Ensembles of multiple (active) cameras yield an important ingredient in modern tracking and surveillance applications. They overcome the limited fields-of-view of single cameras, however, require robust procedures for...
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We propose a person-dependent, manifold-based approach for modeling and tracking rigid and nonrigid 3D facial deformations from a monocular video sequence. The rigid and nonrigid motions are analyzed simultaneously in...
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We propose a person-dependent, manifold-based approach for modeling and tracking rigid and nonrigid 3D facial deformations from a monocular video sequence. The rigid and nonrigid motions are analyzed simultaneously in 3D, by automatically fitting and tracking a set of landmarks. We do not represent all nonrigid facial deformations as a simple complex manifold, but instead decompose them on a basis of eight 1D manifolds. Each 1D manifold is learned offline from sequences of labeled expressions, such as smile, surprise, etc. Any expression is then a linear combination of values along these 8 axes, with coefficient representing the level of activation. We experimentally verify that expressions can indeed be represented this way, and that individual manifolds are indeed 1D. The manifold dimensionality estimation, manifold learning, and manifold traversal operation are all implemented in the N-D Tensor Voting framework. Using simple local operations, this framework gives an estimate of the tangent and normal spaces at every sample, and provides excellent robustness to noise and outliers. The output of our system, besides the tracked landmarks in 3D, is a labeled annotation of the expression. We demonstrate results on a number of challenging sequences.
Camera handoff is a crucial step to generate a continuously tracked and consistently labeled trajectory of the object of interest in multi-camera surveillance systems. Most existing camera handoff algorithms concentra...
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The third international conference on Human-Robot Interaction (HRI-2008) was held in Amsterdam, The Netherlands, March 12-15, 2008. The theme of HRI-2008, "living with robots," highlights the importance of t...
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Spatial-temporal local motion features have shown promising results in complex human action classification. Most of the previous works [6],[16],[21] treat these spatial-temporal features as a bag of video words, omitt...
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ISBN:
(纸本)1424420008
Spatial-temporal local motion features have shown promising results in complex human action classification. Most of the previous works [6],[16],[21] treat these spatial-temporal features as a bag of video words, omitting any long range, global information in either the spatial or temporal domain. Other ways of learning temporal signature of motion tend to impose a fixed trajectory of the features or parts of human body returned by tracking algorithms. This leaves little flexibility for the algorithm to learn the optimal temporal pattern describing these motions. In this paper, we propose the usage of spatial-temporal correlograms to encode flexible long range temporal information into the spatial-temporal motion features. This results into a much richer description of human actions. We then apply an unsupervised generative model to learn different classes of human actions from these ST-correlograms. KTH dataset, one of the most challenging and popular human action dataset, is used for experimental evaluation. Our algorithm achieves the highest classification accuracy reported for this dataset under an unsupervised learning scheme.
Every agent aspiring to human level intelligence, every AGI agent, must be capable of a theory of mind. That is, it must be able to attribute mental states, including intentions, to other agents, and must use such att...
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We propose and evaluate a novel method for enhancing performance of lips contour tracking, which is based on the concept of statistic shape models (ASM) and multi features. On the first image of the video sequence, li...
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We propose and evaluate a novel method for enhancing performance of lips contour tracking, which is based on the concept of statistic shape models (ASM) and multi features. On the first image of the video sequence, lip region is detected using the Bayesian's rule in which lip color information is modeled by using the Gaussian mixture model (GMM) and the GMM is trained by expectation-maximization (EM) algorithm. The lip region is then used to initialize the lip shape model. A single feature-based ASM presents good performance only in particular conditions but gets stuck in local minima for noisy conditions (like beard, wrinkle, poor texture, low contrast between lip and skin, etc). To enhance the convergence, we propose to use 2 features: normal profile and grey level patches, and combine them by using a voting approach. The standard ASM is not able to take into account temporal information from previous frames therefore the lip contours are tracked by replacing the standard ASM with a hybrid active shape model (HASM) which is capable to take advantage of the temporal information. Initial experimental results on video sequences show that MF-HASM is more robust to local minimum problem and gives a higher accuracy than traditional single feature-based method in lip tracking problem.
This paper describes a solution to the problem of landing a helicopter autonomously. The methodology used poses the problem as a discrete time path following control problem where a conveniently defined error state sp...
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This paper describes a solution to the problem of landing a helicopter autonomously. The methodology used poses the problem as a discrete time path following control problem where a conveniently defined error state space model of the helicopter is modified to include the aerodynamic effects of flying within close proximity to the ground. An affine parameter-dependent model representation is adopted that describes the helicopter linearized error dynamics for the predefined landing operating region. A state feedback H{sub}2 control problem for affine parameter-dependent systems is posed and solved using Linear Matrix Inequalities (LMIs). The resulting nonlinear controller is implemented using the D-methodology and dynamic weights to enforce bandwidth constraints on the actuators. The effectiveness of the proposed controller with and without dynamic weights on the actuation is assessed in simulation using the full nonlinear dynamic model of a small-scale helicopter.
We propose and evaluate a novel method for enhancing performance of lips contour tracking, which is based on the concept of active shape models (ASM) and multi features. On the first image of the video sequence, lip r...
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We propose and evaluate a novel method for enhancing performance of lips contour tracking, which is based on the concept of active shape models (ASM) and multi features. On the first image of the video sequence, lip region is detected using the Bayesian's rule in which lip color information is modeled by a Gaussian mixture model (GMM) which is trained by expectation-maximization (EM) algorithm. The lip region is then used to initialize the lip shape model. A single feature-based ASM presents good performance only in particular conditions but gets stuck in local minima for noisy conditions (like beard, wrinkle, poor texture, low contrast between lip and skin, etc). To enhance the convergence, we propose to use 2 features: normal profile and grey level patches, and combine them with a voting approach. The standard ASM is not able to take into account temporal information from previous frames therefore the lip contours are tracked by replacing the standard ASM with a hybrid active shape model (HASM) which is capable to take advantage of the temporal information. Initial experimental results on video sequences show that MF-HASM is more robust to local minimum problem and gives a higher accuracy than traditional single feature-based method in lip tracking problem.
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