Study of digital plane segments (dps) is fundamental to three dimensional digital geometry. In this paper we present an optimal algorithm to characterize a given set S of 3-D digital points as a dps and to construct i...
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ISBN:
(纸本)0819410330
Study of digital plane segments (dps) is fundamental to three dimensional digital geometry. In this paper we present an optimal algorithm to characterize a given set S of 3-D digital points as a dps and to construct its upper supporting plane. We have also formulated a number of area estimators for dps's and have measured their performances analytically and experimentally.
Research in the last decade emphasized the potential of designing adaptive pattern recognition classifiers based on algorithms using multi-layered artificial neural nets. The greatest potential in such endeavors was a...
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ISBN:
(纸本)0819413267
Research in the last decade emphasized the potential of designing adaptive pattern recognition classifiers based on algorithms using multi-layered artificial neural nets. The greatest potential in such endeavors was anticipated to be not only in the adaptivity but also in the high-speed processing through massively parallel VLSI implementation and optical computing. Computational advantages of such algorithms have been demonstrated in a number of papers. Neural networks particularly the self-organizing types have been found quite suitable crisp pattern for clustering of unlabeled datasets. The generalization of Kohonen-type learning vector quantization (LVQ) clustering algorithm to fuzzy LVQ clustering algorithm and its equivalence to fuzzy c-means has been clearly demonstrated recently. On the other hand, Carpenter/Grossberg's ART-type self organizing neural networks have been modified to perform fuzzy clustering by a number of researches in the past few years. The performance of such neuro-fuzzy models in clustering unlabeled data patterns is addressed in this paper. A recent development of a new similarity measure and a new learning rule for updating the centroid of the winning cluster in a fuzzy ART-type neural network is also described. The capability of the above neuro-fuzzy model in better partitioning of datasets into clusters of any shape is demonstrated.
This paper discusses nonlinear behavior in SEM CD measurements stemming from the interaction of the edge detection algorithm and systematic changes in the appearance of the secondary electron signal. A first-order the...
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ISBN:
(纸本)0819411604
This paper discusses nonlinear behavior in SEM CD measurements stemming from the interaction of the edge detection algorithm and systematic changes in the appearance of the secondary electron signal. A first-order theory is developed which describes the effect of changes in apparent sidewall slope and baseline level on common edge detection algorithms. Specifically the theory predicts nonlinear behavior for linear approximation and threshold edge detection algorithms. Experimental verification of the effect is presented. Systematic increases in linewidth of 10% are frequently encountered in practice when making measurements in the sub 0.75 micrometers regime.
The polar regions are expected to be particularly sensitive to anthropogenic global change. Due to the difficulties in modeling high latitude climate and the logistical challenges with polar field work, satellite remo...
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ISBN:
(纸本)0819413089
The polar regions are expected to be particularly sensitive to anthropogenic global change. Due to the difficulties in modeling high latitude climate and the logistical challenges with polar field work, satellite remote sensing will have an increasingly important role to play in polar climate research. For studies of atmospheric radiation and meteorology, accurate cloud detection and classification is crucial. Modern methods for polar cloud classification utilize both multispectral threshold and automated pattern recognition techniques. For monitoring sea ice concentration, passive microwave sensors offer an all-weather advantage over visible or infrared scanners, although over clear-sky scenes the latter can provide a much finer spatial resolution. The various algorithms for satellite retrieval and remote sensing in the polar regions are constantly being refined and improved.
Since phased array radars have the ability to perform adaptive sampling by the radar beam, proper control of the radar has the potential for significantly improving many aspects associated with the tracking of multipl...
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ISBN:
(纸本)0819411906
Since phased array radars have the ability to perform adaptive sampling by the radar beam, proper control of the radar has the potential for significantly improving many aspects associated with the tracking of multiple maneuvering targets. The technique proposed in this paper uses the Interacting Multiple Model (IMM) algorithm to track maneuvering targets and control the sampling time and energy levels. Since the output of the IMM algorithm better represents the accuracy of the state estimates during a maneuver than a single model filter, the IMM algorithm is used to compute and on-line measure of tracking performance to determine the scheduling time of the next track update sample period in order to maintain a given level of performance. The sample time is computed as the one positive root of a polynomial equation of the sample period. The model probabilities of the IMM algorithm are also used to schedule the energy level of a radar dwell. As a result, the update times for the filter are a function of track filter performance and the target trajectory. algorithms for computing the sample time and energy level using the output of the IMM algorithm are developed in this paper. Performance comparisons are given for the IMM algorithm using constant data rates, scheduled energy levels, and adaptive data rates.
A new model is proposed to reconstruct an image from its ray sum using Algebraic Reconstruction Techniques (ART). Assuming that the original image is band limited, an iterative algorithm is developed that evaluates th...
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ISBN:
(纸本)0819411388
A new model is proposed to reconstruct an image from its ray sum using Algebraic Reconstruction Techniques (ART). Assuming that the original image is band limited, an iterative algorithm is developed that evaluates the updated image and reduces the sampling error during each iteration. Depending on a weight factor, estimation of the updated images in each iteration is the contribution of correction to each sample of the ray sum. The weight factor is the fractional area intercepted by the ray sum and the sampling function. To model a 2D image, an optimal sampling function is used where the sampling function is a cylindrical pulse instead of the customary flat-top sample version of a 2D square pulse. Given energy concentration of the pulse, a class of such pulses are generated. A pulse with maximum concentration of energy is used for sampling of the 2D image. By determining the eigenfunctions of a homogeneous Fredholm equation of the second kind with a symmetric kernel such a pulse is generated. Moreover, it is shown that eigenfunctions of the above integral equation are those classes of pulses where the corresponding eigenvalue is the measure of the concentration of an eigenfunction. The desired pulse is an eigenfunction with the maximum eigenvalue.
Fine-grain pipelined adaptive decision-feedback equalizer (ADFE) architectures are developed using the relaxed look-ahead technique. This technique, which is an approximation to the conventional look-ahead computation...
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ISBN:
(纸本)0819412767
Fine-grain pipelined adaptive decision-feedback equalizer (ADFE) architectures are developed using the relaxed look-ahead technique. This technique, which is an approximation to the conventional look-ahead computation, maintains functionality of the algorithm rather than the input-output behavior. Thus, it results in substantial hardware savings as compared to either parallel processing or look-ahead techniques. The delay relaxation, delay transfer relaxation, and sum relaxation are introduced for purposes of pipelining. Both the conventional and the predictor form of ADFE have been pipelined. The performance of the pipelined algorithms for the equalization of a magnetic recording channel is studied. It is demonstrated via simulations that, for a byte error rate of 10-7 or less, speed-ups of up to 8 can be easily achieved with the conventional ADFE. The predictor form of ADFE allows much higher speed-ups (up to 32) for less than 1 dB of SNR degradation.
A video encoder has the task of producing lowest-distortion coded video subject to some constraints on delay, rate, and buffer conditions. We present a general optimization approach to this problem in a framework of d...
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ISBN:
(纸本)0819413690
A video encoder has the task of producing lowest-distortion coded video subject to some constraints on delay, rate, and buffer conditions. We present a general optimization approach to this problem in a framework of delayed coding and we motivate a certain formulation of the optimization objective. Two forms of distortion measures are considered, namely, the maximum distortion and the total distortion, each defined over a segment of the video to be coded. These distortion measures are chosen for their mathematical tractability and practical importance. A solution (computational algorithm) for each case is described. Subject to some conditions, the solutions may be suboptimal. Simulation results show an improved performance with this approach compared to a simple typical approach which varies the quantization scale linearly with the encoder buffer level.
Recently, Smith and collaborators from University of Wisconsin-Madison have clearly established the possibilities of sounding tropospheric temperature and water vapor profiles with a ground-based uplooking interferome...
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ISBN:
(纸本)0819413089
Recently, Smith and collaborators from University of Wisconsin-Madison have clearly established the possibilities of sounding tropospheric temperature and water vapor profiles with a ground-based uplooking interferometer. With the same perspective but for somewhat different applications, the Defence Research Establishment Valcartier (DREV) has initiated a project with the aim of exploring the many possible avenues of similar approaches. DREV, in collaboration with BOMEM (Quebec, Canada), has developed an instrument referred to as the Double Beam Interferometer Sounder (DBIS). This sounder has been conceived to match the needs encountered in many remote sensing scenarios: slant path capability, small field of view, very wide spectral coverage, and high spectral resolution. Preliminary tests with the DBIS have shown sufficient accuracy for remote sensing applications. In a series of field measurements, jointly organized by the Geophysics Directorate/PL, Hanscom AFB, and DREV, the instrument has been run in a wide variety of sky conditions. Several atmospheric emission spectra recorded with the sounder have been compared to calculations with FASCODE and MODTRAN models. The quality of measurement-model comparisons has prompted the development of an inversion algorithm based on these codes. The purpose of this paper is to report the recent progress achieved in this research. First, the design and operation of the instrument are reviewed. Second, recent field measurements of atmospheric emission spectra are analyzed and compared to models predictions. Finally, the simultaneous retrieval approach selected for the inversion of DBIS spectra to obtain temperature and water vapor profiles is described and preliminary results are presented.
When analyzing curves of intensity decay in pulse photometry of optical radiation, the problem of estimation of unknown parameters of the decay function representable as a sum of exponents Ii 1(t) = A1 exp (— t/t1), ...
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ISBN:
(纸本)0819414565
When analyzing curves of intensity decay in pulse photometry of optical radiation, the problem of estimation of unknown parameters of the decay function representable as a sum of exponents Ii 1(t) = A1 exp (— t/t1), i=l (1) where A - amplitudes, rj - decay times, i = 1 , . . . , n, arises. It is rather complicated to carry out such studies because in the majority of cases recorded time responses are in the nanosecond interval of duration. The last requires to take into account the influence of imperfect characteristics of recording equipment, which leads to the necessity of solving integral equations of the convolution type
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