarily as closely related to the charge-exchange process.

Applicability of NASA Polar Technologies to British Antarctic Survey Halley VI Research Station

NASA Technical Reports Server (NTRS)

Flynn, Michael

2005-01-01

From 1993 through 1997 NASA and the National Science Foundation (NSF), developed a variety of environmental infrastructure technologies for use at the Amundsen-Scott South Pole Station. The objective of this program was to reduce the cost of operating the South Pole Station, reduce the environmental impact of the Station, and to increase the quality of life for Station inhabitants. The result of this program was the development of a set of sustainability technologies designed specifically for Polar applications. In the intervening eight years many of the technologies developed through this program have been commercialized and tested in extreme environments and are now available for use throughout Antarctica and circumpolar north. The objective of this document is to provide information covering technologies that might also be applicable to the British Antarctic Survey s (BAS) proposed new Halley VI Research Station. All technologies described are commercially available.

Miniaturized fundus camera

NASA Astrophysics Data System (ADS)

Gliss, Christine; Parel, Jean-Marie A.; Flynn, John T.; Pratisto, Hans S.; Niederer, Peter F.

2003-07-01

We present a miniaturized version of a fundus camera. The camera is designed for the use in screening for retinopathy of prematurity (ROP). There, but also in other applications a small, light weight, digital camera system can be extremely useful. We present a small wide angle digital camera system. The handpiece is significantly smaller and lighter then in all other systems. The electronics is truly portable fitting in a standard boardcase. The camera is designed to be offered at a compatible price. Data from tests on young rabbits' eyes is presented. The development of the camera system is part of a telemedicine project screening for ROP. Telemedical applications are a perfect application for this camera system using both advantages: the portability as well as the digital image.

7. VAL CAMERA STATION, INTERIOR VIEW OF CAMERA MOUNT, COMMUNICATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. VAL CAMERA STATION, INTERIOR VIEW OF CAMERA MOUNT, COMMUNICATION EQUIPMENT AND STORAGE CABINET. - Variable Angle Launcher Complex, Camera Stations, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Sub-Camera Calibration of a Penta-Camera

NASA Astrophysics Data System (ADS)

Jacobsen, K.; Gerke, M.

2016-03-01

Penta cameras consisting of a nadir and four inclined cameras are becoming more and more popular, having the advantage of imaging also facades in built up areas from four directions. Such system cameras require a boresight calibration of the geometric relation of the cameras to each other, but also a calibration of the sub-cameras. Based on data sets of the ISPRS/EuroSDR benchmark for multi platform photogrammetry the inner orientation of the used IGI Penta DigiCAM has been analyzed. The required image coordinates of the blocks Dortmund and Zeche Zollern have been determined by Pix4Dmapper and have been independently adjusted and analyzed by program system BLUH. With 4.1 million image points in 314 images respectively 3.9 million image points in 248 images a dense matching was provided by Pix4Dmapper. With up to 19 respectively 29 images per object point the images are well connected, nevertheless the high number of images per object point are concentrated to the block centres while the inclined images outside the block centre are satisfying but not very strongly connected. This leads to very high values for the Student test (T-test) of the finally used additional parameters or in other words, additional parameters are highly significant. The estimated radial symmetric distortion of the nadir sub-camera corresponds to the laboratory calibration of IGI, but there are still radial symmetric distortions also for the inclined cameras with a size exceeding 5μm even if mentioned as negligible based on the laboratory calibration. Radial and tangential effects of the image corners are limited but still available. Remarkable angular affine systematic image errors can be seen especially in the block Zeche Zollern. Such deformations are unusual for digital matrix cameras, but it can be caused by the correlation between inner and exterior orientation if only parallel flight lines are used. With exception of the angular affinity the systematic image errors for corresponding

3. VAL CAMERA CAR, VIEW OF CAMERA CAR AND TRACK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VAL CAMERA CAR, VIEW OF CAMERA CAR AND TRACK WITH THE VAL TO THE RIGHT, LOOKING NORTHEAST. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Harpicon camera for HDTV

NASA Astrophysics Data System (ADS)

Tanada, Jun

1992-08-01

Ikegami has been involved in broadcast equipment ever since it was established as a company. In conjunction with NHK it has brought forth countless television cameras, from black-and-white cameras to color cameras, HDTV cameras, and special-purpose cameras. In the early days of HDTV (high-definition television, also known as "High Vision") cameras the specifications were different from those for the cameras of the present-day system, and cameras using all kinds of components, having different arrangements of components, and having different appearances were developed into products, with time spent on experimentation, design, fabrication, adjustment, and inspection. But recently the knowhow built up thus far in components, , printed circuit boards, and wiring methods has been incorporated in camera fabrication, making it possible to make HDTV cameras by metbods similar to the present system. In addition, more-efficient production, lower costs, and better after-sales service are being achieved by using the same circuits, components, mechanism parts, and software for both HDTV cameras and cameras that operate by the present system.

JPL Closeup

NASA Technical Reports Server (NTRS)

1983-01-01

Voyager, Infrared Astronomical Satellite, Galileo, Viking, Solar Mesosphere Explorer, Wide-field/Planetary Camera, Venus Mapper, International Solar Polar Mission - Solar Interplanetary Satellite, Extreme Ultraviolet Explores, Starprobe, International Halley Watch, Marine Mark II, Samex, Shuttle Imaging Radar-A, Deep Space Network, Biomedical Technology, Ocean Studies and Robotics are summarized.

From C/Mrkos to P/Halley: 30 years of cometary spectroscopy

NASA Technical Reports Server (NTRS)

Arpigny, C.; Dossin, F.; Woszczyk, A.; Donn, B.; Rahe, J.; Wyckoff, Susan

1991-01-01

An Atlas of Cometary Spectra was compiled, as a sequel to the well-known Atlas published by Swings and Haser in 1956. The new atlas comprises some 400 reproductions of cometary spectra secured in the world's largest observatories during the three decades or so from the passage of comet Mrkos 1957 V, for which the very first high-dispersion spectrum was obtained, to the return of Halley's comet. The illustrations refer to 40 different comet apparitions; they are grouped into a set of 186 loose 11 x 14 in. plates, while the texts, comments, and relevant data are given in a separate booklet. The main purpose of this atlas is to show in detail the tremendous progress which was achieved in cometary spectroscopy during the period covered, essentially thanks to the use of high-resolution coude spectrographs and large telescopes, the considerable extension of the observed wavelength range, and the advent of electronic detectors. It is divided into two parts. Part 1, which contains about two-thirds of the selected material, presents photographic spectra, while electronically recorded spectra covering the vacuum ultraviolet, through the optical, infrared, and radio regions appear in Part 2.

The dust distribution within the inner coma of comet P/Halley 1982i - Encounter by Giotto's impact detectors

NASA Technical Reports Server (NTRS)

Mcdonnell, J. A. M.; Evans, G. C.; Evans, S. T.; Alexander, W. M.; Burton, W. M.; Firth, J. G.; Bussoletti, E.; Grard, R. J. L.; Hanner, M. S.; Sekanina, Z.

1987-01-01

Analyses are presented of Giotto's Dust Impact Detection System experiment measurements of dust grains incident on the Giotto dust shield along its trajectory through the coma of comet P/Halley on March 13 and 14, 1986. Ground-based CCD imagery of the inner coma dust continuum at the time of the encounter are used to derive the area of grains intercepted by Giotto. Data obtained at large masses show clear evidence of a decrease in the mass distribution index at these masses within the coma; it is shown that such a value of the mass index can furnish sufficient mass for consistency with an observed deceleration.

Behavioral Characteristics and CO+CO2 Production Rates of Halley-type Comets Observed by NEOWISE

NASA Astrophysics Data System (ADS)

Rosser, J. D.; Bauer, J. M.; Mainzer, A. K.; Kramer, E.; Masiero, J. R.; Nugent, C. R.; Sonnett, S.; Fernández, Y. R.; Ruecker, K.; Krings, P.; Wright, E. L.; WISE, The; NEOWISE Teams

2018-04-01

From the entire data set of comets observed by NEOWISE, we have analyzed 11 different Halley-type Comets (HTCs) for dust production rates, CO+CO2 production rates, and nucleus sizes. Incorporating HTCs from previous studies and multiple comet visits, we have a total of 21 stacked visits, 13 of which are active and 8 for which we calculated upper limits of production. We determined the nucleus sizes of 27P, P/2006 HR30, P/2012 NJ, and C/2016 S1. Furthermore, we analyzed the relationships between dust production and heliocentric distance, and gas production and heliocentric distance. We concluded that for this population of HTCs, ranging in heliocentric distance from 1.21 to 2.66 au, there was no significant correlation between dust production and heliocentric distance, nor between gas production and heliocentric distance.

Leukocyte Populations in Human Preterm and Term Breast Milk Identified by Multicolour Flow Cytometry

PubMed Central

Trend, Stephanie; de Jong, Emma; Lloyd, Megan L.; Kok, Chooi Heen; Richmond, Peter; Doherty, Dorota A.; Simmer, Karen; Kakulas, Foteini; Strunk, Tobias; Currie, Andrew

2015-01-01

Background Extremely preterm infants are highly susceptible to bacterial infections but breast milk provides some protection. It is unknown if leukocyte numbers and subsets in milk differ between term and preterm breast milk. This study serially characterised leukocyte populations in breast milk of mothers of preterm and term infants using multicolour flow cytometry methods for extended differential leukocyte counts in blood. Methods Sixty mothers of extremely preterm (<28 weeks gestational age), very preterm (28–31 wk), and moderately preterm (32–36 wk), as well as term (37–41 wk) infants were recruited. Colostrum (d2–5), transitional (d8–12) and mature milk (d26–30) samples were collected, cells isolated, and leukocyte subsets analysed using flow cytometry. Results The major CD45+ leukocyte populations circulating in blood were also detectable in breast milk but at different frequencies. Progression of lactation was associated with decreasing CD45+ leukocyte concentration, as well as increases in the relative frequencies of neutrophils and immature granulocytes, and decreases in the relative frequencies of eosinophils, myeloid and B cell precursors, and CD16- monocytes. No differences were observed between preterm and term breast milk in leukocyte concentration, though minor differences between preterm groups in some leukocyte frequencies were observed. Conclusions Flow cytometry is a useful tool to identify and quantify leukocyte subsets in breast milk. The stage of lactation is associated with major changes in milk leukocyte composition in this population. Fresh preterm breast milk is not deficient in leukocytes, but shorter gestation may be associated with minor differences in leukocyte subset frequencies in preterm compared to term breast milk. PMID:26288195

Constrained space camera assembly

DOEpatents

Heckendorn, F.M.; Anderson, E.K.; Robinson, C.W.; Haynes, H.B.

1999-05-11

A constrained space camera assembly which is intended to be lowered through a hole into a tank, a borehole or another cavity is disclosed. The assembly includes a generally cylindrical chamber comprising a head and a body and a wiring-carrying conduit extending from the chamber. Means are included in the chamber for rotating the body about the head without breaking an airtight seal formed therebetween. The assembly may be pressurized and accompanied with a pressure sensing means for sensing if a breach has occurred in the assembly. In one embodiment, two cameras, separated from their respective lenses, are installed on a mounting apparatus disposed in the chamber. The mounting apparatus includes means allowing both longitudinal and lateral movement of the cameras. Moving the cameras longitudinally focuses the cameras, and moving the cameras laterally away from one another effectively converges the cameras so that close objects can be viewed. The assembly further includes means for moving lenses of different magnification forward of the cameras. 17 figs.

Constrained space camera assembly

DOEpatents

Heckendorn, Frank M.; Anderson, Erin K.; Robinson, Casandra W.; Haynes, Harriet B.

1999-01-01

A constrained space camera assembly which is intended to be lowered through a hole into a tank, a borehole or another cavity. The assembly includes a generally cylindrical chamber comprising a head and a body and a wiring-carrying conduit extending from the chamber. Means are included in the chamber for rotating the body about the head without breaking an airtight seal formed therebetween. The assembly may be pressurized and accompanied with a pressure sensing means for sensing if a breach has occurred in the assembly. In one embodiment, two cameras, separated from their respective lenses, are installed on a mounting apparatus disposed in the chamber. The mounting apparatus includes means allowing both longitudinal and lateral movement of the cameras. Moving the cameras longitudinally focuses the cameras, and moving the cameras laterally away from one another effectively converges the cameras so that close objects can be viewed. The assembly further includes means for moving lenses of different magnification forward of the cameras.

Shells in the C2 coma of Comet P/Halley

NASA Technical Reports Server (NTRS)

Schulz, Rita; A'Hearn, Michael F.

1995-01-01

We reanalyzed the CN images of Comet P/Halley, in which jets have been discovered for the first time, in search of shell structures. Shells were actually detected at the outer edges of the frames on those dates for which shells with radii small enough to be covered by the limited field of view of the CCD were predicted. The C2 images of the same data set were subjected to an analogous investigation which led to the discovery of shell structures in C2 as well. The morphology of the CN and the C2 shells is essentially equal on the same observational date. They have the same radii and show almost identical asymmetries which suggests that CN and C2 in the shells originate from the same general source. The comparison of the jets in both species before and after a two-dimensional continuum subtraction supports this supposition. The similar morphology of the jets indicates that both species are produced from the same bulk of precursor material which has been ejected in the form of jets from the same active area. However, similarly located and oriented jets in CN and C2 do not show similar relative intensities in most cases. These differences in the intensity distribution imply that the production rates of CN and C2 follow different laws.

Scientific rationale and strategies for a first comet mission: Report of the Comet Halley science working group

NASA Technical Reports Server (NTRS)

1977-01-01

The science objectives of a first comet mission are reviewed and related to what is known or can be expected to be learned in the near future from ground-based and near earth observations. A set of instruments and their science objectives are defined for a mission to Comet Halley during its 1985/86 apparition. The benefits from a fast flyby, a slow flyby, or a rendezvous mission and the relative impact of each on the instrument payload were assessed. The relative scientific value of encounters with the comet at distances from the sun ranging from 1 AU to 2.5 AU, including possible tradeoffs between flyby velocity and distance was considered. Pre- and post-perihelion encounters were likewise evaluated.

Bulk properties and velocity distributions of water group ions at Comet Halley - Giotto measurements

NASA Astrophysics Data System (ADS)

Coates, A. J.; Wilken, B.; Johnstone, A. D.; Jockers, K.; Glassmeier, K.-H.; Huddleston, D. E.

1990-07-01

In the region upstream of Comet Halley, pickup heavy ions of cometary origin were directly observed by the implanted ion spectrometer on Giotto. Diffusion of this population in pitch angle and in energy, during the approach to the comet and on the outbound leg is discussed. The two data sets are compared and qualitative ideas on scattering timescales are inferred. In addition the bulk parameters of these distributions have been computed and a comparison of the observed speed in the solar wind frame and the observed density with expectations is presented. Pitch angle scattering occurs more slowly than expected with filled shells appearing at 2,500,000 km, and significant energy diffusion does not occur until the bow shock region. Also the shell distributions downstream of the shock flow at the bispherical bulk speed (related to the Alfven speed) along the magnetic field with respect to the solar wind in accordance with conservation of energy between the pickup ions and the wave turbulence.

Microchannel plate streak camera

DOEpatents

Wang, Ching L.

1989-01-01

An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

Digital Pinhole Camera

ERIC Educational Resources Information Center

Lancor, Rachael; Lancor, Brian

2014-01-01

In this article we describe how the classic pinhole camera demonstration can be adapted for use with digital cameras. Students can easily explore the effects of the size of the pinhole and its distance from the sensor on exposure time, magnification, and image quality. Instructions for constructing a digital pinhole camera and our method for…

The origin of Halley-type comets: probing the inner Oort cloud

NASA Astrophysics Data System (ADS)

Levison, H.; Dones, L.; Duncan, M.

2000-10-01

We have integrated the orbits of 27,700 test particles initially entering the planetary system from the Oort cloud in order to study the origin of Halley-type comets (HTCs). We included the gravitational influence of the Sun, giant planets, passing stars, and galactic tides. We find that an isotropically distributed Oort cloud does not reproduce the observed orbital element distribution of the HTCs. In order to match the observations, the initial inclination distribution of the progenitors of the HTCs must be similar to the observed HTC inclination distribution. We can match the observations with an Oort cloud that consists of an isotropic outer cloud and a disk-like massive inner cloud. These idealized two-component models have inner disks with median inclinations that range from 10 to 50o. This analysis represents the first link between observations and the structure of the inner Oort cloud. HFL and LD gratefully acknowledges grants provided by the NASA Origins of Solar Systems and Planetary Geology and Geophysics Programs. MJD is grateful for the continuing financial support of the Natural Science and Engineering Research Council of Canada and for financial support for work done inthe U.S.from NASA Planetary Geology and Geophysics Programs.

Evidence for methane and ammonia in the coma of comet P/Halley

NASA Technical Reports Server (NTRS)

Allen, M.; Delitsky, M.; Huntress, W.; Yung, Y.; Ip, W.-H.

1987-01-01

Methane and ammonia abundances in the coma of Halley are derived from Giotto ion mass spectrometer data using an Eulerian model of chemical and physical processes inside the contact surface to simulate Giotto high-intensity spectrometer ion mass spectral data for mass-to-charge ratios (m/q) from 15 to 19. The ratio m/q = 19/18 as a function of distance from the nucleus is not reproduced by a model for a pure water coma. It is necessary to include the presence of NH3, and uniquely NH3, in coma gases in order to explain the data. A ratio of production rates Q(NH3)/Q(H2O) = 0.01 = 0.02 results in model values approximating the Giotto data. Methane is identified as the most probable source of the distinct peak at m/q = 15. The observations are fit best with Q(CH4)/Q(Q2O) = 0.02. The chemical composition of the comet nucleus implied by these production rate ratios is unlike that of the outer planets. On the other hand, there are also significant differences from observations of gas phase interstellar material.

Relationship between wave energy and free energy from pickup ions in the Comet Halley environment

NASA Technical Reports Server (NTRS)

Huddleston, D. E.; Johnstone, A. D.

1992-01-01

The free energy available from the implanted heavy ion population at Comet Halley is calculated by assuming that the initial unstable velocity space ring distribution of the ions evolves toward a bispherical shell. Ultimately this free energy adds to the turbulence in the solar wind. Upstream and downstream free energies are obtained separately for the conditions observed along the Giotto spacecraft trajectory. The results indicate that the waves are mostly upstream propagating in the solar wind frame. The total free energy density always exceeds the measured wave energy density because, as expected in the nonlinear process of ion scattering, the available energy is not all immediately released. An estimate of the amount which has been released can be obtained from the measured oxygen ion distributions and again it exceeds that observed. The theoretical analysis is extended to calculate the k spectrum of the cometary-ion-generated turbulence.

Analysis of suprathermal electron properties at the magnetic pile-up boundary of Comet P/Halley

NASA Technical Reports Server (NTRS)

Mazelle, C.; Reme, H.; Sauvaud, J. A.; D'Uston, C.; Carlson, C. W.

1989-01-01

Among the plasma discontinuities detected by the Giotto spacecraft around Comet P/Halley, the magnetic pile-up boundary, located at about 135,000 km from the nucleus, has a sharpness which was not foreseen by theoretical models. At this boundary, which marks the beginning of the region where the field lines draped around the nucleus have been piled up, the magnetic field jumps sharply. Electron measurements provided by the RPA experiment show that a clear plasma discontinuity coincides with this magnetic feature. Significant changes occur here in the suprathermal electron distribution function. A magneto-plasma sheet is clearly defined after the boundary. Inside this sheet, close correlations exist between the parameters describing the magnetic field and the electron population. The polytropic equation of state governing the suprathermal electrons in the sheet has been deduced from RPA measurements. Some implications of this law are discussed.

Three-dimensional structure of the heliosphere as inferred from observations with a Japanese Halley spacecraft

NASA Technical Reports Server (NTRS)

Saito, T.; Yumoto, K.; Hirao, K.; Aoyama, I.; Smith, E. J.

1986-01-01

A sinusoidal neutral line with a pair of giant regions appeared on the sun about one year before the launch of 'Sakigake', the first of two Japanese Comet Halley spacecraft. The Sakigake magnetometer data during the early part of the mission (February-March 1985) are well interpreted by an eastward shift of the tilting neutral sheet. The shift is further explained by an effect of a new giant region appearing at about 10 deg heliolatitude and about 50 deg Carrington longitude in August 1984. The toward polarity ratio of IMF observed by Sakigake changed from about 22 percent in February to about 62 percent in early June and then increased rapidly up to 98 percent. This ratio is interpreted as a decrease of the tilt angle of the sheet down to only about 4 deg. It is the first spacecraft observation of 'the disappearing sector structure' with such small tilt angle.

GRACE star camera noise

NASA Astrophysics Data System (ADS)

Harvey, Nate

2016-08-01

Extending results from previous work by Bandikova et al. (2012) and Inacio et al. (2015), this paper analyzes Gravity Recovery and Climate Experiment (GRACE) star camera attitude measurement noise by processing inter-camera quaternions from 2003 to 2015. We describe a correction to star camera data, which will eliminate a several-arcsec twice-per-rev error with daily modulation, currently visible in the auto-covariance function of the inter-camera quaternion, from future GRACE Level-1B product releases. We also present evidence supporting the argument that thermal conditions/settings affect long-term inter-camera attitude biases by at least tens-of-arcsecs, and that several-to-tens-of-arcsecs per-rev star camera errors depend largely on field-of-view.

``A Penny Plain and Twopence Coloured,''- How the Penny Theater format was used to animate and present Mary Chapin Carpenter's book, ``Halley Came to Jackson'' to preschoolers and their families as a STEM outreach program

NASA Astrophysics Data System (ADS)

Jablonski, Elizabeth Jan; Jablonski, Daniel; Jablonski, Matthew; Jablonski, Peter; Green, Maureen; Green, Charles; Wyble, Megan; Ardillo, Margaret

2014-03-01

The goal of this project is to develop a program for young children (3 to 8 years old) that provides basic information about concepts related to space, comets, time, and timelessness in a stimulating, memorable manner. The vehicle for achieving this goal is an adaptation of the children's picture book Halley Came to Jackson to a modern update of the historical Penny Theater format. The resulting ``show'' is rich in the concepts listed above, and has been presented in a variety of venues and with a variety of supplementary activities to several hundred preschoolers and their families. Based on a combination of prior research on how young children learn and careful observation and follow-up to performances of ``Halley,'' numerous findings have been developed. The Penny Theater concept and the findings of this project are discussed herein. Recipient, APS 2012 Outreach mini-grant.

Ringfield lithographic camera

DOEpatents

Sweatt, William C.

1998-01-01

A projection lithography camera is presented with a wide ringfield optimized so as to make efficient use of extreme ultraviolet radiation from a large area radiation source (e.g., D.sub.source .apprxeq.0.5 mm). The camera comprises four aspheric mirrors optically arranged on a common axis of symmetry with an increased etendue for the camera system. The camera includes an aperture stop that is accessible through a plurality of partial aperture stops to synthesize the theoretical aperture stop. Radiation from a mask is focused to form a reduced image on a wafer, relative to the mask, by reflection from the four aspheric mirrors.

Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

NASA Astrophysics Data System (ADS)

Chan, Hoi Ga; Frey, Markus M.; King, Martin D.

2018-02-01

Emissions of nitrogen oxide (NOx = NO + NO2) from the photolysis of nitrate (NO3-) in snow affect the oxidising capacity of the lower troposphere especially in remote regions of high latitudes with little pollution. Current air-snow exchange models are limited by poor understanding of processes and often require unphysical tuning parameters. Here, two multiphase models were developed from physically based parameterisations to describe the interaction of nitrate between the surface layer of the snowpack and the overlying atmosphere. The first model is similar to previous approaches and assumes that below a threshold temperature, To, the air-snow grain interface is pure ice and above To a disordered interface (DI) emerges covering the entire grain surface. The second model assumes that air-ice interactions dominate over all temperatures below melting of ice and that any liquid present above the eutectic temperature is concentrated in micropockets. The models are used to predict the nitrate in surface snow constrained by year-round observations of mixing ratios of nitric acid in air at a cold site on the Antarctic Plateau (Dome C; 75°06' S, 123°33' E; 3233 m a.s.l.) and at a relatively warm site on the Antarctic coast (Halley; 75°35' S, 26°39' E; 35 m a.s.l). The first model agrees reasonably well with observations at Dome C (Cv(RMSE) = 1.34) but performs poorly at Halley (Cv(RMSE) = 89.28) while the second model reproduces with good agreement observations at both sites (Cv(RMSE) = 0.84 at both sites). It is therefore suggested that in winter air-snow interactions of nitrate are determined by non-equilibrium surface adsorption and co-condensation on ice coupled with solid-state diffusion inside the grain, similar to Bock et al. (2016). In summer, however, the air-snow exchange of nitrate is mainly driven by solvation into liquid micropockets following Henry's law with contributions to total surface snow NO3- concentrations of 75 and 80 % at Dome C and Halley

CAOS-CMOS camera.

PubMed

Riza, Nabeel A; La Torre, Juan Pablo; Amin, M Junaid

2016-06-13

Proposed and experimentally demonstrated is the CAOS-CMOS camera design that combines the coded access optical sensor (CAOS) imager platform with the CMOS multi-pixel optical sensor. The unique CAOS-CMOS camera engages the classic CMOS sensor light staring mode with the time-frequency-space agile pixel CAOS imager mode within one programmable optical unit to realize a high dynamic range imager for extreme light contrast conditions. The experimentally demonstrated CAOS-CMOS camera is built using a digital micromirror device, a silicon point-photo-detector with a variable gain amplifier, and a silicon CMOS sensor with a maximum rated 51.3 dB dynamic range. White light imaging of three different brightness simultaneously viewed targets, that is not possible by the CMOS sensor, is achieved by the CAOS-CMOS camera demonstrating an 82.06 dB dynamic range. Applications for the camera include industrial machine vision, welding, laser analysis, automotive, night vision, surveillance and multispectral military systems.

Effects of camera location on the reconstruction of 3D flare trajectory with two cameras

NASA Astrophysics Data System (ADS)

Özsaraç, Seçkin; Yeşilkaya, Muhammed

2015-05-01

Flares are used as valuable electronic warfare assets for the battle against infrared guided missiles. The trajectory of the flare is one of the most important factors that determine the effectiveness of the counter measure. Reconstruction of the three dimensional (3D) position of a point, which is seen by multiple cameras, is a common problem. Camera placement, camera calibration, corresponding pixel determination in between the images of different cameras and also the triangulation algorithm affect the performance of 3D position estimation. In this paper, we specifically investigate the effects of camera placement on the flare trajectory estimation performance by simulations. Firstly, 3D trajectory of a flare and also the aircraft, which dispenses the flare, are generated with simple motion models. Then, we place two virtual ideal pinhole camera models on different locations. Assuming the cameras are tracking the aircraft perfectly, the view vectors of the cameras are computed. Afterwards, using the view vector of each camera and also the 3D position of the flare, image plane coordinates of the flare on both cameras are computed using the field of view (FOV) values. To increase the fidelity of the simulation, we have used two sources of error. One is used to model the uncertainties in the determination of the camera view vectors, i.e. the orientations of the cameras are measured noisy. Second noise source is used to model the imperfections of the corresponding pixel determination of the flare in between the two cameras. Finally, 3D position of the flare is estimated using the corresponding pixel indices, view vector and also the FOV of the cameras by triangulation. All the processes mentioned so far are repeated for different relative camera placements so that the optimum estimation error performance is found for the given aircraft and are trajectories.

Comet Halley in 1910, as viewed from a Maltese perspective

NASA Astrophysics Data System (ADS)

Galea, Adrian

2009-07-01

Comet Halley's return in 1910 was keenly anticipated globally by scientists and the lay public alike. Although cometary science had progressed rapidly during the last quarter of the nineteenth century, superstition remained significant in different parts of the world and there were fears that people would die if the prediction that the Earth would pass through the comet's tail were correct. Malta was a small British island colony in the Mediterranean, and the inhabitants there were no exception. Local newspapers reported concerns from their readers and from foreign sources, but they also included reassuring scientific information about comets. Under the patronage of the colonial government a local amateur astronomer named Francis Reynolds reassured the public through lectures that he delivered. Overall the local population appeared to have been calm about the impending return. The first recorded sighting from Malta was on 24 April 1910 and the first naked eye sighting occurred the following day. Accounts were published in the local newspapers and in private correspondence, suggesting a high level of public interest in this object. No photographs of the comet from Malta have been traced, but the aforementioned Mr Reynolds and a well-known Maltese artist, G. Cali, did make a number of paintings. On the night when the Earth was due to pass through the comet's tail many local people congregated around the bastions of the city under an overcast sky in the early hours of the morning, but no untoward events were experienced.

Advantages of computer cameras over video cameras/frame grabbers for high-speed vision applications

NASA Astrophysics Data System (ADS)

Olson, Gaylord G.; Walker, Jo N.

1997-09-01

Cameras designed to work specifically with computers can have certain advantages in comparison to the use of cameras loosely defined as 'video' cameras. In recent years the camera type distinctions have become somewhat blurred, with a great presence of 'digital cameras' aimed more at the home markets. This latter category is not considered here. The term 'computer camera' herein is intended to mean one which has low level computer (and software) control of the CCD clocking. These can often be used to satisfy some of the more demanding machine vision tasks, and in some cases with a higher rate of measurements than video cameras. Several of these specific applications are described here, including some which use recently designed CCDs which offer good combinations of parameters such as noise, speed, and resolution. Among the considerations for the choice of camera type in any given application would be such effects as 'pixel jitter,' and 'anti-aliasing.' Some of these effects may only be relevant if there is a mismatch between the number of pixels per line in the camera CCD and the number of analog to digital (A/D) sampling points along a video scan line. For the computer camera case these numbers are guaranteed to match, which alleviates some measurement inaccuracies and leads to higher effective resolution.

Nonholonomic camera-space manipulation using cameras mounted on a mobile base

NASA Astrophysics Data System (ADS)

Goodwine, Bill; Seelinger, Michael J.; Skaar, Steven B.; Ma, Qun

1998-10-01

The body of work called `Camera Space Manipulation' is an effective and proven method of robotic control. Essentially, this technique identifies and refines the input-output relationship of the plant using estimation methods and drives the plant open-loop to its target state. 3D `success' of the desired motion, i.e., the end effector of the manipulator engages a target at a particular location with a particular orientation, is guaranteed when there is camera space success in two cameras which are adequately separated. Very accurate, sub-pixel positioning of a robotic end effector is possible using this method. To date, however, most efforts in this area have primarily considered holonomic systems. This work addresses the problem of nonholonomic camera space manipulation by considering the problem of a nonholonomic robot with two cameras and a holonomic manipulator on board the nonholonomic platform. While perhaps not as common in robotics, such a combination of holonomic and nonholonomic degrees of freedom are ubiquitous in industry: fork lifts and earth moving equipment are common examples of a nonholonomic system with an on-board holonomic actuator. The nonholonomic nature of the system makes the automation problem more difficult due to a variety of reasons; in particular, the target location is not fixed in the image planes, as it is for holonomic systems (since the cameras are attached to a moving platform), and there is a fundamental `path dependent' nature of nonholonomic kinematics. This work focuses on the sensor space or camera-space-based control laws necessary for effectively implementing an autonomous system of this type.

Multicolour versus monocolour inking specimens after pancreaticoduodenectomy for periampullary cancer: A single centre prospective randomised clinical trial.

PubMed

Casadei, Riccardo; Ricci, Claudio; Taffurelli, Giovanni; Pacilio, Carlo Alberto; Santini, Donatella; Di Marco, Mariacristina; Minni, Francesco

2018-03-01

R status represents an important prognostic factors in periampullary cancers. Thus, it is useful to verify if it can be influenced by different techniques of margination. Single-centre, randomised clinical trial of patients affected by periampullary cancer who underwent pancreaticoduodenectomies which included two different types of margination: arm A (multicolour inking) and arm B (monocolour inking). The primary endpoint was the overall R1 resection rate and its difference between the two arms. The secondary endpoints were the R1 resection rate in each margin and its difference between the two arms, and the impact of margin status on survival. Fifty patients were randomised, 41 analysed: 22 in arm A, 19 arm B. The overall R1 status was 61%, without significant differences between the two arms. The margin most commonly involved was the superior mesenteric artery (SMA) (36.6%). A trend in favour of arm B was shown for the superior mesenteric artery margin (arm A = 22.7% versus arm B = 52.6%; P = 0.060). The anterior surface (P = 0.015), SMA (P = 0.047) and pancreatic remnant (P = 0.018) margins significantly influenced disease-free survival. The R status was not influenced by different techniques of margination using a standardised pathological protocol. The SMA margin seemed to be the most important margin for evaluating both R status and disease-free survival. Copyright © 2018. Published by Elsevier Ltd.

Image Sensors Enhance Camera Technologies

NASA Technical Reports Server (NTRS)

2010-01-01

In the 1990s, a Jet Propulsion Laboratory team led by Eric Fossum researched ways of improving complementary metal-oxide semiconductor (CMOS) image sensors in order to miniaturize cameras on spacecraft while maintaining scientific image quality. Fossum s team founded a company to commercialize the resulting CMOS active pixel sensor. Now called the Aptina Imaging Corporation, based in San Jose, California, the company has shipped over 1 billion sensors for use in applications such as digital cameras, camera phones, Web cameras, and automotive cameras. Today, one of every three cell phone cameras on the planet feature Aptina s sensor technology.

An attentive multi-camera system

NASA Astrophysics Data System (ADS)

Napoletano, Paolo; Tisato, Francesco

2014-03-01

Intelligent multi-camera systems that integrate computer vision algorithms are not error free, and thus both false positive and negative detections need to be revised by a specialized human operator. Traditional multi-camera systems usually include a control center with a wall of monitors displaying videos from each camera of the network. Nevertheless, as the number of cameras increases, switching from a camera to another becomes hard for a human operator. In this work we propose a new method that dynamically selects and displays the content of a video camera from all the available contents in the multi-camera system. The proposed method is based on a computational model of human visual attention that integrates top-down and bottom-up cues. We believe that this is the first work that tries to use a model of human visual attention for the dynamic selection of the camera view of a multi-camera system. The proposed method has been experimented in a given scenario and has demonstrated its effectiveness with respect to the other methods and manually generated ground-truth. The effectiveness has been evaluated in terms of number of correct best-views generated by the method with respect to the camera views manually generated by a human operator.

Giotto magnetic field observations at the outbound quasi-parallel bow shock of Comet Halley

NASA Technical Reports Server (NTRS)

Neubauer, F. M.; Glassmeier, K. H.; Acuna, M. H.; Mariani, F.; Musmann, G.

1990-01-01

The investigation of the outbound bow shock of Comet Halley using Giotto magnetometer data leads to the following results: the shock is characterized by strong magnetic turbulence associated with an increasing background magnetic field and a change in direction by 60 deg as one goes inward. In HSE-coordinates, the observed normal turned out to be (0.544, - 0.801, 0.249). The thickness of the quasi-parallel shock was 120,000 km. The shock is shown to be a new type of shock transition called a 'draping shock'. In a draping shock with high beta in the transonic transition region, the transonic region is characterized by strong directional variations of the magnetic field. The magnetic turbulence ahead of the shock is characterized by k-vectors parallel or antiparallel to the average field (and, therefore, also to the normal of the quasi-parallel shock) and almost isotropic magnetic turbulence in the shock transition region. A model of the draping shock is proposed which also includes a hypothetical subshock in which the supersonic-subsonic transition is accomplished.

Modeling the Physical Multi-Phase Interactions of HNO3 Between Snow and Air on the Antarctic Plateau (Dome C) and coast (Halley)

NASA Astrophysics Data System (ADS)

Chan, Hoi Ga; Frey, Markus M.; King, Martin D.

2017-04-01

Nitrogen oxides (NOx = NO + NO2) emissions from nitrate (NO3-) photolysis in snow affect the oxidising capacity of the lower troposphere especially in remote regions of the high latitudes with low pollution levels. The porous structure of snowpack allows the exchange of gases with the atmosphere driven by physicochemical processes, and hence, snow can act as both source and sink of atmospheric chemical trace gases. Current models are limited by poor process understanding and often require tuning parameters. Here, two multi-phase physical models were developed from first principles constrained by observed atmospheric nitrate, HNO3, to describe the air-snow interaction of nitrate. Similar to most of the previous approaches, the first model assumes that below a threshold temperature, To, the air-snow grain interface is pure ice and above To, a disordered interface (DI) emerges assumed to be covering the entire grain surface. The second model assumes that Air-Ice interactions dominate over the entire temperature range below melting and that only above the eutectic temperature, liquid is present in the form of micropockets in grooves. The models are validated with available year-round observations of nitrate in snow and air at a cold site on the Antarctica Plateau (Dome C, 75°06'S, 123°33'E, 3233 m a.s.l.) and at a relatively warm site on the Antarctica coast (Halley, 75°35'S, 26°39'E, 35 m a.s.l). The first model agrees reasonably well with observations at Dome C (Cv(RMSE) = 1.34), but performs poorly at Halley (Cv(RMSE) = 89.28) while the second model reproduces with good agreement observations at both sites without any tuning (Cv(RMSE) = 0.84 at both sites). It is therefore suggested that air-snow interactions of nitrate in the winter are determined by non-equilibrium surface adsorption and co-condensation on ice coupled with solid-state diffusion inside the grain. In summer, however, the air-snow exchange of nitrate is mainly driven by solvation into liquid

Making Ceramic Cameras

ERIC Educational Resources Information Center

Squibb, Matt

2009-01-01

This article describes how to make a clay camera. This idea of creating functional cameras from clay allows students to experience ceramics, photography, and painting all in one unit. (Contains 1 resource and 3 online resources.)

Mars Science Laboratory Engineering Cameras

NASA Technical Reports Server (NTRS)

Maki, Justin N.; Thiessen, David L.; Pourangi, Ali M.; Kobzeff, Peter A.; Lee, Steven W.; Dingizian, Arsham; Schwochert, Mark A.

2012-01-01

NASA's Mars Science Laboratory (MSL) Rover, which launched to Mars in 2011, is equipped with a set of 12 engineering cameras. These cameras are build-to-print copies of the Mars Exploration Rover (MER) cameras, which were sent to Mars in 2003. The engineering cameras weigh less than 300 grams each and use less than 3 W of power. Images returned from the engineering cameras are used to navigate the rover on the Martian surface, deploy the rover robotic arm, and ingest samples into the rover sample processing system. The navigation cameras (Navcams) are mounted to a pan/tilt mast and have a 45-degree square field of view (FOV) with a pixel scale of 0.82 mrad/pixel. The hazard avoidance cameras (Haz - cams) are body-mounted to the rover chassis in the front and rear of the vehicle and have a 124-degree square FOV with a pixel scale of 2.1 mrad/pixel. All of the cameras utilize a frame-transfer CCD (charge-coupled device) with a 1024x1024 imaging region and red/near IR bandpass filters centered at 650 nm. The MSL engineering cameras are grouped into two sets of six: one set of cameras is connected to rover computer A and the other set is connected to rover computer B. The MSL rover carries 8 Hazcams and 4 Navcams.

Night Vision Camera

NASA Technical Reports Server (NTRS)

1996-01-01

PixelVision, Inc. developed the Night Video NV652 Back-illuminated CCD Camera, based on the expertise of a former Jet Propulsion Laboratory employee and a former employee of Scientific Imaging Technologies, Inc. The camera operates without an image intensifier, using back-illuminated and thinned CCD technology to achieve extremely low light level imaging performance. The advantages of PixelVision's system over conventional cameras include greater resolution and better target identification under low light conditions, lower cost and a longer lifetime. It is used commercially for research and aviation.

Discovery of a Previously Unrecognised Allusion to the Aurora Borealis in Paradise Lost, and Implications for Edmund Halley Scholarship

NASA Astrophysics Data System (ADS)

Cunningham, Clifford J.

2014-11-01

This research reveals that John Milton employed an allusion to the aurora borealis in the epic poem Paradise Lost which has not been recognised in more than three centuries of scholarly analysis. It further disproves the long-held belief, made popular by the astronomer Edmund Halley, that no notable aurora was visible in England in the seventeenth century. A study of the personal Latin diary of the Elizabethan historian William Camden shows that the famous aurora of 1621 was visible in England. While Pierre Gassendi has been credited with creation of the term 'aurora borealis' based on his report of the 1621 aurora, this study reaffirms a neglected analysis from 1986 that established the term originated with Galileo in 1619.

SPARTAN Near-IR Camera | SOAR

Science.gov Websites

SPARTAN Near-IR Camera SPARTAN Cookbook Ohio State Infrared Imager/Spectrograph (OSIRIS) - NO LONGER Instrumentation at SOAR»SPARTAN Near-IR Camera SPARTAN Near-IR Camera System Overview The Spartan Infrared Camera is a high spatial resolution near-IR imager. Spartan has a focal plane conisisting of four "

Evaluation of multispectral plenoptic camera

NASA Astrophysics Data System (ADS)

Meng, Lingfei; Sun, Ting; Kosoglow, Rich; Berkner, Kathrin

2013-01-01

Plenoptic cameras enable capture of a 4D lightfield, allowing digital refocusing and depth estimation from data captured with a compact portable camera. Whereas most of the work on plenoptic camera design has been based a simplistic geometric-optics-based characterization of the optical path only, little work has been done of optimizing end-to-end system performance for a specific application. Such design optimization requires design tools that need to include careful parameterization of main lens elements, as well as microlens array and sensor characteristics. In this paper we are interested in evaluating the performance of a multispectral plenoptic camera, i.e. a camera with spectral filters inserted into the aperture plane of the main lens. Such a camera enables single-snapshot spectral data acquisition.1-3 We first describe in detail an end-to-end imaging system model for a spectrally coded plenoptic camera that we briefly introduced in.4 Different performance metrics are defined to evaluate the spectral reconstruction quality. We then present a prototype which is developed based on a modified DSLR camera containing a lenslet array on the sensor and a filter array in the main lens. Finally we evaluate the spectral reconstruction performance of a spectral plenoptic camera based on both simulation and measurements obtained from the prototype.

VUV testing of science cameras at MSFC: QE measurement of the CLASP flight cameras

NASA Astrophysics Data System (ADS)

Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, B.; Beabout, D.; Stewart, M.

2015-08-01

The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras were built and tested for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint MSFC, National Astronomical Observatory of Japan (NAOJ), Instituto de Astrofisica de Canarias (IAC) and Institut D'Astrophysique Spatiale (IAS) sounding rocket mission. The CLASP camera design includes a frame-transfer e2v CCD57-10 512 × 512 detector, dual channel analog readout and an internally mounted cold block. At the flight CCD temperature of -20C, the CLASP cameras exceeded the low-noise performance requirements (<= 25 e- read noise and <= 10 e- /sec/pixel dark current), in addition to maintaining a stable gain of ≍ 2.0 e-/DN. The e2v CCD57-10 detectors were coated with Lumogen-E to improve quantum efficiency (QE) at the Lyman- wavelength. A vacuum ultra-violet (VUV) monochromator and a NIST calibrated photodiode were employed to measure the QE of each camera. Three flight cameras and one engineering camera were tested in a high-vacuum chamber, which was configured to operate several tests intended to verify the QE, gain, read noise and dark current of the CCD. We present and discuss the QE measurements performed on the CLASP cameras. We also discuss the high-vacuum system outfitted for testing of UV, EUV and X-ray science cameras at MSFC.

Easily Accessible Camera Mount

NASA Technical Reports Server (NTRS)

Chalson, H. E.

1986-01-01

Modified mount enables fast alinement of movie cameras in explosionproof housings. Screw on side and readily reached through side door of housing. Mount includes right-angle drive mechanism containing two miter gears that turn threaded shaft. Shaft drives movable dovetail clamping jaw that engages fixed dovetail plate on camera. Mechanism alines camera in housing and secures it. Reduces installation time by 80 percent.

Electronic still camera

NASA Astrophysics Data System (ADS)

Holland, S. Douglas

1992-09-01

A handheld, programmable, digital camera is disclosed that supports a variety of sensors and has program control over the system components to provide versatility. The camera uses a high performance design which produces near film quality images from an electronic system. The optical system of the camera incorporates a conventional camera body that was slightly modified, thus permitting the use of conventional camera accessories, such as telephoto lenses, wide-angle lenses, auto-focusing circuitry, auto-exposure circuitry, flash units, and the like. An image sensor, such as a charge coupled device ('CCD') collects the photons that pass through the camera aperture when the shutter is opened, and produces an analog electrical signal indicative of the image. The analog image signal is read out of the CCD and is processed by preamplifier circuitry, a correlated double sampler, and a sample and hold circuit before it is converted to a digital signal. The analog-to-digital converter has an accuracy of eight bits to insure accuracy during the conversion. Two types of data ports are included for two different data transfer needs. One data port comprises a general purpose industrial standard port and the other a high speed/high performance application specific port. The system uses removable hard disks as its permanent storage media. The hard disk receives the digital image signal from the memory buffer and correlates the image signal with other sensed parameters, such as longitudinal or other information. When the storage capacity of the hard disk has been filled, the disk can be replaced with a new disk.

Electronic Still Camera

NASA Technical Reports Server (NTRS)

Holland, S. Douglas (Inventor)

1992-01-01

A handheld, programmable, digital camera is disclosed that supports a variety of sensors and has program control over the system components to provide versatility. The camera uses a high performance design which produces near film quality images from an electronic system. The optical system of the camera incorporates a conventional camera body that was slightly modified, thus permitting the use of conventional camera accessories, such as telephoto lenses, wide-angle lenses, auto-focusing circuitry, auto-exposure circuitry, flash units, and the like. An image sensor, such as a charge coupled device ('CCD') collects the photons that pass through the camera aperture when the shutter is opened, and produces an analog electrical signal indicative of the image. The analog image signal is read out of the CCD and is processed by preamplifier circuitry, a correlated double sampler, and a sample and hold circuit before it is converted to a digital signal. The analog-to-digital converter has an accuracy of eight bits to insure accuracy during the conversion. Two types of data ports are included for two different data transfer needs. One data port comprises a general purpose industrial standard port and the other a high speed/high performance application specific port. The system uses removable hard disks as its permanent storage media. The hard disk receives the digital image signal from the memory buffer and correlates the image signal with other sensed parameters, such as longitudinal or other information. When the storage capacity of the hard disk has been filled, the disk can be replaced with a new disk.

Mars Exploration Rover engineering cameras

USGS Publications Warehouse

Maki, J.N.; Bell, J.F.; Herkenhoff, K. E.; Squyres, S. W.; Kiely, A.; Klimesh, M.; Schwochert, M.; Litwin, T.; Willson, R.; Johnson, Aaron H.; Maimone, M.; Baumgartner, E.; Collins, A.; Wadsworth, M.; Elliot, S.T.; Dingizian, A.; Brown, D.; Hagerott, E.C.; Scherr, L.; Deen, R.; Alexander, D.; Lorre, J.

2003-01-01

NASA's Mars Exploration Rover (MER) Mission will place a total of 20 cameras (10 per rover) onto the surface of Mars in early 2004. Fourteen of the 20 cameras are designated as engineering cameras and will support the operation of the vehicles on the Martian surface. Images returned from the engineering cameras will also be of significant importance to the scientific community for investigative studies of rock and soil morphology. The Navigation cameras (Navcams, two per rover) are a mast-mounted stereo pair each with a 45?? square field of view (FOV) and an angular resolution of 0.82 milliradians per pixel (mrad/pixel). The Hazard Avoidance cameras (Hazcams, four per rover) are a body-mounted, front- and rear-facing set of stereo pairs, each with a 124?? square FOV and an angular resolution of 2.1 mrad/pixel. The Descent camera (one per rover), mounted to the lander, has a 45?? square FOV and will return images with spatial resolutions of ???4 m/pixel. All of the engineering cameras utilize broadband visible filters and 1024 x 1024 pixel detectors. Copyright 2003 by the American Geophysical Union.

Pathfinder operations

NASA Technical Reports Server (NTRS)

Wilcher, J.; Stelzried, C.; Finley, S.

1986-01-01

In 1981, the Inter-Agency Consultative Group (composed of European, Soviet, Japanese and American space agency representatives) conceived the idea of using the two Soviet Vega spacecraft as pathfinders for Giotto since they would arrive at Halley's Comet approximately one week before Giotto. The Vega trajectory data and the Halley camera angle data were combined to improve the comet orbit accuracy. This was used to improve the Giotto fly-by targeting. The DSN performed delta DOR (VLBI) and one-way Doppler measurements of the Vega spacecraft for orbit determination. Although the early part-up phase had many problems, the results during the critical November 30, 1985 to March 4, 1986 operational phase had an overall 95 percent success rate, with 59 successes out of 62 two-station passes.

Mixel camera--a new push-broom camera concept for high spatial resolution keystone-free hyperspectral imaging.

PubMed

Høye, Gudrun; Fridman, Andrei

2013-05-06

Current high-resolution push-broom hyperspectral cameras introduce keystone errors to the captured data. Efforts to correct these errors in hardware severely limit the optical design, in particular with respect to light throughput and spatial resolution, while at the same time the residual keystone often remains large. The mixel camera solves this problem by combining a hardware component--an array of light mixing chambers--with a mathematical method that restores the hyperspectral data to its keystone-free form, based on the data that was recorded onto the sensor with large keystone. A Virtual Camera software, that was developed specifically for this purpose, was used to compare the performance of the mixel camera to traditional cameras that correct keystone in hardware. The mixel camera can collect at least four times more light than most current high-resolution hyperspectral cameras, and simulations have shown that the mixel camera will be photon-noise limited--even in bright light--with a significantly improved signal-to-noise ratio compared to traditional cameras. A prototype has been built and is being tested.

Advanced High-Definition Video Cameras

NASA Technical Reports Server (NTRS)

Glenn, William

2007-01-01

A product line of high-definition color video cameras, now under development, offers a superior combination of desirable characteristics, including high frame rates, high resolutions, low power consumption, and compactness. Several of the cameras feature a 3,840 2,160-pixel format with progressive scanning at 30 frames per second. The power consumption of one of these cameras is about 25 W. The size of the camera, excluding the lens assembly, is 2 by 5 by 7 in. (about 5.1 by 12.7 by 17.8 cm). The aforementioned desirable characteristics are attained at relatively low cost, largely by utilizing digital processing in advanced field-programmable gate arrays (FPGAs) to perform all of the many functions (for example, color balance and contrast adjustments) of a professional color video camera. The processing is programmed in VHDL so that application-specific integrated circuits (ASICs) can be fabricated directly from the program. ["VHDL" signifies VHSIC Hardware Description Language C, a computing language used by the United States Department of Defense for describing, designing, and simulating very-high-speed integrated circuits (VHSICs).] The image-sensor and FPGA clock frequencies in these cameras have generally been much higher than those used in video cameras designed and manufactured elsewhere. Frequently, the outputs of these cameras are converted to other video-camera formats by use of pre- and post-filters.

Ringfield lithographic camera

DOEpatents

Sweatt, W.C.

1998-09-08

A projection lithography camera is presented with a wide ringfield optimized so as to make efficient use of extreme ultraviolet radiation from a large area radiation source (e.g., D{sub source} {approx_equal} 0.5 mm). The camera comprises four aspheric mirrors optically arranged on a common axis of symmetry. The camera includes an aperture stop that is accessible through a plurality of partial aperture stops to synthesize the theoretical aperture stop. Radiation from a mask is focused to form a reduced image on a wafer, relative to the mask, by reflection from the four aspheric mirrors. 11 figs.

Analysis of hydrogen Lyman-alpha observations of the coma of Comet P/Halley near the perihelion

NASA Technical Reports Server (NTRS)

Smyth, William H.; Marconi, M. L.; Combi, Michael R.

1995-01-01

The pioneer Venus Orbiter Ultraviolet Spectrometer measurements of the Lyman-alpha intensity of atomic hydrogen excited by solar resonance scattering in the coma of Comet P/Halley acquired from December 28, 1985, to January 6, 1986, and from January 31, 1986, to March 6, 1986, are simulated with the Monte Carlo Particle Trajectory Model corrected for optical depth effects. Spatially detailed comparisons between data and model show excellent agreement and are used to infer that the highest cometary activity may not be at perihelion, but about 2 1/2 weeks before. An improved set of H2O production rates is presented for the period of time that the spectrometer was observing and is found to be consistent with the rates from other types of measurements. The apparent discrepancy between Stewart (1987) in early March and International Ultraviolet Explorer OH derived rates is resolved. The problem with the conversion of 18-cm OH radio brightness to H2O production rates is also discussed.

LSST Camera Optics Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riot, V J; Olivier, S; Bauman, B

2012-05-24

The Large Synoptic Survey Telescope (LSST) uses a novel, three-mirror, telescope design feeding a camera system that includes a set of broad-band filters and three refractive corrector lenses to produce a flat field at the focal plane with a wide field of view. Optical design of the camera lenses and filters is integrated in with the optical design of telescope mirrors to optimize performance. We discuss the rationale for the LSST camera optics design, describe the methodology for fabricating, coating, mounting and testing the lenses and filters, and present the results of detailed analyses demonstrating that the camera optics willmore » meet their performance goals.« less

Baffling system for the Wide Angle Camera (WAC) of ROSETTA mission

NASA Astrophysics Data System (ADS)

Brunello, Pierfrancesco; Peron, Fabio; Barbieri, Cesare; Fornasier, Sonia

2000-10-01

After the experience of GIOTTO fly-by to comet Halley in 1986, the European Space Agency planned to improve the scientific knowledge of these astronomical objects by means of an even more ambitious rendezvous mission with another comet (P/Wirtanen). This mission, named ROSETTA, will go on from 2003 to 2013, ending after the comet perihelion phase and including also the fly-by with two asteroids of the main belt (140 Siwa and 4979 Otawara). Scientific priority of the mission is the in situ investigation of the cometary nucleus, with the aim of better understanding the formation and the composition of planetesimals and their evolution over the last 4.5 billions of years. In this context, the Authors were involved in the design of the baffling for the Wide Angle Camera (WAC) of the imaging system (OSIRIS) carried on board of the spacecraft. Scientific requirements for the WAC are : a large field of view (FOV) of 12 degree(s) x 12 degree(s) with a resolution of 100 (mu) rad per pixel, UV response, and a contrast ratio of 10-4 in order to detect gaseous and dusty features close to the nucleus of the comet. TO achieve these performances, a fairly novel class of optical solutions employing off-axis sections of concentric mirrors was explored. Regarding baffling, the peculiar demand was the rejection of stray-light generated by the optics for sources within the FOV, since the optical entrance aperture is located at the level of the secondary mirror (instead of the primary as usual). This paper describes the baffle design and analyzes its performances, calculated by numerical simulation with ray tracing methods, at different angles of incidence of the light, for sources both outside and inside the field of view.

The MKID Camera

NASA Astrophysics Data System (ADS)

Maloney, P. R.; Czakon, N. G.; Day, P. K.; Duan, R.; Gao, J.; Glenn, J.; Golwala, S.; Hollister, M.; LeDuc, H. G.; Mazin, B.; Noroozian, O.; Nguyen, H. T.; Sayers, J.; Schlaerth, J.; Vaillancourt, J. E.; Vayonakis, A.; Wilson, P.; Zmuidzinas, J.

2009-12-01

The MKID Camera project is a collaborative effort of Caltech, JPL, the University of Colorado, and UC Santa Barbara to develop a large-format, multi-color millimeter and submillimeter-wavelength camera for astronomy using microwave kinetic inductance detectors (MKIDs). These are superconducting, micro-resonators fabricated from thin aluminum and niobium films. We couple the MKIDs to multi-slot antennas and measure the change in surface impedance produced by photon-induced breaking of Cooper pairs. The readout is almost entirely at room temperature and can be highly multiplexed; in principle hundreds or even thousands of resonators could be read out on a single feedline. The camera will have 576 spatial pixels that image simultaneously in four bands at 750, 850, 1100 and 1300 microns. It is scheduled for deployment at the Caltech Submillimeter Observatory in the summer of 2010. We present an overview of the camera design and readout and describe the current status of testing and fabrication.

Observations and analysis of O(1D) and NH2 line profiles for the coma of comet P/Halley

NASA Technical Reports Server (NTRS)

Smyth, William H.; Combi, Michael R.; Roesler, Fred L.; Scherb, Frank

1995-01-01

A set of high-resolution Fabry-Perot measurements of the coma of comet P/Halley was acquired in the (O I) 6300 A and NH2 6298.62 A emission lines. These high-resolution measurements provide the first optical observations capable of studying directly the photochemical kinetics and dynamic outflow of the coma. The observations were analyzed by a Monte Carlo Particle Trajectory Model. The agreement of the model and observed line profiles was excellent and verified the underlying dynamics, exothermic photodissociative chemistry, and collisional thermalization in the coma. The somewhat wider intrinsic line profile width for the O(1D) emission in 1986 January compared to 1986 May, is, for example, produced by the larger outflow speeds and gas temperatures nearer perihelion in January. The January O(1D) profile, which is wider than the January NH2 profile, is indicative of the photochemical kinetics in the dissociation of the parent molecules H2O and OH in the coma. The absolute calibration of the observations in 1986 January allowed the production rates for H2O and the NH2-parent molecules to be determined. The average daily water production rates derived from the O(1D) emission data for January 16 and 17 are presented. These very large water production rates are consistent with the extrapolated (and 7.6 day time variable) water production rates determined from the analysis of lower spectral resolution observations for O(1D) and H-alpha emissions that covered the time period up to January 13. The large production rates on January 16 and 17 establish that the maximum water production rate for comet Halley accurred pre-perihelion in January. Implications drawn from comparison with 18 cm radio emission data in January suggest that the peak water production rate was even larger. The average production rate for NH3 determined from the NH2 emission data for January 17 was (1.48 +/- 0.10) x 10(exp 28) molecules/s, yielding an NH3/H2O production rate ratio of 0.55%.

Frequency regularities of acoustic modes and multi-colour mode identification in rapidly rotating stars

NASA Astrophysics Data System (ADS)

Reese, D. R.; Lignières, F.; Ballot, J.; Dupret, M.-A.; Barban, C.; van't Veer-Menneret, C.; MacGregor, K. B.

2017-05-01

Context. Mode identification has remained a major obstacle in the interpretation of pulsation spectra in rapidly rotating stars. This has motivated recent work on calculating realistic multi-colour mode visibilities in this type of star. Aims: We would like to test mode identification methods and seismic diagnostics in rapidly rotating stars, using oscillation spectra that are based on these new theoretical predictions. Methods: We investigate the auto-correlation function and Fourier transform of theoretically calculated frequency spectra, in which modes are selected according to their visibilities. Given that intrinsic mode amplitudes are determined by non-linear saturation and cannot currently be theoretically predicted, we experimented with various ad-hoc prescriptions for setting the mode amplitudes, including using random values. Furthermore, we analyse the ratios between mode amplitudes observed in different photometric bands to see up to what extent they can identify modes. Results: When non-random intrinsic mode amplitudes are used, our results show that it is possible to extract a mean value for the large frequency separation or half its value and, sometimes, twice the rotation rate, from the auto-correlation of the frequency spectra. Furthermore, the Fourier transforms are mostly sensitive to the large frequency separation or half its value. The combination of the two methods may therefore measure and distinguish the two types of separations. When the intrinsic mode amplitudes include random factors, which seems more representative of real stars, the results are far less favourable. It is only when the large separation or half its value coincides with twice the rotation rate, that it might be possible to detect the signature of a frequency regularity. We also find that amplitude ratios are a good way of grouping together modes with similar characteristics. By analysing the frequencies of these groups, it is possible to constrain mode identification, as

VUV Testing of Science Cameras at MSFC: QE Measurement of the CLASP Flight Cameras

NASA Technical Reports Server (NTRS)

Champey, Patrick; Kobayashi, Ken; Winebarger, Amy; Cirtain, Jonathan; Hyde, David; Robertson, Bryan; Beabout, Brent; Beabout, Dyana; Stewart, Mike

2015-01-01

The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras were built and tested for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The CLASP camera design includes a frame-transfer e2v CCD57-10 512x512 detector, dual channel analog readout electronics and an internally mounted cold block. At the flight operating temperature of -20 C, the CLASP cameras achieved the low-noise performance requirements (less than or equal to 25 e- read noise and greater than or equal to 10 e-/sec/pix dark current), in addition to maintaining a stable gain of approximately equal to 2.0 e-/DN. The e2v CCD57-10 detectors were coated with Lumogen-E to improve quantum efficiency (QE) at the Lyman- wavelength. A vacuum ultra-violet (VUV) monochromator and a NIST calibrated photodiode were employed to measure the QE of each camera. Four flight-like cameras were tested in a high-vacuum chamber, which was configured to operate several tests intended to verify the QE, gain, read noise, dark current and residual non-linearity of the CCD. We present and discuss the QE measurements performed on the CLASP cameras. We also discuss the high-vacuum system outfitted for testing of UV and EUV science cameras at MSFC.

Significant variation from a 1/R-squared potential in the cumulative flux determined from the Giotto Comet Halley Dust Impact Experiment

NASA Technical Reports Server (NTRS)

Alexander, W. M.; Goad, S.; Mcdonald, R. A.; Tanner, W. G., Jr.; Pollock, J. J.

1989-01-01

The Dust Impact Detection System (DIDSY) aboard the Giotto spacecraft provided the information on the dust flux, mass spectrum, and cumulative mass distribution flux in the coma of Comet Halley. Analysis of discrete pulse height data of cometary particles for the mass range of particles between 4.0 x 10 to the -10th g and 6.0 x 10 to the -6th g registered by the Giotto DIDSY detectors 2, 3, and 4 has been completed, and a cumulative flux has been determined for this size range of particles. Inside the cometopause, anomalous peaks have been identified as deviation from a 1/R-squared curve in both pre- and postencounter measurements.

Streak camera receiver definition study

NASA Technical Reports Server (NTRS)

Johnson, C. B.; Hunkler, L. T., Sr.; Letzring, S. A.; Jaanimagi, P.

1990-01-01

Detailed streak camera definition studies were made as a first step toward full flight qualification of a dual channel picosecond resolution streak camera receiver for the Geoscience Laser Altimeter and Ranging System (GLRS). The streak camera receiver requirements are discussed as they pertain specifically to the GLRS system, and estimates of the characteristics of the streak camera are given, based upon existing and near-term technological capabilities. Important problem areas are highlighted, and possible corresponding solutions are discussed.

Automated Camera Array Fine Calibration

NASA Technical Reports Server (NTRS)

Clouse, Daniel; Padgett, Curtis; Ansar, Adnan; Cheng, Yang

2008-01-01

Using aerial imagery, the JPL FineCalibration (JPL FineCal) software automatically tunes a set of existing CAHVOR camera models for an array of cameras. The software finds matching features in the overlap region between images from adjacent cameras, and uses these features to refine the camera models. It is not necessary to take special imagery of a known target and no surveying is required. JPL FineCal was developed for use with an aerial, persistent surveillance platform.

Automatic calibration method for plenoptic camera

NASA Astrophysics Data System (ADS)

Luan, Yinsen; He, Xing; Xu, Bing; Yang, Ping; Tang, Guomao

2016-04-01

An automatic calibration method is proposed for a microlens-based plenoptic camera. First, all microlens images on the white image are searched and recognized automatically based on digital morphology. Then, the center points of microlens images are rearranged according to their relative position relationships. Consequently, the microlens images are located, i.e., the plenoptic camera is calibrated without the prior knowledge of camera parameters. Furthermore, this method is appropriate for all types of microlens-based plenoptic cameras, even the multifocus plenoptic camera, the plenoptic camera with arbitrarily arranged microlenses, or the plenoptic camera with different sizes of microlenses. Finally, we verify our method by the raw data of Lytro. The experiments show that our method has higher intelligence than the methods published before.

IMAX camera (12-IML-1)

NASA Technical Reports Server (NTRS)

1992-01-01

The IMAX camera system is used to record on-orbit activities of interest to the public. Because of the extremely high resolution of the IMAX camera, projector, and audio systems, the audience is afforded a motion picture experience unlike any other. IMAX and OMNIMAX motion picture systems were designed to create motion picture images of superior quality and audience impact. The IMAX camera is a 65 mm, single lens, reflex viewing design with a 15 perforation per frame horizontal pull across. The frame size is 2.06 x 2.77 inches. Film travels through the camera at a rate of 336 feet per minute when the camera is running at the standard 24 frames/sec.

Multiple Sensor Camera for Enhanced Video Capturing

NASA Astrophysics Data System (ADS)

Nagahara, Hajime; Kanki, Yoshinori; Iwai, Yoshio; Yachida, Masahiko

A resolution of camera has been drastically improved under a current request for high-quality digital images. For example, digital still camera has several mega pixels. Although a video camera has the higher frame-rate, the resolution of a video camera is lower than that of still camera. Thus, the high-resolution is incompatible with the high frame rate of ordinary cameras in market. It is difficult to solve this problem by a single sensor, since it comes from physical limitation of the pixel transfer rate. In this paper, we propose a multi-sensor camera for capturing a resolution and frame-rate enhanced video. Common multi-CCDs camera, such as 3CCD color camera, has same CCD for capturing different spectral information. Our approach is to use different spatio-temporal resolution sensors in a single camera cabinet for capturing higher resolution and frame-rate information separately. We build a prototype camera which can capture high-resolution (2588×1958 pixels, 3.75 fps) and high frame-rate (500×500, 90 fps) videos. We also proposed the calibration method for the camera. As one of the application of the camera, we demonstrate an enhanced video (2128×1952 pixels, 90 fps) generated from the captured videos for showing the utility of the camera.

Electronic camera-management system for 35-mm and 70-mm film cameras

NASA Astrophysics Data System (ADS)

Nielsen, Allan

1993-01-01

Military and commercial test facilities have been tasked with the need for increasingly sophisticated data collection and data reduction. A state-of-the-art electronic control system for high speed 35 mm and 70 mm film cameras designed to meet these tasks is described. Data collection in today's test range environment is difficult at best. The need for a completely integrated image and data collection system is mandated by the increasingly complex test environment. Instrumentation film cameras have been used on test ranges to capture images for decades. Their high frame rates coupled with exceptionally high resolution make them an essential part of any test system. In addition to documenting test events, today's camera system is required to perform many additional tasks. Data reduction to establish TSPI (time- space-position information) may be performed after a mission and is subject to all of the variables present in documenting the mission. A typical scenario would consist of multiple cameras located on tracking mounts capturing the event along with azimuth and elevation position data. Corrected data can then be reduced using each camera's time and position deltas and calculating the TSPI of the object using triangulation. An electronic camera control system designed to meet these requirements has been developed by Photo-Sonics, Inc. The feedback received from test technicians at range facilities throughout the world led Photo-Sonics to design the features of this control system. These prominent new features include: a comprehensive safety management system, full local or remote operation, frame rate accuracy of less than 0.005 percent, and phase locking capability to Irig-B. In fact, Irig-B phase lock operation of multiple cameras can reduce the time-distance delta of a test object traveling at mach-1 to less than one inch during data reduction.

Using DSLR cameras in digital holography

NASA Astrophysics Data System (ADS)

Hincapié-Zuluaga, Diego; Herrera-Ramírez, Jorge; García-Sucerquia, Jorge

2017-08-01

In Digital Holography (DH), the size of the bidimensional image sensor to record the digital hologram, plays a key role on the performance of this imaging technique; the larger the size of the camera sensor, the better the quality of the final reconstructed image. Scientific cameras with large formats are offered in the market, but their cost and availability limit their use as a first option when implementing DH. Nowadays, DSLR cameras provide an easy-access alternative that is worthwhile to be explored. The DSLR cameras are a wide, commercial, and available option that in comparison with traditional scientific cameras, offer a much lower cost per effective pixel over a large sensing area. However, in the DSLR cameras, with their RGB pixel distribution, the sampling of information is different to the sampling in monochrome cameras usually employed in DH. This fact has implications in their performance. In this work, we discuss why DSLR cameras are not extensively used for DH, taking into account the problem reported by different authors of object replication. Simulations of DH using monochromatic and DSLR cameras are presented and a theoretical deduction for the replication problem using the Fourier theory is also shown. Experimental results of DH implementation using a DSLR camera show the replication problem.

Long-term evolution of 1991 DA: A dynamically evolved extinct Halley-type comet

NASA Technical Reports Server (NTRS)

Hahn, Gerhard; Bailey, M. E.

1992-01-01

The long-term dynamical evolution of 21 variational orbits for the intermediate-period asteroid 1991 DA was followed for up to +/-10(exp 5) years from the present. 1991 DA is close to the 2:7 resonance with Jupiter; it has avoided close encounters, within 1 AU, with this planet for at least the past 30,000 years, even at the node crossing. The future evolution typically shows no close encounters with Jupiter within at least 50,000 years. This corresponds to the mean time between node crossings with either Jupiter or Saturn. Close encounters with Saturn and Jupiter lead to a chaotic evolution for the whole ensemble, while secular perturbations cause large-amplitude swings in eccentricity and inclination (the latter covering the range 15 deg approximately less than i approximately less than 85 deg) which correlate with deep excursions of the perihelion distance to values much less than 1 AU. These variations are similar to those found in P/Machholz and a variety of other high-inclination orbits, e.g., P/Hartley-IRAS. We emphasize the connection between the orbital evolution of 1991 DA and that of Halley-type comets. If 1991 DA was once a comet, it is not surprising that it is now extinct.

Depth estimation and camera calibration of a focused plenoptic camera for visual odometry

NASA Astrophysics Data System (ADS)

Zeller, Niclas; Quint, Franz; Stilla, Uwe

2016-08-01

This paper presents new and improved methods of depth estimation and camera calibration for visual odometry with a focused plenoptic camera. For depth estimation we adapt an algorithm previously used in structure-from-motion approaches to work with images of a focused plenoptic camera. In the raw image of a plenoptic camera, scene patches are recorded in several micro-images under slightly different angles. This leads to a multi-view stereo-problem. To reduce the complexity, we divide this into multiple binocular stereo problems. For each pixel with sufficient gradient we estimate a virtual (uncalibrated) depth based on local intensity error minimization. The estimated depth is characterized by the variance of the estimate and is subsequently updated with the estimates from other micro-images. Updating is performed in a Kalman-like fashion. The result of depth estimation in a single image of the plenoptic camera is a probabilistic depth map, where each depth pixel consists of an estimated virtual depth and a corresponding variance. Since the resulting image of the plenoptic camera contains two plains: the optical image and the depth map, camera calibration is divided into two separate sub-problems. The optical path is calibrated based on a traditional calibration method. For calibrating the depth map we introduce two novel model based methods, which define the relation of the virtual depth, which has been estimated based on the light-field image, and the metric object distance. These two methods are compared to a well known curve fitting approach. Both model based methods show significant advantages compared to the curve fitting method. For visual odometry we fuse the probabilistic depth map gained from one shot of the plenoptic camera with the depth data gained by finding stereo correspondences between subsequent synthesized intensity images of the plenoptic camera. These images can be synthesized totally focused and thus finding stereo correspondences is enhanced

Selecting a digital camera for telemedicine.

PubMed

Patricoski, Chris; Ferguson, A Stewart

2009-06-01

The digital camera is an essential component of store-and-forward telemedicine (electronic consultation). There are numerous makes and models of digital cameras on the market, and selecting a suitable consumer-grade camera can be complicated. Evaluation of digital cameras includes investigating the features and analyzing image quality. Important features include the camera settings, ease of use, macro capabilities, method of image transfer, and power recharging. Consideration needs to be given to image quality, especially as it relates to color (skin tones) and detail. It is important to know the level of the photographer and the intended application. The goal is to match the characteristics of the camera with the telemedicine program requirements. In the end, selecting a digital camera is a combination of qualitative (subjective) and quantitative (objective) analysis. For the telemedicine program in Alaska in 2008, the camera evaluation and decision process resulted in a specific selection based on the criteria developed for our environment.

Spacecraft camera image registration

NASA Technical Reports Server (NTRS)

Kamel, Ahmed A. (Inventor); Graul, Donald W. (Inventor); Chan, Fred N. T. (Inventor); Gamble, Donald W. (Inventor)

1987-01-01

A system for achieving spacecraft camera (1, 2) image registration comprises a portion external to the spacecraft and an image motion compensation system (IMCS) portion onboard the spacecraft. Within the IMCS, a computer (38) calculates an image registration compensation signal (60) which is sent to the scan control loops (84, 88, 94, 98) of the onboard cameras (1, 2). At the location external to the spacecraft, the long-term orbital and attitude perturbations on the spacecraft are modeled. Coefficients (K, A) from this model are periodically sent to the onboard computer (38) by means of a command unit (39). The coefficients (K, A) take into account observations of stars and landmarks made by the spacecraft cameras (1, 2) themselves. The computer (38) takes as inputs the updated coefficients (K, A) plus synchronization information indicating the mirror position (AZ, EL) of each of the spacecraft cameras (1, 2), operating mode, and starting and stopping status of the scan lines generated by these cameras (1, 2), and generates in response thereto the image registration compensation signal (60). The sources of periodic thermal errors on the spacecraft are discussed. The system is checked by calculating measurement residuals, the difference between the landmark and star locations predicted at the external location and the landmark and star locations as measured by the spacecraft cameras (1, 2).

PET with the HIDAC camera?

NASA Astrophysics Data System (ADS)

Townsend, D. W.

1988-06-01

In 1982 the first prototype high density avalanche chamber (HIDAC) positron camera became operational in the Division of Nuclear Medicine of Geneva University Hospital. The camera consisted of dual 20 cm × 20 cm HIDAC detectors mounted on a rotating gantry. In 1984, these detectors were replaced by 30 cm × 30 cm detectors with improved performance and reliability. Since then, the larger detectors have undergone clinical evaluation. This article discusses certain aspects of the evaluation program and the conclusions that can be drawn from the results. The potential of the HIDAC camera for quantitative positron emission tomography (PET) is critically examined, and its performance compared with a state-of-the-art, commercial ring camera. Guidelines for the design of a future HIDAC camera are suggested.

Uncooled radiometric camera performance

NASA Astrophysics Data System (ADS)

Meyer, Bill; Hoelter, T.

1998-07-01

Thermal imaging equipment utilizing microbolometer detectors operating at room temperature has found widespread acceptance in both military and commercial applications. Uncooled camera products are becoming effective solutions to applications currently using traditional, photonic infrared sensors. The reduced power consumption and decreased mechanical complexity offered by uncooled cameras have realized highly reliable, low-cost, hand-held instruments. Initially these instruments displayed only relative temperature differences which limited their usefulness in applications such as Thermography. Radiometrically calibrated microbolometer instruments are now available. The ExplorIR Thermography camera leverages the technology developed for Raytheon Systems Company's first production microbolometer imaging camera, the Sentinel. The ExplorIR camera has a demonstrated temperature measurement accuracy of 4 degrees Celsius or 4% of the measured value (whichever is greater) over scene temperatures ranges of minus 20 degrees Celsius to 300 degrees Celsius (minus 20 degrees Celsius to 900 degrees Celsius for extended range models) and camera environmental temperatures of minus 10 degrees Celsius to 40 degrees Celsius. Direct temperature measurement with high resolution video imaging creates some unique challenges when using uncooled detectors. A temperature controlled, field-of-view limiting aperture (cold shield) is not typically included in the small volume dewars used for uncooled detector packages. The lack of a field-of-view shield allows a significant amount of extraneous radiation from the dewar walls and lens body to affect the sensor operation. In addition, the transmission of the Germanium lens elements is a function of ambient temperature. The ExplorIR camera design compensates for these environmental effects while maintaining the accuracy and dynamic range required by today's predictive maintenance and condition monitoring markets.

Deployable Wireless Camera Penetrators

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Jones, Jack; Sherrit, Stewart; Wu, Jiunn Jeng

2008-01-01

A lightweight, low-power camera dart has been designed and tested for context imaging of sampling sites and ground surveys from an aerobot or an orbiting spacecraft in a microgravity environment. The camera penetrators also can be used to image any line-of-sight surface, such as cliff walls, that is difficult to access. Tethered cameras to inspect the surfaces of planetary bodies use both power and signal transmission lines to operate. A tether adds the possibility of inadvertently anchoring the aerobot, and requires some form of station-keeping capability of the aerobot if extended examination time is required. The new camera penetrators are deployed without a tether, weigh less than 30 grams, and are disposable. They are designed to drop from any altitude with the boost in transmitting power currently demonstrated at approximately 100-m line-of-sight. The penetrators also can be deployed to monitor lander or rover operations from a distance, and can be used for surface surveys or for context information gathering from a touch-and-go sampling site. Thanks to wireless operation, the complexity of the sampling or survey mechanisms may be reduced. The penetrators may be battery powered for short-duration missions, or have solar panels for longer or intermittent duration missions. The imaging device is embedded in the penetrator, which is dropped or projected at the surface of a study site at 90 to the surface. Mirrors can be used in the design to image the ground or the horizon. Some of the camera features were tested using commercial "nanny" or "spy" camera components with the charge-coupled device (CCD) looking at a direction parallel to the ground. Figure 1 shows components of one camera that weighs less than 8 g and occupies a volume of 11 cm3. This camera could transmit a standard television signal, including sound, up to 100 m. Figure 2 shows the CAD models of a version of the penetrator. A low-volume array of such penetrator cameras could be deployed from an

COBRA ATD multispectral camera response model

NASA Astrophysics Data System (ADS)

Holmes, V. Todd; Kenton, Arthur C.; Hilton, Russell J.; Witherspoon, Ned H.; Holloway, John H., Jr.

2000-08-01

A new multispectral camera response model has been developed in support of the US Marine Corps (USMC) Coastal Battlefield Reconnaissance and Analysis (COBRA) Advanced Technology Demonstration (ATD) Program. This analytical model accurately estimates response form five Xybion intensified IMC 201 multispectral cameras used for COBRA ATD airborne minefield detection. The camera model design is based on a series of camera response curves which were generated through optical laboratory test performed by the Naval Surface Warfare Center, Dahlgren Division, Coastal Systems Station (CSS). Data fitting techniques were applied to these measured response curves to obtain nonlinear expressions which estimates digitized camera output as a function of irradiance, intensifier gain, and exposure. This COBRA Camera Response Model was proven to be very accurate, stable over a wide range of parameters, analytically invertible, and relatively simple. This practical camera model was subsequently incorporated into the COBRA sensor performance evaluation and computational tools for research analysis modeling toolbox in order to enhance COBRA modeling and simulation capabilities. Details of the camera model design and comparisons of modeled response to measured experimental data are presented.

Electronic Still Camera view of Aft end of Wide Field/Planetary Camera in HST

NASA Image and Video Library

1993-12-06

S61-E-015 (6 Dec 1993) --- A close-up view of the aft part of the new Wide Field/Planetary Camera (WFPC-II) installed on the Hubble Space Telescope (HST). WFPC-II was photographed with the Electronic Still Camera (ESC) from inside Endeavour's cabin as astronauts F. Story Musgrave and Jeffrey A. Hoffman moved it from its stowage position onto the giant telescope. Electronic still photography is a relatively new technology which provides the means for a handheld camera to electronically capture and digitize an image with resolution approaching film quality. The electronic still camera has flown as an experiment on several other shuttle missions.

To catch a comet: Technical overview of CAN DO G-324

NASA Technical Reports Server (NTRS)

Obrien, T. J. (Editor)

1986-01-01

The primary objective of the C. E. Williams Middle School Get Away Special CAN DO is the photographing of Comet Halley. The project will involve middle school students, grades 6 through 8, in the study and interpretation of astronomical photographs and techniques. G-324 is contained in a 5 cubic foot GAS Canister with an opening door and pyrex window for photography. It will be pressurized with one atmosphere of dry nitrogen. Three 35mm still cameras with 250 exposure film backs and different focal length lenses will be fired by a combination of automatic timer and an active comet detector. A lightweight 35mm movie camera will shoot single exposures at about 1/2 minute intervals to give an overlapping skymap of the mission. The fifth camera is a solid state television camera specially constructed for detection of the comet by microprocessor.

Coherent infrared imaging camera (CIRIC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hutchinson, D.P.; Simpson, M.L.; Bennett, C.A.

1995-07-01

New developments in 2-D, wide-bandwidth HgCdTe (MCT) and GaAs quantum-well infrared photodetectors (QWIP) coupled with Monolithic Microwave Integrated Circuit (MMIC) technology are now making focal plane array coherent infrared (IR) cameras viable. Unlike conventional IR cameras which provide only thermal data about a scene or target, a coherent camera based on optical heterodyne interferometry will also provide spectral and range information. Each pixel of the camera, consisting of a single photo-sensitive heterodyne mixer followed by an intermediate frequency amplifier and illuminated by a separate local oscillator beam, constitutes a complete optical heterodyne receiver. Applications of coherent IR cameras are numerousmore » and include target surveillance, range detection, chemical plume evolution, monitoring stack plume emissions, and wind shear detection.« less

Fast Variations In Spectrum of Comet Halley

NASA Astrophysics Data System (ADS)

Borysenko, S. A.

The goal of this work is to research fast variations of spectral lines intensities in spectra of comet Halley. The present research was made on the basis of more then 500 high- resolution spectrogram obtained by L.M. Shulman and H.K. Nazarchuk in November- December, 1985 at the 6-m telescope (SAO, Russia). Some fast variations with different quasiperiods were detected in all the spectrograms. Quasiperiods of these variations were from 15 - 40 min to 1.5 - 2 hours. As data from spacecraft "Vega-2" show, more fast variations with quasiperiods 5 - 10 min are obviously present in cometary time variations. Only the most important lines so as C2, C3, CN, CH and NH2 were analyzed. False periods were checked by comparison of the power spectra of the variations with the computed spectral window of the data. Only false periods about 400 sec (the avarage period of exposition) were detected. An algorithm for analysis of locally Poisson's time series was proposed. Two types of fast variations are detected: 1)high amplitude variations with more long quasiperiods (1.5 - 2 hours) and the coefficient of crosscorrelations between line intensities about 0.9 - 0.95; 2)low amplitude variations with short periods (15 - 40 min), which look like white noise and have the coefficient of crosscorrelations about 0.1 - 0.3. This difference may be caused by nature of variations. The first type variations may be an effect of both active processes in cometary nucleus and streams of solar protons. Analysis of solar proton flux variation with energies >1 MeV in November - Decem- ber 1985 confirms the above-mentioned version. In the second case it may by only inner processes in the nucleus that generate the observed variations. For determination of general parameters of cometary atmosphere, such as the produc- tion rates of radicals C2, C3, CN, CH, and NH2 it was necessary to estimate the contri- bution of dust grains luminiscence into the continuum of the comet. Space and wave- length distribution

Range Finding with a Plenoptic Camera

DTIC Science & Technology

2014-03-27

92 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Simulated Camera Analysis...Varying Lens Diameter . . . . . . . . . . . . . . . . 95 Simulated Camera Analysis: Varying Detector Size . . . . . . . . . . . . . . . . . 98 Simulated ...Matching Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 37 Simulated Camera Performance with SIFT

Development of high-speed video cameras

NASA Astrophysics Data System (ADS)

Etoh, Takeharu G.; Takehara, Kohsei; Okinaka, Tomoo; Takano, Yasuhide; Ruckelshausen, Arno; Poggemann, Dirk

2001-04-01

Presented in this paper is an outline of the R and D activities on high-speed video cameras, which have been done in Kinki University since more than ten years ago, and are currently proceeded as an international cooperative project with University of Applied Sciences Osnabruck and other organizations. Extensive marketing researches have been done, (1) on user's requirements on high-speed multi-framing and video cameras by questionnaires and hearings, and (2) on current availability of the cameras of this sort by search of journals and websites. Both of them support necessity of development of a high-speed video camera of more than 1 million fps. A video camera of 4,500 fps with parallel readout was developed in 1991. A video camera with triple sensors was developed in 1996. The sensor is the same one as developed for the previous camera. The frame rate is 50 million fps for triple-framing and 4,500 fps for triple-light-wave framing, including color image capturing. Idea on a video camera of 1 million fps with an ISIS, In-situ Storage Image Sensor, was proposed in 1993 at first, and has been continuously improved. A test sensor was developed in early 2000, and successfully captured images at 62,500 fps. Currently, design of a prototype ISIS is going on, and, hopefully, will be fabricated in near future. Epoch-making cameras in history of development of high-speed video cameras by other persons are also briefly reviewed.

The abundance of ammonia in Comet P/Halley derived from ultraviolet spectrophotometry of NH by ASTRON and IUE

NASA Technical Reports Server (NTRS)

Feldman, P. D.; Fournier, K. B.; Grinin, V. P.; Zvereva, A. M.

1993-01-01

From an analysis of the spatial profiles of both the NH and OH UV emissions observed by the ASTRON satellite, the ratio of ammonia-to-water production rates in Comet Halley on April 9, 1986 is derived and found to lie in the range of 0.44-0.94 percent. In order to compare this result with those based on both ground-based and in situ observations made on other dates during the 1985-1986 apparition of the comet, the IUE observational data base for December 1985 and March-April 1986 is used to evaluate the ratio of NH to OH column density in the IUE field of view and thus constrain the long-term behavior of this ratio. The IUE data base indicates that, to within a factor of 2, the ammonia-to-water production rate ratio is the same for a small sample of moderately bright comets observed recently.

The development of large-aperture test system of infrared camera and visible CCD camera

NASA Astrophysics Data System (ADS)

Li, Yingwen; Geng, Anbing; Wang, Bo; Wang, Haitao; Wu, Yanying

2015-10-01

Infrared camera and CCD camera dual-band imaging system is used in many equipment and application widely. If it is tested using the traditional infrared camera test system and visible CCD test system, 2 times of installation and alignment are needed in the test procedure. The large-aperture test system of infrared camera and visible CCD camera uses the common large-aperture reflection collimator, target wheel, frame-grabber, computer which reduces the cost and the time of installation and alignment. Multiple-frame averaging algorithm is used to reduce the influence of random noise. Athermal optical design is adopted to reduce the change of focal length location change of collimator when the environmental temperature is changing, and the image quality of the collimator of large field of view and test accuracy are also improved. Its performance is the same as that of the exotic congener and is much cheaper. It will have a good market.

Kitt Peak speckle camera

NASA Technical Reports Server (NTRS)

Breckinridge, J. B.; Mcalister, H. A.; Robinson, W. G.

1979-01-01

The speckle camera in regular use at Kitt Peak National Observatory since 1974 is described in detail. The design of the atmospheric dispersion compensation prisms, the use of film as a recording medium, the accuracy of double star measurements, and the next generation speckle camera are discussed. Photographs of double star speckle patterns with separations from 1.4 sec of arc to 4.7 sec of arc are shown to illustrate the quality of image formation with this camera, the effects of seeing on the patterns, and to illustrate the isoplanatic patch of the atmosphere.

Lytro camera technology: theory, algorithms, performance analysis

NASA Astrophysics Data System (ADS)

Georgiev, Todor; Yu, Zhan; Lumsdaine, Andrew; Goma, Sergio

2013-03-01

The Lytro camera is the first implementation of a plenoptic camera for the consumer market. We consider it a successful example of the miniaturization aided by the increase in computational power characterizing mobile computational photography. The plenoptic camera approach to radiance capture uses a microlens array as an imaging system focused on the focal plane of the main camera lens. This paper analyzes the performance of Lytro camera from a system level perspective, considering the Lytro camera as a black box, and uses our interpretation of Lytro image data saved by the camera. We present our findings based on our interpretation of Lytro camera file structure, image calibration and image rendering; in this context, artifacts and final image resolution are discussed.

Human tracking over camera networks: a review

NASA Astrophysics Data System (ADS)

Hou, Li; Wan, Wanggen; Hwang, Jenq-Neng; Muhammad, Rizwan; Yang, Mingyang; Han, Kang

2017-12-01

In recent years, automated human tracking over camera networks is getting essential for video surveillance. The tasks of tracking human over camera networks are not only inherently challenging due to changing human appearance, but also have enormous potentials for a wide range of practical applications, ranging from security surveillance to retail and health care. This review paper surveys the most widely used techniques and recent advances for human tracking over camera networks. Two important functional modules for the human tracking over camera networks are addressed, including human tracking within a camera and human tracking across non-overlapping cameras. The core techniques of human tracking within a camera are discussed based on two aspects, i.e., generative trackers and discriminative trackers. The core techniques of human tracking across non-overlapping cameras are then discussed based on the aspects of human re-identification, camera-link model-based tracking and graph model-based tracking. Our survey aims to address existing problems, challenges, and future research directions based on the analyses of the current progress made toward human tracking techniques over camera networks.

Microprocessor-controlled wide-range streak camera

NASA Astrophysics Data System (ADS)

Lewis, Amy E.; Hollabaugh, Craig

2006-08-01

Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera's user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.

Omnidirectional Underwater Camera Design and Calibration

PubMed Central

Bosch, Josep; Gracias, Nuno; Ridao, Pere; Ribas, David

2015-01-01

This paper presents the development of an underwater omnidirectional multi-camera system (OMS) based on a commercially available six-camera system, originally designed for land applications. A full calibration method is presented for the estimation of both the intrinsic and extrinsic parameters, which is able to cope with wide-angle lenses and non-overlapping cameras simultaneously. This method is valid for any OMS in both land or water applications. For underwater use, a customized housing is required, which often leads to strong image distortion due to refraction among the different media. This phenomena makes the basic pinhole camera model invalid for underwater cameras, especially when using wide-angle lenses, and requires the explicit modeling of the individual optical rays. To address this problem, a ray tracing approach has been adopted to create a field-of-view (FOV) simulator for underwater cameras. The simulator allows for the testing of different housing geometries and optics for the cameras to ensure a complete hemisphere coverage in underwater operation. This paper describes the design and testing of a compact custom housing for a commercial off-the-shelf OMS camera (Ladybug 3) and presents the first results of its use. A proposed three-stage calibration process allows for the estimation of all of the relevant camera parameters. Experimental results are presented, which illustrate the performance of the calibration method and validate the approach. PMID:25774707

The ion population between 1300 km and 230000 km in the coma of comet P/Halley

NASA Technical Reports Server (NTRS)

Altwegg, K.; Balsiger, H.; Geiss, J.; Goldstein, R.; Ip, W. -H.; Meier, A.; Neugebauer, M.; Rosenbauer, H.; Shelley, E.

1993-01-01

During the encounter of the spacecraft Giotto with Comet Halley the two sensors of the ion mass spectrometer (IMS), high energy range spectrometer (HERS) and high intensity spectrometer (HIS), measured the mass and the three-dimensional velocity distributions of cometary ions. HIS looked mainly at the cold, slow part of the distribution close to the nucleus, HERS at the more energetic pick-up ions further out. After a thorough recalibration of the HIS flight spare unit and an extensive data analysis we present here continuous ion density-, composition-, velocity-, and temperature profiles for the water group ion (mass range 16-19 amu/e) along Giotto's inbound trajectory from 230,000 to 1300 km from the comet nucleus. The two sensors are in very good agreement in the region where their measurements overlap thus giving an excellent data base for the discussion of theoretical comet models. The most prominent feature where models and observations disagree is the so called pile up region between 8000 and 15,000 km from the nucleus.

Phenology cameras observing boreal ecosystems of Finland

NASA Astrophysics Data System (ADS)

Peltoniemi, Mikko; Böttcher, Kristin; Aurela, Mika; Kolari, Pasi; Tanis, Cemal Melih; Linkosalmi, Maiju; Loehr, John; Metsämäki, Sari; Nadir Arslan, Ali

2016-04-01

Cameras have become useful tools for monitoring seasonality of ecosystems. Low-cost cameras facilitate validation of other measurements and allow extracting some key ecological features and moments from image time series. We installed a network of phenology cameras at selected ecosystem research sites in Finland. Cameras were installed above, on the level, or/and below the canopies. Current network hosts cameras taking time lapse images in coniferous and deciduous forests as well as at open wetlands offering thus possibilities to monitor various phenological and time-associated events and elements. In this poster, we present our camera network and give examples of image series use for research. We will show results about the stability of camera derived color signals, and based on that discuss about the applicability of cameras in monitoring time-dependent phenomena. We will also present results from comparisons between camera-derived color signal time series and daily satellite-derived time series (NVDI, NDWI, and fractional snow cover) from the Moderate Resolution Imaging Spectrometer (MODIS) at selected spruce and pine forests and in a wetland. We will discuss the applicability of cameras in supporting phenological observations derived from satellites, by considering the possibility of cameras to monitor both above and below canopy phenology and snow.

Versatile microsecond movie camera

NASA Astrophysics Data System (ADS)

Dreyfus, R. W.

1980-03-01

A laboratory-type movie camera is described which satisfies many requirements in the range 1 microsec to 1 sec. The camera consists of a He-Ne laser and compatible state-of-the-art components; the primary components are an acoustooptic modulator, an electromechanical beam deflector, and a video tape system. The present camera is distinct in its operation in that submicrosecond laser flashes freeze the image motion while still allowing the simplicity of electromechanical image deflection in the millisecond range. The gating and pulse delay circuits of an oscilloscope synchronize the modulator and scanner relative to the subject being photographed. The optical table construction and electronic control enhance the camera's versatility and adaptability. The instant replay video tape recording allows for easy synchronization and immediate viewing of the results. Economy is achieved by using off-the-shelf components, optical table construction, and short assembly time.

Observations of solar wind ion charge exchange in the comet Halley coma

NASA Technical Reports Server (NTRS)

Fuselier, S. A.; Shelley, E. G.; Goldstein, B. E.; Goldstein, R.; Neugebauer, M.; Ip, W.-H.; Balsiger, H.; Reme, H.

1991-01-01

Giotto Ion Mass Spectrometer/High Energy Range Spectrometer (IMS/HERS) observations of solar wind ions show charge exchange effects and solar wind compositional changes in the coma of comet Halley. As the comet was approached, the He(++) to proton density ratio increased until about 1 hour before closest approach after which time it decreased. Abrupt increases in this ratio were also observed in the beginning and near the end of the so-called Mystery Region (8.6 - 5.5(10)(exp 5) km from the comet along the spacecraft trajectory). These abrupt increases in the density ratio were well correlated with enhanced fluxes of keV electrons as measured by the Giotto plasma electron spectrometer. The general increase and then decrease of the He(++) to proton density ratio is quantitatively consistent with a combination of the addition of protons of cometary origin to the plasma and loss of plasma through charge exchange of protons and He(++). In general agreement with the solar wind proton and He(++) observations, solar wind oxygen and carbon ions were observed to charge exchange from higher to lower charge states with decreasing distance to the comet. The more abrupt increases in the He(++) to proton and the He(++) to O(6+) density ratios in the mystery region require a change in the solar wind ion composition in this region while the correlation with energetic electrons indicates processes associated with the comet.

THE DARK ENERGY CAMERA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flaugher, B.; Diehl, H. T.; Alvarez, O.

2015-11-15

The Dark Energy Camera is a new imager with a 2.°2 diameter field of view mounted at the prime focus of the Victor M. Blanco 4 m telescope on Cerro Tololo near La Serena, Chile. The camera was designed and constructed by the Dark Energy Survey Collaboration and meets or exceeds the stringent requirements designed for the wide-field and supernova surveys for which the collaboration uses it. The camera consists of a five-element optical corrector, seven filters, a shutter with a 60 cm aperture, and a charge-coupled device (CCD) focal plane of 250 μm thick fully depleted CCDs cooled inside a vacuummore » Dewar. The 570 megapixel focal plane comprises 62 2k × 4k CCDs for imaging and 12 2k × 2k CCDs for guiding and focus. The CCDs have 15 μm × 15 μm pixels with a plate scale of 0.″263 pixel{sup −1}. A hexapod system provides state-of-the-art focus and alignment capability. The camera is read out in 20 s with 6–9 electron readout noise. This paper provides a technical description of the camera's engineering, construction, installation, and current status.« less

The Dark Energy Camera

DOE PAGES

Flaugher, B.

2015-04-11

The Dark Energy Camera is a new imager with a 2.2-degree diameter field of view mounted at the prime focus of the Victor M. Blanco 4-meter telescope on Cerro Tololo near La Serena, Chile. The camera was designed and constructed by the Dark Energy Survey Collaboration, and meets or exceeds the stringent requirements designed for the wide-field and supernova surveys for which the collaboration uses it. The camera consists of a five element optical corrector, seven filters, a shutter with a 60 cm aperture, and a CCD focal plane of 250-μm thick fully depleted CCDs cooled inside a vacuum Dewar.more » The 570 Mpixel focal plane comprises 62 2k x 4k CCDs for imaging and 12 2k x 2k CCDs for guiding and focus. The CCDs have 15μm x 15μm pixels with a plate scale of 0.263" per pixel. A hexapod system provides state-of-the-art focus and alignment capability. The camera is read out in 20 seconds with 6-9 electrons readout noise. This paper provides a technical description of the camera's engineering, construction, installation, and current status.« less

Coordinating High-Resolution Traffic Cameras : Developing Intelligent, Collaborating Cameras for Transportation Security and Communications

DOT National Transportation Integrated Search

2015-08-01

Cameras are used prolifically to monitor transportation incidents, infrastructure, and congestion. Traditional camera systems often require human monitoring and only offer low-resolution video. Researchers for the Exploratory Advanced Research (EAR) ...

High Speed Digital Camera Technology Review

NASA Technical Reports Server (NTRS)

Clements, Sandra D.

2009-01-01

A High Speed Digital Camera Technology Review (HSD Review) is being conducted to evaluate the state-of-the-shelf in this rapidly progressing industry. Five HSD cameras supplied by four camera manufacturers participated in a Field Test during the Space Shuttle Discovery STS-128 launch. Each camera was also subjected to Bench Tests in the ASRC Imaging Development Laboratory. Evaluation of the data from the Field and Bench Tests is underway. Representatives from the imaging communities at NASA / KSC and the Optical Systems Group are participating as reviewers. A High Speed Digital Video Camera Draft Specification was updated to address Shuttle engineering imagery requirements based on findings from this HSD Review. This draft specification will serve as the template for a High Speed Digital Video Camera Specification to be developed for the wider OSG imaging community under OSG Task OS-33.

ARNICA, the Arcetri Near-Infrared Camera

NASA Astrophysics Data System (ADS)

Lisi, F.; Baffa, C.; Bilotti, V.; Bonaccini, D.; del Vecchio, C.; Gennari, S.; Hunt, L. K.; Marcucci, G.; Stanga, R.

1996-04-01

ARNICA (ARcetri Near-Infrared CAmera) is the imaging camera for the near-infrared bands between 1.0 and 2.5 microns that the Arcetri Observatory has designed and built for the Infrared Telescope TIRGO located at Gornergrat, Switzerland. We describe the mechanical and optical design of the camera, and report on the astronomical performance of ARNICA as measured during the commissioning runs at the TIRGO (December, 1992 to December 1993), and an observing run at the William Herschel Telescope, Canary Islands (December, 1993). System performance is defined in terms of efficiency of the camera+telescope system and camera sensitivity for extended and point-like sources. (SECTION: Astronomical Instrumentation)

HIGH SPEED CAMERA

DOEpatents

Rogers, B.T. Jr.; Davis, W.C.

1957-12-17

This patent relates to high speed cameras having resolution times of less than one-tenth microseconds suitable for filming distinct sequences of a very fast event such as an explosion. This camera consists of a rotating mirror with reflecting surfaces on both sides, a narrow mirror acting as a slit in a focal plane shutter, various other mirror and lens systems as well as an innage recording surface. The combination of the rotating mirrors and the slit mirror causes discrete, narrow, separate pictures to fall upon the film plane, thereby forming a moving image increment of the photographed event. Placing a reflecting surface on each side of the rotating mirror cancels the image velocity that one side of the rotating mirror would impart, so as a camera having this short a resolution time is thereby possible.

LSST camera control system

NASA Astrophysics Data System (ADS)

Marshall, Stuart; Thaler, Jon; Schalk, Terry; Huffer, Michael

2006-06-01

The LSST Camera Control System (CCS) will manage the activities of the various camera subsystems and coordinate those activities with the LSST Observatory Control System (OCS). The CCS comprises a set of modules (nominally implemented in software) which are each responsible for managing one camera subsystem. Generally, a control module will be a long lived "server" process running on an embedded computer in the subsystem. Multiple control modules may run on a single computer or a module may be implemented in "firmware" on a subsystem. In any case control modules must exchange messages and status data with a master control module (MCM). The main features of this approach are: (1) control is distributed to the local subsystem level; (2) the systems follow a "Master/Slave" strategy; (3) coordination will be achieved by the exchange of messages through the interfaces between the CCS and its subsystems. The interface between the camera data acquisition system and its downstream clients is also presented.

IMAX camera in payload bay

NASA Image and Video Library

1995-12-20

STS074-361-035 (12-20 Nov 1995) --- This medium close-up view centers on the IMAX Cargo Bay Camera (ICBC) and its associated IMAX Camera Container Equipment (ICCE) at its position in the cargo bay of the Earth-orbiting Space Shuttle Atlantis. With its own ?space suit? or protective covering to protect it from the rigors of space, this version of the IMAX was able to record scenes not accessible with the in-cabin cameras. For docking and undocking activities involving Russia?s Mir Space Station and the Space Shuttle Atlantis, the camera joined a variety of in-cabin camera hardware in recording the historical events. IMAX?s secondary objectives were to film Earth views. The IMAX project is a collaboration between NASA, the Smithsonian Institution?s National Air and Space Museum (NASM), IMAX Systems Corporation, and the Lockheed Corporation to document significant space activities and promote NASA?s educational goals using the IMAX film medium.

Passive auto-focus for digital still cameras and camera phones: Filter-switching and low-light techniques

NASA Astrophysics Data System (ADS)

Gamadia, Mark Noel

In order to gain valuable market share in the growing consumer digital still camera and camera phone market, camera manufacturers have to continually add and improve existing features to their latest product offerings. Auto-focus (AF) is one such feature, whose aim is to enable consumers to quickly take sharply focused pictures with little or no manual intervention in adjusting the camera's focus lens. While AF has been a standard feature in digital still and cell-phone cameras, consumers often complain about their cameras' slow AF performance, which may lead to missed photographic opportunities, rendering valuable moments and events with undesired out-of-focus pictures. This dissertation addresses this critical issue to advance the state-of-the-art in the digital band-pass filter, passive AF method. This method is widely used to realize AF in the camera industry, where a focus actuator is adjusted via a search algorithm to locate the in-focus position by maximizing a sharpness measure extracted from a particular frequency band of the incoming image of the scene. There are no known systematic methods for automatically deriving the parameters such as the digital pass-bands or the search step-size increments used in existing passive AF schemes. Conventional methods require time consuming experimentation and tuning in order to arrive at a set of parameters which balance AF performance in terms of speed and accuracy ultimately causing a delay in product time-to-market. This dissertation presents a new framework for determining an optimal set of passive AF parameters, named Filter- Switching AF, providing an automatic approach to achieve superior AF performance, both in good and low lighting conditions based on the following performance measures (metrics): speed (total number of iterations), accuracy (offset from truth), power consumption (total distance moved), and user experience (in-focus position overrun). Performance results using three different prototype cameras

Science, conservation, and camera traps

USGS Publications Warehouse

Nichols, James D.; Karanth, K. Ullas; O'Connel, Allan F.; O'Connell, Allan F.; Nichols, James D.; Karanth, K. Ullas

2011-01-01

Biologists commonly perceive camera traps as a new tool that enables them to enter the hitherto secret world of wild animals. Camera traps are being used in a wide range of studies dealing with animal ecology, behavior, and conservation. Our intention in this volume is not to simply present the various uses of camera traps, but to focus on their use in the conduct of science and conservation. In this chapter, we provide an overview of these two broad classes of endeavor and sketch the manner in which camera traps are likely to be able to contribute to them. Our main point here is that neither photographs of individual animals, nor detection history data, nor parameter estimates generated from detection histories are the ultimate objective of a camera trap study directed at either science or management. Instead, the ultimate objectives are best viewed as either gaining an understanding of how ecological systems work (science) or trying to make wise decisions that move systems from less desirable to more desirable states (conservation, management). Therefore, we briefly describe here basic approaches to science and management, emphasizing the role of field data and associated analyses in these processes. We provide examples of ways in which camera trap data can inform science and management.

Electronic cameras for low-light microscopy.

PubMed

Rasnik, Ivan; French, Todd; Jacobson, Ken; Berland, Keith

2013-01-01

This chapter introduces to electronic cameras, discusses the various parameters considered for evaluating their performance, and describes some of the key features of different camera formats. The chapter also presents the basic understanding of functioning of the electronic cameras and how these properties can be exploited to optimize image quality under low-light conditions. Although there are many types of cameras available for microscopy, the most reliable type is the charge-coupled device (CCD) camera, which remains preferred for high-performance systems. If time resolution and frame rate are of no concern, slow-scan CCDs certainly offer the best available performance, both in terms of the signal-to-noise ratio and their spatial resolution. Slow-scan cameras are thus the first choice for experiments using fixed specimens such as measurements using immune fluorescence and fluorescence in situ hybridization. However, if video rate imaging is required, one need not evaluate slow-scan CCD cameras. A very basic video CCD may suffice if samples are heavily labeled or are not perturbed by high intensity illumination. When video rate imaging is required for very dim specimens, the electron multiplying CCD camera is probably the most appropriate at this technological stage. Intensified CCDs provide a unique tool for applications in which high-speed gating is required. The variable integration time video cameras are very attractive options if one needs to acquire images at video rate acquisition, as well as with longer integration times for less bright samples. This flexibility can facilitate many diverse applications with highly varied light levels. Copyright © 2007 Elsevier Inc. All rights reserved.

Solid state television camera

NASA Technical Reports Server (NTRS)

1976-01-01

The design, fabrication, and tests of a solid state television camera using a new charge-coupled imaging device are reported. An RCA charge-coupled device arranged in a 512 by 320 format and directly compatible with EIA format standards was the sensor selected. This is a three-phase, sealed surface-channel array that has 163,840 sensor elements, which employs a vertical frame transfer system for image readout. Included are test results of the complete camera system, circuit description and changes to such circuits as a result of integration and test, maintenance and operation section, recommendations to improve the camera system, and a complete set of electrical and mechanical drawing sketches.

An Automatic Portable Telecine Camera.

DTIC Science & Technology

1978-08-01

five television frames to achieve synchronous operation, that is about 0.2 second. 6.3 Video recorder noise imnunity The synchronisation pulse separator...display is filmed by a modified 16 am cine camera driven by a control unit in which the camera supply voltage is derived from the field synchronisation ...pulses of the video signal. Automatic synchronisation of the camera mechanism is achieved over a wide range of television field frequencies and the

Towards next generation 3D cameras

NASA Astrophysics Data System (ADS)

Gupta, Mohit

2017-03-01

We are in the midst of a 3D revolution. Robots enabled by 3D cameras are beginning to autonomously drive cars, perform surgeries, and manage factories. However, when deployed in the real-world, these cameras face several challenges that prevent them from measuring 3D shape reliably. These challenges include large lighting variations (bright sunlight to dark night), presence of scattering media (fog, body tissue), and optically complex materials (metal, plastic). Due to these factors, 3D imaging is often the bottleneck in widespread adoption of several key robotics technologies. I will talk about our work on developing 3D cameras based on time-of-flight and active triangulation that addresses these long-standing problems. This includes designing `all-weather' cameras that can perform high-speed 3D scanning in harsh outdoor environments, as well as cameras that recover shape of objects with challenging material properties. These cameras are, for the first time, capable of measuring detailed (<100 microns resolution) scans in extremely demanding scenarios with low-cost components. Several of these cameras are making a practical impact in industrial automation, being adopted in robotic inspection and assembly systems.

Automatic multi-camera calibration for deployable positioning systems

NASA Astrophysics Data System (ADS)

Axelsson, Maria; Karlsson, Mikael; Rudner, Staffan

2012-06-01

Surveillance with automated positioning and tracking of subjects and vehicles in 3D is desired in many defence and security applications. Camera systems with stereo or multiple cameras are often used for 3D positioning. In such systems, accurate camera calibration is needed to obtain a reliable 3D position estimate. There is also a need for automated camera calibration to facilitate fast deployment of semi-mobile multi-camera 3D positioning systems. In this paper we investigate a method for automatic calibration of the extrinsic camera parameters (relative camera pose and orientation) of a multi-camera positioning system. It is based on estimation of the essential matrix between each camera pair using the 5-point method for intrinsically calibrated cameras. The method is compared to a manual calibration method using real HD video data from a field trial with a multicamera positioning system. The method is also evaluated on simulated data from a stereo camera model. The results show that the reprojection error of the automated camera calibration method is close to or smaller than the error for the manual calibration method and that the automated calibration method can replace the manual calibration.

Calibration Procedures on Oblique Camera Setups

NASA Astrophysics Data System (ADS)

Kemper, G.; Melykuti, B.; Yu, C.

2016-06-01

Beside the creation of virtual animated 3D City models, analysis for homeland security and city planning, the accurately determination of geometric features out of oblique imagery is an important task today. Due to the huge number of single images the reduction of control points force to make use of direct referencing devices. This causes a precise camera-calibration and additional adjustment procedures. This paper aims to show the workflow of the various calibration steps and will present examples of the calibration flight with the final 3D City model. In difference to most other software, the oblique cameras are used not as co-registered sensors in relation to the nadir one, all camera images enter the AT process as single pre-oriented data. This enables a better post calibration in order to detect variations in the single camera calibration and other mechanical effects. The shown sensor (Oblique Imager) is based o 5 Phase One cameras were the nadir one has 80 MPIX equipped with a 50 mm lens while the oblique ones capture images with 50 MPix using 80 mm lenses. The cameras are mounted robust inside a housing to protect this against physical and thermal deformations. The sensor head hosts also an IMU which is connected to a POS AV GNSS Receiver. The sensor is stabilized by a gyro-mount which creates floating Antenna -IMU lever arms. They had to be registered together with the Raw GNSS-IMU Data. The camera calibration procedure was performed based on a special calibration flight with 351 shoots of all 5 cameras and registered the GPS/IMU data. This specific mission was designed in two different altitudes with additional cross lines on each flying heights. The five images from each exposure positions have no overlaps but in the block there are many overlaps resulting in up to 200 measurements per points. On each photo there were in average 110 well distributed measured points which is a satisfying number for the camera calibration. In a first step with the help of

Relative and Absolute Calibration of a Multihead Camera System with Oblique and Nadir Looking Cameras for a Uas

NASA Astrophysics Data System (ADS)

Niemeyer, F.; Schima, R.; Grenzdörffer, G.

2013-08-01

Numerous unmanned aerial systems (UAS) are currently flooding the market. For the most diverse applications UAVs are special designed and used. Micro and mini UAS (maximum take-off weight up to 5 kg) are of particular interest, because legal restrictions are still manageable but also the payload capacities are sufficient for many imaging sensors. Currently a camera system with four oblique and one nadir looking cameras is under development at the Chair for Geodesy and Geoinformatics. The so-called "Four Vision" camera system was successfully built and tested in the air. A MD4-1000 UAS from microdrones is used as a carrier system. Light weight industrial cameras are used and controlled by a central computer. For further photogrammetric image processing, each individual camera, as well as all the cameras together have to be calibrated. This paper focuses on the determination of the relative orientation between the cameras with the „Australis" software and will give an overview of the results and experiences of test flights.

Camera Operator and Videographer

ERIC Educational Resources Information Center

Moore, Pam

2007-01-01

Television, video, and motion picture camera operators produce images that tell a story, inform or entertain an audience, or record an event. They use various cameras to shoot a wide range of material, including television series, news and sporting events, music videos, motion pictures, documentaries, and training sessions. Those who film or…

System Synchronizes Recordings from Separated Video Cameras

NASA Technical Reports Server (NTRS)

Nail, William; Nail, William L.; Nail, Jasper M.; Le, Doung T.

2009-01-01

A system of electronic hardware and software for synchronizing recordings from multiple, physically separated video cameras is being developed, primarily for use in multiple-look-angle video production. The system, the time code used in the system, and the underlying method of synchronization upon which the design of the system is based are denoted generally by the term "Geo-TimeCode(TradeMark)." The system is embodied mostly in compact, lightweight, portable units (see figure) denoted video time-code units (VTUs) - one VTU for each video camera. The system is scalable in that any number of camera recordings can be synchronized. The estimated retail price per unit would be about $350 (in 2006 dollars). The need for this or another synchronization system external to video cameras arises because most video cameras do not include internal means for maintaining synchronization with other video cameras. Unlike prior video-camera-synchronization systems, this system does not depend on continuous cable or radio links between cameras (however, it does depend on occasional cable links lasting a few seconds). Also, whereas the time codes used in prior video-camera-synchronization systems typically repeat after 24 hours, the time code used in this system does not repeat for slightly more than 136 years; hence, this system is much better suited for long-term deployment of multiple cameras.

Camera/Photometer Results

NASA Astrophysics Data System (ADS)

Clifton, K. S.; Owens, J. K.

1983-04-01

Efforts continue regarding the analysis of particulate contamination recorded by the Camera/Photometers on STS-2. These systems were constructed by Epsilon Laboratories, Inc. and consisted of two 16-mm photographic cameras, using Kodak Double X film, Type 7222, to make stereoscopic observations of contaminant particles and background. Each was housed within a pressurized canister and operated automatically throughout the mission, making simultaneous exposures on a continuous basis every 150 sec. The cameras were equipped with 18-mm f/0.9 lenses and subtended overlapping 20° fields-of-view. An integrating photometer was used to inhibit the exposure sequences during periods of excessive illumination and to terminate the exposures at preset light levels. During the exposures, a camera shutter operated in a chopping mode in order to isolate the movement of particles for velocity determinations. Calculations based on the preflight film calibration indicate that particles as small as 25 μm can be detected from ideal observing conditions. Current emphasis is placed on the digitization of the photographic data frames and the determination of particle distances, sizes, and velocities. It has been concluded that background bright-ness measurements cannot be established with any reliability on the STS-2 mission, due to the preponderance of Earth-directed attitudes and the incidence of light reflected from nearby surfaces.

Transmission electron microscope CCD camera

DOEpatents

Downing, Kenneth H.

1999-01-01

In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

Situational Awareness from a Low-Cost Camera System

NASA Technical Reports Server (NTRS)

Freudinger, Lawrence C.; Ward, David; Lesage, John

2010-01-01

A method gathers scene information from a low-cost camera system. Existing surveillance systems using sufficient cameras for continuous coverage of a large field necessarily generate enormous amounts of raw data. Digitizing and channeling that data to a central computer and processing it in real time is difficult when using low-cost, commercially available components. A newly developed system is located on a combined power and data wire to form a string-of-lights camera system. Each camera is accessible through this network interface using standard TCP/IP networking protocols. The cameras more closely resemble cell-phone cameras than traditional security camera systems. Processing capabilities are built directly onto the camera backplane, which helps maintain a low cost. The low power requirements of each camera allow the creation of a single imaging system comprising over 100 cameras. Each camera has built-in processing capabilities to detect events and cooperatively share this information with neighboring cameras. The location of the event is reported to the host computer in Cartesian coordinates computed from data correlation across multiple cameras. In this way, events in the field of view can present low-bandwidth information to the host rather than high-bandwidth bitmap data constantly being generated by the cameras. This approach offers greater flexibility than conventional systems, without compromising performance through using many small, low-cost cameras with overlapping fields of view. This means significant increased viewing without ignoring surveillance areas, which can occur when pan, tilt, and zoom cameras look away. Additionally, due to the sharing of a single cable for power and data, the installation costs are lower. The technology is targeted toward 3D scene extraction and automatic target tracking for military and commercial applications. Security systems and environmental/ vehicular monitoring systems are also potential applications.

Homography-based multiple-camera person-tracking

NASA Astrophysics Data System (ADS)

Turk, Matthew R.

2009-01-01

Multiple video cameras are cheaply installed overlooking an area of interest. While computerized single-camera tracking is well-developed, multiple-camera tracking is a relatively new problem. The main multi-camera problem is to give the same tracking label to all projections of a real-world target. This is called the consistent labelling problem. Khan and Shah (2003) introduced a method to use field of view lines to perform multiple-camera tracking. The method creates inter-camera meta-target associations when objects enter at the scene edges. They also said that a plane-induced homography could be used for tracking, but this method was not well described. Their homography-based system would not work if targets use only one side of a camera to enter the scene. This paper overcomes this limitation and fully describes a practical homography-based tracker. A new method to find the feet feature is introduced. The method works especially well if the camera is tilted, when using the bottom centre of the target's bounding-box would produce inaccurate results. The new method is more accurate than the bounding-box method even when the camera is not tilted. Next, a method is presented that uses a series of corresponding point pairs "dropped" by oblivious, live human targets to find a plane-induced homography. The point pairs are created by tracking the feet locations of moving targets that were associated using the field of view line method. Finally, a homography-based multiple-camera tracking algorithm is introduced. Rules governing when to create the homography are specified. The algorithm ensures that homography-based tracking only starts after a non-degenerate homography is found. The method works when not all four field of view lines are discoverable; only one line needs to be found to use the algorithm. To initialize the system, the operator must specify pairs of overlapping cameras. Aside from that, the algorithm is fully automatic and uses the natural movement of

Assessment of chromosomal abnormalities in sperm of infertile men using sperm karyotyping and multicolour fluorescence in situ hybridization (FISH)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moosani, N.; Martin, R.H.

1994-09-01

Individuals with male factor infertility resulting from idiopathic oligo-, astheno- or teratozoospermia are frequently offered IVF in an attempt to increase their chances of having a child. A concern remains whether these infertile males have an elevated risk of transmitting chromosomal abnormalities to their offspring. Sperm chromosomal complements from these men were assayed using the human sperm/hamster oocyte fusion system and fluorescence in situ hybridization (FISH) on sperm nuclei. For each of 5 infertile patients, 100 sperm karyotypes were analyzed and multicolour FISH analysis was performed on a minimum of 10,000 sperm nuclei for each chromosome-specific DNA probe for chromosomesmore » 1 (pUC1.77), 12 (D12Z3), X (XC) and Y (DYZ3). As a group, the infertile patients showed increased frequencies of both numerical ({chi}{sup 2}=17.26, {proportional_to} <0.001) and total abnormalities ({chi}{sup 2}=7.78, {proportional_to} <0.01) relative to control donors when assessed by sperm karyotypes. Analysis of sperm nuclei by FISH indicated a significant increase in the frequency of disomy for chromosome 1 in three of the five patients as compared to control donors ({chi}{sup 2}>8.35, {proportional_to} <0.005). In addition, the frequency of XY disomy was significantly higher in four of the five patients studied by FISH ({chi}{sup 2}>10.58, {proportional_to}<0.005), suggesting that mis-segregation caused by the failure of the XY bivalent to pair may play a role in idiopathic male infertility.« less

Solid state replacement of rotating mirror cameras

NASA Astrophysics Data System (ADS)

Frank, Alan M.; Bartolick, Joseph M.

2007-01-01

Rotating mirror cameras have been the mainstay of mega-frame per second imaging for decades. There is still no electronic camera that can match a film based rotary mirror camera for the combination of frame count, speed, resolution and dynamic range. The rotary mirror cameras are predominantly used in the range of 0.1 to 100 micro-seconds per frame, for 25 to more than a hundred frames. Electron tube gated cameras dominate the sub microsecond regime but are frame count limited. Video cameras are pushing into the microsecond regime but are resolution limited by the high data rates. An all solid state architecture, dubbed 'In-situ Storage Image Sensor' or 'ISIS', by Prof. Goji Etoh has made its first appearance into the market and its evaluation is discussed. Recent work at Lawrence Livermore National Laboratory has concentrated both on evaluation of the presently available technologies and exploring the capabilities of the ISIS architecture. It is clear though there is presently no single chip camera that can simultaneously match the rotary mirror cameras, the ISIS architecture has the potential to approach their performance.

Optical design of portable nonmydriatic fundus camera

NASA Astrophysics Data System (ADS)

Chen, Weilin; Chang, Jun; Lv, Fengxian; He, Yifan; Liu, Xin; Wang, Dajiang

2016-03-01

Fundus camera is widely used in screening and diagnosis of retinal disease. It is a simple, and widely used medical equipment. Early fundus camera expands the pupil with mydriatic to increase the amount of the incoming light, which makes the patients feel vertigo and blurred. Nonmydriatic fundus camera is a trend of fundus camera. Desktop fundus camera is not easy to carry, and only suitable to be used in the hospital. However, portable nonmydriatic retinal camera is convenient for patient self-examination or medical stuff visiting a patient at home. This paper presents a portable nonmydriatic fundus camera with the field of view (FOV) of 40°, Two kinds of light source are used, 590nm is used in imaging, while 808nm light is used in observing the fundus in high resolving power. Ring lights and a hollow mirror are employed to restrain the stray light from the cornea center. The focus of the camera is adjusted by reposition the CCD along the optical axis. The range of the diopter is between -20m-1 and 20m-1.

Computing camera heading: A study

NASA Astrophysics Data System (ADS)

Zhang, John Jiaxiang

2000-08-01

An accurate estimate of the motion of a camera is a crucial first step for the 3D reconstruction of sites, objects, and buildings from video. Solutions to the camera heading problem can be readily applied to many areas, such as robotic navigation, surgical operation, video special effects, multimedia, and lately even in internet commerce. From image sequences of a real world scene, the problem is to calculate the directions of the camera translations. The presence of rotations makes this problem very hard. This is because rotations and translations can have similar effects on the images, and are thus hard to tell apart. However, the visual angles between the projection rays of point pairs are unaffected by rotations, and their changes over time contain sufficient information to determine the direction of camera translation. We developed a new formulation of the visual angle disparity approach, first introduced by Tomasi, to the camera heading problem. Our new derivation makes theoretical analysis possible. Most notably, a theorem is obtained that locates all possible singularities of the residual function for the underlying optimization problem. This allows identifying all computation trouble spots beforehand, and to design reliable and accurate computational optimization methods. A bootstrap-jackknife resampling method simultaneously reduces complexity and tolerates outliers well. Experiments with image sequences show accurate results when compared with the true camera motion as measured with mechanical devices.

Voss with video camera in Service Module

NASA Image and Video Library

2001-04-08

ISS002-E-5329 (08 April 2001) --- Astronaut James S. Voss, Expedition Two flight engineer, sets up a video camera on a mounting bracket in the Zvezda / Service Module of the International Space Station (ISS). A 35mm camera and a digital still camera are also visible nearby. This image was recorded with a digital still camera.

Plate refractive camera model and its applications

NASA Astrophysics Data System (ADS)

Huang, Longxiang; Zhao, Xu; Cai, Shen; Liu, Yuncai

2017-03-01

In real applications, a pinhole camera capturing objects through a planar parallel transparent plate is frequently employed. Due to the refractive effects of the plate, such an imaging system does not comply with the conventional pinhole camera model. Although the system is ubiquitous, it has not been thoroughly studied. This paper aims at presenting a simple virtual camera model, called a plate refractive camera model, which has a form similar to a pinhole camera model and can efficiently model refractions through a plate. The key idea is to employ a pixel-wise viewpoint concept to encode the refraction effects into a pixel-wise pinhole camera model. The proposed camera model realizes an efficient forward projection computation method and has some advantages in applications. First, the model can help to compute the caustic surface to represent the changes of the camera viewpoints. Second, the model has strengths in analyzing and rectifying the image caustic distortion caused by the plate refraction effects. Third, the model can be used to calibrate the camera's intrinsic parameters without removing the plate. Last but not least, the model contributes to putting forward the plate refractive triangulation methods in order to solve the plate refractive triangulation problem easily in multiviews. We verify our theory in both synthetic and real experiments.

Low Noise Camera for Suborbital Science Applications

NASA Technical Reports Server (NTRS)

Hyde, David; Robertson, Bryan; Holloway, Todd

2015-01-01

Low-cost, commercial-off-the-shelf- (COTS-) based science cameras are intended for lab use only and are not suitable for flight deployment as they are difficult to ruggedize and repackage into instruments. Also, COTS implementation may not be suitable since mission science objectives are tied to specific measurement requirements, and often require performance beyond that required by the commercial market. Custom camera development for each application is cost prohibitive for the International Space Station (ISS) or midrange science payloads due to nonrecurring expenses ($2,000 K) for ground-up camera electronics design. While each new science mission has a different suite of requirements for camera performance (detector noise, speed of image acquisition, charge-coupled device (CCD) size, operation temperature, packaging, etc.), the analog-to-digital conversion, power supply, and communications can be standardized to accommodate many different applications. The low noise camera for suborbital applications is a rugged standard camera platform that can accommodate a range of detector types and science requirements for use in inexpensive to mid range payloads supporting Earth science, solar physics, robotic vision, or astronomy experiments. Cameras developed on this platform have demonstrated the performance found in custom flight cameras at a price per camera more than an order of magnitude lower.

Selective-imaging camera

NASA Astrophysics Data System (ADS)

Szu, Harold; Hsu, Charles; Landa, Joseph; Cha, Jae H.; Krapels, Keith A.

2015-05-01

How can we design cameras that image selectively in Full Electro-Magnetic (FEM) spectra? Without selective imaging, we cannot use, for example, ordinary tourist cameras to see through fire, smoke, or other obscurants contributing to creating a Visually Degraded Environment (VDE). This paper addresses a possible new design of selective-imaging cameras at firmware level. The design is consistent with physics of the irreversible thermodynamics of Boltzmann's molecular entropy. It enables imaging in appropriate FEM spectra for sensing through the VDE, and displaying in color spectra for Human Visual System (HVS). We sense within the spectra the largest entropy value of obscurants such as fire, smoke, etc. Then we apply a smart firmware implementation of Blind Sources Separation (BSS) to separate all entropy sources associated with specific Kelvin temperatures. Finally, we recompose the scene using specific RGB colors constrained by the HVS, by up/down shifting Planck spectra at each pixel and time.

Microprocessor-controlled, wide-range streak camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amy E. Lewis, Craig Hollabaugh

Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storagemore » using flash-based storage media. The camera’s user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.« less

Autocalibration of a projector-camera system.

PubMed

Okatani, Takayuki; Deguchi, Koichiro

2005-12-01

This paper presents a method for calibrating a projector-camera system that consists of multiple projectors (or multiple poses of a single projector), a camera, and a planar screen. We consider the problem of estimating the homography between the screen and the image plane of the camera or the screen-camera homography, in the case where there is no prior knowledge regarding the screen surface that enables the direct computation of the homography. It is assumed that the pose of each projector is unknown while its internal geometry is known. Subsequently, it is shown that the screen-camera homography can be determined from only the images projected by the projectors and then obtained by the camera, up to a transformation with four degrees of freedom. This transformation corresponds to arbitrariness in choosing a two-dimensional coordinate system on the screen surface and when this coordinate system is chosen in some manner, the screen-camera homography as well as the unknown poses of the projectors can be uniquely determined. A noniterative algorithm is presented, which computes the homography from three or more images. Several experimental results on synthetic as well as real images are shown to demonstrate the effectiveness of the method.

New generation of meteorology cameras

NASA Astrophysics Data System (ADS)

Janout, Petr; Blažek, Martin; Páta, Petr

2017-12-01

A new generation of the WILLIAM (WIde-field aLL-sky Image Analyzing Monitoring system) camera includes new features such as monitoring of rain and storm clouds during the day observation. Development of the new generation of weather monitoring cameras responds to the demand for monitoring of sudden weather changes. However, new WILLIAM cameras are ready to process acquired image data immediately, release warning against sudden torrential rains, and send it to user's cell phone and email. Actual weather conditions are determined from image data, and results of image processing are complemented by data from sensors of temperature, humidity, and atmospheric pressure. In this paper, we present the architecture, image data processing algorithms of mentioned monitoring camera and spatially-variant model of imaging system aberrations based on Zernike polynomials.

Neutron counting with cameras

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Esch, Patrick; Crisanti, Marta; Mutti, Paolo

2015-07-01

A research project is presented in which we aim at counting individual neutrons with CCD-like cameras. We explore theoretically a technique that allows us to use imaging detectors as counting detectors at lower counting rates, and transits smoothly to continuous imaging at higher counting rates. As such, the hope is to combine the good background rejection properties of standard neutron counting detectors with the absence of dead time of integrating neutron imaging cameras as well as their very good spatial resolution. Compared to Xray detection, the essence of thermal neutron detection is the nuclear conversion reaction. The released energies involvedmore » are of the order of a few MeV, while X-ray detection releases energies of the order of the photon energy, which is in the 10 KeV range. Thanks to advances in camera technology which have resulted in increased quantum efficiency, lower noise, as well as increased frame rate up to 100 fps for CMOS-type cameras, this more than 100-fold higher available detection energy implies that the individual neutron detection light signal can be significantly above the noise level, as such allowing for discrimination and individual counting, which is hard to achieve with X-rays. The time scale of CMOS-type cameras doesn't allow one to consider time-of-flight measurements, but kinetic experiments in the 10 ms range are possible. The theory is next confronted to the first experimental results. (authors)« less

Minimum Requirements for Taxicab Security Cameras*

PubMed Central

Zeng, Shengke; Amandus, Harlan E.; Amendola, Alfred A.; Newbraugh, Bradley H.; Cantis, Douglas M.; Weaver, Darlene

2015-01-01

Problem The homicide rate of taxicab-industry is 20 times greater than that of all workers. A NIOSH study showed that cities with taxicab-security cameras experienced significant reduction in taxicab driver homicides. Methods Minimum technical requirements and a standard test protocol for taxicab-security cameras for effective taxicab-facial identification were determined. The study took more than 10,000 photographs of human-face charts in a simulated-taxicab with various photographic resolutions, dynamic ranges, lens-distortions, and motion-blurs in various light and cab-seat conditions. Thirteen volunteer photograph-evaluators evaluated these face photographs and voted for the minimum technical requirements for taxicab-security cameras. Results Five worst-case scenario photographic image quality thresholds were suggested: the resolution of XGA-format, highlight-dynamic-range of 1 EV, twilight-dynamic-range of 3.3 EV, lens-distortion of 30%, and shutter-speed of 1/30 second. Practical Applications These minimum requirements will help taxicab regulators and fleets to identify effective taxicab-security cameras, and help taxicab-security camera manufacturers to improve the camera facial identification capability. PMID:26823992

Circuit design of an EMCCD camera

NASA Astrophysics Data System (ADS)

Li, Binhua; Song, Qian; Jin, Jianhui; He, Chun

2012-07-01

EMCCDs have been used in the astronomical observations in many ways. Recently we develop a camera using an EMCCD TX285. The CCD chip is cooled to -100°C in an LN2 dewar. The camera controller consists of a driving board, a control board and a temperature control board. Power supplies and driving clocks of the CCD are provided by the driving board, the timing generator is located in the control board. The timing generator and an embedded Nios II CPU are implemented in an FPGA. Moreover the ADC and the data transfer circuit are also in the control board, and controlled by the FPGA. The data transfer between the image workstation and the camera is done through a Camera Link frame grabber. The software of image acquisition is built using VC++ and Sapera LT. This paper describes the camera structure, the main components and circuit design for video signal processing channel, clock driver, FPGA and Camera Link interfaces, temperature metering and control system. Some testing results are presented.

Multi-Angle Snowflake Camera Instrument Handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stuefer, Martin; Bailey, J.

2016-07-01

The Multi-Angle Snowflake Camera (MASC) takes 9- to 37-micron resolution stereographic photographs of free-falling hydrometers from three angles, while simultaneously measuring their fall speed. Information about hydrometeor size, shape orientation, and aspect ratio is derived from MASC photographs. The instrument consists of three commercial cameras separated by angles of 36º. Each camera field of view is aligned to have a common single focus point about 10 cm distant from the cameras. Two near-infrared emitter pairs are aligned with the camera’s field of view within a 10-angular ring and detect hydrometeor passage, with the lower emitters configured to trigger the MASCmore » cameras. The sensitive IR motion sensors are designed to filter out slow variations in ambient light. Fall speed is derived from successive triggers along the fall path. The camera exposure times are extremely short, in the range of 1/25,000th of a second, enabling the MASC to capture snowflake sizes ranging from 30 micrometers to 3 cm.« less

Minimum Requirements for Taxicab Security Cameras.

PubMed

Zeng, Shengke; Amandus, Harlan E; Amendola, Alfred A; Newbraugh, Bradley H; Cantis, Douglas M; Weaver, Darlene

2014-07-01

The homicide rate of taxicab-industry is 20 times greater than that of all workers. A NIOSH study showed that cities with taxicab-security cameras experienced significant reduction in taxicab driver homicides. Minimum technical requirements and a standard test protocol for taxicab-security cameras for effective taxicab-facial identification were determined. The study took more than 10,000 photographs of human-face charts in a simulated-taxicab with various photographic resolutions, dynamic ranges, lens-distortions, and motion-blurs in various light and cab-seat conditions. Thirteen volunteer photograph-evaluators evaluated these face photographs and voted for the minimum technical requirements for taxicab-security cameras. Five worst-case scenario photographic image quality thresholds were suggested: the resolution of XGA-format, highlight-dynamic-range of 1 EV, twilight-dynamic-range of 3.3 EV, lens-distortion of 30%, and shutter-speed of 1/30 second. These minimum requirements will help taxicab regulators and fleets to identify effective taxicab-security cameras, and help taxicab-security camera manufacturers to improve the camera facial identification capability.

16 CFR 501.1 - Camera film.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk still...

16 CFR 501.1 - Camera film.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk still...

16 CFR 501.1 - Camera film.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk still...

16 CFR 501.1 - Camera film.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk still...

16 CFR 501.1 - Camera film.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk still...

Camera-on-a-Chip

NASA Technical Reports Server (NTRS)

1999-01-01

Jet Propulsion Laboratory's research on a second generation, solid-state image sensor technology has resulted in the Complementary Metal- Oxide Semiconductor Active Pixel Sensor (CMOS), establishing an alternative to the Charged Coupled Device (CCD). Photobit Corporation, the leading supplier of CMOS image sensors, has commercialized two products of their own based on this technology: the PB-100 and PB-300. These devices are cameras on a chip, combining all camera functions. CMOS "active-pixel" digital image sensors offer several advantages over CCDs, a technology used in video and still-camera applications for 30 years. The CMOS sensors draw less energy, they use the same manufacturing platform as most microprocessors and memory chips, and they allow on-chip programming of frame size, exposure, and other parameters.

Motorcycle detection and counting using stereo camera, IR camera, and microphone array

NASA Astrophysics Data System (ADS)

Ling, Bo; Gibson, David R. P.; Middleton, Dan

2013-03-01

Detection, classification, and characterization are the key to enhancing motorcycle safety, motorcycle operations and motorcycle travel estimation. Average motorcycle fatalities per Vehicle Mile Traveled (VMT) are currently estimated at 30 times those of auto fatalities. Although it has been an active research area for many years, motorcycle detection still remains a challenging task. Working with FHWA, we have developed a hybrid motorcycle detection and counting system using a suite of sensors including stereo camera, thermal IR camera and unidirectional microphone array. The IR thermal camera can capture the unique thermal signatures associated with the motorcycle's exhaust pipes that often show bright elongated blobs in IR images. The stereo camera in the system is used to detect the motorcyclist who can be easily windowed out in the stereo disparity map. If the motorcyclist is detected through his or her 3D body recognition, motorcycle is detected. Microphones are used to detect motorcycles that often produce low frequency acoustic signals. All three microphones in the microphone array are placed in strategic locations on the sensor platform to minimize the interferences of background noises from sources such as rain and wind. Field test results show that this hybrid motorcycle detection and counting system has an excellent performance.

SLR digital camera for forensic photography

NASA Astrophysics Data System (ADS)

Har, Donghwan; Son, Youngho; Lee, Sungwon

2004-06-01

Forensic photography, which was systematically established in the late 19th century by Alphonse Bertillon of France, has developed a lot for about 100 years. The development will be more accelerated with the development of high technologies, in particular the digital technology. This paper reviews three studies to answer the question: Can the SLR digital camera replace the traditional silver halide type ultraviolet photography and infrared photography? 1. Comparison of relative ultraviolet and infrared sensitivity of SLR digital camera to silver halide photography. 2. How much ultraviolet or infrared sensitivity is improved when removing the UV/IR cutoff filter built in the SLR digital camera? 3. Comparison of relative sensitivity of CCD and CMOS for ultraviolet and infrared. The test result showed that the SLR digital camera has a very low sensitivity for ultraviolet and infrared. The cause was found to be the UV/IR cutoff filter mounted in front of the image sensor. Removing the UV/IR cutoff filter significantly improved the sensitivity for ultraviolet and infrared. Particularly for infrared, the sensitivity of the SLR digital camera was better than that of the silver halide film. This shows the possibility of replacing the silver halide type ultraviolet photography and infrared photography with the SLR digital camera. Thus, the SLR digital camera seems to be useful for forensic photography, which deals with a lot of ultraviolet and infrared photographs.

Optical designs for the Mars '03 rover cameras

NASA Astrophysics Data System (ADS)

Smith, Gregory H.; Hagerott, Edward C.; Scherr, Lawrence M.; Herkenhoff, Kenneth E.; Bell, James F.

2001-12-01

In 2003, NASA is planning to send two robotic rover vehicles to explore the surface of Mars. The spacecraft will land on airbags in different, carefully chosen locations. The search for evidence indicating conditions favorable for past or present life will be a high priority. Each rover will carry a total of ten cameras of five various types. There will be a stereo pair of color panoramic cameras, a stereo pair of wide- field navigation cameras, one close-up camera on a movable arm, two stereo pairs of fisheye cameras for hazard avoidance, and one Sun sensor camera. This paper discusses the lenses for these cameras. Included are the specifications, design approaches, expected optical performances, prescriptions, and tolerances.

An Educational PET Camera Model

ERIC Educational Resources Information Center

Johansson, K. E.; Nilsson, Ch.; Tegner, P. E.

2006-01-01

Positron emission tomography (PET) cameras are now in widespread use in hospitals. A model of a PET camera has been installed in Stockholm House of Science and is used to explain the principles of PET to school pupils as described here.

Cameras on Mars 2020 Rover

NASA Image and Video Library

2017-10-31

This image presents a selection of the 23 cameras on NASA's 2020 Mars rover. Many are improved versions of the cameras on the Curiosity rover, with a few new additions as well. https://photojournal.jpl.nasa.gov/catalog/PIA22103

Depth estimation using a lightfield camera

NASA Astrophysics Data System (ADS)

Roper, Carissa

The latest innovation to camera design has come in the form of the lightfield, or plenoptic, camera that captures 4-D radiance data rather than just the 2-D scene image via microlens arrays. With the spatial and angular light ray data now recorded on the camera sensor, it is feasible to construct algorithms that can estimate depth of field in different portions of a given scene. There are limitations to the precision due to hardware structure and the sheer number of scene variations that can occur. In this thesis, the potential of digital image analysis and spatial filtering to extract depth information is tested on the commercially available plenoptic camera.

First results from the TOPSAT camera

NASA Astrophysics Data System (ADS)

Greenway, Paul; Tosh, Ian; Morris, Nigel; Burton, Gary; Cawley, Steve

2017-11-01

The TopSat camera is a low cost remote sensing imager capable of producing 2.5 metre resolution panchromatic imagery, funded by the British National Space Centre's Mosaic programme. The instrument was designed and assembled at the Space Science & Technology Department of the CCLRC's Rutherford Appleton Laboratory (RAL) in the UK, and was launched on the 27th October 2005 from Plesetsk Cosmodrome in Northern Russia on a Kosmos-3M. The camera utilises an off-axis three mirror system, which has the advantages of excellent image quality over a wide field of view, combined with a compactness that makes its overall dimensions smaller than its focal length. Keeping the costs to a minimum has been a major design driver in the development of this camera. The camera is part of the TopSat mission, which is a collaboration between four UK organisations; QinetiQ, Surrey Satellite Technology Ltd (SSTL), RAL and Infoterra. Its objective is to demonstrate provision of rapid response high resolution imagery to fixed and mobile ground stations using a low cost minisatellite. The paper "Development of the TopSat Camera" presented by RAL at the 5th ICSO in 2004 described the opto-mechanical design, assembly, alignment and environmental test methods implemented. Now that the spacecraft is in orbit and successfully acquiring images, this paper presents the first results from the camera and makes an initial assessment of the camera's in-orbit performance.

Camera Trajectory fromWide Baseline Images

NASA Astrophysics Data System (ADS)

Havlena, M.; Torii, A.; Pajdla, T.

2008-09-01

Camera trajectory estimation, which is closely related to the structure from motion computation, is one of the fundamental tasks in computer vision. Reliable camera trajectory estimation plays an important role in 3D reconstruction, self localization, and object recognition. There are essential issues for a reliable camera trajectory estimation, for instance, choice of the camera and its geometric projection model, camera calibration, image feature detection and description, and robust 3D structure computation. Most of approaches rely on classical perspective cameras because of the simplicity of their projection models and ease of their calibration. However, classical perspective cameras offer only a limited field of view, and thus occlusions and sharp camera turns may cause that consecutive frames look completely different when the baseline becomes longer. This makes the image feature matching very difficult (or impossible) and the camera trajectory estimation fails under such conditions. These problems can be avoided if omnidirectional cameras, e.g. a fish-eye lens convertor, are used. The hardware which we are using in practice is a combination of Nikon FC-E9 mounted via a mechanical adaptor onto a Kyocera Finecam M410R digital camera. Nikon FC-E9 is a megapixel omnidirectional addon convertor with 180° view angle which provides images of photographic quality. Kyocera Finecam M410R delivers 2272×1704 images at 3 frames per second. The resulting combination yields a circular view of diameter 1600 pixels in the image. Since consecutive frames of the omnidirectional camera often share a common region in 3D space, the image feature matching is often feasible. On the other hand, the calibration of these cameras is non-trivial and is crucial for the accuracy of the resulting 3D reconstruction. We calibrate omnidirectional cameras off-line using the state-of-the-art technique and Mičušík's two-parameter model, that links the radius of the image point r to the

The sequence measurement system of the IR camera

NASA Astrophysics Data System (ADS)

Geng, Ai-hui; Han, Hong-xia; Zhang, Hai-bo

2011-08-01

Currently, the IR cameras are broadly used in the optic-electronic tracking, optic-electronic measuring, fire control and optic-electronic countermeasure field, but the output sequence of the most presently applied IR cameras in the project is complex and the giving sequence documents from the leave factory are not detailed. Aiming at the requirement that the continuous image transmission and image procession system need the detailed sequence of the IR cameras, the sequence measurement system of the IR camera is designed, and the detailed sequence measurement way of the applied IR camera is carried out. The FPGA programming combined with the SignalTap online observation way has been applied in the sequence measurement system, and the precise sequence of the IR camera's output signal has been achieved, the detailed document of the IR camera has been supplied to the continuous image transmission system, image processing system and etc. The sequence measurement system of the IR camera includes CameraLink input interface part, LVDS input interface part, FPGA part, CameraLink output interface part and etc, thereinto the FPGA part is the key composed part in the sequence measurement system. Both the video signal of the CmaeraLink style and the video signal of LVDS style can be accepted by the sequence measurement system, and because the image processing card and image memory card always use the CameraLink interface as its input interface style, the output signal style of the sequence measurement system has been designed into CameraLink interface. The sequence measurement system does the IR camera's sequence measurement work and meanwhile does the interface transmission work to some cameras. Inside the FPGA of the sequence measurement system, the sequence measurement program, the pixel clock modification, the SignalTap file configuration and the SignalTap online observation has been integrated to realize the precise measurement to the IR camera. Te sequence measurement

Flow visualization by mobile phone cameras

NASA Astrophysics Data System (ADS)

Cierpka, Christian; Hain, Rainer; Buchmann, Nicolas A.

2016-06-01

Mobile smart phones were completely changing people's communication within the last ten years. However, these devices do not only offer communication through different channels but also devices and applications for fun and recreation. In this respect, mobile phone cameras include now relatively fast (up to 240 Hz) cameras to capture high-speed videos of sport events or other fast processes. The article therefore explores the possibility to make use of this development and the wide spread availability of these cameras in the terms of velocity measurements for industrial or technical applications and fluid dynamics education in high schools and at universities. The requirements for a simplistic PIV (particle image velocimetry) system are discussed. A model experiment of a free water jet was used to prove the concept and shed some light on the achievable quality and determine bottle necks by comparing the results obtained with a mobile phone camera with data taken by a high-speed camera suited for scientific experiments.

Optimising Camera Traps for Monitoring Small Mammals

PubMed Central

Glen, Alistair S.; Cockburn, Stuart; Nichols, Margaret; Ekanayake, Jagath; Warburton, Bruce

2013-01-01

Practical techniques are required to monitor invasive animals, which are often cryptic and occur at low density. Camera traps have potential for this purpose, but may have problems detecting and identifying small species. A further challenge is how to standardise the size of each camera’s field of view so capture rates are comparable between different places and times. We investigated the optimal specifications for a low-cost camera trap for small mammals. The factors tested were 1) trigger speed, 2) passive infrared vs. microwave sensor, 3) white vs. infrared flash, and 4) still photographs vs. video. We also tested a new approach to standardise each camera’s field of view. We compared the success rates of four camera trap designs in detecting and taking recognisable photographs of captive stoats ( Mustela erminea ), feral cats (Felis catus) and hedgehogs ( Erinaceus europaeus ). Trigger speeds of 0.2–2.1 s captured photographs of all three target species unless the animal was running at high speed. The camera with a microwave sensor was prone to false triggers, and often failed to trigger when an animal moved in front of it. A white flash produced photographs that were more readily identified to species than those obtained under infrared light. However, a white flash may be more likely to frighten target animals, potentially affecting detection probabilities. Video footage achieved similar success rates to still cameras but required more processing time and computer memory. Placing two camera traps side by side achieved a higher success rate than using a single camera. Camera traps show considerable promise for monitoring invasive mammal control operations. Further research should address how best to standardise the size of each camera’s field of view, maximise the probability that an animal encountering a camera trap will be detected, and eliminate visible or audible cues emitted by camera traps. PMID:23840790

The kinetics and dynamics of the coma of Halley's comet

NASA Technical Reports Server (NTRS)

Combi, Michael R.

1994-01-01

This grant to the University of Michigan supported the efforts of Michael R. Combi to serve as a co-investigator in collaboration with a larger effort by the principal investigator, William Smyth of Atmospheric and Environmental Research, Inc. The overall objective of this project was to analyze in a self-consistent manner unique optical O((sup 1)D) and NH2 ultra-high resolution line profile data of excellent quality and other supporting lower-resolution spectral data for the coma of comet P/Halley by using highly developed and physically-based cometary coma models in order to determine and explain in terms of physical processes the actual dynamics and photochemical kinetics that occur in the coma. The justification for this work is that it provides a valuable and underlying physical base from which to interpret significantly different types of coma observations in a self-consistent manner and hence bring into agreement (or avoid) apparent inconsistencies that arise from non-physically based interpretations. The level of effort for the Michigan component amounted to less than three person-months over a planned period of three years. The period had been extended at no extra cost to four years because the Michigan grant and the AER contract did not have coincident time periods. An effort of somewhat larger scope was undertaken by the PI. The importance of the O((sup 1)D) profiles is that they provide a direct trace of the water distribution in comets. The line profile shape is produced by the convolution of the outflow velocity and thermal dispersion of the parent water molecules with the photokinetic ejection of the oxygen atoms upon photodissociation of the parent water molecules. Our understanding of the NH2 and its precursor ammonia are important for comet-to-comet composition variations as they relate to the cosmo-chemistry of the early solar nebula. Modeling of the distribution of NH2 is necessary in order to infer the ammonia production rates from NH2

Quality controls for gamma cameras and PET cameras: development of a free open-source ImageJ program

NASA Astrophysics Data System (ADS)

Carlier, Thomas; Ferrer, Ludovic; Berruchon, Jean B.; Cuissard, Regis; Martineau, Adeline; Loonis, Pierre; Couturier, Olivier

2005-04-01

Acquisition data and treatments for quality controls of gamma cameras and Positron Emission Tomography (PET) cameras are commonly performed with dedicated program packages, which are running only on manufactured computers and differ from each other, depending on camera company and program versions. The aim of this work was to develop a free open-source program (written in JAVA language) to analyze data for quality control of gamma cameras and PET cameras. The program is based on the free application software ImageJ and can be easily loaded on any computer operating system (OS) and thus on any type of computer in every nuclear medicine department. Based on standard parameters of quality control, this program includes 1) for gamma camera: a rotation center control (extracted from the American Association of Physics in Medicine, AAPM, norms) and two uniformity controls (extracted from the Institute of Physics and Engineering in Medicine, IPEM, and National Electronic Manufacturers Association, NEMA, norms). 2) For PET systems, three quality controls recently defined by the French Medical Physicist Society (SFPM), i.e. spatial resolution and uniformity in a reconstructed slice and scatter fraction, are included. The determination of spatial resolution (thanks to the Point Spread Function, PSF, acquisition) allows to compute the Modulation Transfer Function (MTF) in both modalities of cameras. All the control functions are included in a tool box which is a free ImageJ plugin and could be soon downloaded from Internet. Besides, this program offers the possibility to save on HTML format the uniformity quality control results and a warning can be set to automatically inform users in case of abnormal results. The architecture of the program allows users to easily add any other specific quality control program. Finally, this toolkit is an easy and robust tool to perform quality control on gamma cameras and PET cameras based on standard computation parameters, is free, run on

Inflight Calibration of the Lunar Reconnaissance Orbiter Camera Wide Angle Camera

NASA Astrophysics Data System (ADS)

Mahanti, P.; Humm, D. C.; Robinson, M. S.; Boyd, A. K.; Stelling, R.; Sato, H.; Denevi, B. W.; Braden, S. E.; Bowman-Cisneros, E.; Brylow, S. M.; Tschimmel, M.

2016-04-01

The Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) has acquired more than 250,000 images of the illuminated lunar surface and over 190,000 observations of space and non-illuminated Moon since 1 January 2010. These images, along with images from the Narrow Angle Camera (NAC) and other Lunar Reconnaissance Orbiter instrument datasets are enabling new discoveries about the morphology, composition, and geologic/geochemical evolution of the Moon. Characterizing the inflight WAC system performance is crucial to scientific and exploration results. Pre-launch calibration of the WAC provided a baseline characterization that was critical for early targeting and analysis. Here we present an analysis of WAC performance from the inflight data. In the course of our analysis we compare and contrast with the pre-launch performance wherever possible and quantify the uncertainty related to various components of the calibration process. We document the absolute and relative radiometric calibration, point spread function, and scattered light sources and provide estimates of sources of uncertainty for spectral reflectance measurements of the Moon across a range of imaging conditions.

The Orbiter camera payload system's large-format camera and attitude reference system

NASA Technical Reports Server (NTRS)

Schardt, B. B.; Mollberg, B. H.

1985-01-01

The Orbiter camera payload system (OCPS) is an integrated photographic system carried into earth orbit as a payload in the Space Transportation System (STS) Orbiter vehicle's cargo bay. The major component of the OCPS is a large-format camera (LFC), a precision wide-angle cartographic instrument capable of producing high-resolution stereophotography of great geometric fidelity in multiple base-to-height ratios. A secondary and supporting system to the LFC is the attitude reference system (ARS), a dual-lens stellar camera array (SCA) and camera support structure. The SCA is a 70 mm film system that is rigidly mounted to the LFC lens support structure and, through the simultaneous acquisition of two star fields with each earth viewing LFC frame, makes it possible to precisely determine the pointing of the LFC optical axis with reference to the earth nadir point. Other components complete the current OCPS configuration as a high-precision cartographic data acquisition system. The primary design objective for the OCPS was to maximize system performance characteristics while maintaining a high level of reliability compatible with rocket launch conditions and the on-orbit environment. The full OCPS configuration was launched on a highly successful maiden voyage aboard the STS Orbiter vehicle Challenger on Oct. 5, 1984, as a major payload aboard the STS-41G mission.

Object tracking using multiple camera video streams

NASA Astrophysics Data System (ADS)

Mehrubeoglu, Mehrube; Rojas, Diego; McLauchlan, Lifford

2010-05-01

Two synchronized cameras are utilized to obtain independent video streams to detect moving objects from two different viewing angles. The video frames are directly correlated in time. Moving objects in image frames from the two cameras are identified and tagged for tracking. One advantage of such a system involves overcoming effects of occlusions that could result in an object in partial or full view in one camera, when the same object is fully visible in another camera. Object registration is achieved by determining the location of common features in the moving object across simultaneous frames. Perspective differences are adjusted. Combining information from images from multiple cameras increases robustness of the tracking process. Motion tracking is achieved by determining anomalies caused by the objects' movement across frames in time in each and the combined video information. The path of each object is determined heuristically. Accuracy of detection is dependent on the speed of the object as well as variations in direction of motion. Fast cameras increase accuracy but limit the speed and complexity of the algorithm. Such an imaging system has applications in traffic analysis, surveillance and security, as well as object modeling from multi-view images. The system can easily be expanded by increasing the number of cameras such that there is an overlap between the scenes from at least two cameras in proximity. An object can then be tracked long distances or across multiple cameras continuously, applicable, for example, in wireless sensor networks for surveillance or navigation.

SEOS frame camera applications study

NASA Technical Reports Server (NTRS)

1974-01-01

A research and development satellite is discussed which will provide opportunities for observation of transient phenomena that fall within the fixed viewing circle of the spacecraft. The evaluation of possible applications for frame cameras, for SEOS, are studied. The computed lens characteristics for each camera are listed.

Digital Cameras for Student Use.

ERIC Educational Resources Information Center

Simpson, Carol

1997-01-01

Describes the features, equipment and operations of digital cameras and compares three different digital cameras for use in education. Price, technology requirements, features, transfer software, and accessories for the Kodak DC25, Olympus D-200L and Casio QV-100 are presented in a comparison table. (AEF)

Comparison of myocardial perfusion imaging between the new high-speed gamma camera and the standard anger camera.

PubMed

Tanaka, Hirokazu; Chikamori, Taishiro; Hida, Satoshi; Uchida, Kenji; Igarashi, Yuko; Yokoyama, Tsuyoshi; Takahashi, Masaki; Shiba, Chie; Yoshimura, Mana; Tokuuye, Koichi; Yamashina, Akira

2013-01-01

Cadmium-zinc-telluride (CZT) solid-state detectors have been recently introduced into the field of myocardial perfusion imaging. The aim of this study was to prospectively compare the diagnostic performance of the CZT high-speed gamma camera (Discovery NM 530c) with that of the standard 3-head gamma camera in the same group of patients. The study group consisted of 150 consecutive patients who underwent a 1-day stress-rest (99m)Tc-sestamibi or tetrofosmin imaging protocol. Image acquisition was performed first on a standard gamma camera with a 15-min scan time each for stress and for rest. All scans were immediately repeated on a CZT camera with a 5-min scan time for stress and a 3-min scan time for rest, using list mode. The correlations between the CZT camera and the standard camera for perfusion and function analyses were strong within narrow Bland-Altman limits of agreement. Using list mode analysis, image quality for stress was rated as good or excellent in 97% of the 3-min scans, and in 100% of the ≥4-min scans. For CZT scans at rest, similarly, image quality was rated as good or excellent in 94% of the 1-min scans, and in 100% of the ≥2-min scans. The novel CZT camera provides excellent image quality, which is equivalent to standard myocardial single-photon emission computed tomography, despite a short scan time of less than half of the standard time.

Adaptive DOF for plenoptic cameras

NASA Astrophysics Data System (ADS)

Oberdörster, Alexander; Lensch, Hendrik P. A.

2013-03-01

Plenoptic cameras promise to provide arbitrary re-focusing through a scene after the capture. In practice, however, the refocusing range is limited by the depth of field (DOF) of the plenoptic camera. For the focused plenoptic camera, this range is given by the range of object distances for which the microimages are in focus. We propose a technique of recording light fields with an adaptive depth of focus. Between multiple exposures { or multiple recordings of the light field { the distance between the microlens array (MLA) and the image sensor is adjusted. The depth and quality of focus is chosen by changing the number of exposures and the spacing of the MLA movements. In contrast to traditional cameras, extending the DOF does not necessarily lead to an all-in-focus image. Instead, the refocus range is extended. There is full creative control about the focus depth; images with shallow or selective focus can be generated.

Camera network video summarization

NASA Astrophysics Data System (ADS)

Panda, Rameswar; Roy-Chowdhury, Amit K.

2017-05-01

Networks of vision sensors are deployed in many settings, ranging from security needs to disaster response to environmental monitoring. Many of these setups have hundreds of cameras and tens of thousands of hours of video. The difficulty of analyzing such a massive volume of video data is apparent whenever there is an incident that requires foraging through vast video archives to identify events of interest. As a result, video summarization, that automatically extract a brief yet informative summary of these videos, has attracted intense attention in the recent years. Much progress has been made in developing a variety of ways to summarize a single video in form of a key sequence or video skim. However, generating a summary from a set of videos captured in a multi-camera network still remains as a novel and largely under-addressed problem. In this paper, with the aim of summarizing videos in a camera network, we introduce a novel representative selection approach via joint embedding and capped l21-norm minimization. The objective function is two-fold. The first is to capture the structural relationships of data points in a camera network via an embedding, which helps in characterizing the outliers and also in extracting a diverse set of representatives. The second is to use a capped l21-norm to model the sparsity and to suppress the influence of data outliers in representative selection. We propose to jointly optimize both of the objectives, such that embedding can not only characterize the structure, but also indicate the requirements of sparse representative selection. Extensive experiments on standard multi-camera datasets well demonstrate the efficacy of our method over state-of-the-art methods.

Camera calibration for multidirectional flame chemiluminescence tomography

NASA Astrophysics Data System (ADS)

Wang, Jia; Zhang, Weiguang; Zhang, Yuhong; Yu, Xun

2017-04-01

Flame chemiluminescence tomography (FCT), which combines computerized tomography theory and multidirectional chemiluminescence emission measurements, can realize instantaneous three-dimensional (3-D) diagnostics for flames with high spatial and temporal resolutions. One critical step of FCT is to record the projections by multiple cameras from different view angles. For high accuracy reconstructions, it requires that extrinsic parameters (the positions and orientations) and intrinsic parameters (especially the image distances) of cameras be accurately calibrated first. Taking the focus effect of the camera into account, a modified camera calibration method was presented for FCT, and a 3-D calibration pattern was designed to solve the parameters. The precision of the method was evaluated by reprojections of feature points to cameras with the calibration results. The maximum root mean square error of the feature points' position is 1.42 pixels and 0.0064 mm for the image distance. An FCT system with 12 cameras was calibrated by the proposed method and the 3-D CH* intensity of a propane flame was measured. The results showed that the FCT system provides reasonable reconstruction accuracy using the camera's calibration results.

Electrostatic camera system functional design study

NASA Technical Reports Server (NTRS)

Botticelli, R. A.; Cook, F. J.; Moore, R. F.

1972-01-01

A functional design study for an electrostatic camera system for application to planetary missions is presented. The electrostatic camera can produce and store a large number of pictures and provide for transmission of the stored information at arbitrary times after exposure. Preliminary configuration drawings and circuit diagrams for the system are illustrated. The camera system's size, weight, power consumption, and performance are characterized. Tradeoffs between system weight, power, and storage capacity are identified.

Polarizing aperture stereoscopic cinema camera

NASA Astrophysics Data System (ADS)

Lipton, Lenny

2012-03-01

The art of stereoscopic cinematography has been held back because of the lack of a convenient way to reduce the stereo camera lenses' interaxial to less than the distance between the eyes. This article describes a unified stereoscopic camera and lens design that allows for varying the interaxial separation to small values using a unique electro-optical polarizing aperture design for imaging left and right perspective views onto a large single digital sensor (the size of the standard 35mm frame) with the means to select left and right image information. Even with the added stereoscopic capability the appearance of existing camera bodies will be unaltered.

Polarizing aperture stereoscopic cinema camera

NASA Astrophysics Data System (ADS)

Lipton, Lenny

2012-07-01

The art of stereoscopic cinematography has been held back because of the lack of a convenient way to reduce the stereo camera lenses' interaxial to less than the distance between the eyes. This article describes a unified stereoscopic camera and lens design that allows for varying the interaxial separation to small values using a unique electro-optical polarizing aperture design for imaging left and right perspective views onto a large single digital sensor, the size of the standard 35 mm frame, with the means to select left and right image information. Even with the added stereoscopic capability, the appearance of existing camera bodies will be unaltered.

Raspberry Pi camera with intervalometer used as crescograph

NASA Astrophysics Data System (ADS)

Albert, Stefan; Surducan, Vasile

2017-12-01

The intervalometer is an attachment or facility on a photo-camera that operates the shutter regularly at set intervals over a period. Professional cameras with built in intervalometers are expensive and quite difficult to find. The Canon CHDK open source operating system allows intervalometer implementation on Canon cameras only. However finding a Canon camera with near infra-red (NIR) photographic lens at affordable price is impossible. On experiments requiring several cameras (used to measure growth in plants - the crescographs, but also for coarse evaluation of the water content of leaves), the costs of the equipment are often over budget. Using two Raspberry Pi modules each equipped with a low cost NIR camera and a WIFI adapter (for downloading pictures stored on the SD card) and some freely available software, we have implemented two low budget intervalometer cameras. The shutting interval, the number of pictures to be taken, image resolution and some other parameters can be fully programmed. Cameras have been in use continuously for three months (July-October 2017) in a relevant environment (outside), proving the concept functionality.

Cinematic camera emulation using two-dimensional color transforms

NASA Astrophysics Data System (ADS)

McElvain, Jon S.; Gish, Walter

2015-02-01

For cinematic and episodic productions, on-set look management is an important component of the creative process, and involves iterative adjustments of the set, actors, lighting and camera configuration. Instead of using the professional motion capture device to establish a particular look, the use of a smaller form factor DSLR is considered for this purpose due to its increased agility. Because the spectral response characteristics will be different between the two camera systems, a camera emulation transform is needed to approximate the behavior of the destination camera. Recently, twodimensional transforms have been shown to provide high-accuracy conversion of raw camera signals to a defined colorimetric state. In this study, the same formalism is used for camera emulation, whereby a Canon 5D Mark III DSLR is used to approximate the behavior a Red Epic cinematic camera. The spectral response characteristics for both cameras were measured and used to build 2D as well as 3x3 matrix emulation transforms. When tested on multispectral image databases, the 2D emulation transforms outperform their matrix counterparts, particularly for images containing highly chromatic content.

Camera artifacts in IUE spectra

NASA Technical Reports Server (NTRS)

Bruegman, O. W.; Crenshaw, D. M.

1994-01-01

This study of emission line mimicking features in the IUE cameras has produced an atlas of artifiacts in high-dispersion images with an accompanying table of prominent artifacts and a table of prominent artifacts in the raw images along with a medium image of the sky background for each IUE camera.

The "All Sky Camera Network"

ERIC Educational Resources Information Center

Caldwell, Andy

2005-01-01

In 2001, the "All Sky Camera Network" came to life as an outreach program to connect the Denver Museum of Nature and Science (DMNS) exhibit "Space Odyssey" with Colorado schools. The network is comprised of cameras placed strategically at schools throughout Colorado to capture fireballs--rare events that produce meteorites.…

Vacuum compatible miniature CCD camera head

DOEpatents

Conder, Alan D.

2000-01-01

A charge-coupled device (CCD) camera head which can replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating x-rays, such as within a target chamber where laser produced plasmas are studied. The camera head is small, capable of operating both in and out of a vacuum environment, and is versatile. The CCD camera head uses PC boards with an internal heat sink connected to the chassis for heat dissipation, which allows for close(0.04" for example) stacking of the PC boards. Integration of this CCD camera head into existing instrumentation provides a substantial enhancement of diagnostic capabilities for studying high energy density plasmas, for a variety of military industrial, and medical imaging applications.

Plenoptic camera image simulation for reconstruction algorithm verification

NASA Astrophysics Data System (ADS)

Schwiegerling, Jim

2014-09-01

Plenoptic cameras have emerged in recent years as a technology for capturing light field data in a single snapshot. A conventional digital camera can be modified with the addition of a lenslet array to create a plenoptic camera. Two distinct camera forms have been proposed in the literature. The first has the camera image focused onto the lenslet array. The lenslet array is placed over the camera sensor such that each lenslet forms an image of the exit pupil onto the sensor. The second plenoptic form has the lenslet array relaying the image formed by the camera lens to the sensor. We have developed a raytracing package that can simulate images formed by a generalized version of the plenoptic camera. Several rays from each sensor pixel are traced backwards through the system to define a cone of rays emanating from the entrance pupil of the camera lens. Objects that lie within this cone are integrated to lead to a color and exposure level for that pixel. To speed processing three-dimensional objects are approximated as a series of planes at different depths. Repeating this process for each pixel in the sensor leads to a simulated plenoptic image on which different reconstruction algorithms can be tested.

Gamma ray camera

DOEpatents

Perez-Mendez, Victor

1997-01-01

A gamma ray camera for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array.

Cameras on the moon with Apollos 15 and 16.

NASA Technical Reports Server (NTRS)

Page, T.

1972-01-01

Description of the cameras used for photography and television by Apollo 15 and 16 missions, covering a hand-held Hasselblad camera for black and white panoramic views at locations visited by the astronauts, a special stereoscopic camera designed by astronomer Tom Gold, a 16-mm movie camera used on the Apollo 15 and 16 Rovers, and several TV cameras. Details are given on the far-UV camera/spectrograph of the Apollo 16 mission. An electronographic camera converts UV light to electrons which are ejected by a KBr layer at the focus of an f/1 Schmidt camera and darken photographic films much more efficiently than far-UV. The astronomical activity of the Apollo 16 astronauts on the moon, using this equipment, is discussed.

21 CFR 886.1120 - Opthalmic camera.

Code of Federal Regulations, 2010 CFR

2010-04-01

... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1120 Opthalmic camera. (a) Identification. An ophthalmic camera is an AC-powered device intended to take photographs of the eye and the surrounding area...

Radiation camera motion correction system

DOEpatents

Hoffer, P.B.

1973-12-18

The device determines the ratio of the intensity of radiation received by a radiation camera from two separate portions of the object. A correction signal is developed to maintain this ratio at a substantially constant value and this correction signal is combined with the camera signal to correct for object motion. (Official Gazette)

Sky camera geometric calibration using solar observations

DOE PAGES

Urquhart, Bryan; Kurtz, Ben; Kleissl, Jan

2016-09-05

A camera model and associated automated calibration procedure for stationary daytime sky imaging cameras is presented. The specific modeling and calibration needs are motivated by remotely deployed cameras used to forecast solar power production where cameras point skyward and use 180° fisheye lenses. Sun position in the sky and on the image plane provides a simple and automated approach to calibration; special equipment or calibration patterns are not required. Sun position in the sky is modeled using a solar position algorithm (requiring latitude, longitude, altitude and time as inputs). Sun position on the image plane is detected using a simple image processing algorithm. Themore » performance evaluation focuses on the calibration of a camera employing a fisheye lens with an equisolid angle projection, but the camera model is general enough to treat most fixed focal length, central, dioptric camera systems with a photo objective lens. Calibration errors scale with the noise level of the sun position measurement in the image plane, but the calibration is robust across a large range of noise in the sun position. In conclusion, calibration performance on clear days ranged from 0.94 to 1.24 pixels root mean square error.« less

In-situ observations of a bi-modal ion distribution in the outer coma of comet P/Halley

NASA Technical Reports Server (NTRS)

Thomsen, M. F.; Feldman, W. C.; Wilken, B.; Jockers, K.; Stuedemann, W.

1987-01-01

Observations obtained by the Johnstone Plasma Analyzer on the Giotto fly-by of comet Halley showed a fairly sudden decrease in the count rate of energetic (about 30 KeV) water-group ions inside about 500,000 km from the nucleus. This decrease was accompanied by the appearance of a new water-group ion population at slightly lower energies (less than 10 KeV). Close inspection reveals that this lower-energy peak was also present somewhat earlier in the postshock flow but only became prominent near the sudden transition just described. It is shown that the observed bimodal ion distribution is well explained in terms of the velocity history of the accreting solar wind flow in the outer coma. The decline in count rate of the energetic pick-up distribution is due to a relatively sudden slowing of the bulk flow there and not to a loss of particles. Hence, charge-exchange cooling of the flow is probably not important at these distances from the nucleus. The observations suggest that pitch-angle scattering is fairly efficient at least after the bow shock, but that energy diffusion is probably not very efficient.

Architecture of PAU survey camera readout electronics

NASA Astrophysics Data System (ADS)

Castilla, Javier; Cardiel-Sas, Laia; De Vicente, Juan; Illa, Joseph; Jimenez, Jorge; Maiorino, Marino; Martinez, Gustavo

2012-07-01

PAUCam is a new camera for studying the physics of the accelerating universe. The camera will consist of eighteen 2Kx4K HPK CCDs: sixteen for science and two for guiding. The camera will be installed at the prime focus of the WHT (William Herschel Telescope). In this contribution, the architecture of the readout electronics system is presented. Back- End and Front-End electronics are described. Back-End consists of clock, bias and video processing boards, mounted on Monsoon crates. The Front-End is based on patch panel boards. These boards are plugged outside the camera feed-through panel for signal distribution. Inside the camera, individual preamplifier boards plus kapton cable completes the path to connect to each CCD. The overall signal distribution and grounding scheme is shown in this paper.

Traffic monitoring with distributed smart cameras

NASA Astrophysics Data System (ADS)

Sidla, Oliver; Rosner, Marcin; Ulm, Michael; Schwingshackl, Gert

2012-01-01

The observation and monitoring of traffic with smart visions systems for the purpose of improving traffic safety has a big potential. Today the automated analysis of traffic situations is still in its infancy--the patterns of vehicle motion and pedestrian flow in an urban environment are too complex to be fully captured and interpreted by a vision system. 3In this work we present steps towards a visual monitoring system which is designed to detect potentially dangerous traffic situations around a pedestrian crossing at a street intersection. The camera system is specifically designed to detect incidents in which the interaction of pedestrians and vehicles might develop into safety critical encounters. The proposed system has been field-tested at a real pedestrian crossing in the City of Vienna for the duration of one year. It consists of a cluster of 3 smart cameras, each of which is built from a very compact PC hardware system in a weatherproof housing. Two cameras run vehicle detection and tracking software, one camera runs a pedestrian detection and tracking module based on the HOG dectection principle. All 3 cameras use sparse optical flow computation in a low-resolution video stream in order to estimate the motion path and speed of objects. Geometric calibration of the cameras allows us to estimate the real-world co-ordinates of detected objects and to link the cameras together into one common reference system. This work describes the foundation for all the different object detection modalities (pedestrians, vehicles), and explains the system setup, tis design, and evaluation results which we have achieved so far.

Densities and abundances of hot cometary ions in the coma of P/Halley

NASA Technical Reports Server (NTRS)

Neugebauer, M.; Goldstein, R.; Goldstein, B. E.; Fuselier, S. A.; Balsiger, H.; Ip, W.-H.

1991-01-01

On its flight by P/Halley, the Giotto spacecraft carried a High Energy Range Spectrometer (HERS) for measuring the properties of cometary ions picked up by the solar wind in the nearly collisionless regions of the coma. Preliminary estimates of the ion densities observed by HERS were reevaluated and extended; density profiles along the Giotto trajectory are presented for 13 values of ion mass/charge. Comparison with the physical-chemical model of the interaction of sunlight and the solar wind with the comet by other researchers reveals that, with the exception of protons and H2(+), all ion densities were at least an order of magnitude higher than predicted. The high ion densities cannot be explained on the basis of compression of the plasma, but require additional or stronger ionization mechanisms. Ratios of the densities of different ion species reveal an overabundance of carbonaceous material and an underabundance of H2(+) compared to the predictions of the Schmidt. While the densities of solar wind ions (H(+) and He(++)) changed sharply across a magnetic discontinuity located 1.35(10)(exp 5) km from the comet, this feature, which has been called both the 'cometopause' and the 'magnetic pileup boundary' was barely distinguishable in the density profiles of hot cometary ions. This result is consistent with the interpretation that the magnetic pileup boundary detected by Giotto was caused by a discontinuity in the solar wind and is not an intrinsic feature of the interaction of the solar wind with an active comet.

New Modular Camera No Ordinary Joe

NASA Technical Reports Server (NTRS)

2003-01-01

Although dubbed 'Little Joe' for its small-format characteristics, a new wavefront sensor camera has proved that it is far from coming up short when paired with high-speed, low-noise applications. SciMeasure Analytical Systems, Inc., a provider of cameras and imaging accessories for use in biomedical research and industrial inspection and quality control, is the eye behind Little Joe's shutter, manufacturing and selling the modular, multi-purpose camera worldwide to advance fields such as astronomy, neurobiology, and cardiology.

The NASA - Arc 10/20 micron camera

NASA Technical Reports Server (NTRS)

Roellig, T. L.; Cooper, R.; Deutsch, L. K.; Mccreight, C.; Mckelvey, M.; Pendleton, Y. J.; Witteborn, F. C.; Yuen, L.; Mcmahon, T.; Werner, M. W.

1994-01-01

A new infrared camera (AIR Camera) has been developed at NASA - Ames Research Center for observations from ground-based telescopes. The heart of the camera is a Hughes 58 x 62 pixel Arsenic-doped Silicon detector array that has the spectral sensitivity range to allow observations in both the 10 and 20 micron atmospheric windows.

Attitude identification for SCOLE using two infrared cameras

NASA Technical Reports Server (NTRS)

Shenhar, Joram

1991-01-01

An algorithm is presented that incorporates real time data from two infrared cameras and computes the attitude parameters of the Spacecraft COntrol Lab Experiment (SCOLE), a lab apparatus representing an offset feed antenna attached to the Space Shuttle by a flexible mast. The algorithm uses camera position data of three miniature light emitting diodes (LEDs), mounted on the SCOLE platform, permitting arbitrary camera placement and an on-line attitude extraction. The continuous nature of the algorithm allows identification of the placement of the two cameras with respect to some initial position of the three reference LEDs, followed by on-line six degrees of freedom attitude tracking, regardless of the attitude time history. A description is provided of the algorithm in the camera identification mode as well as the mode of target tracking. Experimental data from a reduced size SCOLE-like lab model, reflecting the performance of the camera identification and the tracking processes, are presented. Computer code for camera placement identification and SCOLE attitude tracking is listed.

Prism-based single-camera system for stereo display

NASA Astrophysics Data System (ADS)

Zhao, Yue; Cui, Xiaoyu; Wang, Zhiguo; Chen, Hongsheng; Fan, Heyu; Wu, Teresa

2016-06-01

This paper combines the prism and single camera and puts forward a method of stereo imaging with low cost. First of all, according to the principle of geometrical optics, we can deduce the relationship between the prism single-camera system and dual-camera system, and according to the principle of binocular vision we can deduce the relationship between binoculars and dual camera. Thus we can establish the relationship between the prism single-camera system and binoculars and get the positional relation of prism, camera, and object with the best effect of stereo display. Finally, using the active shutter stereo glasses of NVIDIA Company, we can realize the three-dimensional (3-D) display of the object. The experimental results show that the proposed approach can make use of the prism single-camera system to simulate the various observation manners of eyes. The stereo imaging system, which is designed by the method proposed by this paper, can restore the 3-D shape of the object being photographed factually.

Plenoptic particle image velocimetry with multiple plenoptic cameras

NASA Astrophysics Data System (ADS)

Fahringer, Timothy W.; Thurow, Brian S.

2018-07-01

Plenoptic particle image velocimetry was recently introduced as a viable three-dimensional, three-component velocimetry technique based on light field cameras. One of the main benefits of this technique is its single camera configuration allowing the technique to be applied in facilities with limited optical access. The main drawback of this configuration is decreased accuracy in the out-of-plane dimension. This work presents a solution with the addition of a second plenoptic camera in a stereo-like configuration. A framework for reconstructing volumes with multiple plenoptic cameras including the volumetric calibration and reconstruction algorithms, including: integral refocusing, filtered refocusing, multiplicative refocusing, and MART are presented. It is shown that the addition of a second camera improves the reconstruction quality and removes the ‘cigar’-like elongation associated with the single camera system. In addition, it is found that adding a third camera provides minimal improvement. Further metrics of the reconstruction quality are quantified in terms of a reconstruction algorithm, particle density, number of cameras, camera separation angle, voxel size, and the effect of common image noise sources. In addition, a synthetic Gaussian ring vortex is used to compare the accuracy of the single and two camera configurations. It was determined that the addition of a second camera reduces the RMSE velocity error from 1.0 to 0.1 voxels in depth and 0.2 to 0.1 voxels in the lateral spatial directions. Finally, the technique is applied experimentally on a ring vortex and comparisons are drawn from the four presented reconstruction algorithms, where it was found that MART and multiplicative refocusing produced the cleanest vortex structure and had the least shot-to-shot variability. Filtered refocusing is able to produce the desired structure, albeit with more noise and variability, while integral refocusing struggled to produce a coherent vortex ring.

Giotto IMS measurements of the production rate of hydrogen cyanide in the coma of Comet Halley

NASA Technical Reports Server (NTRS)

Ip, W.-H.; Balsiger, H.; Geiss, J.; Goldstein, B. E.; Kettmann, G.

1990-01-01

The ion composition measurements in the ionosphere of Comet Halley by the ion mass spectrometer (IMS) experiment on the Giotto spacecraft are used to estimate the relative abundance of HCN. From a comparison of the normalized number density of ions with mass-to-charge (M/q) ratio of 28 AMU/e with steady-state photochemical models, it can be determined that the production rate of HCN directly from the central nucleus is Q(HCN) is less than about 0.0002 Q(H2O) at the time of Giotto encounter. The related photochemical- model calculations also indicate that Q(NH3)/Q(H2O) at the time of Giotto encounter. The related photo-chemical model calculations also indicate that Q(HN3)/Q(H2O) equals about 0.005, in agreement with recent determination from ground-based observations. The estimated value of Q(HCN) is lower than the relative abundance of Q(HCN)/Q(H2O) of about 0.001, as derived from radio observations of the 88.6 GHz emission of the J = 1 - 0 transition of HCN. The difference may be the result of time variations of the coma composition and dynamics, as well as other model-dependent effects.

Qualification Tests of Micro-camera Modules for Space Applications

NASA Astrophysics Data System (ADS)

Kimura, Shinichi; Miyasaka, Akira

Visual capability is very important for space-based activities, for which small, low-cost space cameras are desired. Although cameras for terrestrial applications are continually being improved, little progress has been made on cameras used in space, which must be extremely robust to withstand harsh environments. This study focuses on commercial off-the-shelf (COTS) CMOS digital cameras because they are very small and are based on an established mass-market technology. Radiation and ultrahigh-vacuum tests were conducted on a small COTS camera that weighs less than 100 mg (including optics). This paper presents the results of the qualification tests for COTS cameras and for a small, low-cost COTS-based space camera.

Radio-Observaciones del OH EN la Coma del Cometa Halley Desde EL Hemisferio Sur

NASA Astrophysics Data System (ADS)

Silva, A. M.; Bajaja, E.; Morras, R.; Cersosimo, J. C.; Martin, M. C.; Arnal, E. M.; Poppel, W. G. L.; Colomb, F. R.; Mazzaro, J.; Olalde, J. C.; Boriakoff, V.; Mirabel, I. F.

1987-05-01

Se utilizó una antena de 30 metros del Instituto Argentino de Radioastronomía para observaciones diarias Cf ebrero a abril de 1986) de la transición en 1667 MHz ( λ = 18 cm) del OH en la coma del cometa Halley. De las observaciones realizadas se concluye: 1) El número promedio de moléculas de OH en la coma durante 37 días de observación fue de (8.9±3.5)x1034 moléculas, lo que implica una tasa de producción promedio de OH de 1.8x1029 moléculas seg-1 y consecuentemente una pérdida de masa promedio de 17±6 toneladas seg-1 . Este valor está de acuerdo con las mediciones realizadas por las sondas Vega y Giotto. 2) El monitoreo desde el lAR revela la existencia de variaciones bruscas en los flujos de absorción del OH. Estas variaciones son consistentes con los modelos que representan la producción gaseosa a partir de ejecciones y/o desprendimientos discretos de materia congelada del núcleo. 3) Las variaciones en la densidad de flujo son consistentes con las estimaciones de los tiem- pos de vida medios del H2O y del OH en presencia del campo de radiación solar. 4) Se encuentra una correlación entre la intensidad del flujo absorbido y anisotropías en Ia dinamica de la coma.

Leveraging traffic and surveillance video cameras for urban traffic.

DOT National Transportation Integrated Search

2014-12-01

The objective of this project was to investigate the use of existing video resources, such as traffic : cameras, police cameras, red light cameras, and security cameras for the long-term, real-time : collection of traffic statistics. An additional ob...

Improving the color fidelity of cameras for advanced television systems

NASA Astrophysics Data System (ADS)

Kollarits, Richard V.; Gibbon, David C.

1992-08-01

In this paper we compare the accuracy of the color information obtained from television cameras using three and five wavelength bands. This comparison is based on real digital camera data. The cameras are treated as colorimeters whose characteristics are not linked to that of the display. The color matrices for both cameras were obtained by identical optimization procedures that minimized the color error The color error for the five band camera is 2. 5 times smaller than that obtained from the three band camera. Visual comparison of color matches on a characterized color monitor indicate that the five band camera is capable of color measurements that produce no significant visual error on the display. Because the outputs from the five band camera are reduced to the normal three channels conventionally used for display there need be no increase in signal handling complexity outside the camera. Likewise it is possible to construct a five band camera using only three sensors as in conventional cameras. The principal drawback of the five band camera is the reduction in effective camera sensitivity by about 3/4 of an I stop. 1.

Geometric rectification of camera-captured document images.

PubMed

Liang, Jian; DeMenthon, Daniel; Doermann, David

2008-04-01

Compared to typical scanners, handheld cameras offer convenient, flexible, portable, and non-contact image capture, which enables many new applications and breathes new life into existing ones. However, camera-captured documents may suffer from distortions caused by non-planar document shape and perspective projection, which lead to failure of current OCR technologies. We present a geometric rectification framework for restoring the frontal-flat view of a document from a single camera-captured image. Our approach estimates 3D document shape from texture flow information obtained directly from the image without requiring additional 3D/metric data or prior camera calibration. Our framework provides a unified solution for both planar and curved documents and can be applied in many, especially mobile, camera-based document analysis applications. Experiments show that our method produces results that are significantly more OCR compatible than the original images.

LWIR NUC using an uncooled microbolometer camera

NASA Astrophysics Data System (ADS)

Laveigne, Joe; Franks, Greg; Sparkman, Kevin; Prewarski, Marcus; Nehring, Brian; McHugh, Steve

2010-04-01

Performing a good non-uniformity correction is a key part of achieving optimal performance from an infrared scene projector. Ideally, NUC will be performed in the same band in which the scene projector will be used. Cooled, large format MWIR cameras are readily available and have been successfully used to perform NUC, however, cooled large format LWIR cameras are not as common and are prohibitively expensive. Large format uncooled cameras are far more available and affordable, but present a range of challenges in practical use for performing NUC on an IRSP. Santa Barbara Infrared, Inc. reports progress on a continuing development program to use a microbolometer camera to perform LWIR NUC on an IRSP. Camera instability and temporal response and thermal resolution are the main difficulties. A discussion of processes developed to mitigate these issues follows.

The multifocus plenoptic camera

NASA Astrophysics Data System (ADS)

Georgiev, Todor; Lumsdaine, Andrew

2012-01-01

The focused plenoptic camera is based on the Lippmann sensor: an array of microlenses focused on the pixels of a conventional image sensor. This device samples the radiance, or plenoptic function, as an array of cameras with large depth of field, focused at a certain plane in front of the microlenses. For the purpose of digital refocusing (which is one of the important applications) the depth of field needs to be large, but there are fundamental optical limitations to this. The solution of the above problem is to use and array of interleaved microlenses of different focal lengths, focused at two or more different planes. In this way a focused image can be constructed at any depth of focus, and a really wide range of digital refocusing can be achieved. This paper presents our theory and results of implementing such camera. Real world images are demonstrating the extended capabilities, and limitations are discussed.

Eventos de Desconexão no Cometa P/Halley sob a Ótica do Modelo de Reconexão Magnética

NASA Astrophysics Data System (ADS)

Voelzke, M. R.; Matsuura, O. T.

1998-08-01

531 imagens contidas no The International Halley Watch Atlas of Large-Scale Phenomena (Brandt et al., 1992) cobrindo o período de setembro de 1985 a julho de 1986 foram analisadas visando identificar, caracterizar as propriedades e correlacionar estruturas morfológicas da cauda de plasma do cometa P/Halley. A análise revelou 47 eventos de desconexão (DEs) (Niedner & Brandt, 1979; Jockers, 1985; Celnik et al., 1988; Delva et al., 1991). A análise completa de todas as imagens encontra-se publicada em Voelzke & Matsuura, 1998. A distribuição dos DEs na distância heliocêntrica apresenta um caráter bimodal possivelmente associado com a distribuição espacial das fronteiras de setor magnético do meio interplanetário. Os 47 DEs fotografados em 47 imagens distintas permitiram determinar 19 origens de DEs, ou seja, o instante em que supostamente o cometa cruzou a fronteira entre setores magnéticos do vento solar. Tais dados cometários foram comparados com dados do vento solar provenientes de medidas realizadas in situ pelas sondas IMP-8, ICE e PVO, que mediram a variação da velocidade do vento solar, da densidade e da pressão dinâmica durante o intervalo analisado. Os dados destas sondas espaciais em conjunto com os da sonda Vega 1 foram usados para determinar o tempo das passagens do lençol de corrente. Com base nos dados das sondas foram calculadas as coordenadas heliográficas retroativas do lençol de corrente na "superfície fonte" dos mapas sinóticos do campo magnético de Hoeksema, 1989. O cálculo retroativo é feito através de um modelo simples de expressão do vento solar com velocidade uniforme, sendo considerada a co-rotação da magnetosfera com o Sol. Este trabalho apresenta os resultados desta comparação e a análise cinemática da origem dos DEs, determinada sob a hipótese que o plasma desconectado de um dado DE afasta-se com velocidade constante do núcleo cometário (Voelzke & Matsuura, 1998) e compara esta análise com outras que

Uav Cameras: Overview and Geometric Calibration Benchmark

NASA Astrophysics Data System (ADS)

Cramer, M.; Przybilla, H.-J.; Zurhorst, A.

2017-08-01

Different UAV platforms and sensors are used in mapping already, many of them equipped with (sometimes) modified cameras as known from the consumer market. Even though these systems normally fulfil their requested mapping accuracy, the question arises, which system performs best? This asks for a benchmark, to check selected UAV based camera systems in well-defined, reproducible environments. Such benchmark is tried within this work here. Nine different cameras used on UAV platforms, representing typical camera classes, are considered. The focus is laid on the geometry here, which is tightly linked to the process of geometrical calibration of the system. In most applications the calibration is performed in-situ, i.e. calibration parameters are obtained as part of the project data itself. This is often motivated because consumer cameras do not keep constant geometry, thus, cannot be seen as metric cameras. Still, some of the commercial systems are quite stable over time, as it was proven from repeated (terrestrial) calibrations runs. Already (pre-)calibrated systems may offer advantages, especially when the block geometry of the project does not allow for a stable and sufficient in-situ calibration. Especially for such scenario close to metric UAV cameras may have advantages. Empirical airborne test flights in a calibration field have shown how block geometry influences the estimated calibration parameters and how consistent the parameters from lab calibration can be reproduced.

Schwarzschild camera

NASA Technical Reports Server (NTRS)

1980-01-01

The fabrication procedures for the primary and secondary mirrors for a Schwarzschild camera are summarized. The achieved wave front for the telescope was 1/2 wave at .63 microns. Interferograms of the two mirrors as a system are given and the mounting procedures are outlined.

Feasibility evaluation and study of adapting the attitude reference system to the Orbiter camera payload system's large format camera

NASA Technical Reports Server (NTRS)

1982-01-01

A design concept that will implement a mapping capability for the Orbital Camera Payload System (OCPS) when ground control points are not available is discussed. Through the use of stellar imagery collected by a pair of cameras whose optical axis are structurally related to the large format camera optical axis, such pointing information is made available.

Reconditioning of Cassini Narrow-Angle Camera

NASA Image and Video Library

2002-07-23

These five images of single stars, taken at different times with the narrow-angle camera on NASA Cassini spacecraft, show the effects of haze collecting on the camera optics, then successful removal of the haze by warming treatments.

Unmanned Ground Vehicle Perception Using Thermal Infrared Cameras

NASA Technical Reports Server (NTRS)

Rankin, Arturo; Huertas, Andres; Matthies, Larry; Bajracharya, Max; Assad, Christopher; Brennan, Shane; Bellutta, Paolo; Sherwin, Gary W.

2011-01-01

The ability to perform off-road autonomous navigation at any time of day or night is a requirement for some unmanned ground vehicle (UGV) programs. Because there are times when it is desirable for military UGVs to operate without emitting strong, detectable electromagnetic signals, a passive only terrain perception mode of operation is also often a requirement. Thermal infrared (TIR) cameras can be used to provide day and night passive terrain perception. TIR cameras have a detector sensitive to either mid-wave infrared (MWIR) radiation (3-5?m) or long-wave infrared (LWIR) radiation (8-12?m). With the recent emergence of high-quality uncooled LWIR cameras, TIR cameras have become viable passive perception options for some UGV programs. The Jet Propulsion Laboratory (JPL) has used a stereo pair of TIR cameras under several UGV programs to perform stereo ranging, terrain mapping, tree-trunk detection, pedestrian detection, negative obstacle detection, and water detection based on object reflections. In addition, we have evaluated stereo range data at a variety of UGV speeds, evaluated dual-band TIR classification of soil, vegetation, and rock terrain types, analyzed 24 hour water and 12 hour mud TIR imagery, and analyzed TIR imagery for hazard detection through smoke. Since TIR cameras do not currently provide the resolution available from megapixel color cameras, a UGV's daytime safe speed is often reduced when using TIR instead of color cameras. In this paper, we summarize the UGV terrain perception work JPL has performed with TIR cameras over the last decade and describe a calibration target developed by General Dynamics Robotic Systems (GDRS) for TIR cameras and other sensors.

Harbour surveillance with cameras calibrated with AIS data

NASA Astrophysics Data System (ADS)

Palmieri, F. A. N.; Castaldo, F.; Marino, G.

The inexpensive availability of surveillance cameras, easily connected in network configurations, suggests the deployment of this additional sensor modality in port surveillance. Vessels appearing within cameras fields of view can be recognized and localized providing to fusion centers information that can be added to data coming from Radar, Lidar, AIS, etc. Camera systems, that are used as localizers however, must be properly calibrated in changing scenarios where often there is limited choice on the position on which they are deployed. Automatic Identification System (AIS) data, that includes position, course and vessel's identity, freely available through inexpensive receivers, for some of the vessels appearing within the field of view, provide the opportunity to achieve proper camera calibration to be used for the localization of vessels not equipped with AIS transponders. In this paper we assume a pinhole model for camera geometry and propose perspective matrices computation using AIS positional data. Images obtained from calibrated cameras are then matched and pixel association is utilized for other vessel's localization. We report preliminary experimental results of calibration and localization using two cameras deployed on the Gulf of Naples coastline. The two cameras overlook a section of the harbour and record short video sequences that are synchronized offline with AIS positional information of easily-identified passenger ships. Other small vessels, not equipped with AIS transponders, are localized using camera matrices and pixel matching. Localization accuracy is experimentally evaluated as a function of target distance from the sensors.

Calibration of asynchronous smart phone cameras from moving objects

NASA Astrophysics Data System (ADS)

Hagen, Oksana; Istenič, Klemen; Bharti, Vibhav; Dhali, Maruf Ahmed; Barmaimon, Daniel; Houssineau, Jérémie; Clark, Daniel

2015-04-01

Calibrating multiple cameras is a fundamental prerequisite for many Computer Vision applications. Typically this involves using a pair of identical synchronized industrial or high-end consumer cameras. This paper considers an application on a pair of low-cost portable cameras with different parameters that are found in smart phones. This paper addresses the issues of acquisition, detection of moving objects, dynamic camera registration and tracking of arbitrary number of targets. The acquisition of data is performed using two standard smart phone cameras and later processed using detections of moving objects in the scene. The registration of cameras onto the same world reference frame is performed using a recently developed method for camera calibration using a disparity space parameterisation and the single-cluster PHD filter.

Gamma ray camera

DOEpatents

Perez-Mendez, V.

1997-01-21

A gamma ray camera is disclosed for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array. 6 figs.

Close-range photogrammetry with video cameras

NASA Technical Reports Server (NTRS)

Burner, A. W.; Snow, W. L.; Goad, W. K.

1985-01-01

Examples of photogrammetric measurements made with video cameras uncorrected for electronic and optical lens distortions are presented. The measurement and correction of electronic distortions of video cameras using both bilinear and polynomial interpolation are discussed. Examples showing the relative stability of electronic distortions over long periods of time are presented. Having corrected for electronic distortion, the data are further corrected for lens distortion using the plumb line method. Examples of close-range photogrammetric data taken with video cameras corrected for both electronic and optical lens distortion are presented.

Close-Range Photogrammetry with Video Cameras

NASA Technical Reports Server (NTRS)

Burner, A. W.; Snow, W. L.; Goad, W. K.

1983-01-01

Examples of photogrammetric measurements made with video cameras uncorrected for electronic and optical lens distortions are presented. The measurement and correction of electronic distortions of video cameras using both bilinear and polynomial interpolation are discussed. Examples showing the relative stability of electronic distortions over long periods of time are presented. Having corrected for electronic distortion, the data are further corrected for lens distortion using the plumb line method. Examples of close-range photogrammetric data taken with video cameras corrected for both electronic and optical lens distortion are presented.

Airborne ballistic camera tracking systems

NASA Technical Reports Server (NTRS)

Redish, W. L.

1976-01-01

An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

Cameras for semiconductor process control

NASA Technical Reports Server (NTRS)

Porter, W. A.; Parker, D. L.

1977-01-01

The application of X-ray topography to semiconductor process control is described, considering the novel features of the high speed camera and the difficulties associated with this technique. The most significant results on the effects of material defects on device performance are presented, including results obtained using wafers processed entirely within this institute. Defects were identified using the X-ray camera and correlations made with probe data. Also included are temperature dependent effects of material defects. Recent applications and improvements of X-ray topographs of silicon-on-sapphire and gallium arsenide are presented with a description of a real time TV system prototype and of the most recent vacuum chuck design. Discussion is included of our promotion of the use of the camera by various semiconductor manufacturers.

CameraHRV: robust measurement of heart rate variability using a camera

NASA Astrophysics Data System (ADS)

Pai, Amruta; Veeraraghavan, Ashok; Sabharwal, Ashutosh

2018-02-01

The inter-beat-interval (time period of the cardiac cycle) changes slightly for every heartbeat; this variation is measured as Heart Rate Variability (HRV). HRV is presumed to occur due to interactions between the parasym- pathetic and sympathetic nervous system. Therefore, it is sometimes used as an indicator of the stress level of an individual. HRV also reveals some clinical information about cardiac health. Currently, HRV is accurately measured using contact devices such as a pulse oximeter. However, recent research in the field of non-contact imaging Photoplethysmography (iPPG) has made vital sign measurements using just the video recording of any exposed skin (such as a person's face) possible. The current signal processing methods for extracting HRV using peak detection perform well for contact-based systems but have poor performance for the iPPG signals. The main reason for this poor performance is the fact that current methods are sensitive to large noise sources which are often present in iPPG data. Further, current methods are not robust to motion artifacts that are common in iPPG systems. We developed a new algorithm, CameraHRV, for robustly extracting HRV even in low SNR such as is common with iPPG recordings. CameraHRV combined spatial combination and frequency demodulation to obtain HRV from the instantaneous frequency of the iPPG signal. CameraHRV outperforms other current methods of HRV estimation. Ground truth data was obtained from FDA-approved pulse oximeter for validation purposes. CameraHRV on iPPG data showed an error of 6 milliseconds for low motion and varying skin tone scenarios. The improvement in error was 14%. In case of high motion scenarios like reading, watching and talking, the error was 10 milliseconds.

Light field rendering with omni-directional camera

NASA Astrophysics Data System (ADS)

Todoroki, Hiroshi; Saito, Hideo

2003-06-01

This paper presents an approach to capture visual appearance of a real environment such as an interior of a room. We propose the method for generating arbitrary viewpoint images by building light field with the omni-directional camera, which can capture the wide circumferences. Omni-directional camera used in this technique is a special camera with the hyperbolic mirror in the upper part of a camera, so that we can capture luminosity in the environment in the range of 360 degree of circumferences in one image. We apply the light field method, which is one technique of Image-Based-Rendering(IBR), for generating the arbitrary viewpoint images. The light field is a kind of the database that records the luminosity information in the object space. We employ the omni-directional camera for constructing the light field, so that we can collect many view direction images in the light field. Thus our method allows the user to explore the wide scene, that can acheive realistic representation of virtual enviroment. For demonstating the proposed method, we capture image sequence in our lab's interior environment with an omni-directional camera, and succesfully generate arbitray viewpoint images for virual tour of the environment.

Color Camera for Curiosity Robotic Arm

NASA Image and Video Library

2010-11-16

The Mars Hand Lens Imager MAHLI camera will fly on NASA Mars Science Laboratory mission, launching in late 2011. This photo of the camera was taken before MAHLI November 2010 installation onto the robotic arm of the mission Mars rover, Curiosity.

Performance Characteristics For The Orbiter Camera Payload System's Large Format Camera (LFC)

NASA Astrophysics Data System (ADS)

MoIIberg, Bernard H.

1981-11-01

The Orbiter Camera Payload System, the OCPS, is an integrated photographic system which is carried into Earth orbit as a payload in the Shuttle Orbiter vehicle's cargo bay. The major component of the OCPS is a Large Format Camera (LFC) which is a precision wide-angle cartographic instrument that is capable of produc-ing high resolution stereophotography of great geometric fidelity in multiple base to height ratios. The primary design objective for the LFC was to maximize all system performance characteristics while maintaining a high level of reliability compatible with rocket launch conditions and the on-orbit environment.

Pettit holds cameras in the U.S. Laboratory

NASA Image and Video Library

2012-01-15

ISS030-E-175788 (15 Jan. 2012) --- NASA astronaut Don Pettit, Expedition 30 flight engineer, is pictured with two still cameras mounted together in the Destiny laboratory of the International Space Station. One camera is an infrared modified still camera.

An image-tube camera for cometary spectrography

NASA Astrophysics Data System (ADS)

Mamadov, O.

The paper discusses the mounting of an image tube camera. The cathode is of antimony, sodium, potassium, and cesium. The parts used for mounting are of acrylic plastic and a fabric-based laminate. A mounting design that does not include cooling is presented. The aperture ratio of the camera is 1:27. Also discussed is the way that the camera is joined to the spectrograph.

Measuring Positions of Objects using Two or More Cameras

NASA Technical Reports Server (NTRS)

Klinko, Steve; Lane, John; Nelson, Christopher

2008-01-01

An improved method of computing positions of objects from digitized images acquired by two or more cameras (see figure) has been developed for use in tracking debris shed by a spacecraft during and shortly after launch. The method is also readily adaptable to such applications as (1) tracking moving and possibly interacting objects in other settings in order to determine causes of accidents and (2) measuring positions of stationary objects, as in surveying. Images acquired by cameras fixed to the ground and/or cameras mounted on tracking telescopes can be used in this method. In this method, processing of image data starts with creation of detailed computer- aided design (CAD) models of the objects to be tracked. By rotating, translating, resizing, and overlaying the models with digitized camera images, parameters that characterize the position and orientation of the camera can be determined. The final position error depends on how well the centroids of the objects in the images are measured; how accurately the centroids are interpolated for synchronization of cameras; and how effectively matches are made to determine rotation, scaling, and translation parameters. The method involves use of the perspective camera model (also denoted the point camera model), which is one of several mathematical models developed over the years to represent the relationships between external coordinates of objects and the coordinates of the objects as they appear on the image plane in a camera. The method also involves extensive use of the affine camera model, in which the distance from the camera to an object (or to a small feature on an object) is assumed to be much greater than the size of the object (or feature), resulting in a truly two-dimensional image. The affine camera model does not require advance knowledge of the positions and orientations of the cameras. This is because ultimately, positions and orientations of the cameras and of all objects are computed in a coordinate

Characterization of SWIR cameras by MRC measurements

NASA Astrophysics Data System (ADS)

Gerken, M.; Schlemmer, H.; Haan, Hubertus A.; Siemens, Christofer; Münzberg, M.

2014-05-01

Cameras for the SWIR wavelength range are becoming more and more important because of the better observation range for day-light operation under adverse weather conditions (haze, fog, rain). In order to choose the best suitable SWIR camera or to qualify a camera for a given application, characterization of the camera by means of the Minimum Resolvable Contrast MRC concept is favorable as the MRC comprises all relevant properties of the instrument. With the MRC known for a given camera device the achievable observation range can be calculated for every combination of target size, illumination level or weather conditions. MRC measurements in the SWIR wavelength band can be performed widely along the guidelines of the MRC measurements of a visual camera. Typically measurements are performed with a set of resolution targets (e.g. USAF 1951 target) manufactured with different contrast values from 50% down to less than 1%. For a given illumination level the achievable spatial resolution is then measured for each target. The resulting curve is showing the minimum contrast that is necessary to resolve the structure of a target as a function of spatial frequency. To perform MRC measurements for SWIR cameras at first the irradiation parameters have to be given in radiometric instead of photometric units which are limited in their use to the visible range. In order to do so, SWIR illumination levels for typical daylight and twilight conditions have to be defined. At second, a radiation source is necessary with appropriate emission in the SWIR range (e.g. incandescent lamp) and the irradiance has to be measured in W/m2 instead of Lux = Lumen/m2. At third, the contrast values of the targets have to be calibrated newly for the SWIR range because they typically differ from the values determined for the visual range. Measured MRC values of three cameras are compared to the specified performance data of the devices and the results of a multi-band in-house designed Vis-SWIR camera

Physical properties, transmission and emission spectra of the WASP-19 planetary system from multi-colour photometry

NASA Astrophysics Data System (ADS)

Mancini, L.; Ciceri, S.; Chen, G.; Tregloan-Reed, J.; Fortney, J. J.; Southworth, J.; Tan, T. G.; Burgdorf, M.; Calchi Novati, S.; Dominik, M.; Fang, X.-S.; Finet, F.; Gerner, T.; Hardis, S.; Hinse, T. C.; Jørgensen, U. G.; Liebig, C.; Nikolov, N.; Ricci, D.; Schäfer, S.; Schönebeck, F.; Skottfelt, J.; Wertz, O.; Alsubai, K. A.; Bozza, V.; Browne, P.; Dodds, P.; Gu, S.-H.; Harpsøe, K.; Henning, Th.; Hundertmark, M.; Jessen-Hansen, J.; Kains, N.; Kerins, E.; Kjeldsen, H.; Lund, M. N.; Lundkvist, M.; Madhusudhan, N.; Mathiasen, M.; Penny, M. T.; Prof, S.; Rahvar, S.; Sahu, K.; Scarpetta, G.; Snodgrass, C.; Surdej, J.

2013-11-01

We present new ground-based, multi-colour, broad-band photometric measurements of the physical parameters, transmission and emission spectra of the transiting extrasolar planet WASP-19b. The measurements are based on observations of eight transits and four occultations through a Gunn i filter using the 1.54-m Danish Telescope, 14 transits through an Rc filter at the Perth Exoplanet Survey Telescope (PEST) observatory and one transit observed simultaneously through four optical (Sloan g', r', i', z') and three near-infrared (J, H, K) filters, using the Gamma Ray Burst Optical and Near-Infrared Detector (GROND) instrument on the MPG/ESO 2.2-m telescope. The GROND optical light curves have a point-to-point scatter around the best-fitting model between 0.52 and 0.65 mmag rms. We use these new data to measure refined physical parameters for the system. We find the planet to be more bloated (Rb = 1.410 ± 0.017RJup; Mb = 1.139 ± 0.030MJup) and the system to be twice as old as initially thought. We also used published and archived data sets to study the transit timings, which do not depart from a linear ephemeris. We detected an anomaly in the GROND transit light curve which is compatible with a spot on the photosphere of the parent star. The starspot position, size, spot contrast and temperature were established. Using our new and published measurements, we assembled the planet's transmission spectrum over the 370-2350 nm wavelength range and its emission spectrum over the 750-8000 nm range. By comparing these data to theoretical models we investigated the theoretically predicted variation of the apparent radius of WASP-19b as a function of wavelength and studied the composition and thermal structure of its atmosphere. We conclude that: (i) there is no evidence for strong optical absorbers at low pressure, supporting the common idea that the planet's atmosphere lacks a dayside inversion; (ii) the temperature of the planet is not homogenized, because the high warming of

Multispectral image dissector camera flight test

NASA Technical Reports Server (NTRS)

Johnson, B. L.

1973-01-01

It was demonstrated that the multispectral image dissector camera is able to provide composite pictures of the earth surface from high altitude overflights. An electronic deflection feature was used to inject the gyro error signal into the camera for correction of aircraft motion.

Calibration Target for Curiosity Arm Camera

NASA Image and Video Library

2012-09-10

This view of the calibration target for the MAHLI camera aboard NASA Mars rover Curiosity combines two images taken by that camera during Sept. 9, 2012. Part of Curiosity left-front and center wheels and a patch of Martian ground are also visible.

Camera traps can be heard and seen by animals.

PubMed

Meek, Paul D; Ballard, Guy-Anthony; Fleming, Peter J S; Schaefer, Michael; Williams, Warwick; Falzon, Greg

2014-01-01

Camera traps are electrical instruments that emit sounds and light. In recent decades they have become a tool of choice in wildlife research and monitoring. The variability between camera trap models and the methods used are considerable, and little is known about how animals respond to camera trap emissions. It has been reported that some animals show a response to camera traps, and in research this is often undesirable so it is important to understand why the animals are disturbed. We conducted laboratory based investigations to test the audio and infrared optical outputs of 12 camera trap models. Camera traps were measured for audio outputs in an anechoic chamber; we also measured ultrasonic (n = 5) and infrared illumination outputs (n = 7) of a subset of the camera trap models. We then compared the perceptive hearing range (n = 21) and assessed the vision ranges (n = 3) of mammals species (where data existed) to determine if animals can see and hear camera traps. We report that camera traps produce sounds that are well within the perceptive range of most mammals' hearing and produce illumination that can be seen by many species.

Camera Traps Can Be Heard and Seen by Animals

PubMed Central

Meek, Paul D.; Ballard, Guy-Anthony; Fleming, Peter J. S.; Schaefer, Michael; Williams, Warwick; Falzon, Greg

2014-01-01

Camera traps are electrical instruments that emit sounds and light. In recent decades they have become a tool of choice in wildlife research and monitoring. The variability between camera trap models and the methods used are considerable, and little is known about how animals respond to camera trap emissions. It has been reported that some animals show a response to camera traps, and in research this is often undesirable so it is important to understand why the animals are disturbed. We conducted laboratory based investigations to test the audio and infrared optical outputs of 12 camera trap models. Camera traps were measured for audio outputs in an anechoic chamber; we also measured ultrasonic (n = 5) and infrared illumination outputs (n = 7) of a subset of the camera trap models. We then compared the perceptive hearing range (n = 21) and assessed the vision ranges (n = 3) of mammals species (where data existed) to determine if animals can see and hear camera traps. We report that camera traps produce sounds that are well within the perceptive range of most mammals’ hearing and produce illumination that can be seen by many species. PMID:25354356

A wide-angle camera module for disposable endoscopy

NASA Astrophysics Data System (ADS)

Shim, Dongha; Yeon, Jesun; Yi, Jason; Park, Jongwon; Park, Soo Nam; Lee, Nanhee

2016-08-01

A wide-angle miniaturized camera module for disposable endoscope is demonstrated in this paper. A lens module with 150° angle of view (AOV) is designed and manufactured. All plastic injection-molded lenses and a commercial CMOS image sensor are employed to reduce the manufacturing cost. The image sensor and LED illumination unit are assembled with a lens module. The camera module does not include a camera processor to further reduce its size and cost. The size of the camera module is 5.5 × 5.5 × 22.3 mm3. The diagonal field of view (FOV) of the camera module is measured to be 110°. A prototype of a disposable endoscope is implemented to perform a pre-clinical animal testing. The esophagus of an adult beagle dog is observed. These results demonstrate the feasibility of a cost-effective and high-performance camera module for disposable endoscopy.

Daytime Aspect Camera for Balloon Altitudes

NASA Technical Reports Server (NTRS)

Dietz, Kurt L.; Ramsey, Brian D.; Alexander, Cheryl D.; Apple, Jeff A.; Ghosh, Kajal K.; Swift, Wesley R.

2002-01-01

We have designed, built, and flight-tested a new star camera for daytime guiding of pointed balloon-borne experiments at altitudes around 40 km. The camera and lens are commercially available, off-the-shelf components, but require a custom-built baffle to reduce stray light, especially near the sunlit limb of the balloon. This new camera, which operates in the 600- to 1000-nm region of the spectrum, successfully provides daytime aspect information of approx. 10 arcsec resolution for two distinct star fields near the galactic plane. The detected scattered-light backgrounds show good agreement with the Air Force MODTRAN models used to design the camera, but the daytime stellar magnitude limit was lower than expected due to longitudinal chromatic aberration in the lens. Replacing the commercial lens with a custom-built lens should allow the system to track stars in any arbitrary area of the sky during the daytime.

Lessons Learned from Crime Caught on Camera

PubMed Central

Bernasco, Wim

2018-01-01

Objectives: The widespread use of camera surveillance in public places offers criminologists the opportunity to systematically and unobtrusively observe crime, their main subject matter. The purpose of this essay is to inform the reader of current developments in research on crimes caught on camera. Methods: We address the importance of direct observation of behavior and review criminological studies that used observational methods, with and without cameras, including the ones published in this issue. We also discuss the uses of camera recordings in other social sciences and in biology. Results: We formulate six key insights that emerge from the literature and make recommendations for future research. Conclusions: Camera recordings of real-life crime are likely to become part of the criminological tool kit that will help us better understand the situational and interactional elements of crime. Like any source, it has limitations that are best addressed by triangulation with other sources. PMID:29472728

Stereo Cameras for Clouds (STEREOCAM) Instrument Handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romps, David; Oktem, Rusen

2017-10-31

The three pairs of stereo camera setups aim to provide synchronized and stereo calibrated time series of images that can be used for 3D cloud mask reconstruction. Each camera pair is positioned at approximately 120 degrees from the other pair, with a 17o-19o pitch angle from the ground, and at 5-6 km distance from the U.S. Department of Energy (DOE) Central Facility at the Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) observatory to cover the region from northeast, northwest, and southern views. Images from both cameras of the same stereo setup can be paired together tomore » obtain 3D reconstruction by triangulation. 3D reconstructions from the ring of three stereo pairs can be combined together to generate a 3D mask from surrounding views. This handbook delivers all stereo reconstruction parameters of the cameras necessary to make 3D reconstructions from the stereo camera images.« less

Improving Photometric Calibration of Meteor Video Camera Systems

NASA Technical Reports Server (NTRS)

Ehlert, Steven; Kingery, Aaron; Suggs, Robert

2016-01-01

We present the results of new calibration tests performed by the NASA Meteoroid Environment Oce (MEO) designed to help quantify and minimize systematic uncertainties in meteor photometry from video camera observations. These systematic uncertainties can be categorized by two main sources: an imperfect understanding of the linearity correction for the MEO's Watec 902H2 Ultimate video cameras and uncertainties in meteor magnitudes arising from transformations between the Watec camera's Sony EX-View HAD bandpass and the bandpasses used to determine reference star magnitudes. To address the rst point, we have measured the linearity response of the MEO's standard meteor video cameras using two independent laboratory tests on eight cameras. Our empirically determined linearity correction is critical for performing accurate photometry at low camera intensity levels. With regards to the second point, we have calculated synthetic magnitudes in the EX bandpass for reference stars. These synthetic magnitudes enable direct calculations of the meteor's photometric ux within the camera band-pass without requiring any assumptions of its spectral energy distribution. Systematic uncertainties in the synthetic magnitudes of individual reference stars are estimated at 0:20 mag, and are limited by the available spectral information in the reference catalogs. These two improvements allow for zero-points accurate to 0:05 ?? 0:10 mag in both ltered and un ltered camera observations with no evidence for lingering systematics.

Development of biostereometric experiments. [stereometric camera system

NASA Technical Reports Server (NTRS)

Herron, R. E.

1978-01-01

The stereometric camera was designed for close-range techniques in biostereometrics. The camera focusing distance of 360 mm to infinity covers a broad field of close-range photogrammetry. The design provides for a separate unit for the lens system and interchangeable backs on the camera for the use of single frame film exposure, roll-type film cassettes, or glass plates. The system incorporates the use of a surface contrast optical projector.

Multi-Angle Snowflake Camera Value-Added Product

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shkurko, Konstantin; Garrett, T.; Gaustad, K

The Multi-Angle Snowflake Camera (MASC) addresses a need for high-resolution multi-angle imaging of hydrometeors in freefall with simultaneous measurement of fallspeed. As illustrated in Figure 1, the MASC consists of three cameras, separated by 36°, each pointing at an identical focal point approximately 10 cm away. Located immediately above each camera, a light aims directly at the center of depth of field for its corresponding camera. The focal point at which the cameras are aimed lies within a ring through which hydrometeors fall. The ring houses a system of near-infrared emitter-detector pairs, arranged in two arrays separated vertically by 32more » mm. When hydrometeors pass through the lower array, they simultaneously trigger all cameras and lights. Fallspeed is calculated from the time it takes to traverse the distance between the upper and lower triggering arrays. The trigger electronics filter out ambient light fluctuations associated with varying sunlight and shadows. The microprocessor onboard the MASC controls the camera system and communicates with the personal computer (PC). The image data is sent via FireWire 800 line, and fallspeed (and camera control) is sent via a Universal Serial Bus (USB) line that relies on RS232-over-USB serial conversion. See Table 1 for specific details on the MASC located at the Oliktok Point Mobile Facility on the North Slope of Alaska. The value-added product (VAP) detailed in this documentation analyzes the raw data (Section 2.0) using Python: images rely on OpenCV image processing library and derived aggregated statistics rely on some clever averaging. See Sections 4.1 and 4.2 for more details on what variables are computed.« less

Helms in FGB/Zarya with cameras

NASA Image and Video Library

2001-06-08

ISS002-E-6526 (8 June 2001) --- Astronaut Susan J. Helms, Expedition Two flight engineer, mounts a video camera onto a bracket in the Zarya or Functional Cargo Block (FGB) of the International Space Station (ISS). The image was recorded with a digital still camera.

3D for the people: multi-camera motion capture in the field with consumer-grade cameras and open source software

PubMed Central

Evangelista, Dennis J.; Ray, Dylan D.; Hedrick, Tyson L.

2016-01-01

ABSTRACT Ecological, behavioral and biomechanical studies often need to quantify animal movement and behavior in three dimensions. In laboratory studies, a common tool to accomplish these measurements is the use of multiple, calibrated high-speed cameras. Until very recently, the complexity, weight and cost of such cameras have made their deployment in field situations risky; furthermore, such cameras are not affordable to many researchers. Here, we show how inexpensive, consumer-grade cameras can adequately accomplish these measurements both within the laboratory and in the field. Combined with our methods and open source software, the availability of inexpensive, portable and rugged cameras will open up new areas of biological study by providing precise 3D tracking and quantification of animal and human movement to researchers in a wide variety of field and laboratory contexts. PMID:27444791

Extended spectrum SWIR camera with user-accessible Dewar

NASA Astrophysics Data System (ADS)

Benapfl, Brendan; Miller, John Lester; Vemuri, Hari; Grein, Christoph; Sivananthan, Siva

2017-02-01

Episensors has developed a series of extended short wavelength infrared (eSWIR) cameras based on high-Cd concentration Hg1-xCdxTe absorbers. The cameras have a bandpass extending to 3 microns cutoff wavelength, opening new applications relative to traditional InGaAs-based cameras. Applications and uses are discussed and examples given. A liquid nitrogen pour-filled version was initially developed. This was followed by a compact Stirling-cooled version with detectors operating at 200 K. Each camera has unique sensitivity and performance characteristics. The cameras' size, weight and power specifications are presented along with images captured with band pass filters and eSWIR sources to demonstrate spectral response beyond 1.7 microns. The soft seal Dewars of the cameras are designed for accessibility, and can be opened and modified in a standard laboratory environment. This modular approach allows user flexibility for swapping internal components such as cold filters and cold stops. The core electronics of the Stirlingcooled camera are based on a single commercial field programmable gate array (FPGA) that also performs on-board non-uniformity corrections, bad pixel replacement, and directly drives any standard HDMI display.

Two degree of freedom camera mount

NASA Technical Reports Server (NTRS)

Ambrose, Robert O. (Inventor)

2003-01-01

A two degree of freedom camera mount. The camera mount includes a socket, a ball, a first linkage and a second linkage. The socket includes an interior surface and an opening. The ball is positioned within an interior of the socket. The ball includes a coupling point for rotating the ball relative to the socket and an aperture for mounting a camera. The first and second linkages are rotatably connected to the socket and slidably connected to the coupling point of the ball. Rotation of the linkages with respect to the socket causes the ball to rotate with respect to the socket.

The GISMO-2 Bolometer Camera

NASA Technical Reports Server (NTRS)

Staguhn, Johannes G.; Benford, Dominic J.; Fixsen, Dale J.; Hilton, Gene; Irwin, Kent D.; Jhabvala, Christine A.; Kovacs, Attila; Leclercq, Samuel; Maher, Stephen F.; Miller, Timothy M.;

Imaging Emission Spectra with Handheld and Cellphone Cameras

NASA Astrophysics Data System (ADS)

Sitar, David

2012-12-01

As point-and-shoot digital camera technology advances it is becoming easier to image spectra in a laboralory setting on a shoestring budget and get immediale results. With this in mind, I wanted to test three cameras to see how their results would differ. Two undergraduate physics students and I used one handheld 7.1 megapixel (MP) digital Cannon point-and-shoot auto focusing camera and two different cellphone cameras: one at 6.1 MP and the other at 5.1 MP.

Camera calibration: active versus passive targets

NASA Astrophysics Data System (ADS)

Schmalz, Christoph; Forster, Frank; Angelopoulou, Elli

2011-11-01

Traditionally, most camera calibrations rely on a planar target with well-known marks. However, the localization error of the marks in the image is a source of inaccuracy. We propose the use of high-resolution digital displays as active calibration targets to obtain more accurate calibration results for all types of cameras. The display shows a series of coded patterns to generate correspondences between world points and image points. This has several advantages. No special calibration hardware is necessary because suitable displays are practically ubiquitious. The method is fully automatic, and no identification of marks is necessary. For a coding scheme based on phase shifting, the localization accuracy is approximately independent of the camera's focus settings. Most importantly, higher accuracy can be achieved compared to passive targets, such as printed checkerboards. A rigorous evaluation is performed to substantiate this claim. Our active target method is compared to standard calibrations using a checkerboard target. We perform camera, calibrations with different combinations of displays, cameras, and lenses, as well as with simulated images and find markedly lower reprojection errors when using active targets. For example, in a stereo reconstruction task, the accuracy of a system calibrated with an active target is five times better.

Lunar Reconnaissance Orbiter Camera (LROC) instrument overview

USGS Publications Warehouse

Robinson, M.S.; Brylow, S.M.; Tschimmel, M.; Humm, D.; Lawrence, S.J.; Thomas, P.C.; Denevi, B.W.; Bowman-Cisneros, E.; Zerr, J.; Ravine, M.A.; Caplinger, M.A.; Ghaemi, F.T.; Schaffner, J.A.; Malin, M.C.; Mahanti, P.; Bartels, A.; Anderson, J.; Tran, T.N.; Eliason, E.M.; McEwen, A.S.; Turtle, E.; Jolliff, B.L.; Hiesinger, H.

2010-01-01

The Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) and Narrow Angle Cameras (NACs) are on the NASA Lunar Reconnaissance Orbiter (LRO). The WAC is a 7-color push-frame camera (100 and 400 m/pixel visible and UV, respectively), while the two NACs are monochrome narrow-angle linescan imagers (0.5 m/pixel). The primary mission of LRO is to obtain measurements of the Moon that will enable future lunar human exploration. The overarching goals of the LROC investigation include landing site identification and certification, mapping of permanently polar shadowed and sunlit regions, meter-scale mapping of polar regions, global multispectral imaging, a global morphology base map, characterization of regolith properties, and determination of current impact hazards.

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).

VizieR Online Data Catalog: Isaac Newton Telescope Wide Field Survey (CASU 2002)

NASA Astrophysics Data System (ADS)

Cambridge Astronomical Survey Unit

2002-04-01

The INT Wide Field Survey (WFS) is using the Wide Field Camera (~0.3 square degrees) on the 2.5m Isaac Newton Telescope (INT). The project was initiated in August 1998 and is expected to have a duration of up to five years. Multicolour data will be obtained over 200+ square degrees to a typical depth of ~25 mag (u' through z'). The data is publically accessible via the Cambridge Astronomical Survey Unit to UK and NL communities from day one, with access to the rest of the world after one year. This observation log lists all observations older than the one year proprietary period. (1 data file).

Solid State Television Camera (CID)

NASA Technical Reports Server (NTRS)

Steele, D. W.; Green, W. T.

1976-01-01

The design, development and test are described of a charge injection device (CID) camera using a 244x248 element array. A number of video signal processing functions are included which maximize the output video dynamic range while retaining the inherently good resolution response of the CID. Some of the unique features of the camera are: low light level performance, high S/N ratio, antiblooming, geometric distortion, sequential scanning and AGC.

a Spatio-Spectral Camera for High Resolution Hyperspectral Imaging

NASA Astrophysics Data System (ADS)

Livens, S.; Pauly, K.; Baeck, P.; Blommaert, J.; Nuyts, D.; Zender, J.; Delauré, B.

2017-08-01

Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS) is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600-900 nm) in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots), horticulture (crop status monitoring to evaluate irrigation management in strawberry fields) and geology (meteorite detection on a grassland field). Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475-925 nm), and we discuss future work.

NV-CMOS HD camera for day/night imaging

NASA Astrophysics Data System (ADS)

Vogelsong, T.; Tower, J.; Sudol, Thomas; Senko, T.; Chodelka, D.

2014-06-01

SRI International (SRI) has developed a new multi-purpose day/night video camera with low-light imaging performance comparable to an image intensifier, while offering the size, weight, ruggedness, and cost advantages enabled by the use of SRI's NV-CMOS HD digital image sensor chip. The digital video output is ideal for image enhancement, sharing with others through networking, video capture for data analysis, or fusion with thermal cameras. The camera provides Camera Link output with HD/WUXGA resolution of 1920 x 1200 pixels operating at 60 Hz. Windowing to smaller sizes enables operation at higher frame rates. High sensitivity is achieved through use of backside illumination, providing high Quantum Efficiency (QE) across the visible and near infrared (NIR) bands (peak QE <90%), as well as projected low noise (<2h+) readout. Power consumption is minimized in the camera, which operates from a single 5V supply. The NVCMOS HD camera provides a substantial reduction in size, weight, and power (SWaP) , ideal for SWaP-constrained day/night imaging platforms such as UAVs, ground vehicles, fixed mount surveillance, and may be reconfigured for mobile soldier operations such as night vision goggles and weapon sights. In addition the camera with the NV-CMOS HD imager is suitable for high performance digital cinematography/broadcast systems, biofluorescence/microscopy imaging, day/night security and surveillance, and other high-end applications which require HD video imaging with high sensitivity and wide dynamic range. The camera comes with an array of lens mounts including C-mount and F-mount. The latest test data from the NV-CMOS HD camera will be presented.

Hemispherical Laue camera

DOEpatents

Li, James C. M.; Chu, Sungnee G.

1980-01-01

A hemispherical Laue camera comprises a crystal sample mount for positioning a sample to be analyzed at the center of sphere of a hemispherical, X-radiation sensitive film cassette, a collimator, a stationary or rotating sample mount and a set of standard spherical projection spheres. X-radiation generated from an external source is directed through the collimator to impinge onto the single crystal sample on the stationary mount. The diffracted beam is recorded on the hemispherical X-radiation sensitive film mounted inside the hemispherical film cassette in either transmission or back-reflection geometry. The distances travelled by X-radiation diffracted from the crystal to the hemispherical film are the same for all crystal planes which satisfy Bragg's Law. The recorded diffraction spots or Laue spots on the film thereby preserve both the symmetry information of the crystal structure and the relative intensities which are directly related to the relative structure factors of the crystal orientations. The diffraction pattern on the exposed film is compared with the known diffraction pattern on one of the standard spherical projection spheres for a specific crystal structure to determine the orientation of the crystal sample. By replacing the stationary sample support with a rotating sample mount, the hemispherical Laue camera can be used for crystal structure determination in a manner previously provided in conventional Debye-Scherrer cameras.

Analysis of aerosol optical properties from continuous sun-sky radiometer measurements at Halley and Rothera, Antarctica over seven years

NASA Astrophysics Data System (ADS)

Campanelli, Monica; Estellés, Victor; Colwell, Steve; Shanklin, Jonathan; Ningombam, Shantikumar S.

2015-04-01

The Antarctic continent is located far from most anthropogenic emission sources on the planet, it has limited areas of exposed rock and human activities are less developed. Air circulation over Antarctica also seems to prevent the direct transport of air originating from anthropogenic sources of pollution at lower latitudes. Therefore Antarctica is considered an attractive site for studying aerosol properties as unaltered as possible by human activity. Long term monitoring of the optical and physical properties is necessary for observing possible changes in the atmosphere over time and understanding if such changes are due to human activity or natural variation. Columnar aerosol optical and physical properties can be obtained from sun-sky radiometers, very compact instruments measuring spectral direct and diffuse solar irradiance at the visible wavelengths and using fast and efficient inversion algorithms. The British Antarctic Survey has continuously operated two Prede Pom-01 sun-sky radiometers in Antarctica as part of the ESR-European Skynet Radiometers network (www.euroskyrad.net, Campanelli et al, 2012). They are located at Halley and Rothera, and have operated since 2009 and 2008 respectively. In the present study the aerosol optical thickness, single scattering albedo, Ångström exponent, volume size distribution and refractive index were retrieved from cloud-screened measurements of direct and diffuse solar irradiance using the Skyrad 4.2 pack code (Nakajima et al., 1986). The analysis of the daily and yearly averages showed an important increase of the absorbing properties of particles at Halley from 2013 to the beginning of 2014 related to the increasing presence of smaller particles (from 2012) but with a non-significant variation of aerosol optical depth. The same increase of absorption was visible at Rothera only in 2013. Air pressure measurements, wind directions and intensity, and vertical profiles from radio-soundings, together with HYSPLIT model

A Comparative Study of Microscopic Images Captured by a Box Type Digital Camera Versus a Standard Microscopic Photography Camera Unit

PubMed Central

Desai, Nandini J.; Gupta, B. D.; Patel, Pratik Narendrabhai

2014-01-01

Introduction: Obtaining images of slides viewed by a microscope can be invaluable for both diagnosis and teaching.They can be transferred among technologically-advanced hospitals for further consultation and evaluation. But a standard microscopic photography camera unit (MPCU)(MIPS-Microscopic Image projection System) is costly and not available in resource poor settings. The aim of our endeavour was to find a comparable and cheaper alternative method for photomicrography. Materials and Methods: We used a NIKON Coolpix S6150 camera (box type digital camera) with Olympus CH20i microscope and a fluorescent microscope for the purpose of this study. Results: We got comparable results for capturing images of light microscopy, but the results were not as satisfactory for fluorescent microscopy. Conclusion: A box type digital camera is a comparable, less expensive and convenient alternative to microscopic photography camera unit. PMID:25478350

An evolution of image source camera attribution approaches.

PubMed

Jahanirad, Mehdi; Wahab, Ainuddin Wahid Abdul; Anuar, Nor Badrul

2016-05-01

Camera attribution plays an important role in digital image forensics by providing the evidence and distinguishing characteristics of the origin of the digital image. It allows the forensic analyser to find the possible source camera which captured the image under investigation. However, in real-world applications, these approaches have faced many challenges due to the large set of multimedia data publicly available through photo sharing and social network sites, captured with uncontrolled conditions and undergone variety of hardware and software post-processing operations. Moreover, the legal system only accepts the forensic analysis of the digital image evidence if the applied camera attribution techniques are unbiased, reliable, nondestructive and widely accepted by the experts in the field. The aim of this paper is to investigate the evolutionary trend of image source camera attribution approaches from fundamental to practice, in particular, with the application of image processing and data mining techniques. Extracting implicit knowledge from images using intrinsic image artifacts for source camera attribution requires a structured image mining process. In this paper, we attempt to provide an introductory tutorial on the image processing pipeline, to determine the general classification of the features corresponding to different components for source camera attribution. The article also reviews techniques of the source camera attribution more comprehensively in the domain of the image forensics in conjunction with the presentation of classifying ongoing developments within the specified area. The classification of the existing source camera attribution approaches is presented based on the specific parameters, such as colour image processing pipeline, hardware- and software-related artifacts and the methods to extract such artifacts. The more recent source camera attribution approaches, which have not yet gained sufficient attention among image forensics

Thermal Cameras in School Laboratory Activities

ERIC Educational Resources Information Center

Haglund, Jesper; Jeppsson, Fredrik; Hedberg, David; Schönborn, Konrad J.

2015-01-01

Thermal cameras offer real-time visual access to otherwise invisible thermal phenomena, which are conceptually demanding for learners during traditional teaching. We present three studies of students' conduction of laboratory activities that employ thermal cameras to teach challenging thermal concepts in grades 4, 7 and 10-12. Visualization of…

Improving Photometric Calibration of Meteor Video Camera Systems.

PubMed

Ehlert, Steven; Kingery, Aaron; Suggs, Robert

2017-09-01

We present the results of new calibration tests performed by the NASA Meteoroid Environment Office (MEO) designed to help quantify and minimize systematic uncertainties in meteor photometry from video camera observations. These systematic uncertainties can be categorized by two main sources: an imperfect understanding of the linearity correction for the MEO's Watec 902H2 Ultimate video cameras and uncertainties in meteor magnitudes arising from transformations between the Watec camera's Sony EX-View HAD bandpass and the bandpasses used to determine reference star magnitudes. To address the first point, we have measured the linearity response of the MEO's standard meteor video cameras using two independent laboratory tests on eight cameras. Our empirically determined linearity correction is critical for performing accurate photometry at low camera intensity levels. With regards to the second point, we have calculated synthetic magnitudes in the EX bandpass for reference stars. These synthetic magnitudes enable direct calculations of the meteor's photometric flux within the camera band pass without requiring any assumptions of its spectral energy distribution. Systematic uncertainties in the synthetic magnitudes of individual reference stars are estimated at ∼ 0.20 mag, and are limited by the available spectral information in the reference catalogs. These two improvements allow for zero-points accurate to ∼ 0.05 - 0.10 mag in both filtered and unfiltered camera observations with no evidence for lingering systematics. These improvements are essential to accurately measuring photometric masses of individual meteors and source mass indexes.

Improving Photometric Calibration of Meteor Video Camera Systems

NASA Technical Reports Server (NTRS)

Ehlert, Steven; Kingery, Aaron; Suggs, Robert

2017-01-01

We present the results of new calibration tests performed by the NASA Meteoroid Environment Office (MEO) designed to help quantify and minimize systematic uncertainties in meteor photometry from video camera observations. These systematic uncertainties can be categorized by two main sources: an imperfect understanding of the linearity correction for the MEO's Watec 902H2 Ultimate video cameras and uncertainties in meteor magnitudes arising from transformations between the Watec camera's Sony EX-View HAD bandpass and the bandpasses used to determine reference star magnitudes. To address the first point, we have measured the linearity response of the MEO's standard meteor video cameras using two independent laboratory tests on eight cameras. Our empirically determined linearity correction is critical for performing accurate photometry at low camera intensity levels. With regards to the second point, we have calculated synthetic magnitudes in the EX bandpass for reference stars. These synthetic magnitudes enable direct calculations of the meteor's photometric flux within the camera bandpass without requiring any assumptions of its spectral energy distribution. Systematic uncertainties in the synthetic magnitudes of individual reference stars are estimated at approx. 0.20 mag, and are limited by the available spectral information in the reference catalogs. These two improvements allow for zero-points accurate to 0.05 - 0.10 mag in both filtered and unfiltered camera observations with no evidence for lingering systematics. These improvements are essential to accurately measuring photometric masses of individual meteors and source mass indexes.

Methods for identification of images acquired with digital cameras

NASA Astrophysics Data System (ADS)

Geradts, Zeno J.; Bijhold, Jurrien; Kieft, Martijn; Kurosawa, Kenji; Kuroki, Kenro; Saitoh, Naoki

2001-02-01

From the court we were asked whether it is possible to determine if an image has been made with a specific digital camera. This question has to be answered in child pornography cases, where evidence is needed that a certain picture has been made with a specific camera. We have looked into different methods of examining the cameras to determine if a specific image has been made with a camera: defects in CCDs, file formats that are used, noise introduced by the pixel arrays and watermarking in images used by the camera manufacturer.

Correlative near-infrared light and cathodoluminescence microscopy using Y2O3:Ln, Yb (Ln = Tm, Er) nanophosphors for multiscale, multicolour bioimaging

PubMed Central

Fukushima, S.; Furukawa, T.; Niioka, H.; Ichimiya, M.; Sannomiya, T.; Tanaka, N.; Onoshima, D.; Yukawa, H.; Baba, Y.; Ashida, M.; Miyake, J.; Araki, T.; Hashimoto, M.

2016-01-01

This paper presents a new correlative bioimaging technique using Y2O3:Tm, Yb and Y2O3:Er, Yb nanophosphors (NPs) as imaging probes that emit luminescence excited by both near-infrared (NIR) light and an electron beam. Under 980 nm NIR light irradiation, the Y2O3:Tm, Yb and Y2O3:Er, Yb NPs emitted NIR luminescence (NIRL) around 810 nm and 1530 nm, respectively, and cathodoluminescence at 455 nm and 660 nm under excitation of accelerated electrons, respectively. Multimodalities of the NPs were confirmed in correlative NIRL/CL imaging and their locations were visualized at the same observation area in both NIRL and CL images. Using CL microscopy, the NPs were visualized at the single-particle level and with multicolour. Multiscale NIRL/CL bioimaging was demonstrated through in vivo and in vitro NIRL deep-tissue observations, cellular NIRL imaging, and high-spatial resolution CL imaging of the NPs inside cells. The location of a cell sheet transplanted onto the back muscle fascia of a hairy rat was visualized through NIRL imaging of the Y2O3:Er, Yb NPs. Accurate positions of cells through the thickness (1.5 mm) of a tissue phantom were detected by NIRL from the Y2O3:Tm, Yb NPs. Further, locations of the two types of NPs inside cells were observed using CL microscopy. PMID:27185264

A new system for parallel drug screening against multiple-resistant HIV mutants based on lentiviral self-inactivating (SIN) vectors and multi-colour analyses

PubMed Central

2013-01-01

Background Despite progress in the development of combined antiretroviral therapies (cART), HIV infection remains a significant challenge for human health. Current problems of cART include multi-drug-resistant virus variants, long-term toxicity and enormous treatment costs. Therefore, the identification of novel effective drugs is urgently needed. Methods We developed a straightforward screening approach for simultaneously evaluating the sensitivity of multiple HIV gag-pol mutants to antiviral drugs in one assay. Our technique is based on multi-colour lentiviral self-inactivating (SIN) LeGO vector technology. Results We demonstrated the successful use of this approach for screening compounds against up to four HIV gag-pol variants (wild-type and three mutants) simultaneously. Importantly, the technique was adapted to Biosafety Level 1 conditions by utilising ecotropic pseudotypes. This allowed upscaling to a large-scale screening protocol exploited by pharmaceutical companies in a successful proof-of-concept experiment. Conclusions The technology developed here facilitates fast screening for anti-HIV activity of individual agents from large compound libraries. Although drugs targeting gag-pol variants were used here, our approach permits screening compounds that target several different, key cellular and viral functions of the HIV life-cycle. The modular principle of the method also allows the easy exchange of various mutations in HIV sequences. In conclusion, the methodology presented here provides a valuable new approach for the identification of novel anti-HIV drugs. PMID:23286882

PMMW Camera TRP. Phase 1

NASA Technical Reports Server (NTRS)

1997-01-01

Passive millimeter wave (PMMW) sensors have the ability to see through fog, clouds, dust and sandstorms and thus have the potential to support all-weather operations, both military and commercial. Many of the applications, such as military transport or commercial aircraft landing, are technologically stressing in that they require imaging of a scene with a large field of view in real time and with high spatial resolution. The development of a low cost PMMW focal plane array camera is essential to obtain real-time video images to fulfill the above needs. The overall objective of this multi-year project (Phase 1) was to develop and demonstrate the capabilities of a W-band PMMW camera with a microwave/millimeter wave monolithic integrated circuit (MMIC) focal plane array (FPA) that can be manufactured at low cost for both military and commercial applications. This overall objective was met in July 1997 when the first video images from the camera were generated of an outdoor scene. In addition, our consortium partner McDonnell Douglas was to develop a real-time passive millimeter wave flight simulator to permit pilot evaluation of a PMMW-equipped aircraft in a landing scenario. A working version of this simulator was completed. This work was carried out under the DARPA-funded PMMW Camera Technology Reinvestment Project (TRP), also known as the PMMW Camera DARPA Joint Dual-Use Project. In this final report for the Phase 1 activities, a year by year description of what the specific objectives were, the approaches taken, and the progress made is presented, followed by a description of the validation and imaging test results obtained in 1997.

Color reproduction software for a digital still camera

NASA Astrophysics Data System (ADS)

Lee, Bong S.; Park, Du-Sik; Nam, Byung D.

1998-04-01

We have developed a color reproduction software for a digital still camera. The image taken by the camera was colorimetrically reproduced on the monitor after characterizing the camera and the monitor, and color matching between two devices. The reproduction was performed at three levels; level processing, gamma correction, and color transformation. The image contrast was increased after the level processing adjusting the level of dark and bright portions of the image. The relationship between the level processed digital values and the measured luminance values of test gray samples was calculated, and the gamma of the camera was obtained. The method for getting the unknown monitor gamma was proposed. As a result, the level processed values were adjusted by the look-up table created by the camera and the monitor gamma correction. For a color transformation matrix for the camera, 3 by 3 or 3 by 4 matrix was used, which was calculated by the regression between the gamma corrected values and the measured tristimulus values of each test color samples the various reproduced images were displayed on the dialogue box implemented in our software, which were generated according to four illuminations for the camera and three color temperatures for the monitor. An user can easily choose he best reproduced image comparing each others.

Real-time vehicle matching for multi-camera tunnel surveillance

NASA Astrophysics Data System (ADS)

Jelača, Vedran; Niño Castañeda, Jorge Oswaldo; Frías-Velázquez, Andrés; Pižurica, Aleksandra; Philips, Wilfried

2011-03-01

Tracking multiple vehicles with multiple cameras is a challenging problem of great importance in tunnel surveillance. One of the main challenges is accurate vehicle matching across the cameras with non-overlapping fields of view. Since systems dedicated to this task can contain hundreds of cameras which observe dozens of vehicles each, for a real-time performance computational efficiency is essential. In this paper, we propose a low complexity, yet highly accurate method for vehicle matching using vehicle signatures composed of Radon transform like projection profiles of the vehicle image. The proposed signatures can be calculated by a simple scan-line algorithm, by the camera software itself and transmitted to the central server or to the other cameras in a smart camera environment. The amount of data is drastically reduced compared to the whole image, which relaxes the data link capacity requirements. Experiments on real vehicle images, extracted from video sequences recorded in a tunnel by two distant security cameras, validate our approach.

Wired and Wireless Camera Triggering with Arduino

NASA Astrophysics Data System (ADS)

Kauhanen, H.; Rönnholm, P.

2017-10-01

Synchronous triggering is an important task that allows simultaneous data capture from multiple cameras. Accurate synchronization enables 3D measurements of moving objects or from a moving platform. In this paper, we describe one wired and four wireless variations of Arduino-based low-cost remote trigger systems designed to provide a synchronous trigger signal for industrial cameras. Our wireless systems utilize 315 MHz or 434 MHz frequencies with noise filtering capacitors. In order to validate the synchronization accuracy, we developed a prototype of a rotating trigger detection system (named RoTriDeS). This system is suitable to detect the triggering accuracy of global shutter cameras. As a result, the wired system indicated an 8.91 μs mean triggering time difference between two cameras. Corresponding mean values for the four wireless triggering systems varied between 7.92 and 9.42 μs. Presented values include both camera-based and trigger-based desynchronization. Arduino-based triggering systems appeared to be feasible, and they have the potential to be extended to more complicated triggering systems.

Super-Resolution in Plenoptic Cameras Using FPGAs

PubMed Central

Pérez, Joel; Magdaleno, Eduardo; Pérez, Fernando; Rodríguez, Manuel; Hernández, David; Corrales, Jaime

2014-01-01

Plenoptic cameras are a new type of sensor that extend the possibilities of current commercial cameras allowing 3D refocusing or the capture of 3D depths. One of the limitations of plenoptic cameras is their limited spatial resolution. In this paper we describe a fast, specialized hardware implementation of a super-resolution algorithm for plenoptic cameras. The algorithm has been designed for field programmable graphic array (FPGA) devices using VHDL (very high speed integrated circuit (VHSIC) hardware description language). With this technology, we obtain an acceleration of several orders of magnitude using its extremely high-performance signal processing capability through parallelism and pipeline architecture. The system has been developed using generics of the VHDL language. This allows a very versatile and parameterizable system. The system user can easily modify parameters such as data width, number of microlenses of the plenoptic camera, their size and shape, and the super-resolution factor. The speed of the algorithm in FPGA has been successfully compared with the execution using a conventional computer for several image sizes and different 3D refocusing planes. PMID:24841246

Camera Calibration with Radial Variance Component Estimation

NASA Astrophysics Data System (ADS)

Mélykuti, B.; Kruck, E. J.

2014-11-01

Camera calibration plays a more and more important role in recent times. Beside real digital aerial survey cameras the photogrammetric market is dominated by a big number of non-metric digital cameras mounted on UAVs or other low-weight flying platforms. The in-flight calibration of those systems has a significant role to enhance the geometric accuracy of survey photos considerably. It is expected to have a better precision of photo measurements in the center of images then along the edges or in the corners. With statistical methods the accuracy of photo measurements in dependency of the distance of points from image center has been analyzed. This test provides a curve for the measurement precision as function of the photo radius. A high number of camera types have been tested with well penetrated point measurements in image space. The result of the tests led to a general consequence to show a functional connection between accuracy and radial distance and to give a method how to check and enhance the geometrical capability of the cameras in respect to these results.

Super-resolution in plenoptic cameras using FPGAs.

PubMed

Pérez, Joel; Magdaleno, Eduardo; Pérez, Fernando; Rodríguez, Manuel; Hernández, David; Corrales, Jaime

2014-05-16

Plenoptic cameras are a new type of sensor that extend the possibilities of current commercial cameras allowing 3D refocusing or the capture of 3D depths. One of the limitations of plenoptic cameras is their limited spatial resolution. In this paper we describe a fast, specialized hardware implementation of a super-resolution algorithm for plenoptic cameras. The algorithm has been designed for field programmable graphic array (FPGA) devices using VHDL (very high speed integrated circuit (VHSIC) hardware description language). With this technology, we obtain an acceleration of several orders of magnitude using its extremely high-performance signal processing capability through parallelism and pipeline architecture. The system has been developed using generics of the VHDL language. This allows a very versatile and parameterizable system. The system user can easily modify parameters such as data width, number of microlenses of the plenoptic camera, their size and shape, and the super-resolution factor. The speed of the algorithm in FPGA has been successfully compared with the execution using a conventional computer for several image sizes and different 3D refocusing planes.

The end states of long-period comets and the origin of Halley-type comets

NASA Astrophysics Data System (ADS)

Fernández, Julio A.; Gallardo, Tabaré; Young, Juan D.

2016-09-01

We analyse a sample of 73 old long-period comets (LPCs) (orbital periods 200 < P < 1000 yr) with perihelion distances q < 2.5 au, discovered in the period 1850-2014. We cloned the observed comets and also added fictitious LPCs with perihelia in the Jupiter's zone. We consider both a purely dynamical evolution and a physico-dynamical one with different physical lifetimes. We can fit the computed energy distribution of comets with q < 1.3 au to the observed one only within the energy range 0.01 < x < 0.04 au-1 (or periods 125 < P < 1000 yr), where the `energy' is taken as the inverse of the semimajor axis a, namely x ≡ 1/a. The best results are obtained for physical lifetimes of about 200-300 revolutions (for a comet with a standard q = 1 au). We find that neither a purely dynamical evolution, nor a physico-dynamical one can reproduce the long tail of larger binding energies (x ≳ 0.04 au-1) that correspond to most Halley-type comets (HTCs) and Jupiter-family comets. We conclude that most HTCs are not the end states of the evolution of LPCs, but come from a different source, a flattened one that we identify with the Centaurs that are scattered to the inner planetary region from the trans-Neptunian belt. These results also show that the boundary between LPCs and HTCs should be located at an energy x ˜ 0.04 au-1 (P ˜ 125 yr), rather than the conventional classical boundary at P = 200 yr.

Camera Layout Design for the Upper Stage Thrust Cone

NASA Technical Reports Server (NTRS)

Wooten, Tevin; Fowler, Bart

2010-01-01

Engineers in the Integrated Design and Analysis Division (EV30) use a variety of different tools to aid in the design and analysis of the Ares I vehicle. One primary tool in use is Pro-Engineer. Pro-Engineer is a computer-aided design (CAD) software that allows designers to create computer generated structural models of vehicle structures. For the Upper State thrust cone, Pro-Engineer was used to assist in the design of a layout for two camera housings. These cameras observe the separation between the first and second stage of the Ares I vehicle. For the Ares I-X, one standard speed camera was used. The Ares I design calls for two separate housings, three cameras, and a lighting system. With previous design concepts and verification strategies in mind, a new layout for the two camera design concept was developed with members of the EV32 team. With the new design, Pro-Engineer was used to draw the layout to observe how the two camera housings fit with the thrust cone assembly. Future analysis of the camera housing design will verify the stability and clearance of the camera with other hardware present on the thrust cone.

Two-Camera Acquisition and Tracking of a Flying Target

NASA Technical Reports Server (NTRS)

Biswas, Abhijit; Assad, Christopher; Kovalik, Joseph M.; Pain, Bedabrata; Wrigley, Chris J.; Twiss, Peter

2008-01-01

A method and apparatus have been developed to solve the problem of automated acquisition and tracking, from a location on the ground, of a luminous moving target in the sky. The method involves the use of two electronic cameras: (1) a stationary camera having a wide field of view, positioned and oriented to image the entire sky; and (2) a camera that has a much narrower field of view (a few degrees wide) and is mounted on a two-axis gimbal. The wide-field-of-view stationary camera is used to initially identify the target against the background sky. So that the approximate position of the target can be determined, pixel locations on the image-detector plane in the stationary camera are calibrated with respect to azimuth and elevation. The approximate target position is used to initially aim the gimballed narrow-field-of-view camera in the approximate direction of the target. Next, the narrow-field-of view camera locks onto the target image, and thereafter the gimbals are actuated as needed to maintain lock and thereby track the target with precision greater than that attainable by use of the stationary camera.

Camera Control and Geo-Registration for Video Sensor Networks

NASA Astrophysics Data System (ADS)

Davis, James W.

With the use of large video networks, there is a need to coordinate and interpret the video imagery for decision support systems with the goal of reducing the cognitive and perceptual overload of human operators. We present computer vision strategies that enable efficient control and management of cameras to effectively monitor wide-coverage areas, and examine the framework within an actual multi-camera outdoor urban video surveillance network. First, we construct a robust and precise camera control model for commercial pan-tilt-zoom (PTZ) video cameras. In addition to providing a complete functional control mapping for PTZ repositioning, the model can be used to generate wide-view spherical panoramic viewspaces for the cameras. Using the individual camera control models, we next individually map the spherical panoramic viewspace of each camera to a large aerial orthophotograph of the scene. The result provides a unified geo-referenced map representation to permit automatic (and manual) video control and exploitation of cameras in a coordinated manner. The combined framework provides new capabilities for video sensor networks that are of significance and benefit to the broad surveillance/security community.

Measurement of the timing behaviour of off-the-shelf cameras

NASA Astrophysics Data System (ADS)

Schatz, Volker

2017-04-01

This paper presents a measurement method suitable for investigating the timing properties of cameras. A single light source illuminates the camera detector starting with a varying defined delay after the camera trigger. Pixels from the recorded camera frames are summed up and normalised, and the resulting function is indicative of the overlap between illumination and exposure. This allows one to infer the trigger delay and the exposure time with sub-microsecond accuracy. The method is therefore of interest when off-the-shelf cameras are used in reactive systems or synchronised with other cameras. It can supplement radiometric and geometric calibration methods for cameras in scientific use. A closer look at the measurement results reveals deviations from the ideal camera behaviour of constant sensitivity limited to the exposure interval. One of the industrial cameras investigated retains a small sensitivity long after the end of the nominal exposure interval. All three investigated cameras show non-linear variations of sensitivity at O≤ft({{10}-3}\\right) to O≤ft({{10}-2}\\right) during exposure. Due to its sign, the latter effect cannot be described by a sensitivity function depending on the time after triggering, but represents non-linear pixel characteristics.

Selecting the right digital camera for telemedicine-choice for 2009.

PubMed

Patricoski, Chris; Ferguson, A Stewart; Brudzinski, Jay; Spargo, Garret

2010-03-01

Digital cameras are fundamental tools for store-and-forward telemedicine (electronic consultation). The choice of a camera may significantly impact this consultative process based on the quality of the images, the ability of users to leverage the cameras' features, and other facets of the camera design. The goal of this research was to provide a substantive framework and clearly defined process for reviewing digital cameras and to demonstrate the results obtained when employing this process to review point-and-shoot digital cameras introduced in 2009. The process included a market review, in-house evaluation of features, image reviews, functional testing, and feature prioritization. Seventy-two cameras were identified new on the market in 2009, and 10 were chosen for in-house evaluation. Four cameras scored very high for mechanical functionality and ease-of-use. The final analysis revealed three cameras that had excellent scores for both color accuracy and photographic detail and these represent excellent options for telemedicine: Canon Powershot SD970 IS, Fujifilm FinePix F200EXR, and Panasonic Lumix DMC-ZS3. Additional features of the Canon Powershot SD970 IS make it the camera of choice for our Alaska program.

LAMOST CCD camera-control system based on RTS2

NASA Astrophysics Data System (ADS)

Tian, Yuan; Wang, Zheng; Li, Jian; Cao, Zi-Huang; Dai, Wei; Wei, Shou-Lin; Zhao, Yong-Heng

2018-05-01

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device (CCD) cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2nd Version (RTS2) is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-framework-based control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system.

The GCT camera for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Lapington, J. S.; Abchiche, A.; Allan, D.; Amans, J.-P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J.-J.; Bose, R.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Buckley, J.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Daniel, M. K.; De Franco, A.; De Frondat, F.; Dournaux, J.-L.; Dumas, D.; Ernenwein, J.-P.; Fasola, G.; Funk, S.; Gironnet, J.; Graham, J. A.; Greenshaw, T.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J.-M.; Jankowsky, D.; Jegouzo, I.; Jogler, T.; Kawashima, T.; Kraus, M.; Laporte, P.; Leach, S.; Lefaucheur, J.; Markoff, S.; Melse, T.; Minaya, I. A.; Mohrmann, L.; Molyneux, P.; Moore, P.; Nolan, S. J.; Okumura, A.; Osborne, J. P.; Parsons, R. D.; Rosen, S.; Ross, D.; Rowell, G.; Rulten, C. B.; Sato, Y.; Sayede, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Sol, H.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Trichard, C.; Varner, G.; Vink, J.; Watson, J. J.; White, R.; Yamane, N.; Zech, A.; Zink, A.; Zorn, J.; CTA Consortium

2017-12-01

The Gamma Cherenkov Telescope (GCT) is one of the designs proposed for the Small Sized Telescope (SST) section of the Cherenkov Telescope Array (CTA). The GCT uses dual-mirror optics, resulting in a compact telescope with good image quality and a large field of view with a smaller, more economical, camera than is achievable with conventional single mirror solutions. The photon counting GCT camera is designed to record the flashes of atmospheric Cherenkov light from gamma and cosmic ray initiated cascades, which last only a few tens of nanoseconds. The GCT optics require that the camera detectors follow a convex surface with a radius of curvature of 1 m and a diameter of 35 cm, which is approximated by tiling the focal plane with 32 modules. The first camera prototype is equipped with multi-anode photomultipliers, each comprising an 8×8 array of 6×6 mm2 pixels to provide the required angular scale, adding up to 2048 pixels in total. Detector signals are shaped, amplified and digitised by electronics based on custom ASICs that provide digitisation at 1 GSample/s. The camera is self-triggering, retaining images where the focal plane light distribution matches predefined spatial and temporal criteria. The electronics are housed in the liquid-cooled, sealed camera enclosure. LED flashers at the corners of the focal plane provide a calibration source via reflection from the secondary mirror. The first GCT camera prototype underwent preliminary laboratory tests last year. In November 2015, the camera was installed on a prototype GCT telescope (SST-GATE) in Paris and was used to successfully record the first Cherenkov light of any CTA prototype, and the first Cherenkov light seen with such a dual-mirror optical system. A second full-camera prototype based on Silicon Photomultipliers is under construction. Up to 35 GCTs are envisaged for CTA.

Calibration and verification of thermographic cameras for geometric measurements

NASA Astrophysics Data System (ADS)

Lagüela, S.; González-Jorge, H.; Armesto, J.; Arias, P.

2011-03-01

Infrared thermography is a technique with an increasing degree of development and applications. Quality assessment in the measurements performed with the thermal cameras should be achieved through metrology calibration and verification. Infrared cameras acquire temperature and geometric information, although calibration and verification procedures are only usual for thermal data. Black bodies are used for these purposes. Moreover, the geometric information is important for many fields as architecture, civil engineering and industry. This work presents a calibration procedure that allows the photogrammetric restitution and a portable artefact to verify the geometric accuracy, repeatability and drift of thermographic cameras. These results allow the incorporation of this information into the quality control processes of the companies. A grid based on burning lamps is used for the geometric calibration of thermographic cameras. The artefact designed for the geometric verification consists of five delrin spheres and seven cubes of different sizes. Metrology traceability for the artefact is obtained from a coordinate measuring machine. Two sets of targets with different reflectivity are fixed to the spheres and cubes to make data processing and photogrammetric restitution possible. Reflectivity was the chosen material propriety due to the thermographic and visual cameras ability to detect it. Two thermographic cameras from Flir and Nec manufacturers, and one visible camera from Jai are calibrated, verified and compared using calibration grids and the standard artefact. The calibration system based on burning lamps shows its capability to perform the internal orientation of the thermal cameras. Verification results show repeatability better than 1 mm for all cases, being better than 0.5 mm for the visible one. As it must be expected, also accuracy appears higher in the visible camera, and the geometric comparison between thermographic cameras shows slightly better

Single-pixel camera with one graphene photodetector.

PubMed

Li, Gongxin; Wang, Wenxue; Wang, Yuechao; Yang, Wenguang; Liu, Lianqing

2016-01-11

Consumer cameras in the megapixel range are ubiquitous, but the improvement of them is hindered by the poor performance and high cost of traditional photodetectors. Graphene, a two-dimensional micro-/nano-material, recently has exhibited exceptional properties as a sensing element in a photodetector over traditional materials. However, it is difficult to fabricate a large-scale array of graphene photodetectors to replace the traditional photodetector array. To take full advantage of the unique characteristics of the graphene photodetector, in this study we integrated a graphene photodetector in a single-pixel camera based on compressive sensing. To begin with, we introduced a method called laser scribing for fabrication the graphene. It produces the graphene components in arbitrary patterns more quickly without photoresist contamination as do traditional methods. Next, we proposed a system for calibrating the optoelectrical properties of micro/nano photodetectors based on a digital micromirror device (DMD), which changes the light intensity by controlling the number of individual micromirrors positioned at + 12°. The calibration sensitivity is driven by the sum of all micromirrors of the DMD and can be as high as 10(-5)A/W. Finally, the single-pixel camera integrated with one graphene photodetector was used to recover a static image to demonstrate the feasibility of the single-pixel imaging system with the graphene photodetector. A high-resolution image can be recovered with the camera at a sampling rate much less than Nyquist rate. The study was the first demonstration for ever record of a macroscopic camera with a graphene photodetector. The camera has the potential for high-speed and high-resolution imaging at much less cost than traditional megapixel cameras.

Mirror-mode structures at Comet 1P/Halley: A comparison between VEGA1 and Giotto Flyby

NASA Astrophysics Data System (ADS)

Volwerk, M.; Glassmeier, K.-H.; Schmid, D.; Delva, M.; Koenders, C.

2014-04-01

The pickup of freshly ionized particles emitted by the cometary nucleus creates a particle distribution in phase-space which is, amongst others, mirror-mode unstable. Many detailed studies have shown the presence of mirror-mode structures in the vicinity of comet 1P/Halley, using data from VEGA1/2 and Giotto. In the current presentation the almost similar flybys of VEGA1 and Giotto are compared with respect to the presence and occurrence rate of mirrormode structures. An automated search on the magnetic field data is performed, using minimum variance analysis, which has proved its usefulness in earlier mirror-mode studies at Earth, Venus and comets. It is found that there is an asymmetry between the two flybys: both missions show many events before closest approach and magnetic pile up region, however, after closest approach and magnetic pile up region the mirror-modes are strongly reduced at Giotto, whereas they increase in number for VEGA1. One source of influence could be the solar wind IMF, which is different: VEGA1 IMF ≈ (0, 0, 15) nT, Vsw ≈ 500 km/s and Giotto IMF ≈ (-3/3, -4, 5) nT (Bx rotating over the passage), Vsw ≈ 370 km/s. In this presentation we will discuss the occurrence rate, sizes and other characteristics of the mirror-mode structures.

Tests of commercial colour CMOS cameras for astronomical applications

NASA Astrophysics Data System (ADS)

Pokhvala, S. M.; Reshetnyk, V. M.; Zhilyaev, B. E.

2013-12-01

We present some results of testing commercial colour CMOS cameras for astronomical applications. Colour CMOS sensors allow to perform photometry in three filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR colour system realized in colour CMOS sensors is close to the astronomical Johnson BVR system. The basic camera characteristics: read noise (e^{-}/pix), thermal noise (e^{-}/pix/sec) and electronic gain (e^{-}/ADU) for the commercial digital camera Canon 5D MarkIII are presented. We give the same characteristics for the scientific high performance cooled CCD camera system ALTA E47. Comparing results for tests of Canon 5D MarkIII and CCD ALTA E47 show that present-day commercial colour CMOS cameras can seriously compete with the scientific CCD cameras in deep astronomical imaging.

Camera systems in human motion analysis for biomedical applications

NASA Astrophysics Data System (ADS)

Chin, Lim Chee; Basah, Shafriza Nisha; Yaacob, Sazali; Juan, Yeap Ewe; Kadir, Aida Khairunnisaa Ab.

2015-05-01

Human Motion Analysis (HMA) system has been one of the major interests among researchers in the field of computer vision, artificial intelligence and biomedical engineering and sciences. This is due to its wide and promising biomedical applications, namely, bio-instrumentation for human computer interfacing and surveillance system for monitoring human behaviour as well as analysis of biomedical signal and image processing for diagnosis and rehabilitation applications. This paper provides an extensive review of the camera system of HMA, its taxonomy, including camera types, camera calibration and camera configuration. The review focused on evaluating the camera system consideration of the HMA system specifically for biomedical applications. This review is important as it provides guidelines and recommendation for researchers and practitioners in selecting a camera system of the HMA system for biomedical applications.

Calibration Procedures in Mid Format Camera Setups

NASA Astrophysics Data System (ADS)

Pivnicka, F.; Kemper, G.; Geissler, S.

2012-07-01

A growing number of mid-format cameras are used for aerial surveying projects. To achieve a reliable and geometrically precise result also in the photogrammetric workflow, awareness on the sensitive parts is important. The use of direct referencing systems (GPS/IMU), the mounting on a stabilizing camera platform and the specific values of the mid format camera make a professional setup with various calibration and misalignment operations necessary. An important part is to have a proper camera calibration. Using aerial images over a well designed test field with 3D structures and/or different flight altitudes enable the determination of calibration values in Bingo software. It will be demonstrated how such a calibration can be performed. The direct referencing device must be mounted in a solid and reliable way to the camera. Beside the mechanical work especially in mounting the camera beside the IMU, 2 lever arms have to be measured in mm accuracy. Important are the lever arms from the GPS Antenna to the IMU's calibrated centre and also the lever arm from the IMU centre to the Camera projection centre. In fact, the measurement with a total station is not a difficult task but the definition of the right centres and the need for using rotation matrices can cause serious accuracy problems. The benefit of small and medium format cameras is that also smaller aircrafts can be used. Like that, a gyro bases stabilized platform is recommended. This causes, that the IMU must be mounted beside the camera on the stabilizer. The advantage is, that the IMU can be used to control the platform, the problematic thing is, that the IMU to GPS antenna lever arm is floating. In fact we have to deal with an additional data stream, the values of the movement of the stabiliser to correct the floating lever arm distances. If the post-processing of the GPS-IMU data by taking the floating levers into account, delivers an expected result, the lever arms between IMU and camera can be applied

The future of consumer cameras

NASA Astrophysics Data System (ADS)

Battiato, Sebastiano; Moltisanti, Marco

2015-03-01

In the last two decades multimedia, and in particular imaging devices (camcorders, tablets, mobile phones, etc.) have been dramatically diffused. Moreover the increasing of their computational performances, combined with an higher storage capability, allows them to process large amount of data. In this paper an overview of the current trends of consumer cameras market and technology will be given, providing also some details about the recent past (from Digital Still Camera up today) and forthcoming key issues.

Single chip camera active pixel sensor

NASA Technical Reports Server (NTRS)

Shaw, Timothy (Inventor); Pain, Bedabrata (Inventor); Olson, Brita (Inventor); Nixon, Robert H. (Inventor); Fossum, Eric R. (Inventor); Panicacci, Roger A. (Inventor); Mansoorian, Barmak (Inventor)

2003-01-01

A totally digital single chip camera includes communications to operate most of its structure in serial communication mode. The digital single chip camera include a D/A converter for converting an input digital word into an analog reference signal. The chip includes all of the necessary circuitry for operating the chip using a single pin.

3-D Flow Visualization with a Light-field Camera

NASA Astrophysics Data System (ADS)

Thurow, B.

2012-12-01

Light-field cameras have received attention recently due to their ability to acquire photographs that can be computationally refocused after they have been acquired. In this work, we describe the development of a light-field camera system for 3D visualization of turbulent flows. The camera developed in our lab, also known as a plenoptic camera, uses an array of microlenses mounted next to an image sensor to resolve both the position and angle of light rays incident upon the camera. For flow visualization, the flow field is seeded with small particles that follow the fluid's motion and are imaged using the camera and a pulsed light source. The tomographic MART algorithm is then applied to the light-field data in order to reconstruct a 3D volume of the instantaneous particle field. 3D, 3C velocity vectors are then determined from a pair of 3D particle fields using conventional cross-correlation algorithms. As an illustration of the concept, 3D/3C velocity measurements of a turbulent boundary layer produced on the wall of a conventional wind tunnel are presented. Future experiments are planned to use the camera to study the influence of wall permeability on the 3-D structure of the turbulent boundary layer.Schematic illustrating the concept of a plenoptic camera where each pixel represents both the position and angle of light rays entering the camera. This information can be used to computationally refocus an image after it has been acquired. Instantaneous 3D velocity field of a turbulent boundary layer determined using light-field data captured by a plenoptic camera.

Plume propagation direction determination with SO2 cameras

NASA Astrophysics Data System (ADS)

Klein, Angelika; Lübcke, Peter; Bobrowski, Nicole; Kuhn, Jonas; Platt, Ulrich

2017-03-01

SO2 cameras are becoming an established tool for measuring sulfur dioxide (SO2) fluxes in volcanic plumes with good precision and high temporal resolution. The primary result of SO2 camera measurements are time series of two-dimensional SO2 column density distributions (i.e. SO2 column density images). However, it is frequently overlooked that, in order to determine the correct SO2 fluxes, not only the SO2 column density, but also the distance between the camera and the volcanic plume, has to be precisely known. This is because cameras only measure angular extents of objects while flux measurements require knowledge of the spatial plume extent. The distance to the plume may vary within the image array (i.e. the field of view of the SO2 camera) since the plume propagation direction (i.e. the wind direction) might not be parallel to the image plane of the SO2 camera. If the wind direction and thus the camera-plume distance are not well known, this error propagates into the determined SO2 fluxes and can cause errors exceeding 50 %. This is a source of error which is independent of the frequently quoted (approximate) compensation of apparently higher SO2 column densities and apparently lower plume propagation velocities at non-perpendicular plume observation angles.Here, we propose a new method to estimate the propagation direction of the volcanic plume directly from SO2 camera image time series by analysing apparent flux gradients along the image plane. From the plume propagation direction and the known location of the SO2 source (i.e. volcanic vent) and camera position, the camera-plume distance can be determined. Besides being able to determine the plume propagation direction and thus the wind direction in the plume region directly from SO2 camera images, we additionally found that it is possible to detect changes of the propagation direction at a time resolution of the order of minutes. In addition to theoretical studies we applied our method to SO2 flux

An integrated port camera and display system for laparoscopy.

PubMed

Terry, Benjamin S; Ruppert, Austin D; Steinhaus, Kristen R; Schoen, Jonathan A; Rentschler, Mark E

2010-05-01

In this paper, we built and tested the port camera, a novel, inexpensive, portable, and battery-powered laparoscopic tool that integrates the components of a vision system with a cannula port. This new device 1) minimizes the invasiveness of laparoscopic surgery by combining a camera port and tool port; 2) reduces the cost of laparoscopic vision systems by integrating an inexpensive CMOS sensor and LED light source; and 3) enhances laparoscopic surgical procedures by mechanically coupling the camera, tool port, and liquid crystal display (LCD) screen to provide an on-patient visual display. The port camera video system was compared to two laparoscopic video systems: a standard resolution unit from Karl Storz (model 22220130) and a high definition unit from Stryker (model 1188HD). Brightness, contrast, hue, colorfulness, and sharpness were compared. The port camera video is superior to the Storz scope and approximately equivalent to the Stryker scope. An ex vivo study was conducted to measure the operative performance of the port camera. The results suggest that simulated tissue identification and biopsy acquisition with the port camera is as efficient as with a traditional laparoscopic system. The port camera was successfully used by a laparoscopic surgeon for exploratory surgery and liver biopsy during a porcine surgery, demonstrating initial surgical feasibility.

Active learning in camera calibration through vision measurement application

NASA Astrophysics Data System (ADS)

Li, Xiaoqin; Guo, Jierong; Wang, Xianchun; Liu, Changqing; Cao, Binfang

2017-08-01

Since cameras are increasingly more used in scientific application as well as in the applications requiring precise visual information, effective calibration of such cameras is getting more important. There are many reasons why the measurements of objects are not accurate. The largest reason is that the lens has a distortion. Another detrimental influence on the evaluation accuracy is caused by the perspective distortions in the image. They happen whenever we cannot mount the camera perpendicularly to the objects we want to measure. In overall, it is very important for students to understand how to correct lens distortions, that is camera calibration. If the camera is calibrated, the images are rectificated, and then it is possible to obtain undistorted measurements in world coordinates. This paper presents how the students should develop a sense of active learning for mathematical camera model besides the theoretical scientific basics. The authors will present the theoretical and practical lectures which have the goal of deepening the students understanding of the mathematical models of area scan cameras and building some practical vision measurement process by themselves.

Creating and Using a Camera Obscura

ERIC Educational Resources Information Center

Quinnell, Justin

2012-01-01

The camera obscura (Latin for "darkened room") is the earliest optical device and goes back over 2500 years. The small pinhole or lens at the front of the room allows light to enter and this is then "projected" onto a screen inside the room. This differs from a camera, which projects its image onto light-sensitive material.…

Presence capture cameras - a new challenge to the image quality

NASA Astrophysics Data System (ADS)

Peltoketo, Veli-Tapani

2016-04-01

Commercial presence capture cameras are coming to the markets and a new era of visual entertainment starts to get its shape. Since the true presence capturing is still a very new technology, the real technical solutions are just passed a prototyping phase and they vary a lot. Presence capture cameras have still the same quality issues to tackle as previous phases of digital imaging but also numerous new ones. This work concentrates to the quality challenges of presence capture cameras. A camera system which can record 3D audio-visual reality as it is has to have several camera modules, several microphones and especially technology which can synchronize output of several sources to a seamless and smooth virtual reality experience. Several traditional quality features are still valid in presence capture cameras. Features like color fidelity, noise removal, resolution and dynamic range create the base of virtual reality stream quality. However, co-operation of several cameras brings a new dimension for these quality factors. Also new quality features can be validated. For example, how the camera streams should be stitched together with 3D experience without noticeable errors and how to validate the stitching? The work describes quality factors which are still valid in the presence capture cameras and defines the importance of those. Moreover, new challenges of presence capture cameras are investigated in image and video quality point of view. The work contains considerations how well current measurement methods can be used in presence capture cameras.

Cloud cameras at the Pierre Auger Observatory

NASA Astrophysics Data System (ADS)

Winnick, Michael G.

2010-06-01

This thesis presents the results of measurements made by infrared cloud cameras installed at the Pierre Auger Observatory in Argentina. These cameras were used to record cloud conditions during operation of the observatory's fluorescence detectors. As cloud may affect the measurement of fluorescence from cosmic ray extensive air showers, the cloud cameras provide a record of which measurements have been interfered with by cloud. Several image processing algorithms were developed, along with a methodology for the detection of cloud within infrared images taken by the cloud cameras. A graphical user interface (GUI) was developed to expediate this, as a large number of images need to be checked for cloud. A cross-check between images recorded by three of the observatory's cloud cameras is presented, along with a comparison with independent cloud measurements made by LIDAR. Despite the cloud cameras and LIDAR observing different areas of the sky, a good agreement is observed in the measured cloud fraction between the two instruments, particularly on very clear and overcast nights. Cloud information recorded by the cloud cameras, with cloud height information measured by the LIDAR, was used to identify those extensive air showers that were obscured by cloud. These events were used to study the effectiveness of standard quality cuts at removing cloud afflicted events. Of all of the standard quality cuts studied in this thesis, the LIDAR cloud fraction cut was the most effective at preferentially removing cloud obscured events. A 'cloudy pixel' veto is also presented, whereby cloud obscured measurements are excluded during the standard hybrid analysis, and new extensive air shower reconstructed parameters determined. The application of such a veto would provide a slight increase to the number of events available for higher level analysis.

Miniaturized Autonomous Extravehicular Robotic Camera (Mini AERCam)

NASA Technical Reports Server (NTRS)

Fredrickson, Steven E.

2001-01-01

The NASA Johnson Space Center (JSC) Engineering Directorate is developing the Autonomous Extravehicular Robotic Camera (AERCam), a low-volume, low-mass free-flying camera system . AERCam project team personnel recently initiated development of a miniaturized version of AERCam known as Mini AERCam. The Mini AERCam target design is a spherical "nanosatellite" free-flyer 7.5 inches in diameter and weighing 1 0 pounds. Mini AERCam is building on the success of the AERCam Sprint STS-87 flight experiment by adding new on-board sensing and processing capabilities while simultaneously reducing volume by 80%. Achieving enhanced capability in a smaller package depends on applying miniaturization technology across virtually all subsystems. Technology innovations being incorporated include micro electromechanical system (MEMS) gyros, "camera-on-a-chip" CMOS imagers, rechargeable xenon gas propulsion system , rechargeable lithium ion battery, custom avionics based on the PowerPC 740 microprocessor, GPS relative navigation, digital radio frequency communications and tracking, micropatch antennas, digital instrumentation, and dense mechanical packaging. The Mini AERCam free-flyer will initially be integrated into an approximate flight-like configuration for demonstration on an airbearing table. A pilot-in-the-loop and hardware-in-the-loop simulation to simulate on-orbit navigation and dynamics will complement the airbearing table demonstration. The Mini AERCam lab demonstration is intended to form the basis for future development of an AERCam flight system that provides beneficial on-orbit views unobtainable from fixed cameras, cameras on robotic manipulators, or cameras carried by EVA crewmembers.

A method and results of color calibration for the Chang'e-3 terrain camera and panoramic camera

NASA Astrophysics Data System (ADS)

Ren, Xin; Li, Chun-Lai; Liu, Jian-Jun; Wang, Fen-Fei; Yang, Jian-Feng; Liu, En-Hai; Xue, Bin; Zhao, Ru-Jin

2014-12-01

The terrain camera (TCAM) and panoramic camera (PCAM) are two of the major scientific payloads installed on the lander and rover of the Chang'e 3 mission respectively. They both use a Bayer color filter array covering CMOS sensor to capture color images of the Moon's surface. RGB values of the original images are related to these two kinds of cameras. There is an obvious color difference compared with human visual perception. This paper follows standards published by the International Commission on Illumination to establish a color correction model, designs the ground calibration experiment and obtains the color correction coefficient. The image quality has been significantly improved and there is no obvious color difference in the corrected images. Ground experimental results show that: (1) Compared with uncorrected images, the average color difference of TCAM is 4.30, which has been reduced by 62.1%. (2) The average color differences of the left and right cameras in PCAM are 4.14 and 4.16, which have been reduced by 68.3% and 67.6% respectively.

Semi-autonomous wheelchair system using stereoscopic cameras.

PubMed

Nguyen, Jordan S; Nguyen, Thanh H; Nguyen, Hung T

2009-01-01

This paper is concerned with the design and development of a semi-autonomous wheelchair system using stereoscopic cameras to assist hands-free control technologies for severely disabled people. The stereoscopic cameras capture an image from both the left and right cameras, which are then processed with a Sum of Absolute Differences (SAD) correlation algorithm to establish correspondence between image features in the different views of the scene. This is used to produce a stereo disparity image containing information about the depth of objects away from the camera in the image. A geometric projection algorithm is then used to generate a 3-Dimensional (3D) point map, placing pixels of the disparity image in 3D space. This is then converted to a 2-Dimensional (2D) depth map allowing objects in the scene to be viewed and a safe travel path for the wheelchair to be planned and followed based on the user's commands. This assistive technology utilising stereoscopic cameras has the purpose of automated obstacle detection, path planning and following, and collision avoidance during navigation. Experimental results obtained in an indoor environment displayed the effectiveness of this assistive technology.

MonoSLAM: real-time single camera SLAM.

PubMed

Davison, Andrew J; Reid, Ian D; Molton, Nicholas D; Stasse, Olivier

2007-06-01

We present a real-time algorithm which can recover the 3D trajectory of a monocular camera, moving rapidly through a previously unknown scene. Our system, which we dub MonoSLAM, is the first successful application of the SLAM methodology from mobile robotics to the "pure vision" domain of a single uncontrolled camera, achieving real time but drift-free performance inaccessible to Structure from Motion approaches. The core of the approach is the online creation of a sparse but persistent map of natural landmarks within a probabilistic framework. Our key novel contributions include an active approach to mapping and measurement, the use of a general motion model for smooth camera movement, and solutions for monocular feature initialization and feature orientation estimation. Together, these add up to an extremely efficient and robust algorithm which runs at 30 Hz with standard PC and camera hardware. This work extends the range of robotic systems in which SLAM can be usefully applied, but also opens up new areas. We present applications of MonoSLAM to real-time 3D localization and mapping for a high-performance full-size humanoid robot and live augmented reality with a hand-held camera.

Characterization of the LBNL PEM Camera

NASA Astrophysics Data System (ADS)

Wang, G.-C.; Huber, J. S.; Moses, W. W.; Qi, J.; Choong, W.-S.

2006-06-01

We present the tomographic images and performance measurements of the LBNL positron emission mammography (PEM) camera, a specially designed positron emission tomography (PET) camera that utilizes PET detector modules with depth of interaction measurement capability to achieve both high sensitivity and high resolution for breast cancer detection. The camera currently consists of 24 detector modules positioned as four detector banks to cover a rectangular patient port that is 8.2/spl times/6 cm/sup 2/ with a 5 cm axial extent. Each LBNL PEM detector module consists of 64 3/spl times/3/spl times/30 mm/sup 3/ LSO crystals coupled to a single photomultiplier tube (PMT) and an 8/spl times/8 silicon photodiode array (PD). The PMT provides accurate timing, the PD identifies the crystal of interaction, the sum of the PD and PMT signals (PD+PMT) provides the total energy, and the PD/(PD+PMT) ratio determines the depth of interaction. The performance of the camera has been evaluated by imaging various phantoms. The full-width-at-half-maximum (FWHM) spatial resolution changes slightly from 1.9 mm to 2.1 mm when measured at the center and corner of the field of the view, respectively, using a 6 ns coincidence timing window and a 300-750 keV energy window. With the same setup, the peak sensitivity of the camera is 1.83 kcps//spl mu/Ci.

Astronomy and the camera obscura

NASA Astrophysics Data System (ADS)

Feist, M.

2000-02-01

The camera obscura (from Latin meaning darkened chamber) is a simple optical device with a long history. In the form considered here, it can be traced back to 1550. It had its heyday during the Victorian era when it was to be found at the seaside as a tourist attraction or sideshow. It was also used as an artist's drawing aid and, in 1620, the famous astronomer-mathematician, Johannes Kepler used a small tent camera obscura to trace the scenery.

Enhanced LWIR NUC using an uncooled microbolometer camera

NASA Astrophysics Data System (ADS)

LaVeigne, Joe; Franks, Greg; Sparkman, Kevin; Prewarski, Marcus; Nehring, Brian

2011-06-01

Performing a good non-uniformity correction is a key part of achieving optimal performance from an infrared scene projector, and the best NUC is performed in the band of interest for the sensor being tested. While cooled, large format MWIR cameras are readily available and have been successfully used to perform NUC, similar cooled, large format LWIR cameras are not as common and are prohibitively expensive. Large format uncooled cameras are far more available and affordable, but present a range of challenges in practical use for performing NUC on an IRSP. Some of these challenges were discussed in a previous paper. In this discussion, we report results from a continuing development program to use a microbolometer camera to perform LWIR NUC on an IRSP. Camera instability and temporal response and thermal resolution were the main problems, and have been solved by the implementation of several compensation strategies as well as hardware used to stabilize the camera. In addition, other processes have been developed to allow iterative improvement as well as supporting changes of the post-NUC lookup table without requiring re-collection of the pre-NUC data with the new LUT in use.

Solid-state framing camera with multiple time frames

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, K. L.; Stewart, R. E.; Steele, P. T.

2013-10-07

A high speed solid-state framing camera has been developed which can operate over a wide range of photon energies. This camera measures the two-dimensional spatial profile of the flux incident on a cadmium selenide semiconductor at multiple times. This multi-frame camera has been tested at 3.1 eV and 4.5 keV. The framing camera currently records two frames with a temporal separation between the frames of 5 ps but this separation can be varied between hundreds of femtoseconds up to nanoseconds and the number of frames can be increased by angularly multiplexing the probe beam onto the cadmium selenide semiconductor.

How to Build Your Own Document Camera for around $100

ERIC Educational Resources Information Center

Van Orden, Stephen

2010-01-01

Document cameras can have great utility in second language classrooms. However, entry-level consumer document cameras start at around $350. This article describes how the author built three document cameras and offers suggestions for how teachers can successfully build their own quality document camera using a webcam for around $100.

Heterogeneous Vision Data Fusion for Independently Moving Cameras

DTIC Science & Technology

2010-03-01

target detection , tracking , and identification over a large terrain. The goal of the project is to investigate and evaluate the existing image...fusion algorithms, develop new real-time algorithms for Category-II image fusion, and apply these algorithms in moving target detection and tracking . The...moving target detection and classification. 15. SUBJECT TERMS Image Fusion, Target Detection , Moving Cameras, IR Camera, EO Camera 16. SECURITY

Dark Energy Camera for Blanco

DOE Office of Scientific and Technical Information (OSTI.GOV)

Binder, Gary A.; /Caltech /SLAC

2010-08-25

In order to make accurate measurements of dark energy, a system is needed to monitor the focus and alignment of the Dark Energy Camera (DECam) to be located on the Blanco 4m Telescope for the upcoming Dark Energy Survey. One new approach under development is to fit out-of-focus star images to a point spread function from which information about the focus and tilt of the camera can be obtained. As a first test of a new algorithm using this idea, simulated star images produced from a model of DECam in the optics software Zemax were fitted. Then, real images frommore » the Mosaic II imager currently installed on the Blanco telescope were used to investigate the algorithm's capabilities. A number of problems with the algorithm were found, and more work is needed to understand its limitations and improve its capabilities so it can reliably predict camera alignment and focus.« less

Ultra-fast framing camera tube

DOEpatents

Kalibjian, Ralph

1981-01-01

An electronic framing camera tube features focal plane image dissection and synchronized restoration of the dissected electron line images to form two-dimensional framed images. Ultra-fast framing is performed by first streaking a two-dimensional electron image across a narrow slit, thereby dissecting the two-dimensional electron image into sequential electron line images. The dissected electron line images are then restored into a framed image by a restorer deflector operated synchronously with the dissector deflector. The number of framed images on the tube's viewing screen is equal to the number of dissecting slits in the tube. The distinguishing features of this ultra-fast framing camera tube are the focal plane dissecting slits, and the synchronously-operated restorer deflector which restores the dissected electron line images into a two-dimensional framed image. The framing camera tube can produce image frames having high spatial resolution of optical events in the sub-100 picosecond range.

Perceptual Color Characterization of Cameras

PubMed Central

Vazquez-Corral, Javier; Connah, David; Bertalmío, Marcelo

2014-01-01

Color camera characterization, mapping outputs from the camera sensors to an independent color space, such as XY Z, is an important step in the camera processing pipeline. Until now, this procedure has been primarily solved by using a 3 × 3 matrix obtained via a least-squares optimization. In this paper, we propose to use the spherical sampling method, recently published by Finlayson et al., to perform a perceptual color characterization. In particular, we search for the 3 × 3 matrix that minimizes three different perceptual errors, one pixel based and two spatially based. For the pixel-based case, we minimize the CIE ΔE error, while for the spatial-based case, we minimize both the S-CIELAB error and the CID error measure. Our results demonstrate an improvement of approximately 3% for the ΔE error, 7% for the S-CIELAB error and 13% for the CID error measures. PMID:25490586

Design and Construction of an X-ray Lightning Camera

NASA Astrophysics Data System (ADS)

Schaal, M.; Dwyer, J. R.; Rassoul, H. K.; Uman, M. A.; Jordan, D. M.; Hill, J. D.

2010-12-01

A pinhole-type camera was designed and built for the purpose of producing high-speed images of the x-ray emissions from rocket-and-wire-triggered lightning. The camera consists of 30 7.62-cm diameter NaI(Tl) scintillation detectors, each sampling at 10 million frames per second. The steel structure of the camera is encased in 1.27-cm thick lead, which blocks x-rays that are less than 400 keV, except through a 7.62-cm diameter “pinhole” aperture located at the front of the camera. The lead and steel structure is covered in 0.16-cm thick aluminum to block RF noise, water and light. All together, the camera weighs about 550-kg and is approximately 1.2-m x 0.6-m x 0.6-m. The image plane, which is adjustable, was placed 32-cm behind the pinhole aperture, giving a field of view of about ±38° in both the vertical and horizontal directions. The elevation of the camera is adjustable between 0 and 50° from horizontal and the camera may be pointed in any azimuthal direction. In its current configuration, the camera’s angular resolution is about 14°. During the summer of 2010, the x-ray camera was located 44-m from the rocket-launch tower at the UF/Florida Tech International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL and several rocket-triggered lightning flashes were observed. In this presentation, I will discuss the design, construction and operation of this x-ray camera.

Auto-converging stereo cameras for 3D robotic tele-operation

NASA Astrophysics Data System (ADS)

Edmondson, Richard; Aycock, Todd; Chenault, David

2012-06-01

Polaris Sensor Technologies has developed a Stereovision Upgrade Kit for TALON robot to provide enhanced depth perception to the operator. This kit previously required the TALON Operator Control Unit to be equipped with the optional touchscreen interface to allow for operator control of the camera convergence angle adjustment. This adjustment allowed for optimal camera convergence independent of the distance from the camera to the object being viewed. Polaris has recently improved the performance of the stereo camera by implementing an Automatic Convergence algorithm in a field programmable gate array in the camera assembly. This algorithm uses scene content to automatically adjust the camera convergence angle, freeing the operator to focus on the task rather than adjustment of the vision system. The autoconvergence capability has been demonstrated on both visible zoom cameras and longwave infrared microbolometer stereo pairs.

Mechanical Design of the LSST Camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nordby, Martin; Bowden, Gordon; Foss, Mike

2008-06-13

The LSST camera is a tightly packaged, hermetically-sealed system that is cantilevered into the main beam of the LSST telescope. It is comprised of three refractive lenses, on-board storage for five large filters, a high-precision shutter, and a cryostat that houses the 3.2 giga-pixel CCD focal plane along with its support electronics. The physically large optics and focal plane demand large structural elements to support them, but the overall size of the camera and its components must be minimized to reduce impact on the image stability. Also, focal plane and optics motions must be minimized to reduce systematic errors inmore » image reconstruction. Design and analysis for the camera body and cryostat will be detailed.« less

Navigating surgical fluorescence cameras using near-infrared optical tracking.

PubMed

van Oosterom, Matthias; den Houting, David; van de Velde, Cornelis; van Leeuwen, Fijs

2018-05-01

Fluorescence guidance facilitates real-time intraoperative visualization of the tissue of interest. However, due to attenuation, the application of fluorescence guidance is restricted to superficial lesions. To overcome this shortcoming, we have previously applied three-dimensional surgical navigation to position the fluorescence camera in reach of the superficial fluorescent signal. Unfortunately, in open surgery, the near-infrared (NIR) optical tracking system (OTS) used for navigation also induced an interference during NIR fluorescence imaging. In an attempt to support future implementation of navigated fluorescence cameras, different aspects of this interference were characterized and solutions were sought after. Two commercial fluorescence cameras for open surgery were studied in (surgical) phantom and human tissue setups using two different NIR OTSs and one OTS simulating light-emitting diode setup. Following the outcome of these measurements, OTS settings were optimized. Measurements indicated the OTS interference was caused by: (1) spectral overlap between the OTS light and camera, (2) OTS light intensity, (3) OTS duty cycle, (4) OTS frequency, (5) fluorescence camera frequency, and (6) fluorescence camera sensitivity. By optimizing points 2 to 4, navigation of fluorescence cameras during open surgery could be facilitated. Optimization of the OTS and camera compatibility can be used to support navigated fluorescence guidance concepts. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Development of a camera casing suited for cryogenic and vacuum applications

NASA Astrophysics Data System (ADS)

Delaquis, S. C.; Gornea, R.; Janos, S.; Lüthi, M.; von Rohr, Ch Rudolf; Schenk, M.; Vuilleumier, J.-L.

2013-12-01

We report on the design, construction, and operation of a PID temperature controlled and vacuum tight camera casing. The camera casing contains a commercial digital camera and a lighting system. The design of the camera casing and its components are discussed in detail. Pictures taken by this cryo-camera while immersed in argon vapour and liquid nitrogen are presented. The cryo-camera can provide a live view inside cryogenic set-ups and allows to record video.

In-Situ Cameras for Radiometric Correction of Remotely Sensed Data

NASA Astrophysics Data System (ADS)

Kautz, Jess S.

The atmosphere distorts the spectrum of remotely sensed data, negatively affecting all forms of investigating Earth's surface. To gather reliable data, it is vital that atmospheric corrections are accurate. The current state of the field of atmospheric correction does not account well for the benefits and costs of different correction algorithms. Ground spectral data are required to evaluate these algorithms better. This dissertation explores using cameras as radiometers as a means of gathering ground spectral data. I introduce techniques to implement a camera systems for atmospheric correction using off the shelf parts. To aid the design of future camera systems for radiometric correction, methods for estimating the system error prior to construction, calibration and testing of the resulting camera system are explored. Simulations are used to investigate the relationship between the reflectance accuracy of the camera system and the quality of atmospheric correction. In the design phase, read noise and filter choice are found to be the strongest sources of system error. I explain the calibration methods for the camera system, showing the problems of pixel to angle calibration, and adapting the web camera for scientific work. The camera system is tested in the field to estimate its ability to recover directional reflectance from BRF data. I estimate the error in the system due to the experimental set up, then explore how the system error changes with different cameras, environmental set-ups and inversions. With these experiments, I learn about the importance of the dynamic range of the camera, and the input ranges used for the PROSAIL inversion. Evidence that the camera can perform within the specification set for ELM correction in this dissertation is evaluated. The analysis is concluded by simulating an ELM correction of a scene using various numbers of calibration targets, and levels of system error, to find the number of cameras needed for a full

Next-generation digital camera integration and software development issues

NASA Astrophysics Data System (ADS)

Venkataraman, Shyam; Peters, Ken; Hecht, Richard

1998-04-01

This paper investigates the complexities associated with the development of next generation digital cameras due to requirements in connectivity and interoperability. Each successive generation of digital camera improves drastically in cost, performance, resolution, image quality and interoperability features. This is being accomplished by advancements in a number of areas: research, silicon, standards, etc. As the capabilities of these cameras increase, so do the requirements for both hardware and software. Today, there are two single chip camera solutions in the market including the Motorola MPC 823 and LSI DCAM- 101. Real time constraints for a digital camera may be defined by the maximum time allowable between capture of images. Constraints in the design of an embedded digital camera include processor architecture, memory, processing speed and the real-time operating systems. This paper will present the LSI DCAM-101, a single-chip digital camera solution. It will present an overview of the architecture and the challenges in hardware and software for supporting streaming video in such a complex device. Issues presented include the development of the data flow software architecture, testing and integration on this complex silicon device. The strategy for optimizing performance on the architecture will also be presented.

The Sydney University PAPA camera

NASA Astrophysics Data System (ADS)

Lawson, Peter R.

1994-04-01

The Precision Analog Photon Address (PAPA) camera is a photon-counting array detector that uses optical encoding to locate photon events on the output of a microchannel plate image intensifier. The Sydney University camera is a 256x256 pixel detector which can operate at speeds greater than 1 million photons per second and produce individual photon coordinates with a deadtime of only 300 ns. It uses a new Gray coded mask-plate which permits a simplified optical alignment and successfully guards against vignetting artifacts.

Body worn camera

NASA Astrophysics Data System (ADS)

Aishwariya, A.; Pallavi Sudhir, Gulavani; Garg, Nemesa; Karthikeyan, B.

2017-11-01

A body worn camera is small video camera worn on the body, typically used by police officers to record arrests, evidence from crime scenes. It helps preventing and resolving complaints brought by members of the public; and strengthening police transparency, performance, and accountability. The main constants of this type of the system are video format, resolution, frames rate, and audio quality. This system records the video in .mp4 format with 1080p resolution and 30 frames per second. One more important aspect to while designing this system is amount of power the system requires as battery management becomes very critical. The main design challenges are Size of the Video, Audio for the video. Combining both audio and video and saving it in .mp4 format, Battery, size that is required for 8 hours of continuous recording, Security. For prototyping this system is implemented using Raspberry Pi model B.

Single lens 3D-camera with extended depth-of-field

NASA Astrophysics Data System (ADS)

Perwaß, Christian; Wietzke, Lennart

2012-03-01

Placing a micro lens array in front of an image sensor transforms a normal camera into a single lens 3D camera, which also allows the user to change the focus and the point of view after a picture has been taken. While the concept of such plenoptic cameras is known since 1908, only recently the increased computing power of low-cost hardware and the advances in micro lens array production, have made the application of plenoptic cameras feasible. This text presents a detailed analysis of plenoptic cameras as well as introducing a new type of plenoptic camera with an extended depth of field and a maximal effective resolution of up to a quarter of the sensor resolution.

Combustion pinhole camera system

DOEpatents

Witte, Arvel B.

1984-02-21

A pinhole camera system utilizing a sealed optical-purge assembly which provides optical access into a coal combustor or other energy conversion reactors. The camera system basically consists of a focused-purge pinhole optical port assembly, a conventional TV vidicon receiver, an external, variable density light filter which is coupled electronically to the vidicon automatic gain control (agc). The key component of this system is the focused-purge pinhole optical port assembly which utilizes a purging inert gas to keep debris from entering the port and a lens arrangement which transfers the pinhole to the outside of the port assembly. One additional feature of the port assembly is that it is not flush with the interior of the combustor.

Automatic Camera Calibration Using Multiple Sets of Pairwise Correspondences.

PubMed

Vasconcelos, Francisco; Barreto, Joao P; Boyer, Edmond

2018-04-01

We propose a new method to add an uncalibrated node into a network of calibrated cameras using only pairwise point correspondences. While previous methods perform this task using triple correspondences, these are often difficult to establish when there is limited overlap between different views. In such challenging cases we must rely on pairwise correspondences and our solution becomes more advantageous. Our method includes an 11-point minimal solution for the intrinsic and extrinsic calibration of a camera from pairwise correspondences with other two calibrated cameras, and a new inlier selection framework that extends the traditional RANSAC family of algorithms to sampling across multiple datasets. Our method is validated on different application scenarios where a lack of triple correspondences might occur: addition of a new node to a camera network; calibration and motion estimation of a moving camera inside a camera network; and addition of views with limited overlap to a Structure-from-Motion model.