Search for: mathematical-transformations
0.009 seconds
Total 105 records

    New image-based system for vibration measurment, specially developed for forced human vibration analysis

    , Article 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE, Anaheim, CA, 13 November 2004 through 19 November 2004 ; 2004 , Pages 203-204 ; 03609960 (ISSN) Hoviattalab, M ; Yadolahi, A ; Narimani, R ; Abadpour, A ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2004
    The human being in the environments of modern technology has to endure stresses of many and varied kinds of vibrations. Measuring vibration is an important tool in rehabilitation and biomechanical fields of research. We have proposed image processing as a new method to record and determine the frequency response of human body. The subjects were exposed to whole body periodical vibration while standing on a shaking table. Two digital camcorders were used to capture the motion of colored pencil-dot markers on the skin of human body (forehead) and on the edge of the shaking table. After color spotting each frame, the binary image results were processed using new circle factor criteria proposed... 

    Generating correlated networks from uncorrelated ones

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 67, Issue 4 2 , 2003 , Pages 461071-461076 ; 1063651X (ISSN) Ramezanpour, A ; Karimipour, V ; Mashaghi, A ; Sharif University of Technology
    The characteristics of correlated networks, generated from uncorrelated networks, were studied. New correlated networks with a considerable clustering were obtained from the line graphs of uncorrelated network. The transformation by which random graphs were converted to their line (edge-dual) graphs was explained. The solution for site percolation on the transformed graphs was also studied  

    Analysis of a dissimilar finite wedge under antiplane deformation

    , Article Mechanics Research Communications, Exeter ; Volume 27, Issue 1 , 2000 , Pages 109-116 ; 00936413 (ISSN) Kargarnovin, M. H ; Fariborz, S. J ; Sharif University of Technology
    Elsevier Science Ltd  2000
    The dissimilar wedge with finite radius under antiplane shear deformation is analyzed. The finite Mellin transform is used to solve the governing differential equation. By simply letting the wedge radius approaches infinity, the solution is obtained  

    SM3D studio: A 3D model constructor

    , Article Iranian Conference on Machine Vision and Image Processing, MVIP ; 2013 , Pages 10-15 ; 21666776 (ISSN); 9781467361842 (ISBN) Soleimani, V ; Vincheh, F. H ; Zare, E ; Engineers (IEEE) Antennas and Propagation Society; The Institute of Electrical and Electronics ; Sharif University of Technology
    IEEE Computer Society  2013
    In this paper we describe designing and implementation of a powerful, fast and compact simple 3D modeler (SM3D). In addition to saving cost and time (due to high processing speed), 3D objects can be created with minimum system resources by using this application. Easy learning and using are other strengths of this application. Modularity using classification and applying Dynamic-Link Library files are noted aspects that are regarded in writing the source code and this causes separation of main part and user interface, so the application can be easily expanded in the future. Ability to create primary objects and also applying advanced transformations and modifiers have been considered.... 

    A new adaptive lifting scheme transform for robust object detection

    , Article 2006 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2006, Toulouse, 14 May 2006 through 19 May 2006 ; Volume 2 , 2006 , Pages II749-II752 ; 15206149 (ISSN); 142440469X (ISBN); 9781424404698 (ISBN) Amiri, M ; Rabiee, H. R ; Sharif University of Technology
    This paper presents a new adaptive lifting scheme transform for detecting user-selected objects in a sequence of images. In our algorithm, we first select a set of object features in the wavelet transform domain and then build an adaptive transform by using the selected features. The adaptive transform is constructed based on adaptive prediction in a lifting scheme procedure. Adaptive prediction is performed such that, the large coefficients in the high-pass component of the non-adaptive transform vanishes in the high-pass component of the adaptive transform. Finally, both the non-adaptive and adaptive transforms are applied to a given test image and the transform domain coefficients are... 

    A 1.5V 60MS/s sampled-data filter in 0.18μm CMOS

    , Article 2005 European Conference on Circuit Theory and Design, Cork, 28 August 2005 through 2 September 2005 ; Volume 2 , 2005 , Pages 95-98 ; 0780390660 (ISBN); 9780780390669 (ISBN) Sedighi, B ; Bakhtiar, M. S ; Sharif University of Technology
    A new family of sampled-data filters in which accuracy is a function of the ratio of the resistors is introduced. It is shown that this structure is suitable for low-voltage high-speed applications. A biquad filter with a quality factor of 10 and a clock frequency of 60MHz consuming only 2mW power is also presented  

    Blur identification in noisy images using radon transform and power spectrum modeling

    , Article IWSSIP 2005 - 12th International Workshop on Systems, Signals and Image Processing(SSIP-SPI, 2005), Chalkida, 22 September 2005 through 24 September 2005 ; 2005 , Pages 347-352 ; 0907776205 (ISBN); 9780907776208 (ISBN) Moghaddam, M. E ; Jamzad, M ; Sharif University of Technology
    Motion blur is one of the most common blurs that degrades images. Restoration of such images are highly dependent to estimation of motion blur parameters. Many researchers since 1976 have developed algorithms to estimate linear motion blur parameters. These algorithms are different in their performance, time complexity, precision and their robustness in noisy environments. In this paper we have presented a novel algorithm to estimate linear motion blur parameters such as direction and extend by using Radon transform to find direction and power spectrum modeling to find its extend. The most benefit of this algorithm is its robustness and precision in noisy images. This algorithm is a... 

    An efficient feature extraction methodology for blind image steganalysis using contourlet transform and zernike moments

    , Article 2013 10th International ISC Conference on Information Security and Cryptology, ISCISC 2013 ; Aug , 2013 , Page(s): 1 - 6 Shakeri, E ; Ghaemmaghami, S ; Sharif University of Technology
    IEEE Computer Society  2013
    We propose an effective blind image steganalysis based on contourlet transform and Zernike moments that improves the detection accuracy of universal image steganalysis methods. The proposed method examines randomness in the test image to distinguish between the stego and non-stego images. The suspicious image is decomposed by contourlet transform, and then the absolute Zernike moments of contourlet subbands coefficients of the image and linear prediction error of each contourlet subband are extracted as features for steganalysis. These features are fed to a nonlinear SVM classifier with an RBF kernel to distinguish between cover and stego images. Experimental results show that the proposed... 

    Analog computing using graphene-based metalines

    , Article Optics Letters ; Volume 40, Issue 22 , 2015 , Pages 5239-5242 ; 01469592 (ISSN) AbdollahRamezani, S ; Arik, K ; Khavasi, A ; Kavehvash, Z ; Sharif University of Technology
    OSA - The Optical Society  2015
    We introduce the new concept of "metalines" for manipulating the amplitude and phase profile of an incident wave locally and independently. Thanks to the highly confined graphene plasmons, a transmit-array of graphene-based metalines is used to realize analog computing on an ultracompact, integrable, and planar platform. By employing the general concepts of spatial Fourier transformation, a well-designed structure of such meta-transmit-array, combined with graded index (GRIN) lenses, can perform two mathematical operations, i.e., differentiation and integration, with high efficiency. The presented configuration is about 60 times shorter than the recent structure proposed by Silva et al.... 

    Blind source separation in nonlinear mixture for colored sources using signal derivatives

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 25 August 2015 through 28 August 2015 ; Volume 9237 , August , 2015 , Pages 193-200 ; 03029743 (ISSN) ; 9783319224817 (ISBN) Ehsandoust, B ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
    Springer Verlag  2015
    While Blind Source Separation (BSS) for linear mixtures has been well studied, the problem for nonlinear mixtures is still thought not to have a general solution. Each of the techniques proposed for solving BSS in nonlinear mixtures works mainly on specific models and cannot be generalized for many other realistic applications. Our approach in this paper is quite different and targets the general form of the problem. In this advance, we transform the nonlinear problem to a time-variant linear mixtures of the source derivatives. The proposed algorithm is based on separating the derivatives of the sources by a modified novel technique that has been developed and specialized for the problem,... 

    Fast homography refinement in soccer videos

    , Article 9th Iranian Conference on Machine Vision and Image Processing, 18 November 2015 through 19 November 2015 ; Volume 2016-February , 2015 , Pages 185-188 ; 21666776 (ISSN) ; 9781467385398 (ISBN) Hadian, M ; Kasaei, S ; Sharif University of Technology
    IEEE Computer Society 
    Sports video analysis and camera calibration are important applications which rely on accurate homography computation as a challenging task. Homography refinement is an important step in the task of accurate homography computation and homography tracking. Also, in certain applications (such as homography tracking) the process speed is of great importance. A robust and fast method for accurate refinement of highly inaccurate homographies in soccer video frames is proposed in this paper. To achieve that goal, a new homography model fitting method named the point-line (PL) method is proposed. It uses point-line correspondences to compute the homography, rather than point correspondences or line... 

    Transformation of sliding motion to rolling during spheres collision

    , Article Granular Matter ; Volume 19, Issue 4 , 2017 ; 14345021 (ISSN) Nejat Pishkenari, H ; Kaviani Rad, H ; Jafari Shad, H ; Sharif University of Technology
    In this research, we have investigated the three-dimensional elastic collision of two balls, based on friction in the tangential plane. Our aim is to offer analytical closed form relations for post collision parameters such as linear and angular velocities, collision time and tangential and normal impulse in three dimensions. To simplify the problem, stick regime is not considered. In other words, balls have a low tangential coefficient of restitution. Sliding, sliding then rolling, and rolling at the beginning of contact are three cases that can occur during impact which have been considered in our research. The normal interaction force is described by the Hertz contact force and... 

    A non parametric approach to monitor simple linear profiles in phases I and II

    , Article Communications in Statistics - Theory and Methods ; Volume 46, Issue 11 , 2017 , Pages 5203-5222 ; 03610926 (ISSN) Sayyad, A ; Akhavan Niaki, S. T ; Afshar Najafi, B ; Sharif University of Technology
    Taylor and Francis Inc  2017
    In this paper, a non parametric approach is first proposed to monitor simple linear profiles with non normal error terms in Phase I and Phase II. In this approach, two control charts based on a transformation technique and decision on beliefs are designed in order to monitor the intercept and the slope, simultaneously. Then, some simulation experiments are performed in order to evaluate the performance of the proposed control charts in Phase II under both step and drift shifts in terms of out-of-control average run length (ARL1). Besides, the performance of the proposed control charts is compared to the ones of seven other existing schemes in the literature. Simulation results show that the... 

    Dielectric metasurfaces solve differential and integro-differential equations

    , Article Optics Letters ; Volume 42, Issue 7 , 2017 , Pages 1197-1200 ; 01469592 (ISSN) Abdollahramezani, S ; Chizari, A ; Eshaghian Dorche, A ; Jamali, M. V ; Salehi, J. A ; Sharif University of Technology
    OSA - The Optical Society  2017
    Leveraging subwavelength resonant nanostructures, plasmonic metasurfaces have recently attracted much attention as a breakthrough concept for engineering optical waves both spatially and spectrally. However, inherent ohmic losses concomitant with low coupling efficiencies pose fundamental impediments over their practical applications. Not only can all-dielectric metasurfaces tackle such substantial drawbacks, but also their CMOS-compatible configurations support both Mie resonances that are invariant to the incident angle. Here, we report on a transmittive metasurface comprising arrayed silicon nanodisks embedded in a homogeneous dielectric medium to manipulate phase and amplitude of... 

    Learning a metric when clustering data points in the presence of constraints

    , Article Advances in Data Analysis and Classification ; Volume 14, Issue 1 , 2020 , Pages 29-56 Abin, A. A ; Bashiri, M. A ; Beigy, H ; Sharif University of Technology
    Springer  2020
    Learning an appropriate distance measure under supervision of side information has become a topic of significant interest within machine learning community. In this paper, we address the problem of metric learning for constrained clustering by considering three important issues: (1) considering importance degree for constraints, (2) preserving the topological structure of data, and (3) preserving some natural distribution properties in the data. This work provides a unified way to handle different issues in constrained clustering by learning an appropriate distance measure. It has modeled the first issue by injecting the importance degree of constraints directly into an objective function.... 

    Identification of nonlinear model for rotary high aspect ratio flexible blade using free vibration response

    , Article Alexandria Engineering Journal ; Volume 59, Issue 4 , August , 2020 , Pages 2131-2139 Mahariq, I ; Kavyanpoor, M ; Ghalandari, M ; Nazari, M. A ; Bui, D. T ; Sharif University of Technology
    Elsevier B. V  2020
    Nonlinear identification of a narrow cantilever blade undergoing free vibration was studied. In the absence of forced excitation and because of general data deficiency of this system, the current identification methods cannot be applied with sufficient accuracy. A new identification approach was introduced in the present study based on nonlinear free vibration decay. Nonlinear free response of the presented system is determined by the coupling of generalized variation iteration and the modified differential transformation methods. The comparisons between the experiments and calculations is highlighted the good accuracy of the identified nonlinear model. © 2020 Faculty of Engineering,... 

    Face virtual pose generation using multi resolution subspaces

    , Article 2008 International Symposium on Telecommunications, IST 2008, Tehran, 27 August 2008 through 28 August 2008 ; 2008 , Pages 629-633 ; 9781424427512 (ISBN) Rohban, M. H ; Rabiee, H. R ; Khansari, M ; Sharif University of Technology
    In this paper a new method for face virtual pose generation is presented. The proposed method uses subspace image representation. The general problem of blurring is addressed by introducing a multi resolution time-frequency analysis to subspace image representation. The training gallery contains face images in two different poses. Undecimated Wavelet Transform is applied on all training face images in first pose and the corresponding images in the second pose to produce image subbands. Then, a new subspace is constructed for each subband in both poses. The mapping between two corresponding subbands of two poses is learnt using linear regression. The resulted mapping matrix is used to... 

    Crowded scene object tracking in presence of Gaussian white noise using undecimated wavelet features

    , Article 2007 9th International Symposium on Signal Processing and its Applications, ISSPA 2007, Sharjah, 12 February 2007 through 15 February 2007 ; 2007 ; 1424407796 (ISBN); 9781424407798 (ISBN) Khansari, M ; Rabiee, H. R ; Asadi, M ; Ghanbari, M ; Sharif University of Technology
    In this paper, we propose a new noise robust algorithm 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 coefficients of the UWPT of a user-specified region at the reference frame construct a Feature Vector (FV) for every pixel in that region. Optimal search for the best match of the region in successive frames is then performed by using the generated FVs inside an adaptive search window. Adaptation of the search window is achieved by inter-frame texture analysis to find the direction and speed of the object motion. Noise robustness has been... 

    Skewness reduction approach in multi-attribute process monitoring

    , Article Communications in Statistics - Theory and Methods ; Volume 36, Issue 12 , 2007 , Pages 2313-2325 ; 03610926 (ISSN) Akhavan Niaki , S. T ; Abbasi, B ; Sharif University of Technology
    Since the product quality of many industrial processes depends upon more than one dependent variable or attribute, they are either multivariate or multi-attribute in nature. Although multivariate statistical process control is receiving increased attention in the literature, little work has been done to deal with multi-attribute processes. In this article, we develop a new methodology to monitor multi-attribute processes. To do this, first we transform multi-attribute data in a way that their marginal probability distributions have almost zero skewness. Then, we estimate the transformed covariance matrix and apply the well-known T2 control chart. In order to illustrate the proposed method... 

    Linear motion blur parameter estimation in noisy images using fuzzy sets and power spectrum

    , Article Eurasip Journal on Advances in Signal Processing ; Volume 2007 , 2007 ; 11108657 (ISSN) Ebrahimi Moghaddam, M ; Jamzad, M ; Sharif University of Technology
    Motion blur is one of the most common causes of image degradation. Restoration of such images is highly dependent on accurate estimation of motion blur parameters. To estimate these parameters, many algorithms have been proposed. These algorithms are different in their performance, time complexity, precision,and robustness in noisy environments. In this paper, we present a novel algorithm to estimate direction and length of motion blur,using Radon transform and fuzzy set concepts. The most important advantage of this algorithm is its robustness and precision in noisy images. This method was tested on a wide range of different types of standard images that were degraded with different...