Search for: motion
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    Entropy-based video steganalysis of motion vectors

    , Article Entropy ; Volume 20, Issue 4 , 2018 ; 10994300 (ISSN) Sadat, E. S ; Faez, K ; Saffari Pour, M ; Sharif University of Technology
    MDPI AG  2018
    In this paper, a new method is proposed for motion vector steganalysis using the entropy value and its combination with the features of the optimized motion vector. In this method, the entropy of blocks is calculated to determine their texture and the precision of their motion vectors. Then, by using a fuzzy cluster, the blocks are clustered into the blocks with high and low texture, while the membership function of each block to a high texture class indicates the texture of that block. These membership functions are used to weight the effective features that are extracted by reconstructing the motion estimation equations. Characteristics of the results indicate that the use of entropy and... 

    Empathetic space on screen : constructing powerful place and setting

    , Book D'Adamo, Amedeo
    The Editor(s) (if applicable) and The Author(s)  2018

    Hybrid control and motion planning of dynamical legged locomotion

    , Book ; Sadati, Nasser
    Wiley  2012
    This book provides a comprehensive presentation of issues and challenges faced by researchers and practicing engineers in motion planning and hybrid control of dynamical legged locomotion. The major features range from offline and online motion planning algorithms to generate desired feasible periodic walking and running motions and tow-level control schemes, including within-stride feedback laws, continuous time update laws and event-based update laws, to asymptotically stabilize the generated desired periodic orbits. This book describes the current state of the art and future directions across all domains of dynamical legged locomotion so that readers can extend proposed motion planning... 

    Adaptive block motion prediction

    , Article 6th IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2006, Vancouver, BC, 27 August 2006 through 30 August 2006 ; 2006 , Pages 908-913 ; 0780397541 (ISBN); 9780780397545 (ISBN) Eslami, A ; Babaeizadeh, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2006
    Block motion estimation is an important field of video processing. This paper presents a new scheme to reach in faster block motion estimation based on motion prediction. The scheme exploits an adaptive filter to predict the block motion from its spatio-temporal motion compensated adjacent blocks, the predicted motion determines the initial candidate block for search methods with biased search center, in special case of partial distortion search, this strategy reduces search time by preventing from complete distortion calculation for more loser candidates, after comparison of three conventional adaptive filters, a normalized least mean square filter with convergence monitoring is recommended... 

    Theoretical and experimental study on the motion and shape of viscoelastic falling drops through Newtonian media

    , Article Rheologica Acta ; Volume 55, Issue 11-12 , 2016 , Pages 935-955 ; 00354511 (ISSN) Vamerzani, B. Z ; Norouzi, M ; Firoozabadi, B ; Sharif University of Technology
    Springer Verlag 
    In this paper, creeping motion of a viscoelastic drop falling through a Newtonian fluid is investigated experimentally and analytically. A polymeric solution of 0.08 % xanthan gum in 80:20 glycerol/water and silicon oil is implemented as the viscoelastic drop and the bulk viscous fluids, respectively. The shape and motion of falling drops are visualized using a high speed camera. The perturbation technique is employed for both interior and exterior flows, and Deborah and capillary numbers are considered as perturbation parameters up to second order. The product of Deborah and capillary numbers is also used as a perturbation parameter to apply the boundary condition on the deformation on the... 

    Design and fabrication of a robot for neurorehabilitation; Smart RoboWrist

    , Article 2nd International Conference on Knowledge-Based Engineering and Innovation, 5 November 2015 through 6 November 2015 ; 2015 , Pages 447-450 ; 9781467365062 (ISBN) Faghihi, A ; Haghpanah, S. A ; Farahmand, F ; Jafari, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    In this paper design and fabrication of a wrist exoskeleton robot (ROBOWRIST) has been discussed. The robot has 3 degree of freedom, including flexion/extension, abduction/ adduction and pronation/supination based on the anatomical axis of the body. Four stepper motors are responsible for creating the motion. The exoskeleton can be used for neurorehabilitation and also post-surgery of wrist and forearm. Various therapeutic procedures with a precise tracking can be handled using the control algorithms. Each motor has a separate encoder to measure the angular position and send feedback to the controller. The design goal is to construct a reliable robot that is robust and applicable for... 

    Digital video stabilization using radon transform

    , Article 2012 International Conference on Digital Image Computing Techniques and Applications, DICTA 2012, 3 December 2012 through 5 December 2012 ; December , 2012 ; 9781467321815 (ISBN) Babagholami Mohamadabadi, B ; Bagheri Khaligh, A ; Hassanpour, R ; Sharif University of Technology
    Digital video stabilization is a category of techniques used to reduce the impact of unintentional camera motion such as jitter, jiggle, and other unsteady motions. These unintentional shakings degrade visual quality of videos and reduce the performance of subsequent processes such as video compression. Digital video stabilization which is performed by post processing the acquired frames, suffers from inaccuracy of motion estimation which is mostly due to the local motions of internal moving objects included in videos, and long processing time which prohibits them from being used in real time applications. In this paper we propose a fast and accurate transform based motion estimation method... 

    Investigation on dynamic modeling of SURENA III humanoid robot with heel-off and heel-strike motions

    , Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 41, Issue 1 , 2017 , Pages 9-23 ; 22286187 (ISSN) Sadedel, M ; Yousefi Koma, A ; Khadiv, M ; Mansouri, S ; Sharif University of Technology
    Shiraz University  2017
    The understudy SURENA III humanoid robot was designed and fabricated at the Center of Advanced Systems and Technologies (CAST) located in the Universityof Tehran. In this paper, a full dynamic model of SURENA III in different walking phases including heel-offand heel-strike motions is presented. To this end, first a trajectory planning method based on robot kinematics is introduced. Then, the multi-body dynamics of the robot links are calculated using Lagrange and Kane approaches which are then verified. In this model, the power transmissionsystem is considered to be ideal. Afterward, system identification routine is adopted to model the dynamic behavior of the power transmission system. By... 

    Equations of motion of a ring-like robot with a flexible body and creeping-rolling motion

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings ; 2010 , pp. 191-197 ; ISBN: 9780791843833 Nejad, A. H ; Alasty, A ; Sharif University of Technology
    The robots that can move on rough terrains are very important especially in Rescue operation, exploration, etc. In this research, a mechanism is introduced for a ring-like robot with a flexible body. This robot is moved by arms which are placed radially and have Reciprocating motion in this direction. By controlling the contraction and the extension of the arms which contact lhe ground, the robot will be forced to move which is called rolling-creeping motion. The robot is stable in stationary state.; also the maximum angle which it can be stable is determined. Considering the speed of contracted arm is the input parameter, the speed of the extended arm for locomotion of the robot has been... 

    3D motion recognition using HMM and nearest neighbor method

    , Article Proceedings of the IASTED International Conference on Signal Processing, Pattern Recognition and Applications, SPPRA 2012 ; 2012 , Pages 17-22 ; 9780889869219 (ISBN) Safaei, A ; Jahed, M ; Sharif University of Technology
    ACTA Press  2012
    Gesture and motion recognition are needed for a variety of applications. The use of human hand motions as a natural interface tool has motivated researchers to conduct research in the modeling, analysis and recognition of various hand movements. In this work, we introduce a 3-D hand motion recognition. We use 3-D landmarked points on finger tips and joints followed by a HMM (Hidden Markov Model) to recognize hand motions. Experimentally, in an effort to evaluate the formation of hand gestures similar to those used in rehabilitation sessions, we studied three hand motions. Using natural hand motion features in an uncontrolled environment, we were able to classify, differentiate and quantify... 

    Improved initial value prediction for global motion estimation

    , Article European Signal Processing Conference, 23 August 2010 through 27 August 2010, Aalborg ; 2010 , Pages 2022-2026 ; 22195491 (ISSN) Ahmadi, A ; Salehinejad, H ; Talebi, S ; Koroupi, F ; Sharif University of Technology
    Global motion estimation (GME) algorithms have an imperative role in object-based applications. Gradient-based GME is a well known method among these algorithms. Such algorithms require an initial value for their initialization step. Well estimation of this value plays a significant role in the accuracy of GME. This work introduces a simple but efficient technique for initial value prediction of GME. This technique employs a long-term predictor as well as global motions of previous frames. Simulations results demonstrate faster convergence and less computational complexity of the proposed method versus common presented techniques in the literature with almost same efficiency  

    An approximation algorithm for d1-optimal motion of a rod robot with fixed rotations

    , Article International Journal of Computer Mathematics ; Volume 83, Issue 3 , 2006 , Pages 357-370 ; 00207160 (ISSN) Abam, M. A ; Ghodsi, M ; Sharif University of Technology
    Given a translating and rotating rod robot in a plane in the presence of polygonal obstacles with the initial and final placements of the rod known, the d1-optimal motion planning problem is defined as finding a collision-free motion of the rod such that the orbit length of a fixed but arbitrary point F on the rod is minimized. In this paper we study a special case of this problem in which the rod can translate freely, but can only rotate by some pre-specified given angles around F. We first characterize the d1-optimal motion of the robot under the given conditions and then present a (1 + ε)-approximation algorithm for finding the optimal path. The running time of the algorithm is bounded by... 

    Fractional Brownian Motion and Application in Mathematical Finance

    , M.Sc. Thesis Sharif University of Technology Sabzikar, Farzad (Author) ; Zohuri Zangeneh, Bijan (Supervisor) ; Farhadi, Hamid Reza (Co-Advisor)
    Farctional Brownian motion (fBm) is a Gaussian Stochastic process B={B_t ∶t ≥0} With zero mean and Covariance function given by RH (t,s)=1/2 (t^2H+ S^2H-├|t-├ s┤|┤ 〖^2H〗) Where 0

    Fast two-stage global motion estimation: A blocks and pixels sampling approach

    , Article Smart Innovation, Systems and Technologies ; Volume 11 SIST , 2011 , Pages 143-151 ; 21903018 (ISSN) ; 9783642221576 (ISBN) Ahmadi, A ; Pouladi, F ; Salehinejad, H ; Talebi, S ; Sharif University of Technology
    Global motion estimation (GME) is an important technique in image and video processing. Whereas the direct global motion estimation techniques boast reasonable precision they tend to suffer from high computational complexity. As with indirect methods, though presenting lower computational complexity they mostly exhibit lower accuracy than their direct counterparts. In this paper, the authors introduce a robust algorithm for GME with near identical accuracy and almost 50-times faster than MPEG-4 verification model (VM). This approach entails two stages in which, first, motion vector of sampled block is employed to obtain initial GME then Levenberg-Marquardt algorithm is applied to the... 

    Chaos study of a vibratory micro-robot in hybrid motion

    , Article Nonlinear Dynamics ; Volume 82, Issue 3 , November , 2015 , Pages 1355-1378 ; 0924090X (ISSN) Jalili, H ; Salarieh, H ; Vossoughi, G ; Sharif University of Technology
    Kluwer Academic Publishers  2015
    In this paper, motion of a micro-robot with two perpendicular vibrational actuators is studied. In this work, separation of the micro-robot body from the substrate of motion is modeled. If the applied vertical force to the micro-robot body is greater than its weight, body of the micro-robot jumps apart from the substrate and then returns to it. This motion will continue intermittently until it is damped. In this condition, the motion mechanism of “stick-slip” is not valid, and a hybrid motion according to “stick-slip-jump” mode is governed. By increasing the applied vertical force, the motion velocity of the micro-robot becomes disordered and unrepeatable. By numerical solving of the... 

    A close look at the motion of C60 on gold

    , Article Current Applied Physics ; Volume 15, Issue 11 , November , 2015 , Pages 1402-1411 ; 15671739 (ISSN) Pishkenari, H. N ; Nemati, A ; Meghdari, A ; Sohrabpour, S ; Sharif University of Technology
    Elsevier  2015
    In this paper, we have studied the motion of buckminsterfullerene (C60) on a gold surface by analyzing its potential energy and using classical molecular dynamics method. The results can be employed to investigate the motion of C60-based nanocars which have been made in recent years. For this purpose, we have studied the translational and rotational motions of C60 molecule independently. First, we have calculated the potential energy of a C60 molecule on a gold surface in different orientations and positions and employed this data to predict fullerene motion by examining its potential energy. Then we have simulated the motion of C60 at... 

    Reaction-diffusion equations with polynomial drifts driven by fractional brownian motions

    , Article Stochastic Analysis and Applications ; Volume 28, Issue 6 , Oct , 2010 , Pages 1020-1039 ; 07362994 (ISSN) Zamani, S ; Sharif University of Technology
    A reaction-diffusion equation on [0, 1]d with the heat conductivity k > 0, a polynomial drift term and an additive noise, fractional in time with H > 1/2, and colored in space, is considered. We have shown the existence, uniqueness and uniform boundedness of solution with respect to k Also we show that if k tends to infinity, then the corresponding solutions of the equation converge to a process satisfying a stochastic ordinary differential equation  

    Modeling traffic motion patterns via Non-negative Matrix Factorization

    , Article 4th IEEE International Conference on Signal and Image Processing Applications, ICSIPA 2015, 19 October 2015 through 21 October 2015 ; 2015 , Pages 214-219 ; 9781479989966 (ISBN) Ahmadi, P ; Kaviani, R ; Gholampour, I ; Tabandeh, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Analyzing motion patterns in traffic videos can directly lead to generate some high-level descriptions of the video content. In this paper, an unsupervised method is proposed to automatically discover motion patterns occurring in traffic video scenes. For this purpose, based on optical flow features extracted from video clips, an improved Non-negative Matrix Factorization (NMF) framework is applied for learning of semantic motion patterns. After extracting the motion patterns, each video clip can be sparsely represented as a weighted sum of learned patterns which can further be employed in very large range of applications. Experimental results show that our proposed approach finds accurately... 

    Effects of motion segment simulation and joint positioning on spinal loads in trunk musculoskeletal models

    , Article Journal of Biomechanics ; 2017 ; 00219290 (ISSN) Ghezelbash, F ; Eskandari, A. H ; Shirazi Adl, A ; Arjmand, N ; El-Ouaaid, Z ; Plamondon, A ; Sharif University of Technology
    Elsevier Ltd  2017
    Musculoskeletal models represent spinal motion segments by spherical joints/beams with linear/nonlinear properties placed at various locations. We investigated the fidelity of these simplified models (i.e., spherical joints with/without rotational springs and beams considering nonlinear/linear properties) in predicting kinematics of the ligamentous spine in comparison with a detailed finite element (FE) model while considering various anterior-posterior joint placements. Using the simplified models with different joint offsets in a subject-specific musculoskeletal model, we computed local spinal forces during forward flexion and compared results with intradiscal pressure measurements. In... 

    Human arm motion tracking by inertial/magnetic sensors using unscented Kalman filter and relative motion constraint

    , Article Journal of Intelligent and Robotic Systems: Theory and Applications ; Volume 90, Issue 1-2 , May , 2018 , Pages 161-170 ; 09210296 (ISSN) Atrsaei, A ; Salarieh, H ; Alasty, A ; Abediny, M ; Sharif University of Technology
    Springer Netherlands  2018
    Human motion tracking has many applications in biomedical and industrial services. Low-cost inertial/magnetic sensors are widely used in human motion capture systems to obtain the orientation of the human body segments. In this paper, we have presented a quaternion-based unscented Kalman filter algorithm to fuse inertial/magnetic sensors measurements for tracking human arm movements. In order to have a better estimation of the orientation of the forearm and the upper arm, a constraint equation was developed based on the relative velocity of the elbow joint with respect to the inertial sensors attached to the forearm and the upper arm. Also to compensate for fast body motions, we adapted the...