bluuebunny/crossref_metadata_2025_split huggingface dataset:
A multiangle imaging spectroradiometer for terrestrial remote sensing from the earth observing system
Authors: Diner David J. , Bruegge Carol J. , Martonchik John V. , Bothwell Graham W. , Danielson Eric D. , Floyd Elmer L. , Ford Virginia G. , Hovland Larry E. , Jones Kenneth L. , White Mary L. 
Published: March 2007

AbstractThe Multiangle Imaging SpectroRadiometer (MISR) instrument for the Earth Observing System (EOS) will provide a unique opportunity for studying the ecology and climate of the Earth through the acquisition of systematic, global multiangle imagery in reflected sunlight. MISR employs nine discrete cameras pointed at fixed angles, viewing the nadir direction and forward and aftward along the spacecraft ground track. Each camera is a charge‐coupled‐device –based pushbroom imager. Within a 7‐minute period, every point in a 204‐km‐wide swath is imaged at the nine viewing angles, ensuring observations acquired under virtually identical illumination and atmospheric conditions. The cameras will image the Earth in the nadir direction and at 30.7°, 45.6°, 60.0°, and 72.5° forward and aftward of the local vertical at the Earth's surface. Images at each angle will be obtained in four spectral bands centered at 440, 550, 670, and 860 nm. MISR is capable of taking image data in two different spatial resolution modes: Local Mode, in which selected targets are observed with 240‐m spatial sampling, and Global Mode, where the entire sunlit Earth is observed continuously with 1.92‐km sampling. Absolute radiometric calibration of the MISR instrument will be performed in‐flight using special on‐board hardware. The data produced by MISR will be valuable in a number of scientific discipline areas, and MISR images and geophysical products will be archived at the EOS Data and Information System to make them available to the broad scientific community.
Using image pyramids for the visualization of large terrain data sets
Authors: Stanfill Daniel F. 
Published: March 2007

AbstractViewing terrain data from various remote sensors in three dimensions has proven to be a valuable tool for scientists in understanding a variety of problems. A technique is presented for using image pyramids in such visualization of large terrain data sets, providing up to two orders of magnitude performance enhancement over simpler techniques, while at the same time eliminating false high‐frequency information, which causes animations to sparkle.
On the uniqueness of determination of a polyhedron by its edges with applications to the inverse potential problem
Authors: Brodsky M. A. , Strakhov V. N. 
Published: March 2007

AbstractThe uniqueness of determination of a polyhedron homeomorphic to a bali by its edge graph is proved in the most general situation. Consequences are given that arise from this result in the inverse potential problem. Unsolved problems are formulated.
Recent advances in scanning tomographic acoustic microscopy
Authors: Chiao Richard Y. , Lee Hua 
Published: March 2007

AbstractWe present the recent developments of the Scanning Tomographic Acoustic Microscope (STAM). The STAM was proposed as a method to achieve 3D imaging capability for the Scanning Laser Acoustic Microscope (SLAM). With the addition of a quadrature receiver, the complex scattered wave field can now be detected, and consequently the STAM is capable of subsurface holographic and tomographic imaging. The resolution improvement of the STAM can be attributed directly to the detection of the phase information and the image reconstruction technique. The STAM is sensitive to phase errors in the tomographic projections. In particular, the quadrature phase error and the initial phase error in the complex projections are critical to the tomographic reconstruction process. For multiple‐angle tomography, high‐precision projection registration and alignment become necessary. By obtaining solutions to these implementation problems, we have succeeded in obtaining images superior to the original SLAM images. In addition, quantitative ultrasonic imaging is possible with the STAM, and a method is presented to image the velocity parameter of simple specimens. With these capabilities, the STAM may become a useful tool for high‐resolution subsurface nondestructive evaluation.
Estimating three‐dimensional vehicle motion in an outdoor scene using stereo image sequences
Authors: Leung Mun K. , Huang Thomas S. 
Published: March 2007

AbstractWe propose a motion estimation system that uses stereo image pairs as the input data. To perform experimental work, we also obtain a sequence of outdoor stereo images taken by two metric cameras. The system consists of four main stages, which are (1) determination of point correspondences on the stereo images, (2) correction of distortions in image coordinates, (3) derivation of 3D point coordinates from 2D correspondences, and (4) estimation of motion parameters based on 3D point correspondences. For the first stage of the system, we use a four‐way matching algorithm to obtain matched point on two stereo image pairs at two consecutive time instants (ti and ti + 1). Since the input data are stereo images taken by cameras, it has two types of distortions, which are (i) film distortion and (ii) lens distortion. These two distortions must be corrected before any process can be applied on the matched points. To accomplish this goal, we use (i) bilinear transform for film distortion correction and (ii) lens formulas for lens distortion correction. After correcting the distortions, the results are 2D coordinates of each matched point that can be used to derive 3D coordinates. However, due to data noise, the calculated 3D coordinates to not usually represent a consistent rigid structure that is suitable for motion estimation; therefore, we suggest a procedure to select good 3D point sets as the input for motion estimation. The procedure exploits two constraints, rigidity between different time instants and uniform point distribution across the object on the image. For the last stage, we use an algorithm to estimate the motion parameters. We also wish to know what is the effect of quantization error on the estimated results; therefore an error analysis based on quantization error is performed on the estimated motion parameters. In order to test our system, eight sets of stereo image pairs are extracted from an outdoor stereo image sequence and used as the input data. The experimental results indicate that the proposed system does provide reasonable estimated motion parameters.
An imaging device that uses the wavelet transformation as the image reconstruction algorithm
Authors: Letcher John H. 
Published: March 2007

AbstractMany imaging devices have been constructed that use fourier transform techniques for image reconstruction as well as for image analysis. The basis functions in the fourier transform space are sinusoids. These are not localized. Therefore it should not be expected that highly localized behavior of a signal be characterized well using functions distributed evenly throughout the interval of the integral transform. Also, the phase cancellations of a conventional impulse signal are not handled well by fourier techniques. On the other hand, the basis functions of the wavelet transformation are highly localized, i.e., these exhibit compact support, yet are orthonormal. The multispectral decomposition algorithm of the wavelet transformation is used to analyze the signal returning from the reflections of a single ultrasonic transducer with a focused beam and operated in the focal zone. The choice of frequency depends upon the mutually antagonistic factors of penetration (αf–2) and resolution (αf). The signal sent into the sample should not be the impulse response signal used in conventional devices; rather, it should be a time‐reversed replica of a single or a linear combination of the most highly localized basis function wavelets. The returning signal is a sequence of translates of the wavelets plus perhaps some lower‐resolution wavelets. The translations are proportational to the time of flight of the signal. The wavelet transformation is superb at discriminating the population of each of these translates which is identically the A‐scan signal. The transmitted signal, which is a time‐reversed single wavelet or a linear combination of wavelets, is not easy to produce. Inexpensive ultrasound transducers have resonances which make it difficult to produce any desired wave form. Wavelet shape is far from arbitrary. Precise wave shaping is performed by measuring the impulse response function of the transducer; then, the desired wave shape is convolved with the inverse of the measured impulse response function of the transducer. This produces the signal to be presented to the pulse generation circuit. Care is taken to damp the impulse response so that there are no zeros. The received signal is sampled at an even rate which is carefully chosen to match the time delay of one wavelet translate to the next. B‐scan, C‐scan, and volume imaging are easily accomplished using a sequence of A‐scan data, all by conventional techniques. A single A‐scan requires less than 2 ms to perform and reconstruct with a high‐speed arithmetic unit which was designed in conjunction with this work and is now commercially available.
Application of microwave pulse‐echo radar imaging to the nondestructive evaluation of buildings
Authors: Mast J. E. , Lee H. , Murtha J. P. 
Published: March 2007

AbstractWe present a microwave pulse‐echo radar imaging technique and its application to nondestructive evaluation of structural configurations of the New York State Capitol building. The survey procedure consists of scanning surface areas of the building with the radar data acquisition system, imaging with the backward‐propagation method, and forming an image of the investigated region. This technique not only provides depth and other distance measures, but also provides high‐resolution range and azimuthal spatial visualization of the subsurface region. The results demonstrate the capability of the technique for estimating the depth, span, and size of beams, girders, flues, and masonry arches in floors as well as columns in walls. Also, the mechanical stepping and thickness of outer granite facings on the walls, and the presence of wire mesh and reinforcement in concrete, are also discernible.©1993 John Wiley & Sons Inc
Microwave image understanding and its applications to various imaging schemes
Authors: Li Hsueh‐Jyh , Huang Gen‐Tay 
Published: March 2007

AbstractThree methods of producing microwave images of rotating objects are reviewed and correlated. These are range Doppler processing, coherent tomographic imaging, and a physical optics‐based technique using the Bojarski identity. We use an understanding of these processes to interpret and predict the appearances of images reconstructed from data collected over specified frequency and angular windows. Based on the understanding of the fundamental image formation processes, we have developed several image reconstruction algorithms applicable when objects are situated in different environments. Examples are bistatic imaging, near field imaging, moving target imaging, irregularly spaced array imaging, and imaging of objects embedded in a homogeneous dielectric background. Numerical and experimental results have verified the effectiveness of our proposed algorithms.©1993 John Wiley & Sons Inc
ISAR motion compensation using the burst derivative measure as a focal quality indicator
Authors: Bocker Richard P. , Jones Scott A. 
Published: March 2007

AbstractInverse synthetic aperture radar (ISAR) is an imaging technique that shows great promise in classifying airborne targets in real‐time under all weather conditions. The success of classifying targets using ISAR is predicated upon forming highly focused radar images of these target. Efforts to develop highly focused radar imaging computer software have been challenging, mainly because the imaging depends on and is affected by the motion of the target. Computationally intensive motion compensation algorithms have been developed to remove the unwanted degrading effects of target motion. Those particular motion compensation algorithms which require the use of a space domain focal quality indicator (e.g., entropy) to determine image sharpness as processing proceeds pay a severe computational penalty due to the large number of two‐dimensional fast Fourier transforms (2D‐FFTs) which must be computed. This is due to the fact that the actual processing of ISAR data is done primarily in the spatial frequency domain and not in the space domain where the final ISAR image is displayed. If a focal quality indicator could be developed to measure image sharpness in the spatial frequency domain, then the computational burden introduced by the numerous 2D‐FFTs could be greatly relaxed. This article describes the use of a new focal quality indicator called the burst derivative measure for determining ISAR image sharpness in the spatial frequency domain. Tests have been performed on simulated as well as actual ISAR data using both the burst derivative measure and the entropy measure. Results indicate that the burst derivative measure, when used in conjunction with the entropy measure, can greatly reduce the number of 2D‐FFTS presently required in these motion compensation algorithms.©1993 John Wiley & Sons Inc
Motion and structure from line correspondences: Some further results
Authors: Holt Robert J. , Netravali Arun N. 
Published: March 2007

AbstractA great deal of dynamic computer vision literature deals with the determination of motion and structure of rigid objects by observing points on objects at two or more time instants. In some situations point correspondences may not be available but line correspondences may be, such as when edges on the objects are visible. In this article we investigate the multiplicity of solutions when various numbers of line correspondences among several snapshots of an object are known. The case given the most consideration is that in which the object is moving with constant motion, that is, with constant rotation about an unknown center which itself is moving with constant translation. In this case we show that there is a unique solution given three line correspondences over three frames, two line correspondences over four frames, and one line correspondence over five or more frames. With fewer line correspondences there are infinitely many solutions. In the more general case where the motion is allowed to vary between successive frames, we show that there can be no more than 600 solutions to motion and structure with six line correspondences over three views, and that there is a unique solution with seven line correspondences. Several examples are given to illustrate our results.©1994 John Wiley & Sons Inc
Phase and phase‐difference ionospheric radio tomography
Authors: Kunitsyn V. E. , Andreeva E. S. , Razinkov O. G. , Tereshchenko E. D. 
Published: March 2007

AbstractVariants of ray ionospheric radiotomography (RT) are considered: the phase RT based on measuring the absolute phase or the total electron content and the phase‐difference RT based on measuring the phase‐difference RT based on measuring the phase difference or Doppler frequency. The phase technique is shown to give poor results with typical errors in determining the absolute phase. The previously developed technique of the phase‐difference RT is presented.©1994 John Wiley & Sons Inc
The grand alliance transport system for terrestrial HDTV transmission
Authors: Joseph Kuriacose , Smith Terry , Zdepski Joel , Deiss Michael S. 
Published: March 2007

AbstractThis article describes the format and functionality of the Grand Alliance transport bistream that is intended for the terrestrial broadcast of digital HDTV in the United States. The article begins with an introduction of the HDTV system selection process within the United States, and proceeds with an overview of the Grand Alliance and a description of the Grand Alliance system architecture. The transport functionality and format is the described in detail. The format is based on the use of a fixed‐length packet structure, with packet headers to support different communications protocol functions. The advantages of the packetization approach are first described. The format choice is shown to take into account several diverse system requirements including flexibility, robustness, scalability, and simple interoperability of the bitstream with other transmission media such as ATM network. Higher‐layer protocol functionality in the format, including the ability to extract programs, and the elements of these programs, including the video, audio, and data components, from a multiplexed bitstream, are described. The details of the packet format and the functionality of the different header fields are presented.©1994 John Wiley & Sons Inc
Facts and fiction: Some aspects regarding the design of digital television cameras using CCD image sensors
Authors: Hamalainen Jukka , Leacock Tom , Westerink Peter 
Published: March 2007

AbstractThe architecture of CCD sensors and their relationship to digital processing of images requires a re‐examination of traditional analog signal processing conventions. Digital processing now requires different methods of analysis and processing in areas such as frequencv response, noise, and scanning techniques. The purpose of this paper is to encourage researchers and engineers to forget some of the traditional analog practices and have them step up to the future with an open mind.©1994 John Wiley & Sons Inc
Study of the degree of III conditioning of the phase space of pencil‐beam radiotherapy using singular value decomposition
Authors: Lefkopoulos D. , Grandjean P. , Laouar A. , Schlienger M. 
Published: March 2007

AbstractDose distribution optimization algorithms are necessary in pencil‐beam radiotherapy to exploit efficiently the multiple parameters of this powerful irradiation technique. We propose as an optimization technique singular value decomposition (SVD) analysis, which allows the measurement of ill conditioning of the stereotactic radiotherapy inverse problem and yields optimal weights for conformal treatment. Our approach to dose distribution optimization is to recover estimates of the minibeams weights from well‐defined previsional dose matrices to study the influence of the different parameters on the stereotactic radiotherapy inverse procedure. The adjustment of the different parameters of the stereotactic irradiation to the “SVD optimizer” procedure is realized taking into account the ratio of the quality reconstruction to the calculation time. It will permit a more efficient use of the SVD optimizer in clinical applications with real three‐dimensional lesions. We show the efficiency of the SVD optimizer in analyzing and predicting ill conditioning in stereotactic radiotherapy and in recognizing the topography of the different beams to create an optimal vector containing the beam weights (reconstructed weighting vector).
Effects of large vessels in functional magnetic resonance imaging at 1.5T
Authors: Duyn Jeff H. , Frank Joseph A. , Ramsey Nick R. , Mattay Venkata S. , Sexton Roy H. , Tallent Kathleen A. , Weinberger Daniel R. , Moonen Chrit T. W. , Van Gelderen Peter 
Published: March 2007

AbstractTo further investigate the effects of large vessels on the activation maps generated with functional magnetic resonance imaging at 1.5T, we studied activation of the human visual and motor cortex using a multitude of dedicated FLASH and echo‐planar imaging (EPI) scanning techniques. Both slice and volume scans were performed to assess relative contributions of T2* effects, in‐flow, and phase‐shift effects, specifically within and around the larger vessels (around 1 mm in diameter). The contrast mechanism in single‐slice FLASH studies appeared to be predominantly sensitive to in‐flow and phase effects of the blood water within these larger vessels, and their relative contributions were dependent on experimental parameters and vascular geometry. The contrast mechanism in gradient echo EPI studies was governed predominantly by T2* effects in tissue water (and to a lesser extent cerebrospinal fluid) surrounding the larger vessels.
HST image restoration developments at the ST‐ECF
Authors: Adorf H.‐M. , Hook R. N. , Lucy L. B. 
Published: March 2007

AbstractWhen spherical aberration was found to be degrading the performance of the Hubble Space Telescope (HST), great interest in image restoration methods arose in the astronomical community. The Richardson‐Lucy (RL) method became the preferred tool for restoring such data which typically has Poisson noise characteristics and a low signal‐to‐noise ratio. Subsequently, corrective optics were inserted into the telescope which is now operating close to the original specifications. However, generalized RL methods and some new techniques based on projections onto convex sets have proved useful both for the present HST data, which are often insufficiently sampled, and also for many other classes of astronomical images. The ST‐ECF staff have worked extensively in this and related areas, and some of these developments and their application to real data are described.
Gentamicin‐loaded bioresorbable films for prevention of bacterial infections associated with orthopedic implants
Authors: Aviv Moran , Berdicevsky Israela , Zilberman Meital 
Published: March 2007

AbstractAdhesion of bacteria to biomaterials and the ability of many microorganisms to form biofilms on foreign bodies are well‐established as major contributors to the pathogenesis of implant‐associated infections. Treatment of bone infection remains problematic, due to the difficulty of systemically administered antibiotics to locally penetrate bone. The current research addresses this issue by focusing on the development and study of novel gentamicin‐loaded bioresorbable films designed to serve as “coatings” for fracture fixation devices and prevent implant‐associated infections. Poly(L‐lactic acid) and poly (D,L‐lactic‐co‐glycolic acid) films containing gentamicin were developed through solution processing. The effects of polymer type, drug content, and processing conditions on the drug release profile were studied with respect to film morphology. The examined films generally exhibited a burst effect followed by a moderate approximately constant rate of release. The drug contents in the surrounding medium exceeded the required minimal effective concentration. Various gentamicin concentrations that were released from the films with time exhibited efficacy against bacterial species known to be involved in orthopedic infections. The developed systems can be applied on the surface of any metallic or polymeric fracture fixation device, and may therefore comprise a significant contribution to the field of orthopedic implants. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007