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Design and Implementation of Amplitude Detection Method for Millimeter Wave Imaging
, M.Sc. Thesis Sharif University of Technology ; Khavasi, Amin (Supervisor) ; Fakharzadeh, Mohammad (Co-Supervisor)
Abstract
Conventional imaging systems composed of two linear arrays of antennas as a transmitter and receiver. These arrays of antennas electronically scan along their antenna elements and are mechanically moved along a second orthogonal direction for scanning large two-dimensional areas quickly. In this thesis, the transmitter antenna elements are Tapered slot-line Antenna operating at 20-30GHz. A multiplexer circuit is used to transmit wideband signals to each antenna in the array. The receiver is composed of Schottky diode and pick up antenna that they are printed onto the radiating end of the antennas on the edge of the transmitter circuit board.In the available imaging systems, for achieving the...
Image Processing Using Calculus of Variations and PDEs Tools
, M.Sc. Thesis Sharif University of Technology ; Fotouhi, Morteza (Supervisor)
Abstract
The aim of this thesis is to investigate recent methods for Image Processing(Any signal process which it’s input is an image and it’s ouput is an image or a set of Image parameters) using Calculus of variation tools. Methods which are to be investigated has been divided into two well known parts of Image Processing : Image Restoration and Image Segmentation.Image Processing Chapter includes two sections: one calculus of variations methods(energy method), other methods based on PDEs(heat equation and Malik-Perona equation). In studing each of this methods, It has been tried to include experimental results and negative and positive points of them.In Image Segmentation Chapter, first...
Numerical Electromagnetic Simulation of Millimeter Wave Imaging System and Comparison to Experimental Results
, M.Sc. Thesis Sharif University of Technology ; Khavasi, Amin (Supervisor)
Abstract
Millimeter wave imaging systems have unique features and have been used extensively in a variety of applications including medical imaging, construction operations, places with high security such as airports, Nondestructive testing and etc. These systems provide high resolution, due to the order of wavelength which is several millimeter or centimeter in this band. Also in places with high security and for detecting the concealed objects under people’s clothing, these waves can easily pass through the materials and investigate the person’s body without causing health problems. A wide variety of these imaging systems , each with different design parameters and resolutions, have been proposed....
Elimination of Signal Distortion Using Generative Adversarial Network
, M.Sc. Thesis Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor) ; Pour Mohammad Namvar, Mehrzad (Supervisor)
Abstract
Nowadays millions of images are shared on social media every day , So image inpainting has become an important issue . After advent of Generative adversarial network image inpainting methodes based on deep learning has been revived and significant progress has been made . For a proper image inpainting , The inpainted image must benefit from the appropriate structure and texture in the missing regions . Therefore, in this project , an attempt is made to use a two-stage structure by using Generative adversarial network .in first stage first by using Gabor filters , the image structure is extracted and then the image structure is completed , while the second stage focuses only on the...
Compressed sensing and multiple image fusion: An information theoretic approach
, Article Iranian Conference on Machine Vision and Image Processing, MVIP ; 2013 , Pages 339-342 ; 21666776 (ISSN) ; 9781467361842 (ISBN) ; Mashhadi, S ; Engineers (IEEE) Antennas and Propagation Society; The Institute of Electrical and Electronics ; Sharif University of Technology
IEEE Computer Society
2013
Abstract
In this paper, we propose an information theoretic approach to fuse images compressed by compressed sensing (CS) techniques. The goal is to fuse multiple compressed images directly using measurements and reconstruct the final image only once. Since the reconstruction is the most expensive step, it would be a more economic method than separate reconstruction of each image. The proposed scheme is based on calculating the result using weighted average on the measurements of the inputs, where weights are calculated by information theoretic functions. The simulation results show that the final images produced by our method have higher quality than those produced by traditional methods, especially...
A fast bottom-up approach toward three-dimensional human pose estimation using an array of cameras
, Article Optics and Lasers in Engineering ; Volume 95 , 2017 , Pages 69-77 ; 01438166 (ISSN) ; Kavehvash, Z ; Mehrany, K ; Tayaranian Hosseini, S. M. A ; Sharif University of Technology
Abstract
In this paper, employing recorded images of multiple cameras, we propose a novel fast approach for three-dimensional (3D) human pose reconstruction. Opening a new framework to the pose estimation application, the proposed method is inspired by optical 3D reconstruction algorithms conventionally used for integral imaging. Thanks to the fact that the pose estimation can be carried out by using only key features of the raw recorded images, the computation time and the complexity of our method are considerably reduced. Furthermore, utilizing the here proposed algorithm, rapid variations in actions can be easily tracked. The validity of the proposed method is demonstrated by several experimental...
Fast iterative reconstruction algorithm for microwave-induced thermoacoustic imaging
, Article 12th IEEE Biomedical Circuits and Systems Conference, BioCAS 2016, 17 October 2016 through 19 October 2016 ; 2017 , Pages 1-4 ; 9781509029594 (ISBN) ; Allahgholizadeh Haghi, B ; Aliroteh, M. S ; Fallahpour, M ; Arbabian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
In this paper we propose a fast iterative reconstruction algorithm for microwave-induced thermoacoustic (TA) imaging. Instead of calculating the forward and back projections in real time, we construct a library of the impulse responses of individual pixels in advance. During reconstruction, only covariance calculations are performed to reconstruct the intensity of each pixel. In addition, we propose to use a Wiener filter based-deconvolution to accelerate convergence, enabling even single iteration construction in some scenarios. We validate the proposed method both with simulations as well as experiments. Compared to the time reversal method, the proposed fast iterative reconstruction...
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,...
Contributive representation-based reconstruction for online 3d action recognition
, Article International Journal of Pattern Recognition and Artificial Intelligence ; 2020 ; Mohammadzade, H ; Sharif University of Technology
World Scientific
2020
Abstract
Recent years have seen an increasing trend in developing 3D action recognition methods. However, despite the advances, existing models still suffer from some major drawbacks including the lack of any provision for recognizing action sequences with some missing frames. This significantly hampers the applicability of these methods for online scenarios, where only an initial part of sequences are already provided. In this paper, we introduce a novel sequence-to-sequence representation-based algorithm in which a query sample is characterized using a collaborative frame representation of all the training sequences. This way, an optimal classifier is tailored for the existing frames of each query...
Multiple sclerosis diagnosis based on analysis of subbands of 2-D wavelet transform applied on MR-images
, Article 2007 IEEE/ACS International Conference on Computer Systems and Applications, AICCSA 2007, Amman, 13 May 2007 through 16 May 2007 ; 2007 , Pages 717-721 ; 1424410312 (ISBN); 9781424410316 (ISBN) ; Moradzadeh, H ; Vaziri, R ; Dehestani Ardekani, R ; Fatemizadeh, E ; Sharif University of Technology
2007
Abstract
In this study, we have proposed a novel approach to investigate the features of four subbands of 2-D wavelet transform in magnetic resonance images (MRIs) for normal and abnormal brains which defected by Multiple Sclerosis (MS). Concurrently, another method extracts different kinds of features in spatial domain. Totally, 116 features have been extracted. Before applying the algorithm, we have to use a registration method because of variety in size of brain images. All extracted features have been passed over the Principal Component Analysis (PCA) and have been pushed to an Artificial Neural Network (ANN) that is a feed-forward type. According to changing in position of defected parts of...
Motion blur identification in noisy images using mathematical models and statistical measures
, Article Pattern Recognition ; Volume 40, Issue 7 , 2007 , Pages 1946-1957 ; 00313203 (ISSN) ; Jamzad, M ; Sharif University of Technology
2007
Abstract
Motion blur is one of the most common blurs that degrades images. Restoration of such images is highly dependent on estimation of motion blur parameters. Since 1976, many researchers have developed algorithms to estimate linear motion blur parameters. These algorithms are different in their performance, time complexity, precision and robustness in noisy environments. In this paper, we have presented a novel algorithm to estimate linear motion blur parameters such as direction and length. We used Radon transform to find direction and bispectrum modeling to find the length of motion. Our algorithm is based on the combination of spatial and frequency domain analysis. The great benefit of our...
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) ; Jamzad, M ; Sharif University of Technology
2007
Abstract
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...
Half-pixel accuracy block matching motion estimation algorithms for low bitrate video communications
, Article First IEEE and IFIP International Conference in Central Asia on Internet, 2005, Bishkek, 26 September 2005 through 28 September 2005 ; Volume 2005 , 2005 ; 0780391799 (ISBN); 9780780391796 (ISBN) ; Kasaei, S ; Sharif University of Technology
2005
Abstract
Motion estimation at fractional-pixel accuracy results in higher quality video sequences. However, the higher quality is achieved by more computations and increased required motion field bitrates. In this paper, new half-pixel accuracy block matching-based motion estimation algorithms are proposed to improve the rate-distortion characteristics of low-bitrate video communications. The proposed methods especially tend to decrease the required video bandwidth, with no degradation in quality of reconstructed image sequences. The key idea is to put a deeper focus on the origin (zero motion) based on the center-bias characteristics of low bitrate video motion fields. The experimental results show...
An iterative approach for reconstruction of arbitrary sparsely sampled magnetic resonance images
, Article 18th IEEE Symposium on Computer-Based Medical Systems, Dublin, Ireland, 23 June 2005 through 24 June 2005 ; 2005 , Pages 27-32 ; 10637125 (ISSN) ; Soleymani, M ; Hossein Zadeh, G. A ; Sharif University of Technology
2005
Abstract
In many fast MR imaging techniques, K-space is sampled sparsely in order to gain a fast traverse of K-space. These techniques use non-Cartesian sampling trajectories like radial, zigzag, and spiral. In the reconstruction procedure, usually interpolation methods are used to obtain missing samples on a regular grid. In this paper, we propose an iterative method for image reconstruction which uses the black marginal area of the image. The proposed iterative solution offers a great enhancement in the quality of the reconstructed image in comparison with conventional algorithms like zero filling and neural network. This method is applied on MRI data and its improved performance over other methods...
Unsupervised, fast and efficient colour-image copy protection
, Article IEE Proceedings: Communications ; Volume 152, Issue 5 , 2005 , Pages 605-616 ; 13502425 (ISSN) ; Kasaei, S ; Sharif University of Technology
2005
Abstract
The ubiquity of broadband digital communications and mass storage in modern society has stimulated the widespread acceptance of digital media. However, easy access to royalty-free digital media has also resulted in a reduced perception in society of the intellectual value of digital media and has promoted unauthorised duplication practices. To detect and discourage the unauthorised duplication of media, researchers have investigated watermarking methods to embed ownership data into media. However, some authorities have expressed doubt over the efficacy of watermarking methods to protect digital media. The paper introduces a novel method to discourage unauthorised duplication of digital...
Omni-stereo vision system for an autonomous robot using neural networks
, Article Canadian Conference on Electrical and Computer Engineering 2005, Saskatoon, SK, 1 May 2005 through 4 May 2005 ; Volume 2005 , 2005 , Pages 1590-1593 ; 08407789 (ISSN) ; Jamzad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2005
Abstract
Autonomous robots' vision is one the most important parts in their navigation system and omni-directional stereo vision is an approach to improve this module. Conventional cameras have restricted field of view while omni-directional cameras provide 360-degree field of view. Depth information obtained from stereo vision is very useful for robot navigation in complex environments. This paper presents an omni-directional stereo vision system for Arvand robots constructed by Sharif CE Middle size RoboCup team. We have used two catadioptric cameras aligned vertically. To compute depth, we have used a neural network. In our approach, we trained the neural network without unwrapping the images and...
Multi-Scale Porous Media Reconstruction Using Intelligent Methods
, M.Sc. Thesis Sharif University of Technology ; Masihi, Mohsen (Supervisor) ; Bozorgmehry Boozarjomehry, Ramin (Supervisor) ; Blunt, Martin (Co-Supervisor)
Abstract
Digital analysis of reservoir rocks prepares a powerful tool in the field of porous media studies and provides appropriate information of single / multiphase flows by performing numerical simulations on porous media images. In order to access the necessary tools to benefit from digital rock analysis and characterization, we need accessing the porous media images, the geometric distribution and the spatial distribution of pores and grains through imaging or reconstruction methods. Porous media reconstruction methods are known as an alternative to imaging techniques. In addition, reconstruction methods have the ability to fix problems and imperfections associated with imaging, such as...
Practical design of low-cost instrumentation for industrial electrical impedance tomography (EIT)
, Article ; 2012 IEEE I2MTC - International Instrumentation and Measurement Technology Conference, Proceedings, 13 May 2012 through 16 May 2012, Graz , 2012 , Pages 1259-1263 ; 9781457717710 (ISBN) ; Vosoughi Vahdat, B ; Mortazavi, M ; Hy, W ; Soleimani, M ; Sharif University of Technology
IEEE
2012
Abstract
Electrical Impedance Tomography (EIT), is one of the medical imaging technologies. It can also be used in industrial process monitoring. In this method, the image of the electrical conductivity distribution of the inner part of a conductive subject can be reconstructed. The image reconstruction process is done by injecting an accurate current into the boundary of a conductive subject (e.g. body), measuring the voltages around the boundary and transmitting them to a computer, and processing on acquired data with a software (e.g., MATLAB). The images are obtained from the peripheral data by using an algorithm. Precise EIT instrumentation plays an important role in the final images quality. In...
Reconstruction of tomographic medical images using Kalman filter approach
, Article Proceedings of the 2011 International Conference on Image Processing, Computer Vision, and Pattern Recognition, IPCV 2011, 18 July 2011 through 21 July 2011 ; Volume 1 , July , 2011 , Pages 236-240 ; 9781601321916 (ISBN) ; Ghorshi, S ; Mortazavi, M ; Sharif University of Technology
2011
Abstract
Medical images contain information about vital organic tissues inside of human body and are widely used for diagnoses of disease or for surgical purposes. Image reconstruction is essential for medical images for some applications such as suppression of noise or de-blurring the image to provide images with better quality and contrast. In this paper Kalman filter technique is introduced for medical image reconstruction. This technique is operated in time domain unlike the filtered back projection which operates in frequency domain. Results indicated that as the number of projection increases in both the collected ray sum corrupted by noise and by blurring the quality of reconstructed image...
A Kalman filter technique applied for medical image reconstruction
, Article International Multi-Conference on Systems, Signals and Devices, SSD'11 - Summary Proceedings, 22 March 2011 through 25 March 2011, Sousse ; 2011 ; 9781457704130 (ISBN) ; Ghorshi, S ; Manzuri, M. T ; Mortazavi, M ; Sharif University of Technology
2011
Abstract
Medical images contain information about vital organic tissues inside of human body and are widely used for diagnoses of disease or for surgical purposes. Due to vital rule of image reconstruction in medical sciences the corresponding algorithms with better efficiency and higher speed is desirable. Most algorithms in image reconstruction are operated on frequency domain such as filtered back projection. In this paper, a Kalman filter technique which is operated in time domain is introduced for reconstruction of CT medical images. Results indicated that as the number of projection increases in both normal collected ray sum and the collected ray sum corrupted by noise the quality of...