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Journal articles on the topic 'Techniques: photometric'

Author: Grafiati

Published: 4 June 2021

Last updated: 7 February 2022

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1

Tinbergen, Jaap. "New Techniques." International Astronomical Union Colloquium 136 (1993): 130–46. http://dx.doi.org/10.1017/s025292110000748x.

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AbstractRoutine millimagnitude photometry may require a new approach to reduction of photometric errors. Such an approach is outlined in this paper; it stresses elimination of each error as close to its source as possible. The possibilities provided by modern technology are reviewed in this light. An engineering design group dedicated to photometry is a prerequisite and an on-site photometric technician may be necessary. In this concept, observers are mainly remote users of a database. Implied is the idea of accurate photometry necessarily developing into a single but multi-site astronomical facility (cf. VLBI) and the communal discipline that goes with it.

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2

Walker, Alistair, Saul Adelman, Eugene Milone, Barbara Anthony-Twarog, Pierre Bastien, Wen Ping Chen, Steve Howell, et al. "DIVISION B COMMISSION 25: ASTRONOMICAL PHOTOMETRY AND POLARIMETRY." Proceedings of the International Astronomical Union 11, T29A (August 2015): 159–70. http://dx.doi.org/10.1017/s1743921316000727.

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Commission 25 (C25) deals with the techniques and issues involved with the measurement of optical and infrared radiation intensities and polarization from astronomical sources. As such, in recent years attention has focused on photometric standard stars, atmospheric extinction, photometric passbands, transformation between systems, nomenclature, and observing and reduction techniques. At the start of the trimester C25 changed its name from Stellar Photometry and Polarization to Astronomical Photometry and Polarization so as to explicitly include in its mandate particular issues arising from the measurement of resolved sources, given the importance of photometric redshifts of distant galaxies for many of the large photometric surveys now underway. We begin by summarizing commission activities over the 2012-2014 period, follow with a report on Polarimetry, continue with Photometry topics that have been of interest to C25 members, and conclude with a Vision for the Future.

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Davies, L. J. M., J. E. Thorne, A. S. G. Robotham, S. Bellstedt, S. P. Driver, N. J. Adams, M. Bilicki, et al. "Deep Extragalactic VIsible Legacy Survey (DEVILS): consistent multiwavelength photometry for the DEVILS regions (COSMOS, XMMLSS, and ECDFS)." Monthly Notices of the Royal Astronomical Society 506, no. 1 (June 5, 2021): 256–87. http://dx.doi.org/10.1093/mnras/stab1601.

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ABSTRACT The Deep Extragalactic VIsible Legacy Survey (DEVILS) is an ongoing high-completeness, deep spectroscopic survey of ∼60 000 galaxies to Y < 21.2 mag, over ∼6 deg2 in three well-studied deep extragalactic fields: D10 (COSMOS), D02 (XMMLSS), and D03 (ECDFS). Numerous DEVILS projects all require consistent, uniformly derived and state-of-the-art photometric data with which to measure galaxy properties. Existing photometric catalogues in these regions either use varied photometric measurement techniques for different facilities/wavelengths leading to inconsistencies, older imaging data and/or rely on source detection and photometry techniques with known problems. Here, we use the ProFound image analysis package and state-of-the-art imaging data sets (including Subaru-HSC, VST-VOICE, VISTA-VIDEO, and UltraVISTA-DR4) to derive matched-source photometry in 22 bands from the FUV to 500 $\mu$m. This photometry is found to be consistent, or better, in colour analysis to previous approaches using fixed-size apertures (which are specifically tuned to derive colours), but produces superior total source photometry, essential for the derivation of stellar masses, star formation rates, star formation histories, etc. Our photometric catalogue is described in detail and, after internal DEVILS team projects, will be publicly released for use by the broader scientific community.

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Cabayol-Garcia, L., M. Eriksen, A. Alarcón, A. Amara, J. Carretero, R. Casas, F. J. Castander, et al. "The PAU Survey: background light estimation with deep learning techniques." Monthly Notices of the Royal Astronomical Society 491, no. 4 (November 23, 2019): 5392–405. http://dx.doi.org/10.1093/mnras/stz3274.

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ABSTRACT In any imaging survey, measuring accurately the astronomical background light is crucial to obtain good photometry. This paper introduces BKGnet, a deep neural network to predict the background and its associated error. BKGnet has been developed for data from the Physics of the Accelerating Universe Survey (PAUS), an imaging survey using a 40 narrow-band filter camera (PAUCam). The images obtained with PAUCam are affected by scattered light: an optical effect consisting of light multiply reflected that deposits energy in specific detector regions affecting the science measurements. Fortunately, scattered light is not a random effect, but it can be predicted and corrected for. We have found that BKGnet background predictions are very robust to distorting effects, while still being statistically accurate. On average, the use of BKGnet improves the photometric flux measurements by $7{{\ \rm per\ cent}}$ and up to $20{{\ \rm per\ cent}}$ at the bright end. BKGnet also removes a systematic trend in the background error estimation with magnitude in the i band that is present with the current PAU data management method. With BKGnet, we reduce the photometric redshift outlier rate by $35{{\ \rm per\ cent}}$ for the best $20{{\ \rm per\ cent}}$ galaxies selected with a photometric quality parameter.

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Ackermann, Jens, and Michael Goesele. "A Survey of Photometric Stereo Techniques." Foundations and Trends® in Computer Graphics and Vision 9, no. 3-4 (2015): 149–254. http://dx.doi.org/10.1561/0600000065.

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6

Zhang, Yan-Xia, and Yong-Heng Zhao. "Photometric Redshift Techniques in Big-data Era." Proceedings of the International Astronomical Union 11, S319 (August 2015): 57. http://dx.doi.org/10.1017/s1743921315009886.

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AbstractPhotometric data increase with large survey projects running. The huge volume of data influences the means and methods to deal with them. As such, the techniques of photometric redshift estimation based on photometric data must be developed and improved.

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7

Lee, Bomee, and Ranga-Ram Chary. "Improved photometric redshifts with colour-constrained galaxy templates for future wide-area surveys." Monthly Notices of the Royal Astronomical Society 497, no. 2 (July 17, 2020): 1935–45. http://dx.doi.org/10.1093/mnras/staa2100.

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ABSTRACT Cosmology and galaxy evolution studies with LSST, Euclid, and Roman, will require accurate redshifts for the detected galaxies. In this study, we present improved photometric redshift estimates for galaxies using a template library that populates three-colour space and is constrained by HST/CANDELS photometry. For the training sample, we use a sample of galaxies having photometric redshifts that allows us to train on a large, unbiased galaxy sample having deep, unconfused photometry at optical-to-mid infrared wavelengths. Galaxies in the training sample are assigned to cubes in 3D colour space, V − H, I − J, and z − H. We then derive the best-fitting spectral energy distributions of the training sample at the fixed CANDELS median photometric redshifts to construct the new template library for each individual colour cube (i.e. colour-cube-based template library). We derive photometric redshifts (photo-z) of our target galaxies using our new colour-cube-based template library and with photometry in only a limited set of bands, as expected for the aforementioned surveys. As a result, our method yields σNMAD of 0.026 and an outlier fraction of 6 per cent using only photometry in the LSST and Euclid/Roman bands. This is an improvement of ∼10 per cent on σNMAD and a reduction in outlier fraction of ∼13 per cent compared to other techniques. In particular, we improve the photo-z precision by about 30 per cent at 2 < z < 3. We also assess photo-z improvements by including K or mid-infrared bands to the ugrizYJH photometry. Our colour-cube-based template library is a powerful tool to constrain photometric redshifts for future large surveys.

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8

Barry, D. J., W. G. Bagnuolo, B. D. Mason, H. A. McAlister, and N. H. Turner. "Prospects for Rapid, Routine Speckle Photometry." International Astronomical Union Colloquium 135 (1992): 537–39. http://dx.doi.org/10.1017/s0252921100007077.

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Image reconstruction techniques have rapidly matured over the last decade, and increasing reference to full–aperture and masked aperture results appear in the literature. Although anomalies in morphology are understood, most work uses nonlinear iterative refinements of questionable photometric robustness. Recent development of linear least–squares phase reconstruction techniques from the bispectrum (Glindemann et al. 1991) offers hope for a robust technique using a computational tour de force. However, the field cannot be considered mature until routine photometry of a large number of speckle–resolved objects is performed and demonstrated to be repeatable. We review our work and our expectations for use of both computationally intensive and simple techniques in our routine speckle reductions.

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Newling, J., M. Varughese, B. Bassett, H. Campbell, R. Hlozek, M. Kunz, H. Lampeitl, et al. "Statistical classification techniques for photometric supernova typing." Monthly Notices of the Royal Astronomical Society 414, no. 3 (April 15, 2011): 1987–2004. http://dx.doi.org/10.1111/j.1365-2966.2011.18514.x.

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10

Subbarao, M. U., A. J. Connolly, A. S. Szalay, and D. C. Koo. "Luminosity Functions From Photometric Redshifts. I. Techniques." Astronomical Journal 112 (September 1996): 929. http://dx.doi.org/10.1086/118066.

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11

Cachero, Rocio, and Carlota Abello. "Stereo-photometric techniques for scanning micrometer scale." Virtual Archaeology Review 6, no. 13 (November 24, 2015): 72. http://dx.doi.org/10.4995/var.2015.4380.

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This paper describes a new methodology based on the combination of photogrammetric and stereo-photometric techniques that allows creating virtual replicas reproducing the relief in micrometric scale, with a geometric resolution until 7 microns. The finest details of the texture obtained by photogrammetric methods are translated to the relief of the mesh to provide quality 3D printing by additive manufacturing methods. These results open new possibilities for virtual and physical reproduction of archeological items that need a great accuracy and geometric resolution.

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Luksch, Christian, Lukas Prost, and Michael Wimmer. "Real-time Approximation of Photometric Polygonal Lights." Proceedings of the ACM on Computer Graphics and Interactive Techniques 3, no. 1 (April 18, 2020): 1–18. http://dx.doi.org/10.1145/3384537.

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We present a real-time rendering technique for photometric polygonal lights. Our method uses a numerical integration technique based on a triangulation to calculate noise-free diffuse shading. We include a dynamic point in the triangulation that provides a continuous near-field illumination resembling the shape of the light emitter and its characteristics. We evaluate the accuracy of our approach with a diverse selection of photometric measurement data sets in a comprehensive benchmark framework. Furthermore, we provide an extension for specular reflection on surfaces with arbitrary roughness that facilitates the use of existing real-time shading techniques. Our technique is easy to integrate into real-time rendering systems and extends the range of possible applications with photometric area lights.

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13

Glass, I. S. "Photometry with Infrared Arrays." International Astronomical Union Colloquium 136 (1993): 154–59. http://dx.doi.org/10.1017/s0252921100007508.

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AbstractInfrared arrays have been in use at a number of observatories for several years. They are more complicated in their construction than optical ones and more problems arise in obtaining good photometry from them. The types of arrays currently available are described together with the observational techniques and the problems encountered in obtaining accurate photometric results.

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Butler, R. F., A. Shearer, R. M. Redfern, M. Colhoun, P. O'Kane, A. J. Penny, P. W. Morris, W. K. Griffiths, and M. Cullum. "TRIFFID photometry of globular cluster cores - I. Photometric techniques and variable stars in M15." Monthly Notices of the Royal Astronomical Society 296, no. 2 (May 11, 1998): 379–91. http://dx.doi.org/10.1046/j.1365-8711.1998.01359.x.

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15

Anderson, Jay. "Photometric Techniques for Exploring Multiple Populations in Clusters." Proceedings of the International Astronomical Union 10, H16 (August 2012): 239–40. http://dx.doi.org/10.1017/s1743921314005584.

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AbstractThe advent of the Hubble Space Telescope (HST) and the development of new photometric algorithms that take advantage of its stable observing platform above the atmosphere have allowed us to study the populations in globular clusters with very high precision.

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16

Lumme, K., J. Peltoniemi, and W. M. Irvine. "Some photometric techniques for atmosphereless solar system bodies." Advances in Space Research 10, no. 1 (January 1990): 187–93. http://dx.doi.org/10.1016/0273-1177(90)90103-7.

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17

Jewitt, D. "Cometary Photometry." International Astronomical Union Colloquium 116, no. 1 (1989): 19–65. http://dx.doi.org/10.1017/s0252921100109625.

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AbstractThe study of comets using modern optical photometric techniques is reviewed. Particular emphasis is given to the physical constraints imposed on the nature of comets by photometric data. The photometric study of bare nuclei and of active comets is discussed.

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18

Wilson, Richard, and Heide Friedrich. "Coupling of Ultrasonic and Photometric Techniques for Synchronous Measurements of Unconfined Turbidity Currents." Water 10, no. 9 (September 14, 2018): 1246. http://dx.doi.org/10.3390/w10091246.

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By synchronizing data collection, such as photometric and ultrasonic Doppler profiling (UVP) measurement techniques, new insights can be obtained into environmental flows, such as highly dynamic turbidity currents. We introduce a combined experimental setup, which ultimately allows a time reduction in testing programmes, and discuss the measurement advances with the help of four surface conditions we tested for unconfined turbidity currents: (a) a smooth surface; (b) a smooth surface with an obstacle present; (c) a rough surface; and (d) a rough surface with an obstacle present. We show that data from both measurement techniques indicate that a rough surface reduces global current velocities and the magnitude of turbidity current phenomena, including Kelvin-Helmholtz instabilities and lobe-and-cleft formation. However, by coupling the techniques, photometric data give valuable insight into the spatial development of instabilities, such as the grouping of lobe and cleft formations. The presence of an obstacle causes local regions of an increased and decreased velocity, but does not affect the global current velocity. Additionally, the obstacle created three local intensity maxima upstream, dissipating to two maxima downstream, supporting the presence of local eddies. The study shows that the combination of UVP and photometry is an effective way forward for obtaining detailed qualitative and quantitative insights into turbulent flow characteristics and we highlight the potential for future research.

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Strassmeier, Klaus G. "The zoo of starspots." Proceedings of the International Astronomical Union 6, S273 (August 2010): 174–80. http://dx.doi.org/10.1017/s1743921311015201.

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AbstractStarspots are being observed with many different techniques but not always with coherent results. In particular not if model-dependent data analysis must be employed, e.g. through two-dimensional spot modelling of one-dimensional photometric light curves. I review the zoo of currently available physical spot parameters, i.e. their size, temperature and variability time scales, and also compare results from different techniques. Most of the current values come from Doppler imaging and multi-color photometry. I also list a few cases where starspot detections turned out to be very different to the solar analog.

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Sun, Jiuai, Xiaoping Xu, Abdul Rehman Farooq, Lyndon Neal Smith, and Melvyn Lionel Smith. "A photometric stereo approach for chronic wound measurement." Sensor Review 35, no. 4 (September 21, 2015): 419–24. http://dx.doi.org/10.1108/sr-01-2015-0018.

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Purpose – This paper aims to review state of the art of techniques for dimensioning chronic wounds, and validate the possibilities of employing a new proposed optical imaging approach for general task of wound assessment. Design/methodology/approach – Current techniques used for quantifying wound surface are reviewed and evaluated from various perspectives to exam their usability in wound care clinical settings. A photometric stereo (PS) approach will be identified and verified to work as an alternative solution to better satisfy practical requirements on quantifying the dimension of real and mocked wounds. Findings – Both contact and contactless approaches provide some useful functions for wound management; however, new imaging modalities are still required for achieving good portability, affordability and applicability in assisting decision-making in clinical settings. The PS approach can work as a potential solution to provide these functionalities as well as dense geometrical and color texture information of measured areas. The experiments demonstrate that the new approach is able to conveniently produce comparable results to those from latest stereo vision-based techniques. Research limitations/implications – This work proposed and initially verified the potential of PS technique for the task of wound measurement. Substantial improvements on the prototype and more clinical trials are still required to validate the new technique before it is accepted as a tool for practical wound measurement. Originality/value – This new PS approach has good potential to reliably measure the dimension of wounds as well as recover their color texture which could contain additional valuable information for predicting a healing procedure for those wound occurring deeper underneath the skin surface.

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Hudgins, David W., and Miroslav D. Filipović. "Photometric Techniques Using Small College Research Instruments for Study of the Extrasolar Planetary Transits of HD 209458." Publications of the Astronomical Society of Australia 19, no. 4 (2002): 443–47. http://dx.doi.org/10.1071/as02007.

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AbstractWe present the results of a program to develop techniques that enable high-resolution photometric measurements using modest research instruments available to small colleges, and then demonstrate those techniques in a pilot photometric project.Using a 25 cm Schmidt–Cassegrain telescope and SBIG ST7E CCD camera, we develop techniques that enabled milli-magnitude photometric resolution. The pilot project studied five transits of the recently discovered gas giant planet orbiting HD 209458. We measured a flux drop of 1.46 ± 0.17% during the transit which corresponds to a planetary diameter of 1.39 ± 0.14 RJup, a transit period of 2h 48min ± 21min, and planet orbital inclination of 87.6 ± 1.3°. We determined the orbital period as 3.5234 ± 0.0026 days. These results agree well with other studies which used professional grade research instruments. We suggest a number of other challenging photometric research areas suitable for graduate and undergraduate investigation using equipment common to many small colleges.

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Weiss, W. W., H. E. Fröhlich, T. Kallinger, R. Kuschnig, A. Popowicz, D. Baade, D. Buzasi, et al. "New BRITE-Constellation observations of the roAp star α Cir." Astronomy & Astrophysics 642 (October 2020): A64. http://dx.doi.org/10.1051/0004-6361/202038345.

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Context. Chemically peculiar (CP) stars with a measurable magnetic field comprise the group of mCP stars. The pulsating members define the subgroup of rapidly oscillating Ap (roAp) stars, of which α Cir is the brightest member. Hence, α Cir allows the application of challenging techniques, such as interferometry, very high temporal and spectral resolution photometry, and spectroscopy in a wide wavelength range, that have the potential to provide unique information about the structure and evolution of a star. Aims. Based on new photometry from BRITE-Constellation, obtained with blue and red filters, and on photometry from WIRE, SMEI, and TESS we attempt to determine the surface spot structure of α Cir and investigate pulsation frequencies. Methods. We used photometric surface imaging and frequency analyses and Bayesian techniques in order to quantitatively compare the probability of different models. Results. BRITE-Constellation photometry obtained from 2014 to 2016 is put in the context of space photometry obtained by WIRE, SMEI, and TESS. This provides improvements in the determination of the rotation period and surface features (three spots detected and a fourth one indicated). The main pulsation frequencies indicate two consecutive radial modes and one intermediate dipolar mode. Advantages and problems of the applied Bayesian technique are discussed.

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Lapasset, E., M. Gomez, and R. Fariñas. "Test of the Optimization Techniques for the Photometric Analysis of Contact Binaries." Symposium - International Astronomical Union 151 (1992): 387–90. http://dx.doi.org/10.1017/s0074180900122545.

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We present light curve analyses of contact binaries and comparisons with previously published cross-correlations radial velocity data. The critical parameter q (mass-ratio) obtained from a grid technique is confronted with the spectroscopic value. For total eclipsing systems, both values are always in a good or reasonable agreement, including some stars with shallow light curves. For partial eclipsing systems, convergent photometric and spectroscopic results are obtained for an important set of stars. Two exceptions are V523 Cas and XY Boo for which some arguments are suggested. We concluded that reliable parameter determinations can be obtained from pure photometric solutions, by means of grid techniques.

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Koornneef, J., R. Bohlin, R. Buser, K. Horne, and D. Turnshek. "Synthetic Photometry and the Calibration of the Hubble Space Telescope." Highlights of Astronomy 7 (1986): 833–43. http://dx.doi.org/10.1017/s153929960000736x.

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AbstractThe combined Scientific Instruments (SIs) on the Hubble Space Telescope (HST) feature an extensive wavelength coverage in both photometric and spectrophotometric modes with an overall dynamic range of more than twenty-five magnitudes. We demonstrate how synthetic photometry techniques are to be used to establish and maintain their calibration. This approach makes efficient use of limited HST observing time by taking full advantage of pre-launch knowledge on the SI sensitivity functions and calibration targets.

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Read, S. C., D. J. B. Smith, M. J. Jarvis, and G. Gürkan. "The performance of photometric reverberation mapping at high redshift and the reliability of damped random walk models." Monthly Notices of the Royal Astronomical Society 492, no. 3 (December 20, 2019): 3940–59. http://dx.doi.org/10.1093/mnras/stz3574.

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ABSTRACT Accurate methods for reverberation mapping using photometry are highly sought after since they are inherently less resource intensive than spectroscopic techniques. However, the effectiveness of photometric reverberation mapping for estimating black hole masses is sparsely investigated at redshifts higher than z ≈ 0.04. Furthermore, photometric methods frequently assume a damped random walk (DRW) model, which may not be universally applicable. We perform photometric reverberation mapping using the javelin photometric DRW model for the QSO SDSS-J144645.44+625304.0 at z = 0.351 and estimate the Hβ lag of $65^{+6}_{-1}$ d and black hole mass of $10^{8.22^{+0.13}_{-0.15}}\, \mathrm{M_{\odot }}$. An analysis of the reliability of photometric reverberation mapping, conducted using many thousands of simulated CARMA process light curves, shows that we can recover the input lag to within 6 per cent on average given our target’s observed signal-to-noise of >20 and average cadence of 14 d (even when DRW is not applicable). Furthermore, we use our suite of simulated light curves to deconvolve aliases and artefacts from our QSO’s posterior probability distribution, increasing the signal-to-noise on the lag by a factor of ∼2.2. We exceed the signal-to-noise of the Sloan Digital Sky Survey Reverberation Mapping Project (SDSS-RM) campaign with a quarter of the observing time per object, resulting in a ∼200 per cent increase in signal-to-noise efficiency over SDSS-RM.

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26

Merlin, E., M. Castellano, P. Santini, G. Cipolletta, K. Boutsia, C. Schreiber, F. Buitrago, et al. "The ASTRODEEP-GS43 catalogue: New photometry and redshifts for the CANDELS GOODS-South field." Astronomy & Astrophysics 649 (May 2021): A22. http://dx.doi.org/10.1051/0004-6361/202140310.

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Context. We present ASTRODEEP-GS43, a new multi-wavelength photometric catalogue of the GOODS-South field, which builds and improves upon the previously released CANDELS catalogue. Aims. We provide photometric fluxes and corresponding uncertainties in 43 optical and infrared bands (25 wide and 18 medium filters), as well as the photometric redshifts and physical properties of the 34930 CANDELS H-detected objects, plus an additional sample of 178 H-dropout sources, of which 173 are Ks-detected and five are IRAC-detected. Methods. We keep the CANDELS photometry in seven bands (CTIO U, Hubble Space Telescope WFC3, and ISAAC-K) and measure from scratch the fluxes in the other 36 (23 from Subaru SuprimeCAM and Magellan Baade FourStar and the rest from VIMOS, HST ACS, HAWK-I Ks, and Spitzer IRAC) with state-of-the-art template-fitting techniques. We then compute new photometric redshifts with three different software tools and take the median value as a best estimate. We finally evaluate new physical parameters from spectral energy distribution (SED) fitting, comparing them to previously published ones. Results. Comparing to a sample of 3931 high quality spectroscopic redshifts, for the new photometric redshifts we obtain a normalised median absolute deviation of 0.015, with 3.01% of outliers on the full catalogue (0.011 and 0.22% on the bright end at I814 < 22.5). This is similar to the best available published samples of photometric redshifts, such as the COSMOS UltraVISTA catalogue. Conclusions. The ASTRODEEP-GS43 results are in qualitative agreement with previously published catalogues of the GOODS-South field, improving on them particularly in terms of SED sampling and photometric redshift estimates. The catalogue is available for download from the ASTRODEEP website.

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Cooke, Benjamin F., and Don Pollacco. "specphot: a comparison of spectroscopic and photometric exoplanet follow-up methods." Monthly Notices of the Royal Astronomical Society 495, no. 1 (May 8, 2020): 734–42. http://dx.doi.org/10.1093/mnras/staa1194.

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ABSTRACT We set out a simulation to explore the follow-up of exoplanet candidates. We look at comparing photometric (transit method) and spectroscopic (Doppler shift method) techniques using three instruments: Next-Generation Transit Survey, High-Accuracy Radial-velocity Planetary Search, and CORALIE. We take into account the precision of follow-up and required observing time in attempt to rank each method for a given set of planetary system parameters. The methods are assessed on two criteria: signal-to-noise ratio (S/N) of the detection and follow-up time before characterization. We find that different follow-up techniques are preferred for different regions of parameter space. For S/N, we find that the ratio of spectroscopic to photometric S/N for a given system goes like $R_{\rm p}/P^{{1}/{3}}$. For follow-up time, we find that photometry is favoured for the shortest period systems (<10 d) as well as systems with small planet radii. Spectroscopy is then preferred for systems with larger radius, and thus more massive planets (given our assumed mass–radius relationship). Finally, we attempt to account for the availability of telescopes and weight the two methods accordingly.

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ITO, SHIN'ICHI. "Recycling. Physical Separation Techniques. Hand Picking and Photometric Sorting." Shigen-to-Sozai 113, no. 12 (1997): 908–11. http://dx.doi.org/10.2473/shigentosozai.113.908.

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29

Carlson, Paul J., and Thomas Urbanik. "Validation of Photometric Modeling Techniques for Retroreflective Traffic Signs." Transportation Research Record: Journal of the Transportation Research Board 1862, no. 1 (January 2004): 109–18. http://dx.doi.org/10.3141/1862-13.

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MACHIDA, Kenichiro, Harutaka IMOTO, and Takashi MAEKAWA. "1108 Development of Inspection System Using Photometric Stereo Techniques." Proceedings of Design & Systems Conference 2015.25 (2015): _1108–1_—_1108–6_. http://dx.doi.org/10.1299/jsmedsd.2015.25._1108-1_.

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Kreidl, T. J. "Time-Series Photometry: CCDs vs. PMTs." International Astronomical Union Colloquium 136 (1993): 311–17. http://dx.doi.org/10.1017/s0252921100007703.

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AbstractWith the ability to obtain simultaneous photometry of many objects, CCD time-series photometry is a potentially powerful method for obtaining data, even under non-photometric conditions. In particular, the ability to utilize one or more comparison stars on the same frame without the need to move the telescope to a different field makes for a higher duty cycle than conventional photoelectric photometry. In addition, the ability to determine the local sky in a variety of ways plus the ability to use more complex analysis techniques such as profile fitting and curves of growth permits a variety of analysis options. Some of the advantages of utilizing CCDs and the techniques used in time-series photometry of compact objects are discussed. With the flexibility of modern CCD control systems, possibilities for real-time or near real-time data analysis using readily available computer technology are stressed. Brief discussions of periodicity analysis considerations and other aspects of the data acquisition are presented.

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Stritzinger, M. D., J. P. Anderson, C. Contreras, E. Heinrich-Josties, N. Morrell, M. M. Phillips, J. Anais, et al. "The Carnegie Supernova Project I." Astronomy & Astrophysics 609 (January 2018): A134. http://dx.doi.org/10.1051/0004-6361/201730842.

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The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated supernova follow-up program based at the Las Campanas Observatory that collected science data of young, low-redshift supernovae between 2004 and 2009. Presented in this paper is the CSP-I photometric data release of low-redshift stripped-envelope core-collapse supernovae. The data consist of optical (uBgVri) photometry of 34 objects, with a subset of 26 having near-infrared (YJH) photometry. Twenty objects have optical pre-maximum coverage with a subset of 12 beginning at least five days prior to the epoch of B-band maximum brightness. In the near-infrared, 17 objects have pre-maximum observations with a subset of 14 beginning at least five days prior to the epoch of J-band maximum brightness. Analysis of this photometric data release is presented in companion papers focusing on techniques to estimate host-galaxy extinction and the light-curve and progenitor star properties of the sample. The analysis of an accompanying visual-wavelength spectroscopy sample of ~150 spectra will be the subject of a future paper.

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Karami, A., F. Menna, and F. Remondino. "INVESTIGATING 3D RECONSTRUCTION OF NON-COLLABORATIVE SURFACES THROUGH PHOTOGRAMMETRY AND PHOTOMETRIC STEREO." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2021 (June 28, 2021): 519–26. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2021-519-2021.

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Abstract. 3D digital reconstruction techniques are extensively used for quality control purposes. Among them, photogrammetry and photometric stereo methods have been for a long time used with success in several application fields. However, generating highly-detailed and reliable micro-measurements of non-collaborative surfaces is still an open issue. In these cases, photogrammetry can provide accurate low-frequency 3D information, whereas it struggles to extract reliable high-frequency details. Conversely, photometric stereo can recover a very detailed surface topography, although global surface deformation is often present. In this paper, we present the preliminary results of an ongoing project aiming to combine photogrammetry and photometric stereo in a synergetic fusion of the two techniques. Particularly, hereafter, we introduce the main concept design behind an image acquisition system we developed to capture images from different positions and under different lighting conditions as required by photogrammetry and photometric stereo techniques. We show the benefit of such a combination through some experimental tests. The experiments showed that the proposed method recovers the surface topography at the same high-resolution achievable with photometric stereo while preserving the photogrammetric accuracy. Furthermore, we exploit light directionality and multiple light sources to improve the quality of dense image matching in poorly textured surfaces.

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Altena, B., A. Mousivand, J. Mascaro, and A. Kääb. "POTENTIAL AND LIMITATIONS OF PHOTOMETRIC RECONSTRUCTION THROUGH A FLOCK OF DOVE CUBESATS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W3 (October 19, 2017): 7–11. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w3-7-2017.

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When Earth observation satellite systems are designed, one typically prefers a sun-synchronous orbit. However, the first generations of cubesats from Planet were deployed out of the International Space Station (ISS) and therefore do not obey such an orbit. Their configuration samples at different local times within the mid-latitudes. Consequently, it is in theory possible to exploit photometric techniques and extract highly detailed topographic information. In this study we demonstrate and explore photometry based on Planet cubesat images for Tyndall glacier at the Southern Patagonian icefield, and Zhadang glacier situated on the Tibetan plateau.

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Stobie, R. S., D. Kilkenny, D. O’Donoghue, and A. Chen. "The Edinburgh-Cape Blue Object Survey." International Astronomical Union Colloquium 148 (1995): 280–91. http://dx.doi.org/10.1017/s0252921100022041.

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AbstractThe Edinburgh-Cape Blue Object Survey is a major survey to discover blue stellar objects brighter than B ∼ 18 in the southern sky. It covers an area of sky of 10,000 square degrees with |b| > 30° and δ < 0°. The blue stellar objects are selected by automatic techniques from U and B pairs of UK Schmidt Telescope plates scanned with the COSMOS measuring machine. Follow-up photometry and spectroscopy are being obtained with the SAAO telescopes to classify objects brighter than B = 16.5. This paper describes the survey, the techniques used to extract the blue stellar objects, the photometric accuracy, and the completeness of the survey.

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Maíz Apellániz, J., E. J. Alfaro, R. H. Barbá, G. Holgado, H. Vázquez-Ramió, J. Varela, A. Ederoclite, et al. "The GALANTE photometric survey of the northern Galactic plane: project description and pipeline." Monthly Notices of the Royal Astronomical Society 506, no. 3 (July 2, 2021): 3138–54. http://dx.doi.org/10.1093/mnras/stab1769.

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ABSTRACT The GALANTE optical photometric survey is observing the northern Galactic plane and some adjacent regions using seven narrow- and intermediate-filters, covering a total of 1618 deg2. The survey has been designed with multiple exposure times and at least two different air masses per field to maximize its photometric dynamic range, comparable to that of Gaia, and ensure the accuracy of its photometric calibration. The goal is to reach at least 1 per cent accuracy and precision in the seven bands for all stars brighter than AB magnitude 17 while detecting fainter stars with lower values of the signal-to-noise ratio. The main purposes of GALANTE are the identification and study of extinguished O+B+WR stars, the derivation of their extinction characteristics, and the cataloguing of F and G stars in the solar neighbourhood. Its data will be also used for a variety of other stellar studies and to generate a high-resolution continuum-free map of the Hα emission in the Galactic plane. We describe the techniques and the pipeline that are being used to process the data, including the basis of an innovative calibration system based on Gaia DR2 and 2MASS photometry.

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Maskoliunas, M., J. Zdanavičius, V. Čepas, A. Kazlauskas, R. P. Boyle, K. Zdanavičius, K. Černis, K. Milašius, and M. Macijauskas. "New calibration of the Vilnius photometric system." Proceedings of the International Astronomical Union 14, A30 (August 2018): 486. http://dx.doi.org/10.1017/s1743921319005179.

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AbstractThe medium-band Vilnius photometric system with the mean wavelengths at 345 (U), 374 (P), 405 (X), 466 (Y), 516 (Z), 544 (V), and 656 (S) nm for many years was an important tool to determine interstellar reddenings and distances of single stars due to its ability to classify stars of all temperatures in spectral classes and luminosity classes in the presence of different interstellar reddenings. At present, Gaia DR2 presents distances to stars with an unprecedented accuracy at least up to 3 kpc. However, multicolor photometry, which allows the classification of stars as well as the preliminary determination of stellar temperatures, gravities, metallicities and interstellar reddenings, remains an important method for distant stars. Here we present an empirical calibration of the intrinsic color indices of the Vilnius system in terms of physical parameters of stars for dwarf and giant stars of spectral classes F-G-K-M. In any attempted photometric determination of physical parameters of stars it is important to have an extensive and homogeneous sample of spectroscopically determined parameters for stars for which there are also accurate photometric data. As a source catalogue for the Vilnius photometry the latest updated version of the Catalogue of Photoelectric Observations in the Vilnius System was used, which contains compilations from the published photometry for about 11 000 stars. The stars which had both the Gaia DR2 parallaxes and the determinations of stellar parameters from high-dispersion spectra were extracted from this catalogue. The final sample contains more than 1500 stars of spectral classes F-M. The majority of these stars (ca 70%) are not reddened, for others the values of interstellar reddening AV were determined using the regular techniques of photometric classification in the Vilnius system. The absolute magnitudes MV and consequently the luminosity classes were determined using Gaia DR2 parallaxes. We present the analytical expressions for the effective temperature Teff and surface gravity logg and evaluate the errors of solutions for dwarf and giant stars. To test the accuracy of the proposed method, we have compared our results with the stars observed by Gaia and with the stellar parameters available from the large spectroscopic surveys: APOGEE, Gaia-ESO, GALAH, LAMOST, RAVE and SEGUE. The results of comparison contain 5-6 % outliers.The proposed method allows the fast and straightforward evaluation of stellar physical parameters for the stars observed in the Vilnius photometric system. Despite the fact, that the accuracy of determination is significantly lower than in the case of spectroscopic methods, the method described may be useful for distant faint stars, which are still inaccessible for spectroscopic observations.

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Landolt, A. U., P. Martinez, P. Bastien, S. Fabrika, R. Gilliland, F. Grundahl, C. Jordi, and U. Munari. "Commission 25: Stellar Photometry and Polarimetry." Proceedings of the International Astronomical Union 1, T26A (December 2005): 307–12. http://dx.doi.org/10.1017/s1743921306004753.

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AbstractEven a brief glance at astronomical journals indicates the breadth and depth of observational projects making use of photometric and polarimetric techniques. Examples of ongoing photometric and polarimetric research as related by Commission Members follows. I thank the Commission Members, acknowledged below, for their input.

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Curran, S. J. "QSO photometric redshifts from SDSS, WISE, and GALEX colours." Monthly Notices of the Royal Astronomical Society: Letters 493, no. 1 (January 21, 2020): L70—L75. http://dx.doi.org/10.1093/mnrasl/slaa012.

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ABSTRACT Machine learning techniques, specifically the k-nearest neighbour algorithm applied to optical band colours, have had some success in predicting photometric redshifts of quasi-stellar objects (QSOs): Although the mean of differences between the spectroscopic and photometric redshifts, Δ$z$, is close to zero, the distribution of these differences remains wide and distinctly non-Gaussian. As per our previous empirical estimate of photometric redshifts, we find that the predictions can be significantly improved by adding colours from other wavebands, namely the near-infrared and ultraviolet. Self-testing this, by using half of the 33 643 strong QSO sample to train the algorithm, results in a significantly narrower spread in Δ$z$ for the remaining half of the sample. Using the whole QSO sample to train the algorithm, the same set of magnitudes return a similar spread in Δ$z$ for a sample of radio sources (quasars). Although the matching coincidence is relatively low (739 of the 3663 sources having photometry in the relevant bands), this is still significantly larger than from the empirical method (2 per cent) and thus may provide a method with which to obtain redshifts for the vast number of continuum radio sources expected to be detected with the next generation of large radio telescopes.

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Norris, Ray P., M. Salvato, G. Longo, M. Brescia, T. Budavari, S. Carliles, S. Cavuoti, et al. "A Comparison of Photometric Redshift Techniques for Large Radio Surveys." Publications of the Astronomical Society of the Pacific 131, no. 1004 (August 30, 2019): 108004. http://dx.doi.org/10.1088/1538-3873/ab0f7b.

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Cavuoti, S., C. Tortora, M. Brescia, G. Longo, M. Radovich, N. R. Napolitano, V. Amaro, and C. Vellucci. "Cooperative photometric redshift estimation." Proceedings of the International Astronomical Union 12, S325 (October 2016): 166–72. http://dx.doi.org/10.1017/s1743921317001296.

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AbstractIn the modern galaxy surveys photometric redshifts play a central role in a broad range of studies, from gravitational lensing and dark matter distribution to galaxy evolution. Using a dataset of ~ 25,000 galaxies from the second data release of the Kilo Degree Survey (KiDS) we obtain photometric redshifts with five different methods: (i) Random forest, (ii) Multi Layer Perceptron with Quasi Newton Algorithm, (iii) Multi Layer Perceptron with an optimization network based on the Levenberg-Marquardt learning rule, (iv) the Bayesian Photometric Redshift model (or BPZ) and (v) a classical SED template fitting procedure (Le Phare). We show how SED fitting techniques could provide useful information on the galaxy spectral type which can be used to improve the capability of machine learning methods constraining systematic errors and reduce the occurrence of catastrophic outliers. We use such classification to train specialized regression estimators, by demonstrating that such hybrid approach, involving SED fitting and machine learning in a single collaborative framework, is capable to improve the overall prediction accuracy of photometric redshifts.

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Bateman, V. I., T. G. Carne, D. L. Gregory, S. W. Attaway, and H. R. Yoshimura. "Force Reconstruction for Impact Tests." Journal of Vibration and Acoustics 113, no. 2 (April 1, 1991): 192–200. http://dx.doi.org/10.1115/1.2930169.

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Two force reconstruction techniques were used to evaluate the impact test of a scale model nuclear transportation cask dropped 30 ft. onto an unyielding target. The two techniques are: the sum of weighted acceleration technique (SWAT) and the deconvolution technique (DECON). A brief description and the calibration of the techniques as applied to the cask are presented. For the impact test, both techniques yielded very similar resultant forces and provided more accurate definition of the force-time history for the cask than is available from conventional data reduction methods. An applied moment, measurement previously unobtainable from conventional accelerometer data reduction techniques, was determined with SWAT. The angular velocity calculated with SWAT was verified with photometric measurements.

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Sharma, Rashmi, Manmohan Chhibber, and Susheel K. Mittal. "A new ionophore for chemical sensing of F−, CN− and Co2+ using voltammetric, colorimetric and spectrofluorimetric techniques." RSC Advances 6, no. 56 (2016): 51153–60. http://dx.doi.org/10.1039/c6ra03909j.

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Bontà, Elena Dalla, Roger L. Davies, Ryan C. W. Houghton, Francesco D'Eugenio, Enrico M. Corsini, and Jairo Méndez-Abreu. "Photometric analysis of Abell 1689." Proceedings of the International Astronomical Union 8, S295 (August 2012): 230. http://dx.doi.org/10.1017/s1743921313004857.

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AbstractWe carried out a photometric analysis of a sample of early-type galaxies in Abell~1689 at z = 0.183, using HST/ACS archive images in the rest-frame V band. We performed a two-dimensional photometric decomposition of each galaxy surface-brightness distribution using the GASP2D fitting algorithm (Méndez-Abreu et al. 2008). We adopted both a Sérsic and de Vaucouleurs law. S0 galaxies were analysed also taking into account a disc component described by an exponential law. The derived photometric parameters, together with the ones previously obtained with the curve of growth method (Houghton et al. 2012), will be used to analyse the Fundamental Plane of Abell 1689 and quantify how it is affected by the use of different decomposition techniques (Dalla Bontà et al. 2013, in preparation). The stellar velocity dispersions of the sample galaxies were derived by using GEMINI-N/GMOS and VLT/FLAMES (D'Eugenio et al. 2013) spectroscopic data.

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Ciardullo, Robin, and Howard E. Bond. "Global Photometric Campaigns on Pulsating Planetary Nuclei." Symposium - International Astronomical Union 155 (1993): 490. http://dx.doi.org/10.1017/s0074180900172237.

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As reported in a contributed paper at this symposium, six “O VI”-type planetary nuclei are known to be pulsating variables. Through the techniques of asteroseismology, it should be possible to explore the interior structures of these stars, determine their masses and rotation rates, and measure the stellar evolutionary timescales through observations of changes in the pulsation periods.

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Vologdin, V. A., V. V. Davydov, and E. N. Velichko. "On specific features of investigation of fluid flows by photometric techniques." Journal of Physics: Conference Series 741 (August 2016): 012095. http://dx.doi.org/10.1088/1742-6596/741/1/012095.

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IMOTO, Harutaka, Kenichiro MACHIDA, Yusuke YAMAURA, Hiroshi TADENUMA, and Takashi MAEKAWA. "Development of microscopic shape measuring system using iterative photometric stereo techniques." Transactions of the JSME (in Japanese) 82, no. 835 (2016): 15–00512. http://dx.doi.org/10.1299/transjsme.15-00512.

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Gendy, Amin El, and Ahmed Shalaby. "Mean Profile Depth of Pavement Surface Macrotexture Using Photometric Stereo Techniques." Journal of Transportation Engineering 133, no. 7 (July 2007): 433–40. http://dx.doi.org/10.1061/(asce)0733-947x(2007)133:7(433).

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Grenon, M. "The Stellar Variability From Hipparcos Photometry." Highlights of Astronomy 11, no. 1 (1998): 542–43. http://dx.doi.org/10.1017/s1539299600021997.

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During the development of the Hipparcos satellite, the opportunity to use the star mapper to perform a whole sky two colour intermediate accuracy photometric survey, and the main-mission detector for high accuracy photometry of target stars was identified. The instrument was optimised and the pre-launch calibrations performed to pre-determine the pass-bands with an accuracy sufficient to cope, in-orbit, with the foreseen aging of the detection chains. Photometry became an important by-product of the mission, very complementary to the astrometric results. It was the first opportunity to monitor the sky during 3-4 years without selection biases and with a precision similar to that achieved from the ground with the best classical techniques. A systematic detection of small amplitude variables was the expected return.

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Gruenstein, Eric, and Jesus Luna. "An inexpensive, easy to use video imaging system for intracellular Ca2+ and quantitative fluorescence microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 620–21. http://dx.doi.org/10.1017/s0424820100148939.

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Fura-2 is the most commonly used member of a family of calcium sensitive flourescent dyes that allows the measurement of intracellular free calcium (Cai by dual excitation fluorimetry. The use of this dye in conjunction with video imaging microscopy permits visualization of changes in Cai with a high degree of spatial resolution. This resolution in turn allows the detection of Cai gradients, waves, and other localized cellular responses not easily detected by photometric techniques. Despite these advantages, most published reports have utilized photometry rather than imaging, due largely to the higher cost and greater complexity of use of the latter technique. With these problems in mind, we have developed a turnkey calcium imaging system that is both inexpensive and simple enough to use that it can be mastered in 2-3 hours.Data showing the distribution of free Ca2+ in the cytoplasm of a quiescent human fibroblast and the kinetics of stimulation of these cells with mitogens are illustrated on the next page.

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