Remote Sensing is the science of acquiring, processing and interpreting images that record the interaction between the electromagnetic energy and matter (Sabins, 1997). Remote sensing offers extensive applications in almost every area of science from monitoring forest fires to geologic mapping . Although many aspects of remote sensing are complex and difficult to understand the basic theory behind remote sensing is simple physics.
There are four major stages of remote sensing. The first stage is the source of energy, usually the sun, which sends energy to a target. The second stage is the interactions that the energy will go through as it passes through a vacuum and the earth’s atmosphere. There is then interactions that occurs with the body on earth’s surface. The energy again, goes through the atmosphere and finally the sensor is able to detect and record the electromagnetic energy.
Electromagnetic Energy
Electromagnetic energy is a dynamic form of energy that is caused by the acceleration or oscillation of a charged particle. All substances above absolute zero (0 Kelvin) emit a range of electromagnetic energy. The sun emits electromagnetic energy and practically all of the natural electromagnetic energy injected into the earth is produced by the sun (Prakush, 2002).
Electromagnetic Radiation
Electromagnetic Radiation is the streams of mass-less particles, traveling in a harmonic, sinusoidal fusion at the velocity of light each possessing a specific amount of energy. The distance from one peak to the next is the wavelength and the number of peaks passing through a fixed point per unit time is the wave frequency (Lillesand and Kiefer, 1994). Electromagnetic radiation is Electromagnetic energy in motion and can be described by the basic wave theory.
Electromagnetic Spectrum
Electromagnetic waves are characterized by their wavelength location within the electromagnetic spectrum which is most commonly measured in micrometers. Names are often assigned to regions of the electromagnetic spectrum, but there is no clear cut dividing lines from one region to the next (Lillesand and Kiefer, 1994).
Stefan - Boltzmann Law
How much energy any objects radiates is a function of its surface temperature.
The Stefan - Boltzmann equations tells one that as a temperature of a body increase the total radiance of the body will also increase. (Sabins, 1997).
Interactions
The way electromagnetic radation interacts with matter can be detected with different sensors. How the radation interacts depends upon the properties of the medium, the wavelength of the incedent radation and the incident angle. There are four major types of interactions that occur: transmission, reflection, scattering and absorption (Lillesand and Kiefer, 1994).
Radiation is the emission of electromagnetic energy that is given off in the form of high speed particles that cause ionization. During ionization radiation hits and knocks electrons from an atom creating charged ions. Due to the electron being stripped away from the atom this break the chemical bond. Living tissue within the human body is damaged and attempts to repair it but sometimes the damage is beyond repair.
Now the description of light is harder concept to grasp. We describe light by using wavelength and frequency. Wavelength would be the distance between two corresponding points on a wave. Frequency would be the number of waves that passes a point per second. For example the wavelengths of visible light such as red would be visible at seven hundred nanometers. Another example on how we describe light is to take the color green, for it to be visible it would have a wavelength of five hundred nanometers and a frequency of 6 x 10 14/s. Light can also be described on our scale as both waves and particles or packets of light called photons. The energy of a photon is proportional to the frequency. The last way we can describe light is to use the Atomic Spectra. The atomic spectra give only specific colors in a line spectrum, where each line is a specific wavelength of light. For example colored light, such as light from a neon sign would work perfectly with the atomic spectra.
What is Radiation? Radiation is a A form of energy carried by waves or a stream of particles. Radiation is a fragment that is capable of ionizing atoms or molecules isolating electrons from them due to its sufficiently possessed energy when it is passed through them. Radiations include alpha, beta and gamma rays. They can cause severe damage when absorbed by living tissue, and are therefore a health hazard they can effect the repairing ability of living cells. Ionizing radiation consists of subatomic particles or electromagnetic waves that are energetic enough to detach
Ultraviolet radiation is a type of energy, usually heat or light, that travels through space. The natural source of UV rays come from the sun, but it came be produced artificially through lamps and laser beams. http://science.hq.nasa.gov/kids/imagers/ems/uv.html Gamma rays are the strongest form of radiation. This is why nuclear rays are very dangerous. Gamma rays destroy human and animal tissue and cause harmful mutations. When there is a high amount of gamma rays present, it will kill any, if not all, life forms in a small amount of time. Gamma rays are a type of pure energy. They can be discovered j...
Some Simple Optics Refraction Refraction occurs when light travels from one medium, crosses a boundary, and enters another medium of different properties. For example, light travels from air to water. The amount of refraction (or bending) can be calculated using Snell's Law. Refractor How Refractor Telescopes Work? The principle behind the refractive telescopes is the use of two glass lenses (objective lens and eyepiece lens) to gather and bend parallel light rays in a certain way so that the image fits the size of the eye's pupil.
Radiation is when the heat energy travels in actual waves. The suns energy gets to earth because of radiation. These three types of heat transfer can be easily found in the activities we have been doing the past couple of weeks having to do with a universal dwelling. They can mostly be seen when we are trying to test the heating and cooling capabilities of our universal home model.
Spectrum refers to the electromagnetic spectrum, which is the range of frequencies through which electromagnetic radiation travels. Electromagnetic radiation is the energy that travels at the speed of light in waves as a stream of photon particles. This form of energy encompasses radio waves, microwaves, visible, nonvisible light, X–rays and gamma rays, and these classifications are based upon the frequency at which the energy travels (see figure 1). In order to refer to a specific portion, also called a band, of the electromagnetic spectrum, one uses Hertz (Hz) as the unit of measurement.
However Spectroscopy is not a recent development, as it has been utilized for many years since Isaac Newton made the first advances in 1666. Spectroscopy is the study of light as a function of wavelength that has been emitted, reflected or scattered from a solid, liquid, or gas. Fundamentals of Spectroscopy Spectroscopy is the distribution of electromagnetic energy as a function of wavelength. Spectrum is basically white light dispersed by a prism to produce a rainbow of colours; the rainbow is the spectrum of sunlight refracted through raindrops. All objects with temperatures above absolute zero emit electromagnetic radiation by virtue of their warmth alone; this radiation is emitted at increasingly shorter wavelengths as temperature is increased.
In an electromagnetic wave, the constantly changing electric and magnetic fields affect each other so they both oscillate in different axis while the wave moves in a direction perpendicular to the oscillation of the fields as shown in Figure 1.
Radiation is fundamentally different from both conduction and convection in that the substances exchanging heat need not be in contact with each other. All substances emit radiant energy merely by virtue of having a positive absolute temperature.
Nature of wave: It is an electromagnetic wave as it does not necessarily require a medium for p...
from the sun is absorbed by earth’s system, the earth can get warm. When suns energy is
Electromagnetic radiation is energy that flows through free space. Electromagnetic radiation comes in a list of energies known as the electromagnetic spectrum. Electromagnetic spectrum is the complete range of the different wavelength of electromagnetic radiation. It consists of light, radio waves, visible light, infrared waves, ultraviolet light, x-rays, microwaves and gamma rays.
waves are further divided into two groups or bands such as very low frequency (