Many of today's visual servoing systems rely on the use of markers on the object to provide features for control. There is thus a need for a visual system that provides control features regardless of the appearanc...
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Many of today's visual servoing systems rely on the use of markers on the object to provide features for control. There is thus a need for a visual system that provides control features regardless of the appearance of the object. Region based tracking is a natural approach since it does not require any special type of features. In this paper we present two different approaches to region based tracking: 1) a multi-resolution gradient based approach (using optical flow); and 2) a discrete feature based search approach. We present experiments conducted with both techniques for different types of image motions. Finally, the performance, drawbacks and limitations of used techniques are discussed.
A visually guided mobile platform acting in a dynamic environment needs information, delivered from cues such as stereo and motion. In this paper a binocular stereo system, capable of dynamic vergence and ego-motion e...
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A visually guided mobile platform acting in a dynamic environment needs information, delivered from cues such as stereo and motion. In this paper a binocular stereo system, capable of dynamic vergence and ego-motion estimation, will be presented. The ability to dynamically verge the cameras is essential for visual tasks such as tracking, recognition and manipulation, since the computation of 3D geometry will be considerably simplified at fixation. We will show that the epipolar geometry of the presented system can be estimated in real-time. The number of degrees of freedom has been minimized, without affecting the flexibility of the system. Reconstructed 3D data is used in order to determine the ego-motion of the platform, at a very low computational cost. Finally, it will be shown how disparity maps and estimated ego-motion can facilitate the localization of independently moving objects.
A structural model of a one-component σ-phase crystal has been constructed by means of molecular dynamics simulation. The phonon dispersion curves and the vibrational density of states were computed for this model. T...
A structural model of a one-component σ-phase crystal has been constructed by means of molecular dynamics simulation. The phonon dispersion curves and the vibrational density of states were computed for this model. The dependence of the vibrational properties on the thermodynamical parameters was investigated. The vibrational density of states of the σ-phase structure is found to be similar to that of a one-component glass with icosahedral local order. On the basis of this comparison it is concluded that the σ phase can be considered to be a good crystalline reference structure for this glass.
作者:
Nordlund, PeterEklundh, Jan-Olof
Department of Numerical Analysis and Computing Science Royal Institute of Technology StockholmS-100 44 Sweden
An approach to figure-ground segmentation based on a 2-dimensional histogram in feature space is presented. The histogram is then analyzed with a peak-finding algorithm designed with real-time performance in mind. The...
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NLCk is a family of algebras on vertex-labeled graphs introduced by Wanke. An NLC-decomposition of a graph is a derivation of this graph from single vertices using the operations in question. The width of the decompos...
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In this paper, a person following behaviour for a mobile robot is presented. The head of the person is located using skin colour detection. Then, a control loop is fed with the camera movements required to put the upp...
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In this paper, a person following behaviour for a mobile robot is presented. The head of the person is located using skin colour detection. Then, a control loop is fed with the camera movements required to put the upper part of the person in the center of the image. The algorithm was tested in different rooms of a research lab. It performed well in all lighting conditions except in direct sunlight. Since the background and lighting cannot be controlled, the vision algorithm must be robust to such changes. However, since the computing power is quite limited, the algorithm must have as low complexity as possible.
We extend the notion of linearity testing to the task of checking linear-consistency of multiple functions. Informally, functions are "linear" if their graphs form straight lines on the plane. Two such funct...
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We present the ECHBD system as a new approach to the neuroscientific discipline of brainmapping. The complexity of the brain and the potentially vast amount of brain measurement data collected, shared, and analyzed by...
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We present the ECHBD system as a new approach to the neuroscientific discipline of brainmapping. The complexity of the brain and the potentially vast amount of brain measurement data collected, shared, and analyzed by many different research groups make experimental brain research a key area for use of multimedia database systems in the role of environments for experimental science. The neuroscientific research community has created a demand for such a system, capable of supporting analysis of 3D images of the brain, where ease of use and visual navigation are key issues. The focus of the paper is on how to handle large raster data sets in object oriented databases, visual interaction and Internet accessible research environments.
Abstract: A search for prime factors of the generalized Fermat numbers $F_n(a,b)=a^{2^n}+b^{2^n}$ has been carried out for all pairs $(a,b)$ with $a,b\leq 12$ and GCD$(a,b)=1$. The search limit $k$ on the fact...
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Abstract: A search for prime factors of the generalized Fermat numbers $F_n(a,b)=a^{2^n}+b^{2^n}$ has been carried out for all pairs $(a,b)$ with $a,b\leq 12$ and GCD$(a,b)=1$. The search limit $k$ on the factors, which all have the form $p=k\cdot 2^m+1$, was $k=10^9$ for $m\leq 100$ and $k=3\cdot 10^6$ for $101\leq m\leq 1000$. Many larger primes of this form have also been tried as factors of $F_n(a,b)$. Several thousand new factors were found, which are given in our tables.—For the smaller of the numbers, i.e. for $n\leq 15$, or, if $a,b\leq 8$, for $n\leq 16$, the cofactors, after removal of the factors found, were subjected to primality tests, and if composite with $n\leq 11$, searched for larger factors by using the ECM, and in some cases the MPQS, PPMPQS, or SNFS. As a result all numbers with $n\leq 7$ are now completely factored.
The Matrix-To-Line problem is that of, given an n × n symmetric matrix D, finding an arrangement of n points on the real line such that the so obtained distances agree as well as possible with the by D specified ...
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