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Lip segmentation and tracking under MAP-MRF framework with unknown segment number

NEUROCOMPUTING 2013年 104卷 155-169页

作者： Cheung, Yiu-ming Li, Meng Cao, Xiaochun Hong Kong Baptist Univ Dept Comp Sci Hong Kong Hong Kong Peoples R China Chinese Acad Sci State Key Lab Informat Secur Inst Informat Engn Beijing 100093 Peoples R China

This paper proposes a color lip segmentation method with unknown true segment number. Firstly, we build up a multi-layer hierarchical model, in which each layer corresponds to one segment cluster. Subsequently, a Markov random field derived from this model is obtained such that the segmentation problem is formulated as a labeling optimization problem under the maximum a posteriori Markov random field (MAP-MRF) framework. Suppose the pre-assigned number of segment clusters may overestimate the ground truth, whereby leading to the over-segmentation. We present a rival penalized iterative algorithm capable of performing segment clusters and over-segmentation elimination simultaneously. Based upon this algorithm, we propose a lip segmentation and tracking scheme, featuring the robust performance to the estimate of the number of segment clusters. Experimental results show the efficacy of the proposed method in comparison with the existing counterparts. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Color lip segmentation Hierarchical model MAP-MRF framework segment number

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The European centipedes hitherto referred to Eurygeophilus, Mesogeophilus, and Chalandea (Chilopoda, Geophilomorpha):: taxonomy, distribution, and geographical variation in segment number

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JOURNAL OF NATURAL HISTORY 2006年第7-8期40卷 415-438页

作者： Bonato, Lucio Barber, Anthony Minelli, Alessandro Univ Padua Dipartimento Biol I-35131 Padua Italy Coll St Mark & St John Plymouth Devon England

We have carried out a comprehensive revision of the European centipede species currently assigned to Eurygeophilus, Mesogeophilus, and Chalandea. This was based on comparative morphological study of specimens from throughout the range of the group and representative of the different nominal taxa, as well as a critical evaluation of all relevant literature. We consider this group to be represented by a single genus Eurygeophilus Verhoeff, 1899 [=Geophilus (Mesogeophilus) Verhoeff, 1901, n. syn.;=Chalandea Brolemann, 1909, n. syn.] including two morphologically clearly distinguished species, Eurygeophilus multistiliger (Verhoeff, 1899) [=Eurygeophilus multistiliger velmanyensis Brolemann, 1926, n. syn.] and Eurygeophilus pinguis (Brolemann, 1898) [=Geophilus (Mesogeophilus) baldensis Verhoeff, 1901, n. syn.;=Chalandea cottiana Verhoeff, 1938;=Chalandea cottiana var. castrensis Manfredi, 1948;=Chalandea scheerpeltzi Attems, 1952, n. syn.]. On the basis of analysis of both published and new records these two species appear to be geographically vicariant: E. multistiliger occurs mainly in Mediterranean woodlands of southern regions ( the western part of the Iberian Peninsula, eastern Pyrenees and Sardinia), whereas E. pinguis occurs mainly in temperate deciduous woodlands in montane and more northern regions ( a limited area in Great Britain, the Cantabrian Mountains, most of the western and central Pyrenees, Corsica and the entire Alps). Despite morphological uniformity throughout its range, E. pinguis shows a consistent geographical pattern in variation of the number of segments, the modal values being different between the three major areas: (1) Pyrenees, Cantabrian Mountains and Great Britain, (2) western and central Alps, and (3) eastern Alps.

关键词： Chalandea Chilopoda Eurygeophilus geographical distribution Mesogeophilus segment number taxonomy

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The Parametrized Complexity of the segment number 31st

The Parametrized Complexity of the Segment Number

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31st International Symposium on Graph Drawing and Network Visualization (GD)

作者： Cornelsen, Sabine Da Lozzo, Giordano Grilli, Luca Gupta, Siddharth Kratochvil, Jan Wolff, Alexander Univ Konstanz Constance Germany Roma Tre Univ Rome Italy Univ Perugia Perugia Italy Univ Warwick Coventry W Midlands England Charles Univ Prague Prague Czech Republic Univ Wurzburg Wurzburg Germany

ISBN: (纸本)9783031492747;9783031492754

Given a straight-line drawing of a graph, a segment is a maximal set of edges that form a line segment. Given a planar graph G, the segment number of G is the minimum number of segments that can be achieved by any planar straight-line drawing of G. The line cover number of G is the minimum number of lines that support all the edges of a planar straight-line drawing of G. Computing the segment number or the line cover number of a planar graph is there exists R-complete and, thus, NP-hard. We study the problem of computing the segment number from the perspective of parameterized complexity. We show that this problem is fixed-parameter tractable with respect to each of the following parameters: the vertex cover number, the segment number, and the line cover number. We also consider colored versions of the segment and the line cover number.

关键词： segment number Line cover number Vertex cover number Parameterized complexity Visual complexity

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MAP-MRF BASED LIP segmentATION WITHOUT TRUE segment number

MAP-MRF BASED LIP SEGMENTATION WITHOUT TRUE SEGMENT NUMBER

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18th IEEE International Conference on Image Processing (ICIP)

作者： Cheung, Yiu-ming Li, Meng Hong Kong Baptist Univ Dept Comp Sci Hong Kong Hong Kong Peoples R China

ISBN: (纸本)9781457713033

This paper presents an MAP-MRF (i.e. maximum a posteriori - Markov random field) based image segmentation method to achieve stable performance without knowing the true segment number in advance. Specifically, we firstly assign the segment number a value greater than or equal to the ground truth. Subsequently, cluster centroid of each segment in observation space is initialized randomly so that each pixel can be assigned the Euclidean distance-based membership. Then, a 2-D MRF is constructed on the regular pixel lattice of the interesting image. Under MAP-MRF framework, the image segmentation can be regarded as a labeling problem with the label configuration determined by the segment label of membership winner on each site. We therefore propose an iterative algorithm by optimizing the objective function to fade out the over-segmentation, through which an optimal segmentation is achieved. Finally, an unsupervised lip segmentation scheme based on the proposed method is presented. Experiment shows its outstanding performance.

关键词： Image segmentation MAP-MRF framework segment number

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The segment number: Algorithms and Universal Lower Bounds for Some Classes of Planar Graphs 48th

The Segment Number: Algorithms and Universal Lower Bounds fo...

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48th International Workshop on Graph-Theoretic Concepts in Computer Science (WG)

作者： Goessmann, Ina Klawitter, Jonathan Klemz, Boris Klesen, Felix Kobourov, Stephen Kryven, Myroslav Wolff, Alexander Zink, Johannes Univ Wurzburg Inst Informat Wurzburg Germany Univ Arizona Dept Comp Sci Tucson AZ USA

ISBN: (纸本)9783031159145;9783031159138

The segment number of a planar graph G is the smallest number of line segments needed for a planar straight-line drawing of G. Dujmovie, Eppstein, Suderman, and Wood [CGTA'07] introduced this measure for the visual complexity of graphs. There are optimal algorithms for trees and worst-case optimal algorithms for outerplanar graphs, 2-trees, and planar 3-trees. It is known that every cubic triconnected planar nvertex graph (except K-4) has segment number n/2 + 3, which is the only known universal lower bound for a meaningful class of planar graphs. We show that every triconnected planar 4-regular graph can be drawn using at most n + 3 segments. This bound is tight up to an additive constant, improves a previous upper bound of 7n/4 + 2 implied by a more general result of Dujmovie et al., and supplements the result for cubic graphs. We also give a simple optimal algorithm for cactus graphs, generalizing the above-mentioned result for trees. We prove the first linear universal lower bounds for outerpaths, maximal outerplanar graphs, 2-trees, and planar 3-trees. This shows that the existing algorithms for these graph classes are constant-factor approximations. For maximal outerpaths, our bound is best possible and can be generalized to circular arcs.

关键词： Visual complexity segment number Lower/upper bounds

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Thermodynamics of solutions of cyclic polymethylene ester oligomers in p-dioxane and chloroform

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JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS 2000年第3期38卷 443-455页

作者： Xu, R Leonard, J Bui, VT Univ Laval CERSIM Quebec City PQ G1K 7P4 Canada Univ Laval Dept Chim Quebec City PQ G1K 7P4 Canada Royal Mil Coll Canada Dept Chem & Chem Engn Kingston ON K7K 7B4 Canada

Differential vapor pressures were measured for mixtures of two cyclic polymethylene ester oligomers in p-dioxane and chloroform at 25, 30, 35, and 40 degrees C at five different concentrations ranging from 1 to 20 wt %. The Flory-Huggins interaction parameter (chi) as well as Leonard's interaction parameter (chi') for flexible and semiflexible rings were calculated and compared to one another. A new method for the estimation of the number of segments of a cyclic polymer is proposed that allows Leonard's equations to be applied correctly to a particular cyclic compound. Consistent differences between chi and chi' were observed for all studied mixtures, and the differences became smaller if the cyclic oligomers were considered semiflexible. Interestingly, the enthalpic parameter (kappa) deduced from values of chi and chi' did not differ within their uncertainties. This supports the prediction that mixing cyclic polymer compared to its linear counterpart is mainly due to a molecular configurational entropy difference and that this difference should become less pronounced as the cyclic compound becomes larger. (C) 2000 John Wiley & Sons, Inc.

关键词： cyclic oligomer linear oligomer configuration Leonard's interaction parameter enthalpic parameter entropic parameter segment number vapor pressure

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An adaptive vector quantization approach for image segmentation based on SOM network

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NEUROCOMPUTING 2015年第PartA期149卷 48-58页

作者： De, Ailing Guo, Chengan Dalian Univ Technol Sch Informat & Commun Engn Dalian Peoples R China

Image segmentation can be viewed as an unsupervised clustering process of pixels in the image being processed. Existing segmentation algorithms in common use often take single pixel as processing unit and segment an image mainly based on the gray value information of the image pixels. However, the spatially structural information between pixels provides even more important information on the image contents. In order to effectively exploit both the gray value and the spatial information of pixels, this paper presents an adaptive image segmentation approach based on Vector Quantization (VQ) technique. In the method, the image to be segmented is divided into small sub-blocks with each sub-block constituting a vector and the vectors are clustered by using the VQ method to implement the segmentation. The self-organizing map (SUM) neural network is adopted for realizing the VQ algorithm adaptively. In order to resolve the problem of determining the codebook size (i.e., the segment number) for the SOM-based VQ segmentation approach, an adaptive search algorithm for estimating the optimum codebook size is developed by minimizing the ratio of within-class scatter to between-class scatter in the segmentation process. Experiments have been conducted in the work by using real brain MRI images from the Internet Brain segmentation Repository (IBSR) and some other databases and comparison studies with other algorithms in the state-of-the-art are performed. The experimental results are evaluated both via subjective comparison with human vision and also via quantitative evaluation in terms of the average overlap metric, which shows that the proposed method outperforms the other existing algorithms. 2014 Elsevier B.V. All rights reserved.

关键词： Image segmentation Spatial structure SOM neural network Vector quantization segment number

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Comparison among multi-chain models for entangled polymer dynamics

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SOFT MATTER 2018年第29期14卷 5986-5994页

作者： Masubuchi, Yuichi Uneyama, Takashi Nagoya Univ Dept Mat Phys Nagoya Aichi Japan Nagoya Univ Ctr Computat Sci Nagoya Aichi Japan

Although lots of coarse-grained models have been proposed to trace the long-term behaviors of entangled polymers, compatibility among the different models has not been frequently discussed. In this study, some dynamical and static quantities, such as diffusion, relaxation modulus, chain dimension, and entanglement density, were examined for the multi-chain slip-link model (primitive chain network model) and the multi-chain slip-spring model, and the results were compared with those reported for the standard bead-spring model. For the diffusion, three models are compatible with scale-conversion parameters for units of length, time and bead (segment) number (or the molecular weight). The relaxation modulus is also compatible given that the model dependence can be accommodated by the entanglement density and the additional scale-conversion for the unit of modulus. The chain dimension is reasonably coincident with small deviations due to the weak non-Gaussianity of the models. Apart from these plausible compatibilities, significant discrepancies have been found for the inter-chain cross-correlations in the relaxation modulus.

关键词： network model Entanglement segment number Cross correlation

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Genetic algorithm based deliverable segments optimization for static intensity-modulated radiotherapy

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PHYSICS IN MEDICINE AND BIOLOGY 2003年第20期48卷 3353-3374页

作者： Li, YJ Yao, J Yao, DZ Univ Elect Sci & Technol China Sch Life Sci & Technol Chengdu 610054 Peoples R China Topslane Inc Pleasant Hill CA 94523 USA

The static delivery technique (also called step-and-shoot technique) has been widely used in intensity-modulated radiotherapy (IMRT) because of the simple delivery and easy quality assurance. Conventional static IMRT consists of two steps: first to calculate the intensity-modulated beam profiles using an inverse planning algorithm, and then to translate these profiles into a series of uniform segments using a leaf-sequencing tool. In order to simplify the procedure and shorten the treatment time of the static mode, an efficient technique, called genetic algorithm based deliverable segments optimization (GADSO), is developed in our work, which combines these two steps into one. Taking the pre-defined beams and the total number of segments per treatment as input, the number of segments for each beam, the segment shapes and weights are determined automatically. A group of interim modulated beam profiles quickly calculated using a conjugate gradient (CG) method are used to determine the segment number for each beam and to initialize segment shapes. A modified genetic algorithm based on a two-dimensional binary coding scheme is used to optimize the segment shapes, and a CG method is used to optimize the segment weights. The physical characters of a multileaf collimator, such as the leaves interdigitation limitation and leaves maximum over-travel distance, are incorporated into the optimization. The algorithm is applied to some examples and the results demonstrate that GADSO is able to produce highly conformal dose distributions using 20-30 deliverable segments per treatment within a clinically acceptable computation time.

关键词： Genetic Algorithm (GA) BEAM PROFILES RADIATION DOSE DISTRIBUTIONS Multileaf collimator segments segment number intensity modulated radiation therapy

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PARENTAL CARE IN CLINOPODES FLAVIDUS KOCH (CHILOPODA: GEOPHILOMORPHA: GEOPHILIDAE)

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ANNALES ZOOLOGICI 2010年第4期60卷 633-638页

作者： Mitic, Bojan M. Ilic, Bojan S. Tomic, Vladimir T. Makarov, Slobodan E. Curcic, Bozidar P. M. Univ Belgrade Fac Biol Inst Zool Belgrade 11000 Serbia

Parental care in the centipede Clinopodes flavidus Koch (Chilopoda: Geophilomorpha: Geophilidae) is described for the first time: the female coils round the brood with the sterna outwards, as do the females of most geophilomorphs. Also the variation in body length and major external morphological characters of the early postembryonic stadia are described. The peripatoid and foetus stadium are easily distinguished by the degree of segmentation of the trunk and the appendages, and by the capability of making 'writhing' movements. The variation in the number of leg-bearing segments in mother-offspring broods is analyzed and discussed.

关键词： Centipedes Phylactometria Adesmata breeding behavior sternal glands peripatoid foetus body length segment number

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