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One of the most important problems facing researchers in various fields such as pattern recognition, computer vision, and industrial design is the shape abstraction. A recent shape abstraction method generates an abstracted shape through the correspondences between their features from a given set of shapes. The correspondences are obtained based on the optimal solution of a well known transportation...
The paper represents first part of two contributions dealing with simplified modular design of constrained P and disturbance observer (DO) based PI control with different filtering properties illustrated by example of speed servo control. This first part is devoted to analysis of the core structure of the P controller tuned for different types of nonmodelled or filter dynamics. Openness of the approach...
Topological persistence measures the resilience of extrema of a function to perturbations, and has received increasing attention in computer graphics, visualization and computer vision. While the notion of topological persistence for piece-wise linear functions defined on a simplicial complex has been well studied, the time complexity of all the known algorithms are super-linear (e.g. O(n log n))...
We address an important issue in the design of concentric permutation code based vector quantizers to select the optimal integer partitions. We establish that, for concentric permutation code based vector quantizers, the optimum integer partitions exhibit monotonicity with its index. In addition, a reduced complexity encoding scheme for concentric permutation code based vector quantizers is presented.
This paper proposes a novel approach named Compressed Submanifold Multifactor Analysis (CSMA) to concisely and precisely deal with multifactor analysis. Compared to the state-of-the-art MPCA method that loses the original local geometry structures of input factors due to the averaging process, our proposed approach can preserve their original geometry. In addition, the fast low-rank approximation...
In this paper we propose an original framework for the description and the subsequent recognition of objects of limited size. Although of general applicability, the framework is presented here as a way to trace different yet similar metal tools employed in the mechanical constructions industry. For the purpose of object description, time-varying silhouettes of the object are acquired under turntable...
A linear-time algorithm is proposed for polygonal approximation of digital curves. The direction changes of the x- and y-coordinates are traced to generate a new, compact representation of curves. The algorithm, Direction Change-based Polygonal Approximation (DCPA), has two advantages: linear time complexity and insensitivity to parameter setting. Benchmark results demonstrate the competitive performance...
We propose a new Semi-Lagrangian scheme for the area-preserving Mean Curvature flow. The model uses a level set framework to propagate a closed planar curve. The corresponding flow has been proposed by Sapiro & Tannenbaum [9]. The scheme has the advantage to allow large time step still maintaining a good accuracy. We apply the algorithm to recover the original shape of a synthetic image to which...
To characterize the brain changes associated with aging, we detect brain cortex variability through a spherical harmonic analysis that represents a 3D surface supported by the unit sphere through a linear combination of special basis functions, called spherical harmonics (SHs). The proposed 3D shape analysis is carried out in four steps: (i) 3D Delau-nay triangulation to construct a 3D mesh model...
Fetal head detection and approximation from ultrasound image is an important method in obstetric and gynaecology. In this research, we propose a modification of an efficient algorithm to detect an ellipse shape in an image. Our proposed method is using an efficient way to approximate an ellipse based on its minor axis. By enumerating every possible minor axis from a pairs of pixels, other ellipse...
Nose tip localization is often the basic step for 2.5D face registration and further 3D face processing and as such appears as a side problem of most research works on 2.5D or 3D face recognition. In this paper, we propose to carry out a comprehensive study of four popular rotation invariant differential geometric properties, namely Mean and Gaussian curvature, Shape Index and Curvedness, for the...
Ellipto-Hyperbolic nano-antennas are studied theoretically and experimentally. Self-modes are derived in closed-form, and very high directivity is implied. Ellipto-hyperbolic antennas are under extensive study and only few results are shown here.
Convection-diffusion is a physical phenomenon that appears in a multitude of dynamical systems, e.g. vibrating string with damping or chemical and thermal systems. This paper focuses on a structure preserving spatial discretization scheme of a general dynamical system with convection and diffusion in the port-Hamiltonian framework. The preservation of the port-Hamiltonian structure ensures that specific...
Prolate spheroidal wave functions (PSWF) provide significant advantage in ultra wideband (UWB) pulse-shapes design because of the time limited nature and wide bandwidth of such orthogonal signal waveforms. In this paper, we show the design procedure for UWB pulses utilizing the joining properties of radial and angular PSWF. Results in the paper demonstrate utility of eigenvalues and power spectral...
Monitoring of physical phenomena is one of the most promising application fields of wireless sensor networks. In this work we focus on obtaining the shape of a forest fire. In this kind of applications, the information sensed by network nodes is usually transmitted to a base station located at the border of the network, where it is finally processed. However, such an approach requires that a large...
Pose normalization is an important step to establish shape correspondence for group comparison of anatomical structures. The most basic and widely used way is ellipsoid fitting, which provides three principal axes for shape alignment, and is often solved by least square fitting. In this paper, it is recognized that the deformation caused by neuro-degenerative diseases is usually locally irregular,...
Shape retrieval process is composed of two components: shape representation and matching algorithm. In this paper, we propose a new technique for shape similarity. According to this method, the contours are extracted and decomposed into portions of curves at the concavities points. Each portion curve is described by some parametric curve using the B-spline approximation. A cubic B-spline curve is...
Analysis of the room impulse response is main problem in room acoustics. Here we propose using Katz fractal dimension for analysis of room impulse responses, applied on Schroeder curve. The methodology used in this paper together with the obtained results shows some of the possible directions in the application of fractals in room acoustics.
We address the problem of reconstructing 3D face models from large unstructured photo collections, e.g., obtained by Google image search or from personal photo collections in iPhoto. This problem is extremely challenging due to the high degree of variability in pose, illumination, facial expression, non-rigid changes in face shape and reflectance over time and occlusions. In light of this extreme...
We present a preconditioning scheme for improving the efficiency of optimization of arbitrary difference measures in deformable registration problems. This is of particular interest for high-dimensional registration problems with statistical difference measures such as MI, and the demons method, since in these cases the range of applicable optimization methods is limited. The proposed scheme is simple...
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