BackgroundThe World Health Organization (WHO) has been on alert since the 31st December 2019, following an outbreak of a new strain of coronavirus in Wuhan City, China late last month.Coronavirus is a family of viruses that cause illness ranging from the common cold to more severe diseases such as Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS), pneumonia and bronchitis.This new strain infecting humans was named "2019-nCoV". Little is known about this strain of coronavirus, although human-to-human transmission has been confirmed.Coronaviruses are common amongst animals worldwide, but only a handful of them are known to affect humans.Though the spread of the virus seems to have been contained within a few cities circling Wuhan, there have been a few cases reported outside of China.Chinese officials have effectively sealed off the region with travel bans to and from the affected areas and airports across the world have also stepped up screening passengers coming from that region.What are the symptoms? According to WHO, signs of infection ranges from respiratory symptoms such as fever, cough and breathing difficulties; it also includes impaired liver and kidney function. In more severe cases, it can lead to Pneumonia, SARS, kidney failure and even death. The incubation period of the 2019-nCoV strain is yet to be determined. How is it transmitted? As with other coronaviruses, 2019-nCoV can be transmitted in the following ways: l Through air by coughing sneezing l Close contact such us touching and shaking hands with infected person l Contact with contaminated objects then touching the mouth, eyes or nose.How is it treated?There are no specific treatments for all coronavirus infections and most people will recover on their own, available measures involves rest and medication to relieve symptoms.You are however advised to drink a lot of fluids and have enough rest should you worry about your symptoms.There is no vaccine for the new coronavirus (2019-nCoV).
Radiometric correction is the process of removing sensor and environmental errors from satellite images so that the measured brightness values (Digital Numbers or DNs) truly represent the Earth's surface reflectance or radiance. In other words, it corrects for sensor defects, illumination differences, and atmospheric effects. 1. Detector Response Calibration Satellite sensors use multiple detectors to scan the Earth's surface. Sometimes, each detector responds slightly differently, causing distortions in the image. Calibration adjusts all detectors to respond uniformly. This includes: (a) De-Striping Problem: Sometimes images show light and dark vertical or horizontal stripes (banding). Caused by one or more detectors drifting away from their normal calibration — they record higher or lower values than others. Common in early Landsat MSS data. Effect: Every few lines (e.g., every 6th line) appear consistently brighter or darker. Soluti...


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