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71.
Isoperimetric graph partitioning for image segmentation 总被引:5,自引:0,他引:5
Grady L Schwartz EL 《IEEE transactions on pattern analysis and machine intelligence》2006,28(3):469-475
Spectral graph partitioning provides a powerful approach to image segmentation. We introduce an alternate idea that finds partitions with a small isoperimetric constant, requiring solution to a linear system rather than an eigenvector problem. This approach produces the high quality segmentations of spectral methods, but with improved speed and stability. 相似文献
72.
研究和讨论了图像质量评估方法,提出一种基于模糊推理的块效应评估标准。假设图像由平滑区域、边缘区域以及纹理区域等组成,而且不同的区域应采用不同的方法进行质量评估。在此基础上,给出了三个分别适用于不同区域的图像质量评估因子,并提出了一个灵活的模糊图像质量评估方法。此方法把块效应和图像本身具有的边缘分开,防止了边缘会被误认为是块效应。仿真结果表明,提出的标准对于不同的图像具有鲁棒性,有一般图像质量评价标准的性能。 相似文献
73.
74.
Random walks for image segmentation 总被引:3,自引:0,他引:3
Grady L 《IEEE transactions on pattern analysis and machine intelligence》2006,28(11):1768-1783
A novel method is proposed for performing multilabel, interactive image segmentation. Given a small number of pixels with user-defined (or predefined) labels, one can analytically and quickly determine the probability that a random walker starting at each unlabeled pixel will first reach one of the prelabeled pixels. By assigning each pixel to the label for which the greatest probability is calculated, a high-quality image segmentation may be obtained. Theoretical properties of this algorithm are developed along with the corresponding connections to discrete potential theory and electrical circuits. This algorithm is formulated in discrete space (i.e., on a graph) using combinatorial analogues of standard operators and principles from continuous potential theory, allowing it to be applied in arbitrary dimension on arbitrary graphs 相似文献
75.
76.
Abstract. Although entity-relationship modelling is the most popular means of specifying the conceptual schema for the data perspective of an information system, an alternative design approach known as fact-oriented modelling appears to offer advantages. This paper provides an overview of fact-oriented modelling, including some recent revisions and an evaluation of how the method has coped with large-scale practical applications. One distinguishing feature of the approach is its emphasis on natural verbalization of information examples in terms of elementary facts. This notion of elementarity is clarified to cater for a problematic case involving compositely identified object types. Finally, the algorithm for mapping a conceptual to a relational schema is revised to cater for lazy object types. 相似文献
77.
The paper describes the accurate calibration of the camera transformation for a vision system consisting of a camera mounted on a robot. The calibration includes an analysis of the linearity of the camera. A knowledge of the camera transformation allows the three-dimensional position of the object points to be determined using triangulation. 相似文献
78.
To mix single‐walled carbon nanotubes (SWCNTs) with a polymer and to achieve low percolation thresholds, a low‐viscosity liquid has been required in order to achieve sufficiently good dispersion. In this article, data are presented which show that percolation occurs at ~0.14 wt % carbon nanotubes and the dispersion procedure does not involve dispersing the SWCNTs in a low‐viscosity liquid. Specifically, ultrahigh‐molecular‐weight polyethylene powder was mixed with a powder containing nanotubes and catalyst support, e.g., the powder contains 93% silica and 7% SWCNTs. The powder blend is compression molded into sheets using high pressure and temperature. Because of the very high viscosity of the resin, the nanotube/silica mixture largely stays segregated at the interface as shown by scanning electron microscopy. A significant drop in tensile properties (modulus, tensile strength, and elongation at break) occurs with filler incorporation. Non isothermal crystallization measurements indicate that this filler does not nucleate crystallinity when mixed in this manner; although there is a definite sharpening of the melt endotherm indicating that crystallites with smaller lamellar thicknesses are reduced significantly with filler addition. The addition of filler also slightly reduces the overall fractional crystallinity measured after a constant cooling rate. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献
79.
80.
D Mack J Riedewald H Rohde T Magnus HH Feucht HA Elsner R Laufs ME Rupp 《Canadian Metallurgical Quarterly》1999,67(2):1004-1008
Hemagglutination of erythrocytes is a common property of Staphylococcus epidermidis strains, which is related to adherence and biofilm formation and may be essential for the pathogenesis of biomaterial-associated infections caused by S. epidermidis. In three independent biofilm-producing, hemagglutination-positive S. epidermidis isolates, interruption of the icaADBC operon essential for polysaccharide intercellular adhesin (PIA) synthesis by Tn917 insertions led to a hemagglutination-negative phenotype. An immunoglobulin G fraction of antiserum to PIA greatly reduced hemagglutination. Purified PIA led to a 64-fold decrease of hemagglutination titers of these strains; however, it did not mediate hemagglutination by itself. These observations define PIA as the hemagglutinin of S. epidermidis or at least as its major functional component. 相似文献