946 research outputs found
Modeling and Measurement of Image Sensor Characteristics
The optical transfer function (OTF), as an objective measure of the quality of optical and electro-optical systems, is closely related to the point spread function (PSF) and other derived characteristics, such as the modulation transfer function (MTF) and the phase transfer function (PTF). The paper focused to the use a generalized OTF, which is primarily dedicated to the description of linear space invariant systems (LSI), for the purpose of sampled structures of image sensors (e.g. CCD, CMOS, CID), and to implement the derived results while utilizing the graphical user's interface (GUI) in Matlab. The model used considers the effects of the detector photo sensitive area, sampling process, as well as other CCD specific parameters, such as the charge transfer efficiency (CTE) or diffusion in order to derive the overall MTF shape. The paper also includes an experimental measurement in the real system and a comparison with the results of modeling
Time frequency requirements for radio interferometric earth physics
Two systems of VLBI (Very Long Baseline Interferometry) are now applicable to earth physics: an intercontinental baseline system using antennas of the NASA Deep Space Network, now observing at one-month intervals to determine UTI for spacecraft navigation; and a shorter baseline system called ARIES (Astronomical Radio Interferometric Earth Surveying), to be used to measure crustal movement in California for earthquake hazards estimation. On the basis of experience with the existing DSN system, a careful study has been made to estimate the time and frequency requirements of both the improved intercontinental system and of ARIES. Requirements for the two systems are compared and contrasted
2D Iterative MAP Detection: Principles and Applications in Image Restoration
The paper provides a theoretical framework for the two-dimensional iterative maximum a posteriori detection. This generalization is based on the concept of detection algorithms BCJR and SOVA, i.e., the classical (one-dimensional) iterative detectors used in telecommunication applications. We generalize the one-dimensional detection problem considering the spatial ISI kernel as a two-dimensional finite state machine (2D FSM) representing a network of the spatially concatenated elements. The cellular structure topology defines the design of the 2D Iterative decoding network, where each cell is a general combination-marginalization statistical element (SISO module) exchanging discrete probability density functions (information metrics) with neighboring cells. In this paper, we statistically analyse the performance of various topologies with respect to their application in the field of image restoration. The iterative detection algorithm was applied on the task of binarization of images taken from a CCD camera. The reconstruction includes suppression of the defocus caused by the lens, CCD sensor noise suppression and interpolation (demosaicing). The simulations prove that the algorithm provides satisfactory results even in the case of an input image that is under-sampled due to the Bayer mask
Frequency standards requirements of the NASA deep space network to support outer planet missions
Navigation of Mariner spacecraft to Jupiter and beyond will require greater accuracy of positional determination than heretofore obtained if the full experimental capabilities of this type of spacecraft are to be utilized. Advanced navigational techniques which will be available by 1977 include Very Long Baseline Interferometry (VLBI), three-way Doppler tracking (sometimes called quasi-VLBI), and two-way Doppler tracking. It is shown that VLBI and quasi-VLBI methods depend on the same basic concept, and that they impose nearly the same requirements on the stability of frequency standards at the tracking stations. It is also shown how a realistic modelling of spacecraft navigational errors prevents overspecifying the requirements to frequency stability
Jack Kerouac\u27s Pursuit of The American West
Called alternately the father of hip, King of the Beats, the daddy of the swinging psychedelic generation, Jack Kerouac was less a thrill-seeking hipster than a serious author whose life and novels speak of our shared need to explore alternatives and renew ourselves, and of our frustration and regret for our movement away from tradition. Kerouac\u27s life and literature can be viewed as an extended quest, an episodic series of explorations for meaning and for a way of life. He continually addressed the modernist question How shall we live?, seeking answers in what one biographer calls an ongoing pattern of finding, losing, and struggling to find again (Stephenson 22). Recurrently restless, he spent most of his life looking for understanding and peace, a serious, searching soul in John Clellon Holmes\u27 words, who from an early age felt the need to live correctly and joyfully in what he saw to be a world of suffering. He considered his fiction archetypal autobiography, and the novels On The Road, The Dharma Bums, and Desolation Angels present phases of his ongoing quest, as recorded in the body of his life\u27s work, which makes up The Duluoz Legend. The Dharma Bums reflects a possible conclusion to the quest, the model for a way of life linked with the American West, expressing a prevailing theme in western American literature and a mythos surrounding the American West
Torts - Newton v. National Broadcasting Co., Inc.: Evidence of Actual Malice, the Editorial Process and the Mafia in Public Figure Defamation Law
Free Exercise Fidelity and the Religious Freedom Restoration Act of 1993: Where We Are, Where We Have Been, and Where We Are Going
LIBRA: An inexpensive geodetic network densification system
A description is given of the Libra (Locations Interposed by Ranging Aircraft) system, by which geodesy and earth strain measurements can be performed rapidly and inexpensively to several hundred auxiliary points with respect to a few fundamental control points established by any other technique, such as radio interferometry or satellite ranging. This low-cost means of extending the accuracy of space age geodesy to local surveys provides speed and spatial resolution useful, for example, for earthquake hazards estimation. Libra may be combined with an existing system, Aries (Astronomical Radio Interferometric Earth Surveying) to provide a balanced system adequate to meet the geophysical needs, and applicable to conventional surveying. The basic hardware design was outlined and specifications were defined. Then need for network densification was described. The following activities required to implement the proposed Libra system are also described: hardware development, data reduction, tropospheric calibrations, schedule of development and estimated costs
Torts - Newton v. National Broadcasting Co., Inc.: Evidence of Actual Malice, the Editorial Process and the Mafia in Public Figure Defamation Law
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