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Total 46 records

    Secant method for bearing-only tracking problem

    , Article Proceedings International Radar Symposium, Dresden ; Volume 1 , June , 2013 , Pages 393-398 ; 21555753 (ISSN) ; 9783954042234 (ISBN) Khalili, M. M ; Hejazi, F ; Norouzi, Y ; Nayebi, M. M ; Sharif University of Technology
    2013
    Abstract
    In this paper, a new method is proposed for solving bearing-only tracking when the target moves with constant velocity. The proposed method is compared to Pseudo Linear Estimator. Simulation results show that the proposed method outperforms PLE and estimation error is in vicinity of the CRLB  

    Design of a supervisory controller for CLOS guidance with lead angle

    , Article Aircraft Engineering and Aerospace Technology ; Volume 78, Issue 5 , 2006 , Pages 395-406 ; 00022667 (ISSN) Nobahari, H ; Alasty, A ; Pourtakdoust, S. H ; Sharif University of Technology
    2006
    Abstract
    Purpose - The purpose of this paper is to propose a supervisory command-to-line-of-sight guidance law with lead angle which keeps the missile flight within the tracking beam. Design/methodology/approach - A nonlinear supervisory controller is designed and coupled with the main sliding mode controller in the form of an additional control signal. The supervisory control signal is activated when the beam angle constraint goes to be violated. Initially a supervisory controller is designed using nonlinear control theory. Subsequently the main tracking controller is designed using sliding mode approach which forces the missile to fly along the desired line-of-sight. The stability of the... 

    A new pseudolinear solution to bearing-only tracking

    , Article IEEE National Radar Conference - Proceedings ; 2013 ; 10975659 (ISSN) ; 9781467357920 (ISBN) Hejazi, F ; Khalili, M. M ; Norouzi, Y ; Nayebi, M. M ; Sharif University of Technology
    2013
    Abstract
    The main focus of this paper is on the estimation of target motion parameters using bearing measurements. Here, based on a linearization of measurements, a recursive least squares (RLS) solution is developed. The performance of the proposed method is compared to PLE which uses the same approach in measurement linearization. Simulation results show the excellence of the proposed method over the PLE, and RLS results are in vicinity of the CRLB  

    Extract Non-Line-of-Sight state of base stations and error mitigation technique for wireless localization in micro-cell networks

    , Article Computer Communications ; Volume 35, Issue 7 , 2012 , Pages 885-893 ; 01403664 (ISSN) Dehghani, H. L ; Golmohammadi, S ; Shadi, K ; Sharif University of Technology
    2012
    Abstract
    Non Line of Sight (NLOS) propagation is a challenging issue which the performance of network based wireless localization is limited by errors primarily caused by NLOS corruption. NLOS is inherently a dominant source of errors in metropolitan area wireless networks, like cellular one, so in this paper we discuss our proposed algorithm within cellular network terminology. This paper contributes two novel algorithms. The first one is to extract the NLOS state of base station (BS) and the second one is a correction algorithm to enhance the measurements accuracy. Our proposed algorithm discuses a novel localization technique to estimate true mobile terminal (MT) location from a set of possibly... 

    An adaptive method for moving object blending in dynamic mosaicing

    , Article 13th International Computer Society of Iran Computer Conference on Advances in Computer Science and Engineering, CSICC 2008, Kish Island, 9 March 2008 through 11 March 2008 ; Volume 6 CCIS , 2008 , Pages 203-210 ; 18650929 (ISSN); 3540899847 (ISBN); 9783540899846 (ISBN) Bagheri, M ; Lotfi, T ; Kasaei, S ; Sharif University of Technology
    2008
    Abstract
    Various video applications such as mosaicing and object insertion require blending of image regions. The blending quality is often measured subjectively by considering the similarity of the blended image to each of the input images and the visibility of the seams among stitched regions. This paper presents a novel method to blend the moving objects in the related background mosaic based on an adaptive alpha blending method. In order to compute the best possible value for the alpha blending coefficient in dynamic mosaic updating, here we propose a fuzzy method based on relative speed and scale parameters of moving objects. Conducted experiments show that the proposed method improves the... 

    Object tracking in crowded video scenes based on the undecimated wavelet features and texture analysis

    , Article Eurasip Journal on Advances in Signal Processing ; Volume 2008 , 2008 ; 16876172 (ISSN) Khansari, M ; Rabiee, H. R ; Asadi, M ; Ghanbari, M ; Sharif University of Technology
    2008
    Abstract
    We propose a new algorithm for object tracking in crowded video scenes by exploiting the properties of undecimated wavelet packet transform (UWPT) and interframe texture analysis. The algorithm is initialized by the user through specifying a region around the object of interest at the reference frame. Then, coefficients of the UWPT of the region are used to construct a feature vector (FV) for every pixel in that region. Optimal search for the best match is then performed by using the generated FVs inside an adaptive search window. Adaptation of the search window is achieved by interframe texture analysis to find the direction and speed of the object motion. This temporal texture analysis... 

    Occlusion handling for object tracking in crowded video scenes based on the undecimated wavelet features

    , Article 2007 IEEE/ACS International Conference on Computer Systems and Applications, AICCSA 2007, Amman, 13 May 2007 through 16 May 2007 ; 2007 , Pages 692-699 ; 1424410312 (ISBN); 9781424410316 (ISBN) Khansari, M ; Rabiee, H. R ; Asadi, M ; Ghanbari, M ; Sharif University of Technology
    2007
    Abstract
    In this paper, we propose a new algorithm for occlusion handling for object tracking in the crowded video scenes. The algorithm exploits the properties of undecimated wavelet packet transform (UWPT) coefficients and texture analysis to track arbitrary objects. The algorithm is initialized by the user through specifying a region around the object of interest at the reference frame. Then, coefficients of the UWPT of the region construct a Feature Vector (FV) for every pixel in that region. Optimal search for the best match is then performed by using the generated FVs inside an adaptive search window. Adaptation of the search window is achieved by interframe texture analysis to find the... 

    Adaptive regulation and set-point tracking of the Lorenz attractor

    , Article Chaos, Solitons and Fractals ; Volume 32, Issue 2 , 2007 , Pages 832-846 ; 09600779 (ISSN) Nejat Pishkenari, H ; Shahrokhi, M ; Mahboobi, S. H ; Sharif University of Technology
    2007
    Abstract
    In this paper, an approach is proposed for controlling the uncertain Lorenz system. Based on an identification technique, a controller is designed that guarantees the regulation of all states in the presence of system uncertainty. Since in some applications the challenging problem of output tracking is desired, we have proposed several effective set-point tracking control techniques. The control schemes that are based on the feedback linearization method, can stabilize the internal dynamics of the system. Simulation results have illustrated the effectiveness of the proposed schemes. © 2005 Elsevier Ltd. All rights reserved  

    Novel minimum time trajectory planning in terrain following flights

    , Article IEEE Transactions on Aerospace and Electronic Systems ; Volume 43, Issue 1 , 2007 , Pages 2-12 ; 00189251 (ISSN) Malaek, S. M ; Kosari, A. R ; Sharif University of Technology
    2007
    Abstract
    A new methodology has been proposed to enhance inverse dynamics applications in the process of trajectory planning and optimization in terrain following flights (TFFs). The new approach uses a least square scheme to solve a general two-dimensional (2-D) TFF in a vertical plane. In the mathematical process, Chebyshev polynomials are used to model the geographical data of the terrain in a given route in a manner suitable for the aircraft at hand. The aircraft then follows the modeled terrain with sufficient clearance. In this approach the terrain following (TF) problem is effectively converted to an optimal tracking problem. Results show that this method provides a flexible approach to solve... 

    The large-scale dynamic maximal covering location problem

    , Article Mathematical and Computer Modelling ; Volume 57, Issue 3-4 , February , 2013 , Pages 710-719 ; 08957177 (ISSN) Zarandi, M. H. F ; Davari, S ; Sisakht, S. A. H ; Sharif University of Technology
    2013
    Abstract
    Most of the publications regarding the maxim covering location problem (MCLP) address the case where the decision is to be made for one period. In this paper, we deal with a rather untouched version of MCLP which is called dynamic MCLP (DMCLP). In order to solve this problem, a simulated annealing (SA) has been presented. The proposed solution algorithm is capable of solving problems with up to 2500 demand nodes and 200 potential facilities with a fair amount of exactness. Our experiments showed that the proposed approach finds solutions with errors less than one percent  

    Visual tracking by dictionary learning and motion estimation

    , Article 2012 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012 ; 2012 , Pages 274-279 ; 9781467356060 (ISBN) Jourabloo, A ; Babagholami-Mohamadabadi, B ; Feghahati, A. H ; Manzuri-Shalmani, M. T ; Jamzad, M ; Sharif University of Technology
    2012
    Abstract
    In this paper, we present a new method to solve tracking problem. The proposed method combines sparse representation and motion estimation to track an object. Recently. sparse representation has gained much attention in signal processing and computer vision. Sparse representation can be used as a classifier but has high time complexity. Here, we utilize motion information in order to reduce this computation time by not calculating sparse codes for all the frames. Experimental results demonstrates that the achieved result are accurate enough and have much less computation time than using just a sparse classifier  

    Visual tracking using sparse representation

    , Article 2012 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012, 12 December 2012 through 15 December 2012, Ho Chi Minh City ; 2012 , Pages 304-309 ; 9781467356060 (ISBN) Feghahati, A. H ; Jourabloo, A ; Jamzad, M ; Manzuri Shalmani, M. T ; Sharif University of Technology
    2012
    Abstract
    In this work we present a sparse dictionary learning method, specifically tuned to solve the tracking problem. Recently, sparse representation has drawn much attention because of its genuineness and strong mathematical background. In this paper we present an online method for dictionary learning which is desirable for problems such as tracking. Online learning methods are preferable because the whole data are not available at the current time. The presented method tries to use the advantages of the generative and discriminative models to achieve better performance. The experimental results show our method can overcome many tracking challenges  

    Visual tracking using D2-clustering and particle filter

    , Article 2012 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012 ; 2012 , Pages 230-235 ; 9781467356060 (ISBN) Raziperchikolaei, R ; Jamzad, M ; Sharif University of Technology
    2012
    Abstract
    Since tracking algorithms should be robust with respect to appearance changes, online algorithms has been investigated recently instead of offline ones which has shown an acceptable performance in controlled environments. The most challenging issue in online algorithms is updating of the model causing tracking failure because of introducing small errors in each update and disturbing the appearance model (drift). in this paper, we propose an online generative tracking algorithm in order to overcome the challenges such as occlusion, object shape changes, and illumination variations. In each frame, color distribution of target candidates is obtained and the candidate having the lowest distance... 

    Recursive sensor placement in two dimensional TDOA based localization

    , Article 24th Iranian Conference on Electrical Engineering, 10 May 2016 through 12 May 2016 ; 2016 , Pages 300-304 ; 9781467387897 (ISBN) Hamdollahzadeh, M ; Adelipour, S ; Behnia, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    Abstract
    This paper presents a new approach to sensor placement strategy in emitter localization problem which is based on Time Difference of Arrival (TDOA) measurements. The advantage of this method is its flexibility and capability of positioning sensors in constrained or non-stationary situations in which the positions of the sensors are restricted to certain portions of the space and/or needed to be changed repeatedly. The validity of the proposed algorithm is assessed by three different simulation scenarios and the results verify its proper operation  

    Implementation of optical tracker system for marker-based human motion tracking

    , Article 15th IASTED International Conference on Applied Simulation and Modelling, Rhodes, 26 June 2006 through 28 June 2006 ; Volume 2006 , 2006 , Pages 252-257 ; 0889865612 (ISBN); 9780889865617 (ISBN) Colahi, A ; Hoviatalab, M ; Rezaeian, T ; Alizadeh, M ; Bostan, M ; Sharif University of Technology
    2006
    Abstract
    In this paper a complete design of a high speed optical human motion tracking system has been described for biomechanical human motion analysis and animation craft applications. The main core of the image processing unit that is implemented by the differential algorithm procedure and some intelligent and conservative procedures that facilitate the search algorithm have also been proposed and implemented for the processing of human motions tracking images. In the next step an optimized modified direct linear transformation (MDLT) method has been used to reconstruct 3D locations of markers as an input data for animation unit. The low computational cost and the high precision in detecting and... 

    Design of a navigator for the optimized path-tracking of underwater ROVs using a nero-genetic fuzzy controller

    , Article 2006 World Automation Congress, WAC'06, Budapest, 24 June 2006 through 26 June 2006 ; 2006 ; 1889335339 (ISBN); 9781889335339 (ISBN) Kashani, H ; Saghafi, M. H ; Fathy, M ; Soriani, M ; Sharif University of Technology
    IEEE Computer Society  2006
    Abstract
    This paper proposes a sublime-optimum soft- computing based controller to follow a desired path with a desired velocity by mobile robots with identified dynamical behavior. This method consists of a fuzzy controller where a trained Neural Network sets its membership functions values in On-line mode. Training of the Network is done by a Genetic Algorithm for various vehicle initial positions and different path convexities in Off-line. After the training of the network, during vehicle motion, it retrieves sub-optimized fuzziness values and sends them to the fuzzy control algorithm according to the vehicle position. Meanwhile, the influential of the path convexity is considered in fuzziness of... 

    Robust tracking control of attitude satellite with using new SMC and EKF for large maneuvers

    , Article 2006 IEEE Aerospace Conference, Big Sky, MT, 4 March 2006 through 11 March 2006 ; Volume 2006 , 2006 ; 1095323X (ISSN); 0780395468 (ISBN); 9780780395466 (ISBN) Jafarboland, M ; Sadati, N ; Momeni, H ; Sharif University of Technology
    2006
    Abstract
    Control1,2 of a class of uncertain nonlinear systems which estimates unavailable state variables is considered. A new approach for robust tracking control problem of satellite for large rotational maneuvers is presented in this paper. The features of this approach include -a strong algorithm to estimate attitude, based on discrete extended kalman filter combined with a continuous extended kalman filter and attitude nonlinear model -a robust controller based on sliding-mode with perturbation estimation. The estimation result of interval kalman filtering is a sequence of interval estimates that encompasses all possible optimal attitude estimates, which the interval system may generate. The... 

    How to synchronize and register an optical-inertial tracking system

    , Article Applied Mechanics and Materials ; Volume 332 , 2013 , Pages 130-136 ; 16609336 (ISSN) ; 9783037857335 (ISBN) Soroush, A ; Akbar, M ; Farahmand, F ; Sharif University of Technology
    2013
    Abstract
    Multi-sensor tracking is widely used for augmentation of tracking accuracy using data fusion. A basic requirement for such applications is the real time temporal synchronization and spatial registration of two sensory data. In this study a new method for time and space coordination of two tracking sensor measurements has been presented. For spatial registration we used a body coordinate system and then applied the effect of the level arm. The time synchronization was done based on least mean square (LMS) error method. This method was implemented to synchronize the position and orientation of an object using Inertial (1IMU) and Optical (Optotrak) tracking systems. The results of synchronized... 

    Distibuted human tracking in smart camera networks by adaptive particle filtering and data fusion

    , Article 2012 6th International Conference on Distributed Smart Cameras, ICDSC 2012, 30 October 2012 through 2 November 2012 ; November , 2012 ; 9781450317726 (ISBN) Rezaei, F ; Khalaj, B. H ; Sharif University of Technology
    2012
    Abstract
    Human tracking is an essential step in many computer vision-based applications. As single view tracking may not be sufficiently robust and accurate, tracking based on multiple cameras has been widely considered in recent years. This paper presents a distributed human tracking method in a smart camera network and introduces a particle filter design based on Histogram of Oriented Gradients (HOG) and color histogram. The proposed adaptive motion model also estimates the target speed from the history of its latest displacement and improves the robustness of the tracker by decreasing the probability of missing targets. In addition, a distributed data fusion method is proposed which fuses the... 

    Design and implementation of an improved real-time tracking system for navigation surgery by fusion of optical and inertial tracking methods

    , Article Applied Mechanics and Materials ; Volume 186 , 2012 , Pages 273-279 ; 16609336 (ISSN) ; 9783037854440 (ISBN) Soroush, A ; Farahmand, F ; Salarieh, H ; Sharif University of Technology
    2012
    Abstract
    The fusion of the optical and inertial tracking systems seems an attractive solution to solve the shadowing problem of the optical tracking systems, and remove the time integration troubles of the inertial sensors. We developed a fusion algorithm for this purpose, based on the Kalman filter, and examined its efficacy to improve the position and orientation data, obtained by each individual system. Experimental results indicated that the proposed fusion algorithm could effectively estimate the 2 seconds missing data of the optical tracker