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Simple lossless and near-lossless medical image compression based on enhanced DPCM transformation
, Article IEEE Pacific RIM Conference on Communications, Computers, and Signal Processing - Proceedings ; 2011 , Pages 66-72 ; 9781457702518 (ISBN) ; Mortazavi, M ; Ghorshi, S ; Choupan, J ; Sharif University of Technology
2011
Abstract
Medical images include information about human body which are used for different purposes such as surgical and diagnostic plans. Compression of medical images is used in some applications such as profiling patient's data and transmission systems. Regard to importance of medical images information, lossless or near-lossless compression is preferred. Lossless JPEG, JPEG-LS and lossless version of JPEG2000 are few well-known methods for lossless compression. JPEG2000 is one of the latest and provides good compression ratio, however, it is complex [1]. In real time application which needs hardware implementation, low complex algorithm accelerates compression process. In this paper, a lossless...
Efficient DPCM predictor for hardware implementation of lossless medical brain CT image compression
, Article International Conference on Signals and Electronic Systems, ICSES'10 - Conference Proceeding, 7 September 2010 through 10 September 2010 ; September , 2010 , Pages 123-126 ; 9788390474342 (ISBN) ; Mortazavi, M ; Ghorshi, S ; Sharif University of Technology
2010
Abstract
Computed Tomography (CT) medical images show a specific part of human body and present it in a digital form. Lossless image compression is one of the medical imaging applications. To implement such application on hardware we need a simple and fast algorithm. Differential pulse code modulation (DPCM) is a simple and efficient method for transforming image. In this paper best predictor for DPCM introduce in a manner in which has the best result in compression and also be efficient for hardware implementation. After transforming image by DPCM, Huffman encoding used to compress image. We introduce this method with application to brain CT images
Efficient medical image transformation method for lossless compression by considering real time applications
, Article 4th International Conference on Signal Processing and Communication Systems, ICSPCS'2010 - Proceedings, 13 December 2010 through 15 December 2010, Gold Coast, QLD ; 2010 ; 9781424479078 (ISBN) ; Mortazavi, M ; Ghorshi, S ; Choupan, J ; Sharif University of Technology
2010
Abstract
Medical images contain human body pictures and used widely in diagnosis and surgical purposes [1]. Compression is needed for medical images for some applications such as profiling patient's data or transmission systems Due to the importance of the information of medical images, lossless or visually lossless compression preferred. Lossless compression mainly consists of transformation and encoding steps. On the other hand, hardware implementation of lossless compression algorithm accelerates real time tasks such as online diagnosis and telemedicine. Lossless JPEG, JPEG-LS and lossless version of JPEG2000 are few well known methods for lossless compression. This paper is focused on the...
Processing Images with Hexagonal Pixels
, M.Sc. Thesis Sharif University of Technology ; Mahdavi Amiri, Nezameddin (Supervisor)
Abstract
Image processing is very important in several applications. Here we use a rectangular grid for image processing. Other approaches exist in the literature. One new approach is to change the grid from rectangular to hexagonal, due to its various advantages over the latter. Main advantage of the hexagonal structure in image processing is its resemblance with the arrangement of photoreceptors in the human eyes. The change in arrangement amounts to requiring less pixels. There is no inconsistency in pixel connectivity and thus angular resolution is higher in this arrangement. Our goal here is to study lossless compression algorithms for images with hexagonal pixels. First, we consider the...
Efficient Hardware Implementation of Lossless Medical Image Compression
, M.Sc. Thesis Sharif University of Technology ; Mortazavi, Mohammad (Supervisor) ; Ghorshi, Mohammad Ali (Co-Advisor)
Abstract
Medical images contain human body pictures and are widely used for diag-nosis and surgical purposes. Compression is needed for medical images for some applications such as profiling a patient's data or transmission systems. Due to the importance of the information of medical images, lossless or visually lossless compression is preferred. Lossless compression mainly consists of transformation and encoding steps. On the other hand, hardware implementation of lossless compression algorithm accelerates real time tasks such as online diagnosis and telemedicine. Lossless JPEG, JPEG-LS and lossless version of JPEG2000 are few well known methods for lossless compression. In this thesis, we introduce...
Ultrawide band negative refraction based on moving media concept
, Article Applied Computational Electromagnetics Society Journal ; Volume 27, Issue 11 , November , 2012 , Pages 931-937 ; 10544887 (ISSN) ; Jafargholi, A ; Sharif University of Technology
2012
Abstract
The anomalous wave propagation in a homogeneous, isotropic and lossless medium that moves with a constant velocity along the axis of a rectangular waveguide; and its interesting properties lead us to the fact that the moving media may be regarded as double negative metamaterial (DNG). In this paper, the correct sign of the permittivity and permeability of an equivalent stationary media, for each TE and TM modes and for both low and high dielectric velocities are investigated and it is shown that this medium acts as a DNG material over specific frequency ranges
Polaritonic frequency-comb generation and breather propagation in a negative-index metamaterial with a cold four-level atomic medium
, Article Physical Review A ; Volume 99, Issue 5 , 2019 ; 24699926 (ISSN) ; Berini, P ; Sanders, B. C ; Sharif University of Technology
American Physical Society
2019
Abstract
We develop a concept for a waveguide that exploits spatial control of nonlinear surface-polaritonic waves. Our scheme includes an optical cavity with four-level N-type atoms in a lossless dielectric placed above a negative-index metamaterial layer. We propose exciting a polaritonic Akhmediev breather at a certain position of the interface between the atomic medium and the metamaterial by modifying laser-field intensities and detunings. Furthermore, we propose generating position-dependent polaritonic frequency combs by engineering widths of the electromagnetically induced transparency window commensurate with the surface-polaritonic modulation instability. Therefore, this waveguide acts as a...
Fast estimation of propagation constants in crossed gratings
, Article Journal of Optics (United Kingdom) ; Volume 22, Issue 2 , 2020 ; Akbari, M ; Nekuee, S. A. H ; Sharif University of Technology
IOP Publishing Ltd
2020
Abstract
Fourier-based modal methods are among the most effective numerical tools for the accurate analysis of crossed gratings. However, leading to computationally expensive eigenvalue equations significantly restricts their applicability, particularly when large truncation orders are required. The resultant eigenvalues are the longitudinal propagation constants of the grating and play a key role in applying the boundary conditions, as well as in the convergence and stability analyses. This paper aims to propose simple techniques for the fast estimation of propagation constants in crossed gratings, predominantly with no need to solve an eigenvalue equation. In particular, we show that for regular...
Binary hybrid GA-PSO based algorithm for compression of hyperspectral data
, Article 5th International Conference on Signal Processing and Telecommunication Systems, ICSPCS'2011, Honolulu, HI, 12 December 2011 through 14 December 2011 ; 2011 ; 9781457711800 (ISBN) ; Sepehrband, F ; Choupan, J ; Mortazavi, M ; Sharif University of Technology
Abstract
This paper introduces two new compression methods. One of these methods is adaptive and powerful for the compression of hyperspectral data, which is based on separating the bands with different specifications by the histogram analyzes and new version of Binary Hybrid GA-PSO (BHGAPSO) and compressing each one with a different manner. The new proposed methods improve the compression ratio of the JPEG standards and save storage space the transmission system. The proposed methods are applied on different test cases, and the results are evaluated and compared with some other compression methods, such as lossless JPEG and JPEG2000
New rectangular partitioning methods for lossless binary image compression
, Article International Conference on Signal Processing Proceedings, ICSP, 24 October 2010 through 28 October 2010 ; 2010 , Pages 694-697 ; 9781424458981 (ISBN) ; Hosseini, H ; Beygiharchegani, S ; Pad, P ; Marvasti, F ; Sharif University of Technology
Abstract
In this paper, we propose two lossless compression techniques that represent a two dimensional Run-length Coding which can achieve high compression ratio. This method works by partitioning the block regions of the input image into rectangles instead of working by runs of adjacent pixels, so it is found to be more efficient than 1D RLE Run-length Coding for transmitting texts and image. In the first method, length and width of consecutive black and white rectangles are transmitted. The idea of this method is new and it can be very effective for some images which have large blocks of black or white pixels. But in the second method only black rectangles are considered in order to transmit and...
An efficient lossless medical image transformation method by improving prediction model
, Article International Conference on Signal Processing Proceedings, ICSP, 24 October 2010 through 28 October 2010 ; 2010 , Pages 728-731 ; 9781424458981 (ISBN) ; Mortazavi, M ; Ghorshi, S ; IEEE Beijing Section; The Chinese Institute of Electronics (CIE); The Institution of Engineering and Technology (IET); Union Radio Scientifique Internationale (URSI); National Natural Science Foundation of China ; Sharif University of Technology
Abstract
Medical images include human body picture and it is used in diagnosis purpose [1]. Lossless compression of medical image is an application of medical imaging. During lossless compression task, transformation algorithm can be used to increase compression ratio. In Real time applications such as telemedicine and online diagnosis, hardware implementation accelerates the process. Hence, for such purposes medical compression is better to be simple. Lossless JPEG and JPEG2000 are some compression method. JPEG2000 gives better compression ratio. However, it is complex. In this paper an efficient method of lossless image transformation has been introduced by improving prediction model. Simulation...
Roi-based 3D human brain magnetic resonance images compression using adaptive mesh design and region-based discrete wavelet transform
, Article International Journal of Wavelets, Multiresolution and Information Processing ; Volume 8, Issue 3 , 2010 , Pages 407-430 ; 02196913 (ISSN) ; Shooshtari, P ; Sharif University of Technology
Abstract
Due to the large volume required for medical images for transmission and archiving purposes, the compression of medical images is known as one of the main concepts of medical image processing. Lossless compression methods have the drawback of a low compression ratio. In contrast, lossy methods have a higher compression ratio and suffer from lower quality of the reconstructed images in the receiver. Recently, some selective compression methods have been proposed in which the main image is divided into two separate regions: Region of Interest (ROI), which should be compressed in a lossless manner, and Region of Background (ROB), which is compressed in a lossy manner with a lower quality. In...
A robust copyright protection scheme based on discrete cosine transform and image normalization
, Article 2011 7th Iranian Conference on Machine Vision and Image Processing, MVIP 2011 - Proceedings ; 2011 ; 9781457715358 (ISBN) ; Jamzad, M ; Sharif University of Technology
2011
Abstract
Watermarking is a way that is used to protect the copyright of images. As the existing watermarking methods are not robust enough a new novel scheme is needed. In this paper, we propose a zero-watermark discrete cosine transformation-based copyright protection scheme, in which a normalization procedure is applied in both watermark embedding and extraction to make our scheme more robust to geometric distortions. This method is resistant to malicious signal processing and geometric attacks such as blurring, JPEG compression, noise adding, sharpening, scaling, rotation and cropping. Experimental results on images with different complexity show that our proposed scheme outperforms related...
On the transmission of correlated sources over relay channels
, Article IEEE International Symposium on Information Theory - Proceedings, 31 July 2011 through 5 August 2011 ; August , 2011 , Pages 1352-1356 ; 21578104 (ISSN) ; 9781457705953 (ISBN) ; Aref, M. R ; Sharif University of Technology
2011
Abstract
In this paper, we consider the reliable transmission of correlated sources over the relay channel. The destination wishes to find a lossless reconstruction of both sources. We find the sufficient conditions under which the relay can partially cooperate with the sender to transmit the sources to the destination. The achievability scheme is based on regular encoding/backward decoding strategy. The proposed region includes the known region for multiple-access channel with correlated sources and the achievable rate of relay channel with partial decode-and-forward strategy, as special cases. A class of deterministic relay channels is considered. It is shown that the error-free transmission of...
Reversible date hiding using multi level integer wavelet decomposition and intelligent coefficient selection
, Article IEEE International Conference onMultimedia and Expo, ICME 2007, Beijing, 2 July 2007 through 5 July 2007 ; August , 2007 , Pages 2130-2133 ; 1424410177 (ISBN); 9781424410170 (ISBN) ; Rabiee, H. R ; Yousefi, E ; Ghanbari, M ; Sharif University of Technology
2007
Abstract
This paper presents a lossless data hiding method using coefficients of integer wavelet domain. The modification of selected small coefficients of the high frequency subbands are used to embed data. We use the histogram modification to intelligently select the proper coefficients for data hiding. Data embedding is done by processing these selected coefficients. We show that at low payload data hiding our method has comparable PSNR than the best known reversible data hiding techniques, while at higher payloads it has significant superiority on image quality. ©2007 IEEE
Simple and efficient remote sensing image transformation for lossless compression
, Article Proceedings of SPIE - The International Society for Optical Engineering ; Volume 8285 , 2011 ; 0277786X (ISSN) ; 9780819489326 (ISBN) ; Ghamisi, P ; Mortazavi, M ; Choupan, J ; Sharif University of Technology
2011
Abstract
Remote Sensing (RS) images or satellite images include information about earth. Compression of RS images is important in the field of satellite transmission systems and mass storage purposes. Because of importance of information and existent of large amount of details, lossless compression preferred. Real time compression technique is applied on satellite and aerial transmission systems [1]. A simple algorithm accelerates the whole process in real time purposes. Lossless JPEG, JPEG-LS and JPEG2000 are some famous lossless compression methods. Transformation is the first step of these methods. In this paper, a simple and efficient method of lossless image transformation has been introduced by...
Optimal sub-graph selection over coded networks with delay and limited-size buffering
, Article IET Communications ; Volume 5, Issue 11 , August , 2011 , Pages 1497-1505 ; 17518628 (ISSN) ; Raayatpanah, M. A ; Khalaj, B. H ; Bakhshi, H ; Sharif University of Technology
2011
Abstract
The authors consider the problem of finding a minimum cost multicast sub-graph based on network coding, where delay values associated with each link, limited buffer-size of the intermediate nodes and link capacity variations over time are taken into account. The authors consider static multicast (where membership of the multicast group remains constant for the duration of the connection) in lossless wireline networks. For such networks, first the continuous-time (asynchronous packet transmissions) model is formulated. Subsequently, the discrete-time model for the synchronous packet transmissions scenario is derived. Then, by using an auxiliary time-expanded network, a decentralised algorithm...
Nonlinear frequency conversions via weak surface polaritonic wave breaking in a hybrid plasmonic waveguide
, Article Optics Letters ; Volume 45, Issue 19 , 2020 , Pages 5432-5435 ; Sanders, B. C ; Sharif University of Technology
OSA - The Optical Society
2020
Abstract
Material design and input field properties limit high-harmonic excitation efficiency of surface-plasmon polaritons (SPPs) in a nanoscopic device. We remedy these limitations by developing a concept for a plasmonic waveguide that exploits spatiotemporal control of a weak surface polaritonic field to create efficient four-wave mixing (FWM) and periodic phase singularities. Our configuration comprises four-level double 3-type atomic medium (43 As) doped in a lossless dielectric situated above a negative-index metamaterial (NIMM) layer. We report the coherent excitation and propagation of the multiple surface polaritonic shock waves (SWs) and establish the highly efficient frequency combs by...
Concept of best energy transfer scenario and a true expression for power factor
, Article IEEE Power and Energy Society 2008 General Meeting: Conversion and Delivery of Electrical Energy in the 21st Century, PES, Pittsburgh, PA, 20 July 2008 through 24 July 2008 ; 2008 ; 9781424419067 (ISBN) ; Khajehoddin, S. A ; Bakhshai, A ; Sharif University of Technology
2008
Abstract
The best energy transfer scenario (BETS) is a situation under which the optimum transfer of power (or energy) from the electric utility to an electric power consumer is achieved. Such a scenario is important because it is used as a reference point to evaluate how efficient the load operates. The index of power factor (PF) is used to quantify such an efficiency. The closer the PF to unity corresponds to more efficient performance of the load. This paper is to show that the conventional definition of the BETS is inadequate and results in an unfair value for the PF unless the transmission line is perfect and lossless (which is an unrealistic condition). The paper also investigates an...
Interaction of quantum dot molecules with multi-mode radiation fields
, Article Scientia Iranica ; Volume 17, Issue 1 D , 2010 , Pages 59-70 ; 10263098 (ISSN) ; Naqavi, A ; Khorasani, S ; Sharif University of Technology
2010
Abstract
In this article, the interaction of an arbitrary number of quantum dots behaving as artificial molecules with different energy levels and a multi-mode electromagnetic field is studied. We make the assumption that each quantum dot can be represented as an atom with zero kinetic energy, and that all excitonic effects except dipole-dipole interactions may be. disregarded. We use the. Jaynes-Cummings-Paul model with applications to quantum systems based on a time-dependent Hamiltonian and entangled states. We obtain a system of equations describing the interaction, and present a method to solve the equations analytically for a single mode fi,eld within the Rotating-Wave Approximation. As an...