14-07-2012, 04:34 PM
Optoelectronics
[attachment=27693]
Radiometry and Photometry
Radiometry is measuring radiation brightness within a fixed band of wavelengths.
Photometry is measuring visible and ultraviolet light radiation brightness.
Uses
Uses for this type of sensing apparatus would be:
Satellite technology Astronomy Digital photography
These instruments are a lot like eyes. They rely on waves of scattered and emitted electromagnetic radiation as their means for gathering information.
Electromagnetic Radiation
All objects that are not at absolute zero temperature emit electromagnetic radiation in the form of waves of energy.
Electromagnetic radiation occurs over a continuum of wavelengths from very long radio waves to extremely short gamma rays.
The ordered arrangement of electromagnetic radiation as a function of wavelength is called the electromagnetic spectrum.
Reflection
Our main concern is with the reflected portion.
It is usually this which is returned to the sensor system.
Exactly how much is reflected will vary, and will depend upon the nature of the material and where in the electromagnetic spectrum our measurement is being taken.
As a result, if we look at the nature of this reflected component over a range of wavelengths, we can characterize the material.
Emitters and Receivers
For any sensor to work it needs to be able to send and/or receive information.
They are able to do this with emitters and receivers:
Emitter broadcasts a signal
Receiver receives the signal
[attachment=27693]
Radiometry and Photometry
Radiometry is measuring radiation brightness within a fixed band of wavelengths.
Photometry is measuring visible and ultraviolet light radiation brightness.
Uses
Uses for this type of sensing apparatus would be:
Satellite technology Astronomy Digital photography
These instruments are a lot like eyes. They rely on waves of scattered and emitted electromagnetic radiation as their means for gathering information.
Electromagnetic Radiation
All objects that are not at absolute zero temperature emit electromagnetic radiation in the form of waves of energy.
Electromagnetic radiation occurs over a continuum of wavelengths from very long radio waves to extremely short gamma rays.
The ordered arrangement of electromagnetic radiation as a function of wavelength is called the electromagnetic spectrum.
Reflection
Our main concern is with the reflected portion.
It is usually this which is returned to the sensor system.
Exactly how much is reflected will vary, and will depend upon the nature of the material and where in the electromagnetic spectrum our measurement is being taken.
As a result, if we look at the nature of this reflected component over a range of wavelengths, we can characterize the material.
Emitters and Receivers
For any sensor to work it needs to be able to send and/or receive information.
They are able to do this with emitters and receivers:
Emitter broadcasts a signal
Receiver receives the signal