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Iranian Machine Vision and Image processing (MVIP)

作者： Mehdi Sajjadi Rassoul Amirfattahi Mohammad Reza Ahmadzadeh Digital Signal Processing Research Laboratory Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran

Brain CT images are extensively used in detection of Cerebrovascular Accidents (CVA). But CT scan is not really a sensitive test for diagnosis of ischemic stroke. Most of the times, early CT images barely show or even don 't show any noticeable sign of ischemia. But it is possible to put emphasis on subtle signs of ischemia by means of image contrast enhancement. Contrast enhancement using multiscale transforms is one of the most popular approaches in recent years. Nonsubsampled Contourlet Transform (NSCT) is a directional multiscale transform that is able to take geometrical structures into account. In this paper we are about to customize this transform and improve its performance in contrast enhancement of brain CT images. To this end, we propose a set of simpler and more efficient filters for Nonsubsampled Pyramid (NSP) and introduce an improved method for modification of directional subbands' coefficients.

关键词： Filter banks Finite impulse response filter Computed tomography Equations Wavelet transforms Image enhancement

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A block-based 2D Discrete Wavelet Transform structure with new scan method for overlapped sections

A block-based 2D Discrete Wavelet Transform structure with n...

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Middle East Conference on Biomedical engineering (MECBME)

作者： Sayed Ahmad Salehi Rasoul Amirfattahi Department of Electrical and Computer Engineering Digital Signal Processing Research Laboratory Isfahan University of Technology Isfahan Iran

Regarding internal memory size, we proposed a new scan method for block-based structure to provide an efficient parametric structure for two Dimensional Discrete Wavelet Transform (2-D DWT). The main challenge in 2-D DWT structure is the amount of internal memory required to produce wavelet coefficients. The previous structures need fixed memory size depend on input frame size, but in proposed architecture, memory size is parametric and in trade off with the number of output memory access. Lifting scheme is incorporated to implement DWT.

关键词： Discrete wavelet transforms Memory management Hardware Pixel

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Context-Aware Scheduling in Wireless Networks with Successive Interference Cancellation

Context-Aware Scheduling in Wireless Networks with Successiv...

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IEEE International Conference on Communications Workshops

作者： Shaohe Lv Weihua Zhuang Xiaodong Wang Xingming Zhou National Laboratory of Parallel and Distributed Processing National University of Defense Technology Department of Electrical and Computer Engineering University of Waterloo

ISBN: (纸本)9781612842325

We consider the greedy scheduling based on the physical model in wireless networks with successive interference cancellation (SIC). There are two major stages in a scheduling scheme, link selection (to decide which link is scheduled next) and time slot selection (to deciding which slot is allocated to a given link). Most available schemes take a first-fit policy in the latter and strive to achieve good performance by careful selection of link ordering with respect to interference. Due to the accumulation effect and sequential detection nature of SIC, however, it is difficult to evaluate the interference of a link. As a result, many existing scheduling schemes become less efficient. In this paper, we take a new look on the problem and focus to the time slot selection stage. We define tolerance margin to measure the saturation of a link set and present two heuristic policies: one is to schedule a link to a slot such that the resulting set of links has a maximum tolerance margin;the other is to choose a slot such that the increase of tolerance margin is minimum. Simulation results show that the performance of the proposed schemes is better than the first-fit policy and is close to the optimal solution.

关键词： Link scheduling Successive interference cancellation Physical interference model

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Evaluation of some physiological statements about seizure, using processing of epileptic EEG signals

Evaluation of some physiological statements about seizure, u...

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Iranian Conference on electrical engineering (ICEE)

作者： F. Shayegh R. Amirfattahi S. Sadri K. Ansari-Asl Digital signal Processing Laboratory Department of Electrical and Computer Engineering Isfahan University of Technology Iran Electrical Department Engineering Faculty Shahid Chamran University of Ahvaz Iran

Seizure genesis is usually attributed to imbalance of the excitation and inhibition activities of neurons. It is claimed that slow inhibition mechanism is responsible for controlling the variations of the excitation mechanism, and any deficiency in this function will lead to disturbance of their natural balance. Fast inhibition mechanism is also known to collaborate with slow inhibitory processes. Any proof about the excitation and inhibition mechanisms refers to the ex-vivo or in-vitro experiments, i.e. from the microscopic point of view. Up to now, there is not a straight road into evaluating these hypotheses from the macroscopic view. In this paper we try to interpret the excitation-inhibition sequences extracted from some depth-EEG signals through an identification-based procedure. The aim is to check out whether the statements gained from microscopic observations are re-established in population of neurons in the case of MTLE or not. Using Neyman-Pearson hypothesis test technique we try to answer these questions. We observe that even in population of neurons slow inhibition is responsible for compensating excitatory processes to balance inhibitory /excitatory ratio, such that when it is impaired causes seizures to arise; also the average fast inhibitory process of population of neurons follows its slow inhibition dynamics. Also, we check the differentiation of the excitation-inhibition ratio between normal and ictal states, as well as between normal and pre-ictal states. Ictal activity is properly a state of abnormal high excitation-inhibition ratio but before beginning of seizures there are not unique patterns.

关键词： Brain modeling Electroencephalography Noise Mathematical model Neurons Cost function Equations

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New image compression algorithm using proposed quantization approach

New image compression algorithm using proposed quantization ...

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International Conference on Pattern Analysis and Intelligent Robotics (ICPAIR)

作者： Seyed Mehdi Moghadas Hossein Pourghasem Rasoul Amirfattahi Department of Electrical Engineering Islamic Azad University Najafabad Iran Digital Signal Processing Research Laboratory Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran

A new quantization method is proposed in this paper. This method is useful for enhancement of compression quality when each kind of neural network is used to compress the image. By quantizing the image with the proposed method, the numbers of samples which must be reconstructed by neural network is reduced. This causes a remarkable increase in quality of the reconstructed image. For testing the proposed method we use autoassociative transform coding and by merging it with the proposed quantization method a new compression algorithm is obtained. Then results of compression by the merged method are compared with some previous works. Obtained results show that the proposed compression algorithm increases the compression quality of the images remarkably. Compression time and complexity in the merged method is also better than JPEG and make it suitable for the systems with low processor and hardware implementation.

关键词： Image coding Biological neural networks Image reconstruction Transform coding Neurons PSNR Training

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Creation of virtual worlds from 3D models retrieved from content aware networks based on sketch and image queries

Creation of virtual worlds from 3D models retrieved from con...

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12th International Workshop on Image Analysis for Multimedia Interactive Services, WIAMIS 2011

作者： Semertzidis, Theodoros McGuinness, Kevin Daras, Petros Makris, Lambros E'Connor, Noel O. Strintzis, Michael G. Information Processing Laboratory Department of Electrical and Computer Engineering Aristotle University of Thessaloniki GR54124 Thessaloniki Greece Informatics and Telematics Institute Centre for Research and Technology Hellas GR57001 Thessaloniki Greece CLARITY: Center for Sensor Web Technology Dublin City University Glasnevin Dublin 9 Ireland

The recent emergence of user generated content requires new content creation tools that will be both easy to learn and easy to use. These new tools should enable the user to construct new high-quality content with minimum effort;it is essential to allow existing multimedia content to be reused as building blocks when creating new content. In this work we present a new tool for automatically constructing virtual worlds with minimum user intervention. Users can create these worlds by drawing a simple sketch, or by using interactively segmented 2D objects from larger images. The system receives as a query the sketch or the segmented image, and uses it to find similar 3D models that are stored in a Content Centric Network. The user selects a suitable model from the retrieved models, and the system uses it to automatically construct a virtual 3D world.

关键词： Virtual reality

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Analysis of Fast Ionization Wave discharge propagation in a rectangular geometry

Analysis of Fast Ionization Wave discharge propagation in a ...

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42nd AIAA plasmadynamics and Lasers Conference 2011

作者： Takashima, Keisuke Adamovich, Igor V. Xiong, Zhongmin Kushner, Mark J. Starikovskaia, Svetlana Czarnetzki, Uwe Luggenhölscher, Dirk Department of Mechanical and Aerospace Engineering The Ohio State University Columbus OH 43021 United States Department of Mechanical and Aerospace Engineering The Ohio State University Columbus OH 43210 United States Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI 48109 United States Michigan Institute for Plasma Science and Engineering Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI 48109 United States Ecole Polytechnique Laboratory for Physics and Technology of Plasmas 91128 Palaiseau Cedex France Department of Physics and Astronomy Ruhr University Bochum 44780 Bochum Germany

ISBN: (纸本)9781624101472

Fast Ionization Wave (FIW), nanosecond pulse discharge propagation in nitrogen and helium in a rectangular geometry channel / waveguide is studied experimentally using calibrated capacitive probe measurements. The repetitive nanosecond pulse discharge in the channel was generated using a custom designed pulsed plasma generator (peak voltage 10-40 kV, pulse duration 30-100 nsec, voltage rise time ~1 kV/nsec), generating a sequence of alternating polarity high-voltage pulses at a pulse repetition rate of 20 Hz. Both negative polarity and positive polarity ionization waves have been studied. Ionization wave speed, as well as time-resolved potential distributions and axial electric field distributions in the propagating discharge are inferred from the capacitive probe data. ICCD images show that at the present conditions the FIW discharge in helium is diffuse and volume-filling, while in nitrogen the discharge propagates along the walls of the channel. FIW discharge propagation has been analyzed numerically using quasi-one-dimensional and two-dimensional kinetic models in a hydrodynamic (drift-diffusion), local ionization approximation. The wave speed and the electric field distribution in the wave front predicted by the model are in good agreement with the experimental results. A self-similar analytic solution of the fast ionization wave propagation equations has also been obtained. The analytic model of the FIW discharge predicts key ionization wave parameters, such as wave speed, peak electric field in the front, potential difference across the wave, and electron density as functions of the waveform on the high voltage electrode, in good agreement with the numerical calculations and the experimental results. © 2011 by Igor V. Adamovich. Published by the American Institute of Aeronautics and Astronautics, Inc.

关键词： Nitrogen

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Separation of ion and photon damage effects on novel dielectric materials during plasma exposure

Separation of ion and photon damage effects on novel dielect...

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IEEE International Conference on plasma Science (ICOPS)

作者： H. Ren G.A. Antonelli Y. Nishi J.L. Shohet Plasma Processing & Technology Laboratory and Department 0/ Electrical and Computer Engineering University of Wisconsin Madison Madison WI USA Novellus Systems Inc. Albany NY USA University of Stanford Stanford CA USA

Summary form only given. Damage induced in high and low-k thin dielectric films by exposure to an electron cyclotron resonance (ECR) plasma was investigated. The effects of charged-particle bombardment and vacuum ultraviolet radiation were separated by varying plasma parameters and using a capillary-array window. Damage was measured by examining the surface potential, defect concentrations, chemical and physical structures after plasma exposure. For high-k dielectric films (HfO 2 ), most of the charge accumulation came from the ion fluence, while photon fluence introduced most of the defect-state modifications. It was further shown that, during plasma exposure, UV photons penetrate through the dielectric layer and cause modifications of the defect states. Based on the results, optimized conditions were found to minimize both charge accumulation and defect state formation during plasma exposure. For low-k porous organosilicate glass (SiCOH) dielectric films, it was found that during argon ECR plasma processing, 75% of the charge accumulation comes from ions at the surface, while 25% of the charge accumulation occurs from charge trapped within the bulk of the dielectric film due to photon bombardment. Fourier transform infrared spectroscopy (FTIR) results showed no significant change except for the physical Si-(CH 3 ) X bonds. The results were verified by ellipsometric measurements. It was shown that both the dielectric thickness and the dielectric constant changed during plasma exposure.

关键词： Dielectric materials Photonics plasmas

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The texture classification using the fusion of decisions from different texture classifiers

The texture classification using the fusion of decisions fro...

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International Conference on electrical engineering/Electronics, computer, Telecommunications and Information technology, ECTI-CON

作者： S. Pharsook T. Kasetkasem P. Larmsrichan S. Siddhichai T. Chanwimaluang T. Isshiki Department of Electrical Engineering Kasetsart University Thailand Image Processing Laboratory National Electronics and Computer Technology Center Thailand Department of Communication and Integrated Systems Tokyo Institue of Technology Japan

The improved of texture classification accuracy by using the probability weighted combination method of three texture features extraction consist of thE0020 Gray-Level Co-occurrence Matrix (GLCM), Semivariogram Function and Gaussian Markov Random Fields (GMRFs). Five different textures images are used in the experiment. The classifier that use for classify the extracted features in this research is Support Vector Machines (SVMs). The experimental result shows that the average accuracy of the combination method with probability weight up to 95.71%, which is better than the simple combination method about 2%.

关键词： Markov processes Tutorials Entropy Arrays Sensors

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Towards energy saving and load balancing data aggregation for wireless sensor networks

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Information technology Journal 2011年第2期10卷 409-415页

作者： Liang, Wei Xu, Jianbo Liu, Yuanyuan Key Laboratory of Knowledge Processing and Networked Manufacturing School of Computer Science and Engineering Hunan University of Science and Technology Xiangtan 411201 China Department of Electrical Engineering Guangdong Songshan Polytechnic College Shaoguang 512126 China

In this study, we focus on the development of energy efficient and achievable load balancing mechanisms for wireless sensor networks. Due to resource constraint and tremendous amount of sensors, one possible way of achieving maximum lifetime of the network is applying data aggregation on sensor data. However, existing approaches introduce significant computation and control overheads that often not suitable for sensor networks applications. In view of this, we propose an in-network data aggregation scheme by exploiting the inherent spatial correlation of the sensed data. Each sensor multiplies its reading with a random coefficient and sends the product to the next hop to calculate a weighted sum of all the massage. Instead of receiving individual sensor readings, the sink will receive all weighted sum and restore the original data. By doing so, each node only performs one addition and one multiplication in order to compute one weighted sum and consume the same amount of energy. Simulation results demonstrate that the proposed scheme is efficient and outperforms existing schemes in terms of energy gain and network lifetime. © 2011 Asian Network for Scientific Information.

关键词： Energy efficiency

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