10.c. EO/IR Flashcards
Natural Sources of EO Radiation? (3)
Sun
Moon
Stars
Artificial Sources of Electro-Optical Radiation?
Turbojet Exhaust
Lights
Flares
Lasers
What is a Black Body
Theoretical object which absorbs all energy and re-radiates that energy based on temperature. Reflects no light.
Gray Bodies
Imperfect black body. This is what real objects are. It is a combination of emmitted and reflected energy.
Beer’s Law
Accounts for the amount of image light absorbed between the target scene and the sensor.
What are atmospheric effects on EO radiation?
Absorption
Scattering
What is IR Absorption
Radiated photons are absorbed by gas molecules in the atmosphere and converted to kinetic energy which is manifested asa temperature change in the molecule.
What are IR transmission windows?
The absorbtion rates vary with wavelength, giving two optimal ranges.
What is IR Scattering
Redirection of radiation by particles in the air
What two natural things can cause reflections?
Clouds
Sea surface
How does humidity affect IR Radiation?
High absolute humidity: high absorption by the water vapour
How does temperature affect the MW and LW wavelengths?
MW less affected by high temperatures.
