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A robust image recognition algorithm has been developed aiming at direct implementation in a bio-inspired hardware accelerator chip. The characteristic features in an original gray-scale image of 64×64-pels (i.e., a 4096-dimension vector) are extracted by a newly-developed Principal Axes Projection (PAP) method and compressed to form a 64-dimension characteristic vector. Despite the large dimensionality...
This paper develops some new results on semistability and asymptotic stability of switched systems using multiple Lyapunov functions. The main results of the paper involve sufficient conditions for guaranteeing semistability and asymptotic stability of switched systems using multiple Lyapunov functions and a class of switching conditions. Moreover, converse Lyapunov theorems for a finite family of...
In this paper, we propose a general purpose video-based tracking system that is robust to occlusion. The system is tracking moving objects that are represented by connected regions of pixels that are tracked over the video frames. The proposed tracking system design is based on recent ideas and results on robust set-valued state estimation for uncertain control systems.
We propose a method to compute invariant subsets of the robust region-of-attraction for the asymptotically stable equilibrium points of systems with polynomial nominal vector fields and unmodeled dynamics. The effects of unmodeled dynamics are accounted for as systems satisfying certain gain relations or dissipation inequalities. The methodology is extended to systems with parametric uncertainties...
For discrete-time linear time-invariant systems with input disturbances and constraints on inputs and states, we develop an algorithm to determine explicitly, as a function of the initial state, the solution to robust optimal control problems based on min-max optimization. We show that the optimal control sequence is a piecewise linear function of the initial state. Thus, when the optimal control...
In this paper we address the problem of robustly embedding 64 bits into an image while taking into account the H VS. The proposed method is general in that any mask can be adopted. The main advantage of the framework we present is that we demonstrate how to optimally embed a watermark given the constraints imposed by the mask in the spatial domain. This is in sharp contrast with the bulk of publications...
This paper addresses the robust fault detection observer design issue for linear time invariant (LTI) systems with parameter uncertainties in a polytope and subjected to unknown inputs. The observer design is investigated under the H∞/H− index framework in the finite frequency domain where the generalized KYP lemma is utilized. The threshold design and the worst undetectable fault size estimation...
In this paper we propose a spatio-temporal digital video hashing scheme. In the proposed scheme, the digital video is treated as a three dimensional signal. Edge Orientation Histogram (EOH) is computed for each frame in the digital video, then a temporal discrete cosine transform (DCT) for the magnitude of each EOH bin is computed. A subset of the resulting DCT coefficients are then pseudo-randomly...
We present a robust algorithm that registers one point set to another for nonrigid case. We formulate the problem as a Gaussian mixture model (GMM) density estimation by considering one of the point sets as the GMM centroids and the other as the data points generated by GMM. We displace the centroids and make them register to the data by maximizing the likelihood. To facilitate the process, we introduce...
We present a novel part-based method for model-free tracking. In our model, key points are considered as elementary predictors, collaborating to localize the target. In order to differentiate reliable features from outliers and bad predictors, we define the notion of feature saliency including three factors: the persistence, the spatial consistency, and the predictive power of local features. Saliency...
In this paper, we propose a new estimation method for the time difference of arrival (TDOA) between two microphones with improved accuracy by exploiting higher-order moments. In the proposed method analyzes the steered response power (SRP) of the observed signals after nonlinearly mapped onto a higher-dimensional space. Since the mapping operation enhances the linear independence between different...
Intrinsic variation is one of the major factors that aggravate performance of speaker verification system dramatically. In this paper, we focus on alleviating influence caused by intrinsic variation using sparse representation. Because the over-complete dictionary increases the flexibility and the ability to adapt to variable data in signal representation, we expect redundancy of the dictionary could...
In this paper, we consider the design of robust linear precoders for MU-MISO systems where users have perfect Channel State Information (CSI) while the BS has partial CSI. In particular, the BS has access to imperfect estimates of the channel vectors, in addition to the covariance matrices of the estimation error vectors. A closed-form expression for the Average Minimum Mean Square Error (AMMSE) is...
We consider the problem of power-efficient transmit beamforming design at multi-antenna base stations (BSs) of a multicell network, when the channel state information (CSI) at both transceiver ends are imperfect. We introduce an optimization problem that accounts for robustness at, both, the constraints and the objective function. The robust constraints guarantee the quality of service (QoS) at mobile...
Frequency hopping signals have been widely employed in wireless networks due to its robustness in anti-jamming and interference. In the scenario of coexistent networks, however, each user inevitably receives multiple unknown frequency hopping signals from different networks. In wireless networks with energy constraint, conventional re-transmission strategy is not affordable if collision happens. This...
In this work, we experimentally evaluate and verify model assumptions for our recently proposed algorithm (practical ReProCS) for recovering a time sequence of sparse vectors St and a time sequence of dense vectors Lt from their sum, Mt := St + Lt, when Lt lies in a slowly changing low-dimensional subspace. A key application where this problem occurs is in video layering where the goal is to separate...
In this paper, we propose a novel biométrie authentication system using motion vectors of lips. We have already proposed a biométrie authentication system using multimodal features of utterance. However, since both the edges and texture of lips can be easily extracted from a still image, an imposter may be recognized as a registrant by using a still image of the registrant. Therefore, the robustness...
This paper presents a development for the model predictive control (MPC) of nonlinear systems employing the quadratic dissipativity constraint (QDC). In this QDC strategy for nonlinear input-affine systems, a compound output vector is engaged to the supply rate such that the stability condition based on linear matrix inequality (LMI) can be rendered for nonlinear systems. The compound vector shares...
Aircraft are non-minimum phase, MIMO and highly nonlinear systems which undergo significant disturbances and variation in system parameters during operation. In spite of the prosperous literature in adaptive control, application of the promising control strategy on aircraft control has been restricted by the lack of assurance in closed-loop stability. This paper proposes a robust adaptive control...
An algorithm for the robust detection and recognition of gestures for the interaction between human and a domestic floor cleaner robot is presented. The gestures are selected through a user study, in which the participants are asked to show natural gestures to the robot in given specific interaction scenarios. The gestures selected are those repeated by majority of participants and consist both commanding...
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