Informatics Publishing Limited

P. Rajalakshmi ¹, I. Daphne ¹

Affiliations
1 Department of ECE, Velammal Institute of Technology, Chennai – 601204, Tamil Nadu, IN

Abstract

Background/Objectives: Images that are affected by noise should be denoised in order to obtain information from it. In this paper an efficient denoising algorithm based on adaptive and unsymmetric trimmed median filter is proposed which effectively gets rid off the high-density salt and pepper noise. Methods/Stastical Analysis: The proposed algorithm restores the noisy pixel with the trimmed median value when, 0’s and 255’s are found in the neighborhood and also adaptively controls the neighborhood size based on the relative amount of noisy pixels in the selected neighborhood. Many of the existing algorithms do not preserve fine details of the image while removing noise at high noise densities. Results/Findings: The Proposed Algorithm (PA) is tested against grayscale and color images and it gives an exceptional Peak Signal to Noise Ratio (PSNR) and Image Enhancement Factor (IEF) especially at higher noise densities. Conclusion/Application: This algorithm effectively removes high density noise caused by bit error transmission or introduced during the image acquisition stage.

Keywords

Image Denoising, Impulse Noise, Median Filter, Mid Point Filter, Salt and Pepper Noise

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Y. Raja Vara Prasad ¹, Mirza Sami Baig ¹, Rahul K. Mishra ², P. Rajalakshmi ¹, U. B. Desai ¹, S. N. Merchant ²

Affiliations
1 Department of Electrical Engineering, Indian Institute of Technology Hyderabad, IN
2 Department of Electrical Engineering, Indian Institute of Technology Bombay, IN

Abstract

Air pollution has significant influence on the concentration of constituents in the atmosphere leading to effects like global warming and acid rains. To avoid such adverse imbalances in the nature, an air pollution monitoring system is utmost important. This paper attempts to develop an effective solution for pollution monitoring using wireless sensor networks (WSN) on a real time basis namely real time wireless air pollution monitoring system. Commercially available discrete gas sensors for sensing concentration of gases like CO2, NO2, CO and O2 are calibrated using appropriate calibration technologies. These pre-calibrated gas sensors are then integrated with the wireless sensor motes for field deployment at the campus and the Hyderabad city using multi hop data aggregation algorithm. A light weight middleware and a web interface to view the live pollution data in the form of numbers and charts from the test beds was developed and made available from anywhere on the internet. Other parameters like temperature and humidity were also sensed along with gas concentrations to enable data analysis through data fusion techniques. Experimentation carried out using the developed wireless air pollution monitoring system under different physical conditions show that the system collects reliable source of real time fine-grain pollution data.

Keywords

Wireless Sensor Networks (WSN), Gas Sensor Calibration, Light Weight Middleware, Multihop Data Aggregation, Web Interface.

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P. Rajalakshmi ¹, G. Myvizhi ¹

Affiliations
1 Assistant Professor, Department of Chemistry, P.K.R. Arts College for Women, Gobichettipalayam – 638476, Tamil Nadu, IN

Abstract

⁸⁹Sr a radionuclide used for bone pain palliation — is produced in Fast Breeder Test Reactor (FBTR) via the ⁸⁹Y (n, p) ⁸⁹Sr reaction. The final ⁸⁹Sr source is obtained after processing the irradiated Y₂ O₃ target using nitric acid. The final product ⁸⁹Sr is injected in HCl medium whose concentration must be 0.05–0.5M. The final product which was obtained after the chemical processing in the nitric acid is converted into its chloride form. The estimation of nitrate ion in the ⁸⁹Sr source is an indication of i) the efficiency of the conversion and ii) the ⁸⁹Sr source is free from the nitrate ion impurity. Hence it is necessary to determine the presence of nitrate in the product. So a method was developed in the laboratory to estimate the nitrate ion concentration in presence of bulk chloride ion concentration by spectrophotometric method.

Keywords

Spectrophotometry, Nitrate ion, Chloride matrix, Diazotization

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