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A Fast Algorithm for Shadow Generation with Low Distortion Based on Shadow Map Technique
, M.Sc. Thesis Sharif University of Technology ; Jamzad, Mansour (Supervisor)
Abstract
Shadows are one of the most important details in graphical images. There exist many shadow generation algorithms each of which suffers from some problems. High processing time and ill-shaped shadow borders, known as alasing, are some of such problems. In this paper, we propose a heuristic method based on standard shadow map technique, named rotated shadow maps, to generate excellent hard shadows. Our method uses some shadow maps which are generated from the same view but objects are slightly rotated around the center of view area. Rotated shadow maps can be considered as an independent hard shadow generation algorithm. Also it can be combined with other shadow map based approaches. Utilizing...
Aerial Vision-Based Navigation and Monitoring in Special Conditions
, Ph.D. Dissertation Sharif University of Technology ; Malaek, Mohammad Bagher (Supervisor)
Abstract
This research is dedicated to specific issues in the field of Aerial Vision Based Navigation (VBN). It focuses mainly on vehicles with no pilot such as RPVs and small aircraft; having in mind their safety which must be close to commercial applications. Various methods have been studied and the simplest one; which is based on observation, identification and utilization of landmarks is selected for detailed implementation. In this work, we concentrate on using a single-camera while flying in an unknown environment (MonoSLAM). Other available sensors are accelerometer and GPS receiver to keep the cost down. Different studies show that using a low-cost single camera system is much more efficient...
Human body 3D reconstruction in multiview soccer scenes by depth optimization
, Article 24th Iranian Conference on Electrical Engineering, 10 May 2016 through 12 May 2016 ; 2016 , Pages 1591-1596 ; 9781467387897 (ISBN) ; Kasaei, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
In soccer matches, 3D reconstruction is a main part of many applications including free-viewpoint broadcasting, match analysis, augmented reality, and refereeing examination. The main challenge of 3D reconstruction in soccer scenes is the human body reconstruction. Although 3D reconstruction methods have been improved to a high extent in controlled condition, still there are lots of uncovered issues in outdoor scene reconstructions with uncontrolled conditions. In this paper, a view-dependent depth optimization method is presented which addresses two of these issues in soccer scenes. These issues include inaccurate camera calibrations and limited number of input cameras. This method will...
Adaptive sparse matrix representation for efficient matrix–vector multiplication
, Article Journal of Supercomputing ; November , 2015 , Pages 1-21 ; 09208542 (ISSN) ; Khunjush, F ; Sarbazi Azad, H ; Sharif University of Technology
Springer New York LLC
2015
Abstract
A wide range of applications in engineering and scientific computing are based on the sparse matrix computation. There exist a variety of data representations to keep the non-zero elements in sparse matrices, and each representation favors some matrices while not working well for some others. The existing studies tend to process all types of applications, e.g., the most popular application which is matrix–vector multiplication, with different sparse matrix structures using a fixed representation. While Graphics Processing Units (GPUs) have evolved into a very attractive platform for general purpose computations, most of the existing works on sparse matrix–vector multiplication (SpMV, for...
Adaptive sparse matrix representation for efficient matrix–vector multiplication
, Article Journal of Supercomputing ; Volume 72, Issue 9 , Volume 72, Issue 9 , 2016 , Pages 3366-3386 ; 09208542 (ISSN) ; Khunjush, F ; Sarbazi Azad, H ; Sharif University of Technology
Springer New York LLC
Abstract
A wide range of applications in engineering and scientific computing are based on the sparse matrix computation. There exist a variety of data representations to keep the non-zero elements in sparse matrices, and each representation favors some matrices while not working well for some others. The existing studies tend to process all types of applications, e.g., the most popular application which is matrix–vector multiplication, with different sparse matrix structures using a fixed representation. While Graphics Processing Units (GPUs) have evolved into a very attractive platform for general purpose computations, most of the existing works on sparse matrix–vector multiplication (SpMV, for...
Similarity measures for intersection of camera view frustums
, Article Iranian Conference on Machine Vision and Image Processing, MVIP ; Volume 2017-November , 2018 , Pages 171-175 ; 21666776 (ISSN); 9781538644041 (ISBN) ; Shirzad, H ; Kasaei, S ; Sharif University of Technology
IEEE Computer Society
2018
Abstract
For a moving camera recognizing that it has seen a place before now, is one the most important issues in the 3D reconstruction problems. In these problems, the main goal is to create a three-dimensional model from a sequence of 2D captured images during different times. That part of the scene which is rendered by a camera is often modeled by a frustum. Calculating the amount of intersection of two camera view frustums at different times can help to solve this problem. However, there are two major difficulties. First, calculating the intersection of two frustums, in general, is so complicated. And second, there are some uncertainties in the moving camera parameters over time. In this paper,...
A method for reducing the complexity, and increasing the accuracy of field emission electron gun simulations
, Article Vacuum ; Volume 95 , 2013 , Pages 50-65 ; 0042207X (ISSN) ; Rashidian, B ; Sharif University of Technology
2013
Abstract
Problems regarding simulation of field emitter array (FEA) electron guns are discussed. A simple method is proposed to significantly reduce computational requirements such as computation power, system memory, and time of FEA electron gun simulation and modeling. The method can be applied to any numerical solver regardless of its meshing technique. In order to extract field emission parameter from any experimental cathode I-V curve, a partly numerical algorithm, which uses the presented truncation method at the heart of its solver, is proposed. The proposed method and algorithm are applied to a number of examples, including a double-gated FEA problem, and its effectiveness in terms of error...
Model based hand motion estimation through stereo vision
, Article Proceedings of the 2013 6th International Congress on Image and Signal Processing, CISP 2013 ; Volume 1 , Dec , 2013 , Pages 117-121 ; 9781479927647 (ISBN) ; Jahed, M ; Sharif University of Technology
2013
Abstract
Recognition of hand movements plays a key role in both human computer interaction and rehabilitation activities. This paper focuses on hand pose estimation and motion tracking through a model-based stereo vision-based system. To allow for a complete 3D motion, initially a simple hand model with 20 landmark points was constructed and used to track its motion through a sequence of stereo images. Furthermore, a skeletal model representing the kinematical features of the hand was utilized to provide a meaningful hand motion and gesticulation. To evaluate and eventually recognize the performed hand motion, Kalman filter and Kalman smoother algorithms were implemented to evaluate the efficacy and...
Experimental and numerical study of the effect of pulsating flow on the turbocharger turbine performance parameters
, Article SAE Technical Papers ; Volume 2 , April , 2013 ; Boroomand, M ; Taeibi Rahni, M ; Sharif University of Technology
2013
Abstract
The pulsating flow in the exhaust gas of a SI engine causes an unsteady flow at the inlet to the turbocharger turbine. In a four cylinder four stroke engine, the pulse frequency varies between 20 and 200 Hz. Three dimensional pulsating flows in a vane-less turbocharger turbine of a 1.7 liters SI engine are simulated numerically and validated experimentally. Simulations are done for 720 degree engine cycle at three engine speeds. The results are shown the inlet pulsating flow has significant effects on several turbine parameters especially the inlet total pressure, the reduced mass flow rate and the efficiency. The results show a very good agreement between the three-dimensional unsteady...
An exploratory study on application of various classification models to distinguish switchable-hydrophilicity solvents based on 3D-descriptors
, Article Separation Science and Technology (Philadelphia) ; 2020 ; Shiri, F ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
A set of solvents were classified into the switchable-hydrophilicity solvents (SHSs) and non-switchable-hydrophilicity solvents based on forming or not forming a biphasic mixture with water. SHSs have been developed to make the reaction and product separation processes easier. Herein, three classifier algorithms and various feature selection techniques relay on 3D-molecular descriptors to characterize chemicals and forecast their classes were employed. Cfs-SVM method was employed to perform a classification study. The importance of this study helps to understand more about the presence of hydrophobic groups, their position, and their shape in the molecule. © 2020, © 2020 Taylor & Francis...
An exploratory study on application of various classification models to distinguish switchable-hydrophilicity solvents based on 3D-descriptors
, Article Separation Science and Technology (Philadelphia) ; Volume 56, Issue 5 , 2021 , Pages 961-969 ; 01496395 (ISSN) ; Shiri, F ; Sharif University of Technology
Bellwether Publishing, Ltd
2021
Abstract
A set of solvents were classified into the switchable-hydrophilicity solvents (SHSs) and non-switchable-hydrophilicity solvents based on forming or not forming a biphasic mixture with water. SHSs have been developed to make the reaction and product separation processes easier. Herein, three classifier algorithms and various feature selection techniques relay on 3D-molecular descriptors to characterize chemicals and forecast their classes were employed. Cfs-SVM method was employed to perform a classification study. The importance of this study helps to understand more about the presence of hydrophobic groups, their position, and their shape in the molecule. © 2020 Taylor & Francis Group, LLC
Login to internet websites by next generation game console
, Article 2006 2nd IEEE/IFIP International Conference in Central Asia on Internet, ICI 2006, Tashkent, 19 September 2006 through 21 September 2006 ; 2006 ; 1424405432 (ISBN); 9781424405435 (ISBN) ; Sharif University of Technology
IEEE Computer Society
2006
Abstract
By a great leap, the computer game industry has today reached fame as big as filmmaking industry. Upon introduction of the new generation of game consoles, this industry will witness spectacular progress. One of these next generation consoles is Nintendo console named "Wii". This console has a new game pad which utilizes motion sensors. On the other hand, facilities such as internet connection are added in new consoles and they are not merely for playing. It is observed that placing password for creating usernames by game consoles is difficult. By the use of the specifications of Wii console game pads, a method for user authentication and entering password is proposed in this paper. By using...
Three-dimensional continuous-time integrated guidance and control design using model predictive control
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; 2022 ; 09544100 (ISSN) ; Khankalantary, S ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
In this study, a novel three-dimensional continuous-time integrated guidance and control (IGC) scheme is presented. The proposed method is developed on the basis of generalized model predictive control (GMPC) approach and super-twisting extended state observer (STESO). The GMPC is used to generate the optimal closed form control law for the interceptor and the STESO is applied to estimate the maneuvering target lateral accelerations as well as the lumped disturbances. To the aim of IGC design, a six-degrees-of-freedom model based on the interceptor-target kinematics and interceptor dynamics is constructed. Afterward, the GMPC control law formulation for a nonlinear system exposed to...
A hybrid of statistical and conditional generative adversarial neural network approaches for reconstruction of 3D porous media (ST-CGAN)
, Article Advances in Water Resources ; Volume 158 , 2021 ; 03091708 (ISSN) ; Masihi, M ; Bozorgmehry Boozarjomehry, R ; Blunt, M. J ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
A coupled statistical and conditional generative adversarial neural network is used for 3D reconstruction of both homogeneous and heterogeneous porous media from a single two-dimensional image. A statistical approach feeds the deep network with conditional data, and then the reconstruction is trained on a deep generative network. The conditional nature of the generative model helps in network stability and convergence which has been optimized through a gradient-descent-based optimization method. Moreover, this coupled approach allows the reconstruction of heterogeneous samples, a critical and serious challenge in conventional reconstruction methods. The main contribution of this work is to...
A robust zero-watermark copyright protection scheme based on DWT and image normalization
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 20 November 2011 through 23 November 2011 ; Volume 7088 LNCS, Issue PART 2 , November , 2011 , Pages 359-370 ; 03029743 (ISSN) ; 9783642253454 (ISBN) ; Jamzad, M ; Sharif University of Technology
2011
Abstract
Recently, protecting the copyright of digital media has become an imperative issue due to the growing illegal reproduction and modification of digital media. A large number of digital watermarking algorithms have been proposed to protect the integrity and copyright of images. Traditional watermarking schemes protect image copyright by embedding a watermark in the spatial or frequency domain of an image. However, these methods degrade the quality of the original image in some extend. In recent years, a new approach called zero-watermarking algorithms is introduced. In these methods, the watermark does not require to be embedded into the protected image but is used to generate a verification...
Numerical anaysis of a thermopneumatic micropump
, Article ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels Collocated with 3rd Joint US-European Fluids Engineering Summer Meeting, ICNMM2010, 1 August 2010 through 5 August 2010, Montreal, QC ; 2010 , Pages 1135-1140 ; 9780791854501 (ISBN) ; Shafii, M. B ; Saidi, M. H ; Sharif University of Technology
2010
Abstract
Thermopneumatic micropump is one type of positive displacement micropump, which has many applications due to its relatively large stroke volume, low working voltage, and simple fabrication in microscale. In this paper, a numerical study of heat transfer and fluid flow in a valveless thermopneumatically driven micropump is presented. For rectifying the bidirectional flow, a nozzle and a diffuser are used as the inlet and outlet channels of the chamber. Since the fluid flow is induced by the motion of a diaphragm, the numerical simulation includes fluid structure interaction, which requires applying a dynamic mesh. The domain of solution is divided into two sections; the actuator unit, which...
GPU implementation of split-field finite difference time-domain method for drudelorentz dispersive media
, Article Progress in Electromagnetics Research ; Volume 125 , 2012 , Pages 55-77 ; 10704698 (ISSN) ; Rashidian, B ; Sharif University of Technology
2012
Abstract
Split-field finite-difference time-domain (SF-FDTD) method can overcome the limitation of ordinary FDTD in analyzing periodic structures under oblique incidence. On the other hand, huge run times of 3D SF-FDTD, is practically a major burden in its usage for analysis and design of nanostructures, particularly when having dispersive media. Here, details of parallel implementation of 3D SF-FDTD method for dispersive media, combined with totalfield/ scattered-field (TF/SF) method for injecting oblique plane wave, are discussed. Graphics processing unit (GPU) has been used for this purpose, and very large speed up factors have been achieved. Also a previously reported formulation of SF-FDTD based...
Application-aware deadlock-free oblivious routing based on extended turn-model
, Article IEEE/ACM International Conference on Computer-Aided Design, Digest of Technical Papers, ICCAD, 7 November 2011 through 10 November 2011, San Jose, CA ; 2011 , Pages 213-218 ; 10923152 (ISSN) ; 9781457713989 (ISBN) ; Zolghadr, M ; Arjomand, M ; Sarbazi-Azad, H ; Sharif University of Technology
Abstract
Programmable hardware is gaining popularity as it can keep pace with growing performance demand in tight power budget, design and test cost, and serious reliability concerns of future multiprocessor embedded systems. Compatible with this trend, Network-on-Chip, as a potential bottleneck of future multi-cores, should also support pro-grammability. Here, we address this issue in design and implementation of routing algorithm for two-dimensional mesh. To this end, we allocate paths based on input traffic pattern and in parallel with customizing routing restriction for deadlock freedom. To achieve this, we propose extended turn model (ETM), a novel parametric deadlock-free routing for 2D meshes...
Hybrid CDN-P2P architectures for live video streaming: Comparative study of connected and unconnected meshes
, Article 2011 International Symposium on Computer Networks and Distributed Systems, CNDS 2011, 23 February 2011 through 24 February 2011, Tehran ; 2011 , Pages 175-180 ; 9781424491544 (ISBN) ; Akbari, B ; Sharif University of Technology
2011
Abstract
There are two main scalable methods for streaming live video over the Internet: Content Delivery Networks (CDNs) and Peer-to-Peer (P2P) networks. Though both have their own problems, P2P streaming systems challenge delivering video with constant quality and CDNs approaches require deployment of large number of servers throughout the Internet that is costly. Recently, using hybrid architectures based on both CDN and P2P networks has shown to be an efficient approach for large-scale video distribution over the Internet. This paper is compared the performance of two main hybrid CDN-P2P architectures includes: (i) CDN-P2P unconnected mesh in which independent P2P mesh networks are constructed...
3D reconstruction of non-rigid surfaces from realistic monocular video
, Article 9th Iranian Conference on Machine Vision and Image Processing, 18 November 2015 through 19 November 2015 ; Volume 2016-February , 2015 , Pages 199-202 ; 21666776 (ISSN) ; 9781467385398 (ISBN) ; Kasaei, S ; Sharif University of Technology
IEEE Computer Society
Abstract
A novel algorithm for recovering the 3D shape of deformable objects purely from realistic monocular video is presented in this paper. Unlike traditional non-rigid structure from motion (NRSfM) methods, which have been studied only on synthetic datasets and controlled lab environments that needs some prior constraints (such as manually segmented objects, limited rotations and occlusions, or full-length trajectories), the proposed method has been described and tested on realistic video sequences, which have been downloaded from some social networks (such as Facebook and Twitter). In order to apply NRSfM to the realistic video sequences, because of no-prior information about the scene and...