Ahmad Reza Naghsh Nilchi

Work place: Department of Artificial Intelligence and Multimedia Engineering, University of Isfahan, Iran

E-mail: nilchi@eng.ui.ac.ir

Website:

Research Interests: Data Structures, Data Structures and Algorithms, Data Compression, Data Mining, Medical Image Computing, Image Processing, Image Manipulation

Biography

Ahmad R. Naghsh Nilchi, PhD, received his B.S. and M.S., and PhD degrees from Electrical and Computer Engineering Department in 1988, 1989, and 1996, respectively, all from the University of Utah, Salt Lake City, Utah, USA. He is an Associate Professor of Computer Engineering with the University of Isfahan, Iran, and was the Chairman of the Computer Engineering department for three terms and now is the Chairman of the Artificial Intelligence and Multimedia Engineering at the same institution. He has been awarded several research grants from distinguished research institutions including U.S. National Science Foundation and has completed a number of research projects for Iranian industries. He is the author and co-author of several journal articles and conference papers. In addition, he has collaborated with internationally known institutions and peers, and was a Research Scholar with the National University of Ireland, Mynooth, Ireland, in 2011, and with the University of California, Irvine, in 2012. He also is the chief editor of the Journal of Computing and Security. His research interests include medical image and signal processing, data hiding, as well as intensive computing. He was listed in Who’s Who in the World in 2011.

Author Articles
Speech Emotion Recognition based on SVM as Both Feature Selector and Classifier

By Amirreza Shirani Ahmad Reza Naghsh Nilchi

DOI: https://doi.org/10.5815/ijigsp.2016.04.05, Pub. Date: 8 Apr. 2016

The aim of this paper is to utilize Support Vector Machine (SVM) as feature selection and classification techniques for audio signals to identify human emotional states. One of the major bottlenecks of common speech emotion recognition techniques is to use a huge number of features per utterance which could significantly slow down the learning process, and it might cause the problem known as "the curse of dimensionality". Consequently, to ease this challenge this paper aims to achieve high accuracy system with a minimum set of features. The proposed model uses two methods, namely "SVM features selection" and the common "Correlation-based Feature Subset Selection (CFS)" for the feature dimensions reduction part. In addition, two different classifiers, one Support Vector Machine and the other Neural Network are separately adopted to identify the six emotional states of anger, disgust, fear, happiness, sadness and neutral. The method has been verified using Persian (Persian ESD) and German (EMO-DB) emotional speech databases, which yield high recognition rates in both databases. The results show that SVM feature selection method provides better emotional speech-recognition performance compared to CFS and baseline feature set. Moreover, the new system is able to achieve a recognition rate of (99.44%) on the Persian ESD and (87.21%) on Berlin Emotion Database for speaker-dependent classification. Besides, promising result (76.12%) is obtained for speaker-independent classification case; which is among the best-known accuracies reported on the mentioned database relative to its little number of features. 

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Automatic Speech Segmentation Based On Audio and Optical Flow Visual Classification

By Behnam Torabi Ahmad Reza Naghsh Nilchi

DOI: https://doi.org/10.5815/ijigsp.2014.11.06, Pub. Date: 8 Oct. 2014

Automatic speech segmentation as an important part of speech recognition system (ASR) is highly noise dependent. Noise is made by changes in the communication channel, background, level of speaking etc. In recent years, many researchers have proposed noise cancelation techniques and have added visual features from speaker’s face to reduce the effect of noise on ASR systems. Removing noise from audio signals depends on the type of the noise; so it cannot be used as a general solution. Adding visual features improve this lack of efficiency, but advanced methods of this type need manual extraction of visual features. In this paper we propose a completely automatic system which uses optical flow vectors from speaker’s image sequence to obtain visual features. Then, Hidden Markov Models are trained to segment audio signals from image sequences and audio features based on extracted optical flow. The developed segmentation system based on such method acts totally automatic and become more robust to noise.

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Block Texture Pattern Detection Based on Smoothness and Complexity of Neighborhood Pixels

By Amir Farhad Nilizadeh Ahmad Reza Naghsh Nilchi

DOI: https://doi.org/10.5815/ijigsp.2014.05.01, Pub. Date: 8 Apr. 2014

In this paper, a novel method for detecting Block Texture Patterns (BTP), based on two measures: smoothness and complexity of neighborhood pixels is proposed. With these two measures, a new classification for texture detection is defined. Texture detection with these measures can be used in many image processing and computer vision applications. As an example, the applicability of BTP on data hiding algorithms is discussed, and the advantages of this classification on these algorithms are shown.

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Steganography on RGB Images Based on a “Matrix Pattern” using Random Blocks

By Amir Farhad Nilizadeh Ahmad Reza Naghsh Nilchi

DOI: https://doi.org/10.5815/ijmecs.2013.04.02, Pub. Date: 8 Apr. 2013

In this paper, we describe a novel spatial domain method for steganography in RGB images where a secret message is embedded in the blue layer of certain blocks. In this algorithm, each block first chooses a unique t1xt2 matrix of pixels as a “matrix pattern” for each keyboard character, using the bit difference of neighbourhood pixels. Next, a secret message is embedded in the remaining part of the block, those without any role in the “matrix pattern” selection procedure. In this procedure, each pattern sums up with the blue layer of the image. For increasing the security, blocks are chosen randomly using a random generator. The results show that this algorithm is highly resistant against the frequency and spatial domain attacks including RS, Sample pair, X2 and DCT based attacks. In addition, the proposed algorithm could provide more than 84.26 times of capacity comparing with a competitive method. Moreover, the results indicated that stego-image has almost 1.73 times better transparency than the competitive algorithm.

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