Disconnected skeletons for shape recognition

Aslan, Çağrı
This study presents a new shape representation scheme based on disconnected symmetry axes along with a matching framework to address the problem of generic shape recognition. The main idea is to define the relative spatial arrangement of local symmetry axes in a shape centered coordinate frame. The resulting descriptions are invariant to scale, rotation, small changes in viewpoint and articulations. Symmetry points are extracted from a surface whose level curves roughly mimic the motion by curvature. By increasing the amount of smoothing on the evolving curve, only those symmetry axes that correspond to the most prominent parts of a shape are extracted. The representation does not suffer from the common instability problems of the traditional connected skeletons. It captures the perceptual properties of shapes well. Therefore, finding the similarities and the differences among shapes becomes easier. The matching process is able to find the correct correspondence of parts under various visual transformations. Highly successful classification results are obtained on a moderate sized 2D shape database.


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Tola, Ömer Önder; Yarman Vural, Fatoş Tunay; Department of Computer Engineering (2004)
In this thesis, we introduce a new shape descriptor and a graph based matching algorithm to detect a template shape in an image that contains a single object. The shape descriptor, Generalized Beam Angle Statistics, GBAS is obtained with the generalization of the boundary based shape descriptor, Beam Angle Statistics, BAS
Semi-analytical solution of MHD flow through boundary integrals on the pipe wall
Tezer, Münevver; Bozkaya, Canan (Wiley, 2019-05-01)
A mathematical model is given for the magnetohydrodynamic (MHD) pipe flow as an inner Dirichlet problem in a 2D circular cross section of the pipe, coupled with an outer Dirichlet or Neumann magnetic problem. Inner Dirichlet problem is given as the coupled convection-diffusion equations for the velocity and the induced current of the fluid coupling also to the outer problem, which is defined with the Laplace equation for the induced magnetic field of the exterior region with either Dirichlet or Neumann boun...
A mathematical modeling and approximation of gene expression patterns by linear and quadratic regulatory relations and analysis of gene networks
Yılmaz, Fatma Bilge; Weber, Gerhard Wilhelm; Department of Scientific Computing (2004)
This thesis mainly concerns modeling, approximation and inference of gene regulatory dynamics on the basis of gene expression patterns. The dynamical behavior of gene expressions is represented by a system of ordinary di erential equations. We introduce a gene-interaction matrix with some nonlinear entries, in particular, quadratic polynomials of the expression levels to keep the system solvable. The model parameters are determined by using optimization. Then, we provide the time-discrete approximation of o...
Quadrature error compensation and its effects on the performance of fully decoupled MEMS gyroscopes
Tatar, Erdinç; Akın, Tayfun; Department of Electrical and Electronics Engineering (2010)
This thesis, for the first time in the literature, presents the effect of quadrature error compensation on the performance of a fully decoupled MEMS gyroscope and provides experimental data on the sources of quadrature error. Dedicated quadrature error cancellation electrodes operating with only differential DC potentials are designed. Gyroscopes with intentionally placed imperfections are fabricated with SOG based SOI process which provides higher yield and uniformity compared to SOG process. Tests show th...
Finite strip with a central crack under tension
Yetmez, M; Gecit, MR (Elsevier BV, 2005-03-01)
In this study, a symmetrical finite strip with a length of 2L and a width of 2h, containing a transverse symmetrical crack of width 2a at the midplane is considered. Two rigid plates are bonded to the ends of the strip through which uniformly distributed axial tensile load of magnitude 2hp(0) is applied. The material of the strip is assumed to be linearly elastic and isotropic. Both edges of the strip are free of stresses. Solution for this finite strip problem is obtained by means of an infinite strip of w...
Citation Formats
Ç. Aslan, “Disconnected skeletons for shape recognition,” M.S. - Master of Science, Middle East Technical University, 2005.