Informatics Publishing Limited

M. Tamilarasi ¹, C. Manishekar ¹, N. Ramakrishnan ¹, K. Ashok ¹

Affiliations
1 Dept.of ECE, Pondicherry Engineering College, Puducherry, IN

Abstract

A modem modulates outgoing digital signals from a computer or other digital device to analog signals and demodulates the incoming analog signal and converts it to a digital signal for the digital device. Almost all the modems implemented on field programmable gate array (FPGA) concentrate only on the modulation and demodulation part. They do not take into account the processes involved before modulation at the transmitting end and the processes involved after the demodulation at the receiving end. This paper aims at implementing and testing a programmable modulation scheme using SpartanXC3S500E FPGA. The modulation scheme adopted in this paper/work is quadrature phase shift keying (QPSK). A modem is implemented on the FPGA to test the modulation scheme and a reduced instruction set computing processor (RISC) is used to program the modem. The feature of this implementation is the realization of a complete communication system which considers all the features right from packet formation to modulation at the transmitting end to the recovery and error free reconstruction of the transmitted message at the receiving end.

Keywords

FPGA, Modem, QPSK Modulation RISC Processor.

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K. Sivakumar ¹, M. Tamilarasi ²

Affiliations
1 Tata Consultancy Services, Chennai-603103, IN
2 Pondicherry Engineering College, Pondy-605014, IN

Abstract

Increased system capacity, improved coverage and services to different mobility users assumed importance with the tremendous increase in the number of mobile communication users. Adoption of hierarchical cellular system (HCS) is a way to address these issues. Though HCS has the efficiency to provide cells of different radius and treating the subscribers of higher and lower mobility separately, the disadvantage is that it increases the number of handoffs which in turn increases the processing overhead. In order to reduce the number of handoffs, the hysteresis concept based on the velocity of the mobile user is taken into account by us in this paper. The inclusion of hysteresis concept, allows the mobile user to roam in the same cell if its velocity changes back within a set threshold values. From the simulation results, it is observed that the number of handoffs is reduced considerably in the hysteresis introduced handoff scheme compared with that of conventional scheme. The percentage of microcell overlay in macro cell region is also examined.

Keywords

Handoff, Hierarchical Cellular System, Hysteresis, Microcell, Macrocell.

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S. Batmavady ¹, M. Tamilarasi ², K. Manivannan ³, D. N. V. Sukesh ³

Affiliations
1 Department of ECE, Pondicherry Engineering College, Pillaichavady, Puducherry, IN
2 Dept. of ECE, Pondicherry Engineering College, Pillaichavady, Puducherry, IN
3 Pondicherry Engineering College, IN

Abstract

Image fusion techniques are applied in various fields such as remote sensing, medical imaging, concealed weapon detection, etc. Combining two or more images of the same scene usually produces an output image which provides increased interpretation capabilities and reliable results. In image fusion, data with different specifications such as resolution, spectral and spatial coordinates are combined. Image fusion algorithm can be categorized into pixel and feature levels. Region based method is one way of achieving the feature- level fusion. Segmentation plays a vital role in this fusion process where the features of the source images are extracted first using Edge based segmentation Consequently, the Contourlet transform is applied on the different regions and the coefficients from different regions are merged separately. Finally, the fused image is obtained by performing inverse Contourlet transform. The Laplacian pyramid employed in Contourlet transform is not the perfect transform from the point of view of image fusion, since it involves down-sampling procedure which makes it shift variant. Therefore, in order to yield better performance metric in the proposed work, the Contourlet transform is modified by replacing the Laplacian pyramid by Contrast pyramid. Region based image fusion using modified Contourlet transform and the Contourlet transform are applied on various images to compare their performances. Simulation results indicate that Region Based Image Fusion using Modified Contourlet transform produces better results than Contourlet transform in terms of entropy, correlation coefficient, PSNR and average gradient.

Keywords

Contrast Pyramid, Directional Filter Bank, Image Fusion, Modified Contourlet Transform, Segmentation.

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M. Tamilarasi ¹, V. Palanisamy ²

Affiliations
1 Department of Electronics and Communication Engg, Chettinad College of Engineering and Technology, Puliyur, IN
2 Info Institute of Engineering, Coimbatore, IN

Abstract

The main objective of this paper is to compress a medical image using contourlet transform used in different modalities of medical imaging. Recent reports on natural image compression have shown superior performance of contourlet transform, a new extension to the wavelet transform in two dimensions using nonseparable and directional filter banks. As far as medical images are concerned the diagnosis part(ROI) is of much important compared to other regions. Therefore those portions are segmented from the whole image using neural network based fuzzy logic technique. Contourlet transform is then applied to ROI portion which performs Laplacian Pyramid(LP) and directional filter banks to the resultant because of irectionality and anisotropy. The region of less significance are compressed using Discrete Wavelet Transform and finally modified embedded zerotree wavelet algorithm is applied which uses six symbols instead of four symbols used in Shapiro’s EZW to the resultant image which shows better PSNR and high compression ratio and finally Huffman coding is applied to get the compressed image.

Keywords

Compression Ratio, Contourlet, DFB, DWT, EZW, Medical Imaging, PSNR, Region of Interest.

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M. Tamilarasi ¹, V. Saradha Ramadas ¹

Affiliations
1 Department of Food Service Management and Dietetics, Avinashilingam Deemed University, Coimbatore -641 043, IN

Abstract

Health as a personal quality has been highly valued and persued throughout the history of mankind. The healthy well being of the mankind solely depends on the consumption of quality food. Fats and oils have nutritional significance as they are the most energy dense sources, enhance palatability and satiety and increase the likelihood of overeating.

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