IOSR Journal of VLSI and Signal Processing (IOSR-JVSP)

Current Issue Vol2-Issue6

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Paper Type : Research Paper
Title : A Survey of Image Segmentation Algorithms Based on Expectation-Maximization
Country : India
Authors : R. Ravindraiah, K. Tejaswini
: 10.9790/4200-0260107      logo

ABSTRACT:Medical image segmentation plays an important role in one of the most challenging fields of engineering. Imaging modality provides detailed information about anatomy. It is also helpful in the finding of the disease and its progressive treatment. More research and work on it has enhanced more effectiveness as far as the subject is concerned. Different methods are used for medical image segmentation such as Clustering methods, Thresholding method, Classifier, Region Growing, Deformable Model, Markov Random Model etc. The main purpose of this survey is to provide a comprehensive reference source for the researchers involved in Expectation-Maximization based medical image processing. There are different types of Expectation-Maximization algorithms for medical image. Their advantages and disadvantages are discussed.

Keywords: Image segmentation, Medical Image Processing, Expectation-Maximization

[1] SANJAY-GOPAL, S. and HEBERT, T.J.: 'Bayesian pixel classification using spatially variant finite mixtures and the Generalized EM algorithm', IEEE Trans. Image Proc., 1998, 7, pp.1014-1028

[2] HAKER, S., SAPIRO, G. and TANNENBAUM, A.: 'Knowledge-based segmentation of SAR data with learned priors', IEEE Trans. Image Proc., 2000, 9, pp.299-301

[3] G. Boccignone, M. Ferraro, An Information-theoretic Approach to Interactions in Images, Spatial Vision 12 (1999) 345-362.

[4] S. Sanjay-Gopal, T.J. Hebert, Bayesian pixel classification using spatially variant finite mixtures and the generalized EM algorithm, IEEE Trans. Image Proc. 7 (1998) 1014-1028.

[5] Y. Zhang, M. Brady, and S. Smith, Segmentation of Brain MR Images Through a Hidden Markov Random Field Model and the Expectation-Maximization Algorithm, IEEE Transactions on Medical Imaging 20(1) (2001) 45-57.

[6] S. Haker, G. Sapiro, A. Tannenbaum, Knowledge-based segmentation of SAR data with learned priors, IEEE Trans Image Proc. 9 (2000) 299-301.

[7] D.J.C. MacKay, Information Theory, Inference, and Learning Algorithms, Cambridge University Press, UK, 2003.

[8] L. Xu, M. Jackowski, A. Goshtasby, D. Roseman, S. Bines ,C. Yu, A. Dhawan, A. Huntley, Segmentation of skin cancer images, Image and Vision Computing 17(1999) 65-74.

[9] Dempster, A.P.—Laird, N.M.—Rubin, D.B.: Maximum-Likelihood from Incomplete Data Via the EM Algorithm. J.Roy. Statist. Soc., Vol. B39, 1077, pp. 1–38.

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Paper Type : Research Paper
Title : Auditory-Tactile Interaction Using Digital Signal Processing In Musical Instruments
Country : India
Authors : Parul Chauhan
: 10.9790/4200-0260813      logo

ABSTRACT:This paper lays emphasis on research that gives an insight to the auditory-tactile perception in electronic musical instruments (here, electronic violin) stating that most traditional musical instruments inherently convey tactile feedback to the performer along with the auditory feedback which leads to a tight performer-instrument relationship which is not found in electronic musical instruments. Hence, introducing the phenomenon of coupled perception of sound and vibration using digital signal processing in order to facilitate better auditory perception in electronic instruments. Thus the main objective of study is Audio-Driven Vibration Feedback for auditory perception by the violinists in an Electronic Violin. The expected results of the research project ((here electronic violin) are supposed to be claimed beneficial for introducing the phenomenon of coupled perception of sound and vibration in order to facilitate better auditory perception in electronic instruments.

Keywords: Amplitude modulation, Audio-Driven Vibration Feedback , Digital Signal Processing, Octave Shift, Vibrotactile.

[1] Mark T. Marshall, Marcelo M. Wanderley (Input Devices and Musical Interaction Laboratory McGill University - Music Technology), "Vibrotactile Feedback in Digital Musical Instruments" in proceedings of the 2006 International Conference on New Interfaces for Musical Expression (NIME06), Paris, France.

[2] Mark T. Marshall, Marcelo M. Wanderley "Examining the Effects of Embedded Vibrotactile Feedback on the Feel of a Digital Musical Instrument", Input Devices and Music Interaction Laboratory Centre for Interdisciplinary Research in Music Media and Technology McGill University – Montreal, QC, Canada

[3] M. E. Altinsoy, "Auditory-Tactile Interaction in Virtual Environments" (PhD Thesis, Shaker Verlag) (2006). N. Armstrong. "An Enactive Approach to Digital Musical Instrument Design." PhD thesis, Princeton University, Nov. 2006.

[4] M. E. Altinsoy, "Auditory-Tactile Interaction in Virtual Environments" (PhD Thesis, Shaker Verlag) (2006).

[5] Wollmana, C. Fritza and J. Frelatb, " Vibrotactile feedback in the left hand of violinists", in proceedings of the Acoustics 2012 Nantes Conference 23-27 April 2012, Nantes, France 3605.

[6] Sebastian Merchel and M. Ercan Altinsoy "Vibration in Music Perception" Presented the Audio Engineering Society, 134th Convention 2013 May 4-7, Rome, Italy

[7] Joseph Malloch, "Adding vibrotactile feedback to the T-stick digital musical instrument" Input Devices and Music Interaction Laboratory Centre for Interdisciplinary Research in Music Media and Technology McGill University – Montreal, QC, Canada

[8] Sebastian Merchel, M. Ercan Altinsoy and Maik Stamm, "Touch the Sound: Audio-Driven Tactile Feedback for Audio Mixing Applications", Chair of Communication Acoustics, Dresden University of Technology, Germany

[9] C. Chafe." Tactile audio feedback." In Proceedings of the 1993 International Computer Music Conference (ICMC93), pages 76 79, 1993.Journal / Conference Papers.

[10] D. Birnbaum and M. M.Wanderley. "A systematic approach to musical vibrotactile feedback." In Proceedings of the International Computer Music Conference '07 (ICMC'07), volume 2, page 397, Copenhagen, Denmark, 2007.

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Paper Type : Research Paper
Title : Design of RNS Converters for moduli sets with Dynamic Ranges up to 6n-bit
Country : India
Authors : Shubham Kaushik, Ashish Srivastava
: 10.9790/4200-0261419      logo

ABSTRACT: The RNS has been considered as an interesting area for researchers in recent year. This paper presents memoryless and area efficient RNS converters for moduli set with dynamic ranges up to 6n-bit. Residue number system (RNS) has mainly targeted parallelism and larger dynamic ranges. In this paper, we start from the moduli sets {2n, 2n - 1, 2n + 1, 2n – 2(n+1)/2 + 1, 2n + 2(n+1)/2 + 1} with dynamic range of 5n-bit and propose vertical extension in order to improve the parallelism and increase the dynamic range. The vertical extension increase the value of the power of 2 modulus in the five-moduli set. The Chinese remainder theorem is applied in this paper to derive an efficient reverse converter. This paper also proposed a conventional binary to RNS representation called RNS Forward conversion. The RNS forward converter is more efficient in terms of area, delay and power. Synthesis results suggest that the proposed vertical extension in RNS reverse converter allow reducing the area-delay product in comparison with the related state-of-the-art.

Keywords- Chinese Remainder theorem, Forward converter, Residue Number system, Reverse converter

[1] Hector Pettenghi and Leonel Sousa. "RNS Reverse Converters for Moduli Sets with Dynamic Ranges up to (8n+1)."Member, IEEE, Ricardo Chaves, Member, IEEE, Senior v Member, IEEE
[2] A. Hiasat, "VLSI implementation of new arithmetic residue to binary decoders," IEEE Trans. Very Large Scale Integr. (VLSI) Syst., vol. 13, no. 1, pp. 153–158, Jan. 2005.
[3] P. Mohan, "RNS-to-binary converter for a new three-moduli set," IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 54, no. 9, pp. 775–779, Sep. 2007.
[4] Hariri,K.Navi, and R. Rastegar, "A newhigh dynamic range moduli set with efficient reverse converter," Trans. Comput. Math. Appl., pp. 660–668, Apr. 2008.
[5] Omar Abdelfattah, "Data Conversion in Residue Number System." Department of Electrical Computer Engineering McGill University Montreal, Canada January 2011.
[6] A. Skavantzos and M. Abdallah, "Implementation issues of the two level residue number system with pairs of conjugate moduli," IEEE Trans. Signal Process. vol. 47, no. 3, pp. 826–838, Mar. 1999.
[7] A. Skavantzos and Y. Wang, "New efficient RNS-to-weighted decoders for conjugate-pair moduli residue number systems," in Proc.33rd Asilomar Conf. Signals, Systems, Comput., 1999, vol. 2, pp. 1345–1350.
[8] A. Skavantzos, "An efficient residue to weighted converter for a new residue number system," in proc. Great Lakes Symp. VLSI, 1998, pp. 185-191.
[9] J. Sorenson, "Two fast GCD algorithms," Trans.J.Algor., vol. 16, no. 1, pp. 110-144, Jan. 1994.
[10] H. Pettenghi, R. Chaves, and L. Sousa, "Multiplicative Inverses for Moduli Sets with Dynamic Ranges of 5n+β-bit," INESC-ID Tec. Rep., no. 15/2012, May 2012 [Online]. Available:

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Paper Type : Research Paper
Title : High Performances Block Matching Algorithms for Motion Estimation
Country : China
Authors : Moussa Bellal, Belloulata Kamel, Shiping Zhu
: 10.9790/4200-0262028      logo

ABSTRACT: This paper is a review of the block matching algorithms used for motion estimation in video compression. It implements and compares 8 different types of block matching algorithms that range from the very basic Exhaustive Search to the recent fast adaptive algorithms like Adaptive Rood Pattern Search. The algorithms that are evaluated in this paper are widely accepted by the video compressing community and have been used in implementing various standards, ranging from MPEG1 / H.261 to MPEG4 / H.263. The paper also presents a very brief introduction to the entire flow of video compression.

Index Terms: Block matching, Estimation / motion compensation and disparity, H.264/MPEG-4 AVC.

[1] Aroh Barjatya,Block Matching Algorithms For Motion Estimation,Student Member, IEEE, DIP 6620 Spring 2004 Final Project Paper.

[2] Renxiang Li, Bing Zeng, and Ming L. Liou, "A New Three-Step Search Algorithm for Block Motion Estimation", IEEE Trans. Circuits And Systems For Video Technology, vol 4., no. 4, pp. 438-442, August 1994.

[3] Jianhua Lu, and Ming L. Liou, "A Simple and Efficent Search Algorithm for Block-Matching Motion Estimation", IEEE Trans. Circuits And Systems For Video Technology, vol 7, no. 2, pp. 429-433, April 1997

[4] Lai-Man Po, and Wing-Chung Ma, "A Novel Four-Step Search Algorithm for Fast Block Motion Estimation", IEEE Trans. Circuits And Systems For Video Technology, vol 6, no. 3, pp. 313-317, June 1996.

[5] Shan Zhu, and Kai-Kuang Ma, " A New Diamond Search Algorithm for Fast Block-Matching Motion Estimation", IEEE Trans. Image Processing, vol 9, no. 2, pp. 287-290, February 2000.

[6] Ce Zhu, Xiao Lin, and Lap-Pui Chau, "Hexagon Search Pattern for Fast Block-Matching Motion Estimation", IEEE Trans. On circuit and systems for video technology, vol 12, no. 5, pp. 349-355, May 2000.

[7] Yao Nie, and Kai-Kuang Ma, "Adaptive Rood Pattern Search for Fast Block-Matching Motion Estimation", IEEE Trans. Image Processing, vol 11, no. 12, pp. 1442-1448, December 2002.

[8] Chun-Ho Cheung, and Lai-Man Po, "A Novel Small Cross-Diamond Search Algorithm for Fast Video Coding and Video Conferencing Applications", Proc. IEEE ICIP, September 2002.

[9] Shiping Zhu, Jun Tian, Xiaodong Shen, and Kamel, "A novel cross-hexagon search algorithm based on motion vector field prediction," in Proceedings of the IEEE International Symposium on Industrial Electronics, (ISIE '09), pp. 1870–1874, Seoul, Korea, July 2009.

[10] C Shiping Zhu, Jun Tian, Xiaodong Shen, and Kamel Belloulata, "A New Cross-Diamond Search Algorithm for Fast Block Matching Motion Estimation", in Proceedings of the IEEE International Conference on Image Processing (ICIP '09), vol. 1, pp. 1581–1584, Cairo, Egypt, November 2009.

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Paper Type : Research Paper
Title : Area-Power Efficient Multi Staged Pipelined CORDIC Using Micro-Rotation Selection
Country : India
Authors : Mahendra Kumar M. D., Sunil M. P.
: 10.9790/4200-0262936      logo

ABSTRACT: CORDIC is an acronym for COrdinate Rotation Digital Computer. The CORDIC method is the most versatile of all the algorithms that can be used to evaluate elementary functions. It has established its popularity in several important areas of application, like generation of sine and cosine functions, calculation of discrete sinusoidal transforms like fast Fourier transform (FFT), discrete sine/cosine transforms (DST/DCT), householder transform (HT), etc. CORDIC algorithm, on the other hand, offers an excellent alternative, and its best characteristic is flexibility. Its quantization accuracy is a function of word length. Hardware implementation of CORDIC results increase in Critical path delay. Pipelined architecture is used in CORDIC to increase the clock speed and to reduce the Critical path delay, it is multiplier less approach and it saves a lot of hardware and hence power dissipation is very low as compared to other methods. Due to the simplicity of the involved operations, the CORDIC algorithm is very well suited for VLSI implementation. In this paper, a multi stage pipelined CORDIC architecture is compared and used for designing a flexible and scalable digital sine and cosine waves generator. The design of an application specific CORDIC processor in circular rotation mode give a high system throughput due to pipelined architecture by reducing latency in the each individual pipelined stages. Saving area on FPGA is essential to the design of pipelined CORDIC and can be achieved through optimizing the number of micro rotations. An FPGA-based architecture is presented the design has been implemented on a Xilinx Spartan 3 (xc3s200) device. Synthesis and implementation results are shown and also we use Most-significant-1 bit detection technique for micro-rotation sequence generation to reduce the number of iteration.

Keywords: Co-ordinate rotation digital computer (CORDIC), cosine/sine, Fast fourier transform (FFT), Discrete sine/cosine transforms (DST/DCT), Householder transform (HT), Most-significant-1, Field programmable gate array (FPGA).

[1] J. E. Volder, "The CORDIC trigonometric computing technique," IRE Trans. Electron. Comput., vol. EC-8, pp. 330–334, Sep. 1959. [2] J.S Walther. "A Unified Algorithm for Elementary Functions", AIFS Spring Joint Computer Conference, pp.375-385, 1971.

[3] Supriya Aggarwal, Pramod K. Meher, and Kavita khare, IEEE transactions on" very large scale integration (vlsi) systems", vol. 20, no. 8, august 2012

[4] P. K. Meher, J.Walls, T.-B. Juang, K. Sridharan, and K. Maharatna, "50years of CORDIC: Algorithms, architectures and applications," IEEETrans. Circuits Syst. I, Reg. Papers, vol. 56, no. 9, pp. 1893–1907, Sep.2009. [5] C.-S.Wu, A.-Y.Wu, and C.-H. Lin, "A high-performance/low-latency vector rotational CORDIC architecture based on extended elementary angle set and trellis-based searching schemes," IEEE Trans. Circuits Syst. II, Analog Digit. Signal Process, vol. 50, no. 9, pp. 589–601, Sep.2003.

[6] M. G. B. Sumanasena, "A scale factor correction scheme for the CORDIC algorithm," IEEE Trans. Comput., vol. 57, no. 8, pp.1148–1152, Aug. 2008.

[7] J. Villalba, T. Lang, and E. L. Zapata, "Parallel compensation of scale factor for the CORDIC algorithm," J. VLSI Signal Process. Syst., vol.19, no. 3, pp. 227–241, Aug. 1998.

[8] L. Vachhani, K. Sridharan, and P. K. Meher, "Efficient CORDIC algorithms and architectures for low area and high throughput implementation,"IEEE Trans. Circuit Syst. II, Exp. Briefs, vol. 56, no. 1, pp. 61–65,Jan. 2009.

[9] K. Maharatna, S. Banerjee, E. Grass, M. Krstic, and A. Troya, "Modified virtually scaling-free adaptive CORDIC rotator algorithm and architecture,"IEEE Trans. Circuits Syst. Video Technol., vol. 11, no. 11,pp. 1463–1474, Nov. 2005.

[10] F. J. Jaime, M. A. Sanchez, J. Hormigo, J. Villalba, and E. L. Zapata,"Enhanced scaling-free CORDIC," IEEE Trans. Circuits Syst. I, Reg.Papers, vol. 57, no. 7, pp. 1654–1662, Jul. 2010.

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Paper Type : Research Paper
Title : Pattern of Cervical Smear Cytology in Calabar, Nigeria,
Country : Nigeria
Authors : Odusolu P. O., Omotoso A. J., Nnoli M., Agan T. U., Bassey I. E., Ekanem I. A., Ekanem A. D.
: 10.9790/4200-0263741      logo

ABSTRACT: Background: Cancer of the cervix is the most common cancer of the female genital tract and accounts for about two hundred and fifty thousand deaths yearly. Most of these occur in the developing countries mainly Africa, because of poverty, lack of awareness, and absence of organised population based screening programmes which has greatly reduced the incidence in the developed world. Objective: The study is aimed at determining the pattern of cervical cytology of smears received in the Department of Pathology, University of Calabar Teaching Hospital, Calabar. Method: A retrospective study of all cervical smears received and processed at the Department of Pathology, University of Calabar Teaching Hospital, Calabar between January 2001 and December 2010.Those with inadequate data were excluded from the study. Classification was by the Bethesda system and analysis was by simple statistical methods. Results: During the study period, 98.3% of the 848 cervical smears received were satisfactory for analysis. Six hundred and ninety eight (83.7%) were negative smears while (16.3% )were abnormal, 2.6% of the abnormal samples were frankly malignant (invasive cancer), while 6.5% and 5.4% were high grade squamous intraepithelial lesions (HGSIL) and low grade squamous intraepithelial lesions (LGSIL) respectively. Conclusion: There is an urgent need for increase awareness for cervical cancer and population screening programmes should be encouraged to reduce the prevalence of cancer of the cervix in our population.

[1]. Adebamowo C.A, Ajayi O.O, Breast cancer in Nigeria. West Afr J Med 2000;19:179- 194
[2]. Madong BM, Madaka AKJ, Mannaseh AN. Malignant disease in Jos: a follow up. Ann Afr Med 2003;2:48-53
[3]. Adefuye PO. Knowledge and practice of cervical screening among professional health workers in a suburban district in Nigeria. Nigerian Medical Practitioner 2006;50:19-22
[4]. Bassey EA, Ekpo MD, Abasiasia A. 2007. Female genital tract malignancies in Uyo, South- South, Nigeria. Nigerian Postgraduate Medical Journal 14:134–136.
[5]. Adewuyi SA, Shittu SO, Rafindadi AH. 2008. Sociodemographic and clinicopathologic characterization of cervical cancers in northern Nigeria. European Journal of Gynaecological Oncology 29:61–64.
[6]. Shafi MI. 2007. Premalignant and Malignant disease of the cervix. In: Edmonds DK, editor. Dewhurst's textbook of obstetrics and gynaecology. 7th ed. Oxford: Blackwell Publishing. P 614–624.
[7]. Jimoh AS, Abdul IF. A review of one hundred and three (103) histologically confirmed cases of carcinoma of the cervix at the University of Ilorin Teaching Hospital, Nigeria. Nigerian Medical Practitioner 2004;45: 55-60
[8]. Durosinmi-Etti FA. Cancer patients in Nigeria: causes of delay in diagnosis and treatment. Nigerian Quarterly Journal of Hospital Medicine 1985;3:28-30
[9]. Audu B.M, Elnafaty A.U, Pindiga H.U; Sporadic screening in a gynaecological clinic; Nig Med Pract. Vol51, No 6, 2007. (114 - 118)
[10]. Ayre J.E (1954). A simple office test for uterine cancer diagnosis. Can Med Ass J; 53:17 – 22.

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Paper Type : Research Paper
Title : Histopathological analysis of appendectomy specimens in Calabar, south –southern Nigeria
Country : Nigeria
Authors : A. J. Omotoso, M. A. Nnoli, IE Bassey, A. O. Akintomide, O. E. Ngim, I. A. Ekanem
: 10.9790/4200-0264246      logo

ABSTRACT: Background: Appendectomy is one of the commonest surgical intervention worldwide with a very high incidence in Nigeria. The various histologic patterns of these lesions are diverse with little information about this in this part of the country. Aim: To analyse various histologic pattern of appendectomy specimens received in University of Calabar teaching Hospital. Materials and Methods: This is an eleven year (1999-2009) retrospective study involving review of the histologic records of all patients with gastrointestinal lesions received in the Department of Pathology, UCTH. The patients' biodata and histologic diagnosis were retrieved. Analysis was done using simple statistical operation. Results: We found that 46.2% of all the gastrointestinal lesions were appendectomy specimens: Out of these, 44.7% were acute appendicitis with or without complications while 7.8% belong with appendix specimens that either had no pathology or were autolysed and the remaining 48% show either reactive lymphoid hyperplasia or appendix with chronic inflammatory response. There was no neoplasia or carcinoid found among the lesions. Furthermore, we found a male to female incidence of 1: 1.45 for the acute appendicitis, with the mean age being 35 and 31years old for males and females. In our series, the youngest patient was 6months old while the oldest was 73.

Conclusion: Appendectomy specimen is the commonest gastrointestinal lesion received in Histopathology Department of UCTH, Calabar. Appendicitis remains commoner among the females than the males. Significant number of these patients had lymphoid hyperplasia.

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[9]. Tauro LF, Premanand TS, Aithala PS, George C, Suresh HB et al Ultrasonography is still a useful diagnostic tool in acute appendicitis, Jounal of Clinical and diagnostic research 2009; 3;5: 1731-1736
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[13]. Iribhogbe P., Omorogiuwa I. Acute Appendicitis In Young Children-A Diagnostic Challenge JMBR: A Peer-review Journal of Biomedical Sciences 2006; 5 (2)40-43
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Paper Type : Research Paper
Title : Hardware implementation of Modified Decision Based Unsymmetric Trimmed Median Filter (MDBUTMF)
Country : India
Authors : Lakshmi Darsi, G. Vara Lakshmi
: 10.9790/4200-0264751      logo

ABSTRACT: For the restoration of images (gray scale or color images) contaminated by the high density salt and pepper noise, an efficient filter(MDBUTMF) scheme is used. In this noise pixel is replaced with mean/median of the element of window. Compared to existing system the MDBUTMF gives results better than the existing one. For different gray scale and color images processed using MDBUTMF. It gives reduced MSE and better PSNR than existing system

Keywords: Impulse noise, Median filter, Salt and Pepper noise, Unsymmetrical trimmed median filter

[1] J. Astola and P. Kuosmaneen, Fundamentals of Nonlinear Digital Filtering. Boca Raton, FL: CRC, 1997.

[2] H. Hwang and R. A. Hadded, "Adaptive median filter: New algorithms and results," IEEE Trans. Image Process., vol. 4, no. 4, pp. 499–502, Apr. 1995.

[3] S. Zhang and M. A. Karim, "A new impulse detector for switching median filters," IEEE Signal Process. Lett., vol. 9, no. 11, pp. 360–363, Nov. 2002.

[4] P. E. Ng and K. K. Ma, "A switching median filter with boundary discriminative noise detection for extremely corrupted images," IEEE Trans. Image Process., vol. 15, no. 6, pp. 1506–1516, Jun. 2006.

[5] K. S. Srinivasan and D. Ebenezer, "A new fast and efficient decision based algorithm for removal of high density impulse noise," IEEE Signal Process. Lett., vol. 14, no. 3, pp. 189–192, Mar. 2007.

[6] V. Jayaraj and D. Ebenezer, "A new switching-based median filtering scheme and algorithmfor removal of high-density salt and pepper noise in image," EURASIP J. Adv. Signal Process., 2010.

[7] K. Aiswarya, V. Jayaraj, and D. Ebenezer, "A new and efficient algorithm for the removal of high density salt and pepper noise in images and videos," in Second Int. Conf. Computer Modeling and Simulation,2010, pp. 409–413

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Paper Type : Research Paper
Title : Mathematical Modeling of Ultrasonic Phased Array for Obstacle Location for Visually Impaired
Country : India
Authors : Ashwini Naik, Dr. M. S. Panse
: 10.9790/4200-0265256      logo

ABSTRACT: Ultrasonic beam steering characteristics of phased array transducer is mathematically modeled to detect and locate the obstacle for the visually impaired. The main purpose of Beam steering is to steer the beam at a given angle to investigate the object along the beam direction. The effects of various transducer parameters on beam steering properties are studied and optimal phased array is simulated. The device is constructed using 40 KHz practically available ultrasonic sensors of 16mm dimension. The main objective in designing is to minimize the main lobe width, to eliminate the grating lobes and to suppress the side lobes. In this paper the geometric parameters such as, number of elements, inter-element spacing, steering angle and array aperture are considered and transducer array is mathematically analyzed. The radiation pattern of the results is shown by the polar plots. These polar plots are simulated using LabVIEW (Laboratory virtual instrument engineering workbench) developed by National Instrument, is a graphical Programming environment suited for high-level or system level design. Advantage of this approach is the flexibility and very rapid development time offered by this graphical programming software.

Keywords: Grating lobes, LabVIEW, Radiation pattern, Ultrasonic Phased array

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[2] Shi-Chang Wooh and Yijun Shi. : A Simulation Study of the Beam Steering Characteristics for Linear Phased Arrays: Journal of Non-destructive Evaluation, 18(2 ), pp 39-57,1999.

[3] Alfred Hanssen, Wavefields, in Simon Haykin, 1(Wiley 2010), Handbook on Array Processing and Sensor Networks, 5-30.
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[5] J.Huang, P.W.Que, and J.H.Jin, A Parametric study of Beam steering for ultrasonic linear phased array transducer, Russian Journal of Nondestructive Testing, 40(4), pp254-259,2004.

[6] C.A. Balanis, Antenna Theory: Analysis and Design, (John Wiley and Sons, NewYork, 1997).
[7] Sevan Harput, Ayhan Bozkurt, Ultrasonic Phased Array Device for Acoustic Imaging in Air, IEEE Sensors Journal, l 8(11), pp 1755-1762,2008.