Computers are used to process the data. The data about the amount of blue, green and red light reflected off the earth’s surface is put together to make a satellite image. Scientists use these remote sensing images to study the earth. There are two types of remote sensing instruments-passive and active.
Passive instruments detect natural energy that is reflected or emitted from the observed scene. Passive instruments such as camera, radiometer etc., sense only radiation emitted by the object being viewed or reflected by the object from a source other than the instrument. Reflected sunlight is the most common external source of radiation sensed by passive instruments. Scientists use a variety of passive remote sensors.
Active systems such as radar and sonar send artificially produced energy beam to target and record the reflected component.
Passive instruments detect natural energy that is reflected or emitted from the observed scene. Passive instruments such as camera, radiometer etc., sense only radiation emitted by the object being viewed or reflected by the object from a source other than the instrument. Reflected sunlight is the most common external source of radiation sensed by passive instruments. Scientists use a variety of passive remote sensors.
Active systems such as radar and sonar send artificially produced energy beam to target and record the reflected component.
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