AN ADAPTIVE SAR IMAGE DESPECKLING ALGORITHM USING STATIONARY WAVELET TRANSFORM

In this paper, we present a Stationary Wavelet Transform (SWT) based method for the purpose of despeckling the Synthetic Aperture radar (SAR) images by applying a maximum a posteriori probability (MAP) condition to estimate the noise free wavelet coefficients. The solution of the MAP estimator is based on the assumption that the wavelet coefficients have a known distribution. Rayleigh distribution is used for modeling the speckle noise and Laplacian distribution for modeling the statistics of the noise free wavelet coefficients for the purpose of designing the MAP estimator. Rayleigh distribution is used for modeling the speckle noise since speckle noise can be well described by it. The parameters required for MAP estimator is determined by the technique used for parameter estimation after SWT. The experimental results show that the proposed despeckling algorithm efficiently removes speckle noise from the SAR images

The epidemiological and neurological risk factors of Japanese encephalitis virus in the population of Assam, Northeast India

Japanese encephalitis is one of the world's most common public health issues, particularly it is prevalent in the north-eastern Indian states of Assam. This study aimed to find out the risk factors linked to clinical and epidemiological characteristics. A total of 245 cases were found as PCR-positive in Assam. The most common clinical symptoms were fever (87%), seizure (65%), altered sensorium (60%), cold with shivering (74%), vomiting (68%), throat irritation (31%), cough (67%), chest pain (10%), joint pain (18%), mouth ulcer (18%), diarrhea (29%), pain in the abdomen (42.9%), runny nose (64%), redness in eyes (78%), jaundice (25%), and blood in the sputum (25%).   Further, the neurological symptoms included vision problems (66.5%), hearing difficulties (55 %), neck stiffness (62%), limb numbness (65%), dizziness (77%), headaches (75.5%), speaking difficulties (63%), hydrophobia (47%), and abnormal behavior (66%). The epidemiological risk factors included contact with pigs (57%), bats (21%), cattle (32%), and rates (66%). In addition, 24.5% of patients observed the death of animals/birds. The protection measure included window screening, sleeping under a mosquito net, and use of insect repellent while sleeping in open compounds (29%) and floods (63%) are considered important risk factors. JE-positive cases include daily habits like working in agriculture fields (28%), in standing water (16%), swimming in nearby lakes (24%), traveling outside their village (40%), and wearing shirts while working in the field (20%), storing water in open containers in or outside the house (62%). These were the epidemiological factors that affected the abundance of the potential mosquito vectors of the JE infection