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1.
In our earlier work, a two-pass motion estimation algorithm (TPA) was developed to estimate a motion field for two adjacent frames in an image sequence where contextual constraints are handled by several Markov random fields (MRFs) and the maximum a posteriori (MAP) configuration is taken to be the resulting motion field. In order to provide a trade-off between efficiency and effectiveness, the mean field theory (MFT) was selected to carry out the optimization process to locate the MAP with desirable performance. Given that currently in the disciplines of digital library [IEEE Trans. PAMI 18 (8) (1996); IEEE Trans. Image Process. 11 (8) (2002) 912] and video processing [IEEE Trans. Circ. Sys. Video Tech. 7 (1) (1997)] of utmost interest are the extraction and representation of visual objects, instead of estimating motion field, in this paper we focus on segmenting out visual objects based on spatial and temporal properties present in two contiguous frames in the same MRF–MAP–MFT framework. To achieve object segmentation, a “motion boundary field” is introduced which can turn off interactions between different object regions and in the mean time remove spurious object boundaries. Furthermore, in light of the generally smooth and slow velocities in-between two contiguous frames, we discover that in the process of calculating matching blocks, assigning different weights to different locations can result in better object segmentation. Experimental results conducted on both synthetic and real-world videos demonstrate encouraging performance. 相似文献
2.
EA Koller L Green JM Gertner M Bost SN Malozowski 《Canadian Metallurgical Quarterly》1998,83(7):2380-2383
A role for GH in the pathogenesis of diabetic retinopathy has long been postulated. Previous clinical studies, however, have been confounded by hyperglycemia. We have identified 2 cases of retinopathy associated with exogenous GH therapy in nondiabetic patients. Cases were identified through the MedWatch drug surveillance system of the U.S. Food and Drug Administration. Causality by concomitant medications was excluded by a search of the literature and the FDA data base. The first patient, an obese, 31-yr-old male with traumatic hypothalamic injury, presented with nonproliferative retinopathy and macular edema, resulting in decreased visual acuity (OD 20/40-1; OS count fingers), which required laser surgery. Human GH had been initiated at 0.009 mg/ kg.day, 14 months earlier, and titrated to 0.017 mg/kg.day. The second patient, a nonobese, 11-yr-old girl receiving GH for the management of short stature in Turner's Syndrome, presented with neovascularization. GH doses were 0.033 mg/kg.day for the first 17 months and 0.043 mg/ kg.day for the following 5 months. Cumulative laboratory and clinical observations suggest that GH and related peptides have a role in retinal pathology independent of the degree of glucose tolerance. 相似文献
3.
A number of N-alkyl substituted α-sulfo-β-alanines were synthesized by direct sulfonation of the corresponding N-alkyl-β-alanines. 相似文献
4.
E. R. Gertner A. M. Andrews L. O. Bubulac D. T. Cheung M. J. Ludowise R. A. Riedel 《Journal of Electronic Materials》1979,8(4):545-554
Reported here, for the first time, is the lattice matched growth of InAs1-xSbx on GaSb. The thermodynamic incompatibility of the system, i.e., the strong tendency for the In-As-Sb liquid to dissolve the
GaSb substrate, was solved via a novel liquid phase epitaxial growth technique. Liquid compositions for lattice matching conditions
have been determined in the 400-600°C range. Epitaxial growth has been examined for (100), (111)B and (111)A orientations.
Dislocation etch pit densities for lattice matched, and near lattice matched conditions are shown to be less than 104-cm−2 and 105-cm−4, respectively. The composition of the epitaxial layers are determined by the Gandolfi X-ray diffraction technique and compositional
homogeneity has been confirmed by SEM X-ray analysis. Some material related device properties which demonstrate the reproducibility
of the growth technique are presented. 相似文献
5.
Variable temperature Hall effect measurements have been made down to 9–10K on p-type Hg1−xCdxTe grown by liquid phase epitaxy on both CdTe and sapphire substrates. Carrier freeze-out was usually observed throughout
the measured temperature range. For most samples, the hole mobility was well-behaved and exhibited a maximum at ˜ 35K. Values
of acceptor ionization energy EA and donor concentration ND were estimated from the data, using a model assuming significant compensation, which provided a good fit to the low temperature
data. In addition, values of ND were also estimated from an analysis of the low temperature mobility using the hole effective mass as a parameter to provide
reasonable agreement between the ND values calculated from the Hall coefficient and mobility data. The measured carrier concentration is a result of close compensation
between stoichiometric acceptors and donors, with ND usually in the low-1017 cm−3 range. Average values of EA for as-grown, undoped x = 0.32 layers on CdTe and sapphire substrates are 7.4 and 6.6 meV, respectively. An activation energy
of 0.84 meV was determined for a Cu-doped x = 0.32 layer that was annealed in Hg vapor to reduce the number of Hg vacancies.
The average EA for undoped Hg-annealed x = 0.22 layers on CdTe substrates is 2.35 meV. Layers with x = 0.32 grown on sapphire substrates
have average carrier concentrations of 2.92 (σ = 0.54) × 1016 cm−3, compared with 4.64 (θ = 1.26) × 1016 cm−3 for the same composition layers grown on CdTe substrates. 相似文献
6.
Poly-tributyl and -triphenyltin esters or ethers were prepared by reaction of various natural and synthetic polymers containing carboxyl, sulfonic or hydroxyl groups with organotin chlorides, hydroxides or oxides. The biocidal properties of the polymers were investigated. 相似文献
7.
A parallel algorithm is proposed for the two-dimensional discrete Fourier transform (2-D DFT) computation which eliminates interprocessor communications and uses only O(N ) processors. The mapping of the algorithm onto architectures with broadcast and report capabilities is discussed. Expressions are obtained for estimating the speed performance on these machines as a function of the size N ×N of the 2-D DFT, the bandwidth of the communications channel, the time for an addition, the time T ( F N) for a single processing element to perform an N -point DFT, and the degree of parallelism. For single I/O channel machines that are capable of exploiting the full degree of parallelism of the algorithm, attainable execution times are as low as the time T (F N) plus the I/O time for data upload and download. An implementation on a binary tree computer is discussed 相似文献
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10.
Oligomeric stannoxanes having the general formula were prepared by treating amino and N-acylamino-acids with polymeric dibutyltin oxide at molar ratios less than 1. Shorter oligomers were built up to higher oligomers by insertion of dibutyltin oxide units. 相似文献