Remote Sensing Electromagnetic Radiation Remote Sensing Definition I

Remote Sensing Electromagnetic Radiation

Remote Sensing Definition "I want to know how God created this world. I am not interested in this or that phenomenon, in the spectrum of this or that element. I want to know His thoughts; -the rest are details. “ Albert Einstein

Remote Sensing Definition ► Science and art of obtaining information about an object, area, or phenomenon through the analysis of data acquired by a device that is not in contact with object, area, or phenomenon.

Remote Sensing Processes ► Data acquisition - energy sources - energy through the atmosphere - interaction with surface features - retransmission - sensor systems - data - interpretation and analysis

Remote Sensing Processes. .

Remote Sensing Processes. . Data analysis: - data processing - compilation - application ► “DIKI” data information knowledge intelligence ►

Electronic Radiation ► The sun produces a full spectrum of electromagnetic radiation http: //csep 10. phys. utk. edu/astr 162/lect/light/spectrum. html http: //kr. blog. yahoo. com/bmw 26 z/2188

Two Components of EM Radiation ► Electrical field (E): varies in magnitude in a direction perpendicular to the direction of propagation ► Magnetic field (M): at right angle to the electrical field, is propagated in phase with the electrical field

Components of EM Radiation v

Three Properties of EM Energy Wavelength ( ) ► Frequency ( ) ► Amplitude ►

Wavelength ( ) The distance from one wave crest to the next ► Measurement units: micrometer (mm) 1 m = 1, 000 mm, 1 mm = 1, 000 microm ►

Frequency ( ) The number of crests passing a fixed point in a given period of time ► Measure units: hertz (cycle per second) ►

Amplitude The height of each peak ► Measured as watts per square meter (energy level) ►

Three Properties ► Among the three properties, wavelength is the most commonly used in the field of remote sensing

Three Properties. .

Speed of EM ► The speed of EM energy c 300, 000 km/second, c = and are inversely related

Electromagnetic Spectrum ► Spectrum of electromagnetic radiation ► Major divisions of EM spectrum http: //csep 10. phys. utk. edu/astr 162/lect/light/spectrum. html http: //imagers. gsfc. nasa. gov/ems. html

Major Divisions of EM Spectrum Ultraviolet spectrum: 0. 3 - 0. 38 microm ► Visible spectrum: - blue 0. 4 - 0. 5 microm - green 0. 5 - 0. 6 microm - red 0. 6 - 0. 72 microm ► 1 m = 1, 000 mm = 1, 000 micrometer ►

Major Divisions of EM Spectrum ► ► Infrared spectrum: - near infrared: 0. 72 - 1. 3 microm - mid infrared: 1. 30 - 3. 0 microm - far infrared: 7. 00 - 15 microm, emitted from the earth Microwave spectrum: 1 mm - 1 m

The Dual Nature of Light (Newton) Light is formed by a stream of quanta (photons) that travels in straight line. The size of each quantum is directly proportional to the frequency of the energy's radiation Q = h ► The quantum model best explains the photoelectric effect ►

The Dual Nature of Light ► ► EM energy propagates as a series of waves The wave model best explains the refraction and diffraction

Readings ► Chapter 1