Informatics Publishing Limited

J. Nithya ¹, M. Madheswaran ²

Affiliations
1 Department of Information Technology, K. S. Rangasamy College of Technology, IN
2 Department of Electronics and Communication Engineering, Mahendra Engineering College, IN

Abstract

The random speckle noise in the acquired fetal ultrasound images is caused by the interference of reflected ultrasound wave fronts. The presence of speckle noise will degrade the quality of the image and even hide image details, which in turn affect the process of image segmentation, feature extraction and recognition and most importantly disease diagnosis. The standardization of measurements from the fetal ultrasound images will help the physicians to make correct diagnosis. The accuracy of diagnosis is possible only when the image is noise free. Hence it is very much important to perform filtering of the speckle noise. It is proposed that curvelet transform serves as a better edge preserving filter compared to other speckle reducing anisotropic diffusion filters. Curvelet transform is designed to handle images which involve curves using only a less number of coefficients. Hence a multiscale representation called curvelet transform is applied to enhance the visual quality of the ultrasound images. The experimented results indicate that the proposed curvelet denoising suppresses the noise effectively both in quantitative and visual means by producing high PSNR.

Keywords

Speckle Noise, Despeckling, Curvelet Transform, Anisotropic Diffusion.

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M. Madheswaran ¹, V. Jayaprakasan ²

Affiliations
1 Centre for Advanced Research, Department of Electronics and Communication, Mahendra Engineering College, IN
2 Department of Electronics and Communication, Jawaharlal Nehru Technological University, IN

Abstract

This paper briefs an implementation of different CIC filter architectures for decimation. The different decimation filter structures are implemented using cascaded integrator-comb filter to work for the down sampling ratio of 8. The prototype is designed with MATLAB Simulink model and it is converted to VHDL code using Xilinx system generator. Prototype is implemented in Virtex VXC5VLX110T- 3ff1136 FPGA kit and simulation results and device utilization reports are generated and tabulated. Finally different architectures are compared using number of used LUTs, Registers, Power consumption etc.

Keywords

FPGA – Field Programmable Gate Arrays, SRC - Sampling Rate Conversion, DDC – Digital Down Converter, CIC - Cascaded Integrator Comb Filter.

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M. Madheswaran ¹, K. R. Kavitha ²

Affiliations
1 Mahendra Engineering College, IN
2 Department of Electronics and Communication Engineering, Sona College of Technology, IN

Abstract

The theoretical estimation of dark and illumination characteristics of InGaAs quantum dot photo detector is developed and presented in this paper. The exact potential and energy profile of the Quantum Dot is computed by obtaining the solution of 3D Poisson and Schrodinger equations using Homotopy analysis. The dark current, photo current, responsivity, detectivity and efficiency of the model are calculated by considering the structural parameters Quantum Dot density, applied voltage, length of quantum dot array, number of quantum dot array, light intensity and temperature. The results obtained show that the dark current and photo current are strongly influenced by Quantum Dot density and applied voltage. The developed model is purely physics based one and overcomes the limitations of the existing analytical models. The model is validated by comparing the results obtained with the existing models.

Keywords

Quantum Dots, Poisson Equation, Homotopy Analysis, Dark Current, Photo Current.

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M. Madheswaran ¹, R. N. Shanmugasundaram ²

Affiliations
1 Centre for Advanced Research, Department of Electronics and Communication Engineering, Mahendra Engineering College, IN
2 Department of Electronics and Communication Engineering, Vidyaa Vikas College of Engineering and Technology, IN

Abstract

Low Energy Adaptive Clustering Hierarchy (LEACH) protocol is the first hierarchical cluster based routing protocol successfully used in the Wireless Sensor Networks (WSN). In this paper, various enhancements used in the original LEACH protocol are examined. The basic operations, advantages and limitations of the modified LEACH algorithms are compared to identify the research issues to be solved and to give the suggestions for the future proposed routing algorithms of wireless networks based on LEACH routing algorithm.

Keywords

LEACH, Modified LEACH, Hierarchical Cluster Based Routing, Wireless Sensor Networks (WSN).

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M. Madheswaran ¹, P. Suresh Kumar ¹

Affiliations
1 Center for Advanced Research, Department of Electronics and Communication Engineering, Muthayammal Engineering College, IN

Abstract

Modern fighter aircrafts, ships, missiles etc need to be very low Radar Cross Section (RCS) designs, to avoid detection by hostile radars. Hence accurate prediction of RCS of complex objects like aircrafts is essential to meet this requirement. A simple and efficient numerical procedure for treating problems of wide band RCS prediction Perfect Electric Conductor (PEC) objects is developed using Method of Moment (MoM). Implementation of MoM for prediction of RCS involves solving Electric Field Integral Equation (EFIE) for electric current using the vector and scalar potential solutions, which satisfy the boundary condition that the tangential electric field at the boundary of the PEC body is zero. For numerical purposes, the objects are modeled using planar triangular surfaces patches. Set of special sub-domain type basis functions are defined on pairs of adjacent triangular patches. These basis functions yield a current representation free of line or point charges at sub-domain boundaries. Once the current distribution is obtained, dipole model is used to find Scattering field in free space. RCS can be calculated from the scattered and incident fields. Numerical results for a square plate, a cube, and a sphere are presented over a bandwidth.

Keywords

Dipole Model, Method of Moment (MoM), Perfectly Electric Conductor (PEC), Radar Cross Section (RCS), Triangular Patch Model.

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M. Madheswaran ¹, C. Venkatesh ¹

Affiliations
1 Centre for Advanced Research, Department of Electronics and Communication Engineering, Muthayammal Engineering College, IN

Abstract

Ultra wideband (UWB) communication is mainly used for short range of communication in wireless personal area networks. Orthogonal Frequency Division Multiplexing (OFDM) is being used as a key physical layer technology for Fourth Generation (4G) wireless communication. OFDM based communication gives high spectral efficiency and mitigates Inter-symbol Interference (ISI) in a wireless medium. In this paper the IEEE 802.15.3a based Multiband OFDM (MB OFDM) system is considered. The pilot based channel estimation techniques are considered to analyze the performance of MB OFDM systems over Liner Time Invariant (LTI) Channel models. In this paper, pilot based Least Square (LS) and Least Minimum Mean Square Error (LMMSE) channel estimation technique has been considered for UWB OFDM system. In the proposed method, the estimated Channel Impulse Responses (CIRs) are filtered in the time domain for the consideration of the channel delay spread. Also the performance of proposed system has been analyzed for different modulation techniques for various pilot density patterns.

Keywords

UWB, OFDM, Least Square, Wireless Channel, Least Minimum Mean Square.

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D. Sasikala ¹, M. Madheswaran ²

Affiliations
1 Department of Electronics and Communication Engineering, Vivekanandha College of Engineering for Women, IN
2 Mahendra Engineering College, IN

Abstract

Speckle is modeled as a signal dependent noise, which tends to reduce the image resolution and contrast, thereby reducing the diagnostic values of the ultrasound imaging modality. Reduction of speckle noise is one of the most important processes to increase the quality of biomedical images. Filters are used to improve the quality of ultrasound images by removing the noise. This paper compares the performance of the thresholding technique Bayes Shrink in despeckling the medical ultrasound images with other classical speckle reduction filters like Lee, Frost, Median, Kaun, Wavelet Bayes, Anisotropic diffusion and Wavelet. The performance of these filters is analyzed by the statistical measures such as Peak Signal-to Noise Ratio, Mean Square Error and Equivalent Number of Looks. To produce a better quality resolution picture, the filter should have high Peak Signal to Noise Ratio, low Mean Square Error, high Equivalent Number of Looks. The results obtained are presented in the form of filtered images, statistical tables and graphs. Finally, the best filter has been recommended based on the statistical and experimental results. From the results obtained Lee and Frost filter outperforms the other mentioned filters in terms of high PSNR and low MSE for high variance of noise where as anisotropic diffusion filter outperforms with high PSNR and low MSE with maximum ENL for low variance values of noise.

Keywords

Speckle Noise, Image Denoising, Wavelet Thresholding, Filters.

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M. Madheswaran ¹, S. Jerald Jeba Kumar ²

Affiliations
1 Center for Advanced Research, Muthayammal Engineering College, IN
2 Department of Electronics and Communication Engineering, The Rajaas Engineering College, IN

Abstract

An improved Computer Aided Clinical Decision Support System has been developed for grading the retinal images using neural network and presented in this paper. Hard exudates, Cotton wool spots, large plaque hard exudates, Microaneurysms and Hemorrhages have been extracted. SVM classifiers have been used for classification. Further rule based classifiers have been used to grade the retinal images. The percentages of sensitivity, specificity have been found for both bright lesions and dark lesions. The accuracy of the proposed method is capable of detecting the bright and dark lesions sharply with an average accuracy of 98.19% and 97.51% respectively.

Keywords

Bright Lesion, Dark Lesion, Hard Exudates, Cotton Wool Spots, LPHE, Microaneurysms, Hemorrhages, SVM, Diabetic Retinopathy (DR), Non Proliferative Diabetic Retinopathy (NPDR).

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M. Madheswaran ¹, S. Saravanan ¹

Affiliations
1 Centre for Advanced Research, Department of Electronics and Communication Engineering, Muthayammal Engineering College, IN

Abstract

The design of low power high performance Multiply and Accumulate (MAC) unit is presented in this paper. The power analysis for MAC unit is carried out for image filtering application exploiting insignificant bits in pixel values. The developed technique is found to reduce dynamic power consumption by analyzing the bit patterns in the input data which reduces the switching activities. The power consumption of the developed multiplier is compared with existing multiplier techniques and found that is performs better. It is observed from the simulation using SYNOPSIS EDA tool that the proposed pixel properties reusability technique saves power up to 88% with small area over head when used in MAC unit.

Keywords

Low Power, VLSI Design, Booth Multiplier, MAC.

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M. Madheswaran ¹, M. Muruganandam ¹

Affiliations
1 Centre for Advanced Research, Muthayammal Engineering College, IN

Abstract

The closed loop control of PMDC drive with an inner current controller and an outer PID-ANN (Proportional Integral Derivative - Artificial Neural Network) based speed controller is designed and presented in this paper. Motor is fed by DC / DC buck converter (DC Chopper). The controller is used to change the duty cycle of the converter and thereby, the voltage fed to the PMDC motor to regulate the speed. The PID-ANN controller designed was evaluated by computer simulation and it was implemented using an 8051 based embedded system. This system will operate in forward motoring with variable speed.

Keywords

PMDC Motor, ANN Controller, DC Chopper, Embedded System, MATLAB Simulink.

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