772 research outputs found

    Shift-encoded optically multiplexed imaging

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    In a multiplexed image, multiple fields-of-view (FoVs) are superimposed onto a common focal plane. The attendant gain in sensor FoV provides a new degree of freedom in the design of an imaging system, allowing for performance tradeoffs not available in traditional optical designs. We explore design choices relating to a shift-encoded optically multiplexed imaging system and discuss their performance implications. Unlike in a traditional imaging system, a single multiplexed image has a fundamental ambiguity regarding the location of objects in the image. We present a system that can shift each FoV independently to break this ambiguity and compare it to other potential disambiguation techniques. We then discuss the optical, mechanical, and encoding design choices of a shift-encoding midwave infrared imaging system that multiplexes six 15×15  deg FoVs onto a single one megapixel focal plane. Using this sensor, we demonstrate a computationally demultiplexed wide FoV video.United States. Air Force Office of Scientific Research (FA8721-05-C-0002

    Sub-pixel Layout for Super-Resolution with Images in the Octic Group

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    13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part IThis paper presents a novel super-resolution framework by exploring the properties of non-conventional pixel layouts and shapes. We show that recording multiple images, transformed in the octic group, with a sensor of asymmetric sub-pixel layout increases the spatial sampling compared to a conventional sensor with a rectilinear grid of pixels and hence increases the image resolution. We further prove a theoretical bound for achieving well-posed super-resolution with a designated magnification factor w.r.t. the number and distribution of sub-pixels. We also propose strategies for selecting good sub-pixel layouts and effective super-resolution algorithms for our setup. The experimental results validate the proposed theory and solution, which have the potential to guide the future CCD layout design with super-resolution functionality.United States. Air Force (Assistant Secretary of Defense for Research & Engineering Contract #FA8721-05-C-0002)SUTD-MIT International Design Centre (Joint Postdoctoral Programme)Singapore University of Technology and Design (SUTD StartUp Grant ISTD 2011 016)Singapore. Ministry of Education (MOE Academic Research Fund MOE2013-T2-1-159

    Investigating Prosodic Accommodation in Clinical Interviews with Depressed Patients

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    Six in-depth clinical interviews, involving six elderly female patients (aged 60+) and one female psychiatrist, were recorded and analysed for a number of prosodic accommodation variables. Our analysis focused on pitch, speaking time, and vowel-space ratio. Findings indicate that there is a dynamic manifestation of prosodic accommodation over the course of the interactions. There is clear adaptation on the part of the psychiatrist, even going so far as to have a reduced vowel-space ratio, mirroring a reduced vowel-space ratio in the depressed patients. Previous research has found a reduced vowel-space ratio to be associated with psychological distress; however, we suggest that it indicates a high level of adaptation on the part of the psychiatrist and needs to be considered when analysing psychiatric clinical interactions

    Observation of Hadronic W Decays in t-tbar Events with the Collider Detector at Fermilab

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    We observe hadronic W decays in t-tbar -> W (-> l nu) + >= 4 jet events using a 109 pb-1 data sample of p-pbar collisions at sqrt{s} = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass distribution is obtained that is consistent with W decay and inconsistent with the background prediction by 3.3 standard deviations. From this peak we measure the W mass to be 77.2 +- 4.6 (stat+syst) GeV/c^2. This result demonstrates the presence of two W bosons in t-tbar candidates in the W (-> l nu) + >= 4 jet channel.Comment: 20 pages, 4 figures, submitted to PR

    Search for Chargino-Neutralino Associated Production at the Fermilab Tevatron Collider

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    We have searched in ppˉp \bar{p} collisions at s\sqrt{s} = 1.8 TeV for events with three charged leptons and missing transverse energy. In the Minimal Supersymmetric Standard Model, we expect trilepton events from chargino-neutralino (\chione \chitwo) pair production, with subsequent decay into leptons. We observe no candidate e+ee±e^+e^-e^\pm, e+eμ±e^+e^-\mu^\pm, e±μ+μe^\pm\mu^+\mu^- or μ+μμ±\mu^+\mu^-\mu^\pm events in 106 pb1^{-1} integrated luminosity. We present limits on the sum of the branching ratios times cross section for the four channels: \sigma_{\chione\chitwo}\cdot BR(\chione\chitwo\to 3\ell+X) 81.5 \mgev\sp and M_\chitwo > 82.2 \mgev\sp for tanβ=2\tan\beta=2, μ=600\mu =-600~\mgev\sp and M_\squark= M_\gluino.Comment: 9 pages and 3 figure

    Search for charged Higgs decays of the top quark using hadronic tau decays

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    We present the result of a search for charged Higgs decays of the top quark, produced in ppˉp\bar{p} collisions at s=\surd s = 1.8 TeV. When the charged Higgs is heavy and decays to a tau lepton, which subsequently decays hadronically, the resulting events have a unique signature: large missing transverse energy and the low-charged-multiplicity tau. Data collected in the period 1992-1993 at the Collider Detector at Fermilab, corresponding to 18.7±\pm0.7~pb1^{-1}, exclude new regions of combined top quark and charged Higgs mass, in extensions to the standard model with two Higgs doublets.Comment: uuencoded, gzipped tar file of LaTeX and 6 Postscript figures; 11 pp; submitted to Phys. Rev.

    Measurement of WγW\gamma and ZγZ\gamma Production in ppˉp\bar{p} Collisions at s\sqrt{s} = 1.96 TeV

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    The Standard Model predictions for WγW\gamma and ZγZ\gamma production are tested using an integrated luminosity of 200 pb1^{-1} of \ppbar collision data collected at the Collider Detector at Fermilab. The cross sections are measured selecting leptonic decays of the WW and ZZ bosons, and photons with transverse energy ET>7E_T>7 GeV that are well separated from leptons. The production cross sections and kinematic distributions for the WγW\gamma and ZγZ\gamma are compared to SM predictions.Comment: 7 pages, 4 figures, submitted to PR

    Measurement of the lepton charge asymmetry in W-boson decays produced in p-pbar collisions

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    We describe a measurement of the charge asymmetry of leptons from W boson decays in the rapidity range 0 enu, munu events from 110+/-7 pb^{-1}of data collected by the CDF detector during 1992-95. The asymmetry data constrain the ratio of d and u quark momentum distributions in the proton over the x range of 0.006 to 0.34 at Q2 \approx M_W^2. The asymmetry predictions that use parton distribution functions obtained from previously published CDF data in the central rapidity region (0.0<|y_l|<1.1) do not agree with the new data in the large rapidity region (|y_l|>1.1).Comment: 13 pages, 3 tables, 1 figur

    Search for a High-Mass Diphoton State and Limits on Randall-Sundrum Gravitons at CDF

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    We have performed a search for new particles which decay to two photons using 1.2/fb of integrated luminosity from p-pbar collisions at sqrt(s) = 1.96 TeV collected using the CDF II Detector at the Fermilab Tevatron. We find the diphoton mass spectrum to be in agreement with the standard model expectation, and set limits on the cross section times branching ratio for the Randall-Sundrum graviton, as a function of diphoton mass. We subsequently derive lower limits for the graviton mass of 230 GeV/c2 and 850 GeV/c2, at the 95% confidence level, for coupling parameters (k/M_Pl) of 0.01 and 0.1 respectively.Comment: submitted to Phys. Rev. Let

    Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV

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    We search for the standard model Higgs boson produced in association with an electroweak vector boson in events with no identified charged leptons, large imbalance in transverse momentum, and two jets where at least one contains a secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1 integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV recorded by the CDF II experiment at the Tevatron. We find 268 (16) single (double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are expected from standard model background processes. We place 95% confidence level upper limits on the Higgs boson production cross section for several Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115 GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let
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