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GEOG 372 February 2 2009. Instructor Dr. Christopher Neigh NASA Goddard Space flight Center Building 33 Room F120 Telephone: 301 614 6681 UMD office: TBD E-mail: cneigh@gmail.com. Christopher S. Neigh Office Hours: Mon/Wed 11:00 to 12:00 am or by appointment
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Instructor Dr. Christopher Neigh NASA Goddard Space flight Center Building 33 Room F120 Telephone: 301 614 6681 UMD office: TBD E-mail: cneigh@gmail.com
Christopher S. Neigh Office Hours: Mon/Wed 11:00 to 12:00 am or by appointment Do not hesitate to contact me for an appointment!!!!!
Course Textbook • Campbell, J.B., Introduction to Remote Sensing, 4thedition, The Gulford Press, 2007.
Class Web Page All class materials will be placed on the Department of Geographies Courses Webpage: http://www.geog.umd.edu/ Click onto Academics/Course Information/ Course Materials/GEOG 372
Summary of Remote Sensing Courses in the Department of Geography GEOG 372 – Introduction to Remote Sensing GEOG 472 – Principles of Remote Sensing GEOG671- Remote sensing instrumentation and observing systems GEOG672- Physical principles of remote sensing and land surface characterization Geog 788A – Seminar in Remote Sensing
Course Goals • Provide the student with a basic understanding of the science and technology of remote sensing • Provide a strong foundation for GEOG 472 • Enable the student to understand the differences between the various satellite remote sensing systems that are in existence today • Enable the student to differentiate between the different types of information products generated from data collected by these systems
Course Structure • Two lectures per week • Readings assigned for most lectures • One lab per week • Most labs will be written up and graded • Additional work outside of the lab will be required to complete lab assignments
Evaluation of Students • 4 Pop quizzes – each 2.5% (10% total) • 2 hourly exams - each 20% (40% total) • Comprehensive final exam – 25% • Laboratory Exercises – ~3% each (25% total) • Test Grading Policy – One abnormally low score (out of three) will be partially discounted
Exams • Each exam will cover 1/3 of course material • Final exam will also include material from entire course • Only cover material presented in Lecture, but readings provide important supplemental material for student • Exam dates • 25 February (normal class time) • 08 April (normal class time) • Final, will notify asap
Grading – Lab Exercises • Each lab exercise is worth 10 points and is due at the beginning of the next lab period • Lab exercises turned in late will not receive full credit
Late Lab Exercises • Up to 4 days late – 8 points maximum • 5 to 7 days late – 5 points maximum • 8 to 14 days late – 2 points maximum • > 14 days late – 0 points
SyllabusLecture/Hourly Exam Schedule and Assigned Readings (Subject to Change) Week Date Lecture Topic Reading Part I Remote Sensing Basics 1 26-Jan 1 Introduction to Remote Sensing Ch 1 28-Jan University Closed2 02-Feb 2 Principles of EM radiometry and basic EM Theory Ch 2 04-Feb Principles of EM radiometry and basic EM Theory II3 09-Feb 3 Atmospheric Influences on EM Radiation I 11-Feb 4 Photographic Systems/Image Interpretation Ch 3,54 16-Feb 5 The Digital Image I Ch 4,10 18-Feb The Digital Image II5 23-Feb 6 Applications with areal and space photography 25-Feb Exam 1 26-Feb Lab 1 Introduction to ENVI – manipulation of digital imagery
Lecture 2 The Basics of Electromagnetic Radiation (EM)February 2nd 2009
Reading Assignment • Campbell, Chapter 2 Unless otherwise noted, all images in this lecture are from • Jensen, J.R., Remote Sensing of the Environment - An Earth Resource Perspective, 544 pp., Prentice Hall, Upper Saddle River, NJ, 2000.
Ultraviolet ( < 0.4 m) Visible ( 0.4 m < < 0.7 m) Reflected IR ( 0.7 m < < 2.8 m) Emitted (thermal) IR ( 2.4 m < < 20 m) Microwave ( 1 cm < < 1 m) EM Spectrum Regions Used in Remote Sensing = EM radiation wavelength
Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission
Types of Thermal Energy Transfer • Energy is the ability to do work • There are three ways to transfer thermal energy from one place or object to another • Conduction • Convection • Radiation
Conduction – transfer of energy through collisions of atoms or molecules
Convection - physically moving the molecules/atoms from one place to another
Radiation – Emission or transfer of energy in the form of electromagnetic waves or particles
Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission
What is EM Radiation? Two models have been developed to describe EM radiation or energy • Particle Model of EM Energy – describes how EM radiation interacts with matter • Wave Model of EM Energy – describes how EM radiation is propagated, e.g., how it moves through space
Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission
EM Radiation Particle Model -Radiation from Atomic Structures Einstein discovered that when light (visible EM radiation) interacts with matter, it behaves like it is composed of photons • Photons carry energy and momentum, i.e., particle like properties • Thus, light is considered to be a unique type of matter
Important components of the Particle Model of EM Radiation • When EM energy strikes an atom, excitation occurs, e.g., thermal energy from the EM energy (e.g., a photon) is absorbed by the atom, the atom is warmed, and an electron in the atom gains enough energy to obtain a higher orbit • When atom cools down, it can do so by releasing EM energy – this process is called de-excitation – it releases a photon of EM energy
Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission
EM radiation can be thought of as the propagation through space of two wave fields: electrical wave field and a magnetic wave field v
Polarization • Polarization refers to the relative orientation of the electrical field of an EM wave • Horizontal polarization - an EM wave that is parallel to the earth’s surface • Vertical polarization - an EM wave that is perpendicular to the earth’s surface
Active Microwave (RADAR) systems control the polarization of both the transmitted and received microwave EM energy Figure 9.6 from Jensen
The Electromagnetic Wave • EM energy travels with the speed of light, c, • Within a vacuum c = 3 x 108 m sec-1
EM Radiation is created whenever an electrical charge is accelerated • Two characteristics of EM waves Wavelength () – depends on the length of time over which the electrical charge is accelerated – distance between two wave crests Frequency () depends on the number of accelerations per second – how many waves per unit time are being generated
EM Frequency () • Frequency is expressed in hertz (Hz), where one hertz is one cycle or wavelength per second • Shorter wavelengths have higher frequencies • Longer wavelengths have lower frequencies
Microwave remote sensing systems are often defined by the frequency of the EM radiation MHz = 1 million Hz (106 Hz) GHz = 1 billion Hz (109 Hz)
Relationship between c, , and c = = c / = c / - In visible, near IR, and thermal IR remote sensing, wavelength () is used to describe a system In microwave remote sensing, frequency () is often used to describe a system
Example – What is the frequency () of EM energy with a wavelength () of 6 cm (= .06 m = 6 x 10-2 m) = c / = (3 x 108 m sec-1) / (6 x 10-2 m) = 0.5 x 1010 cycles/sec = 5 x 109 Hz = 5 GHz
Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission
Emittance • Emittance refers to the ability of the surface to emit radiant energy All matter that has a temperature above 0 degree Kelvin (-273 degrees C or -459 degrees F) are emitting EM radiation across the entire EM spectrum (e.g., at all wavelengths/frequencies) Matter temperature defines characteristics of EM radiation
Stefan-Boltzmann Law* • The amount of EM radiation (M) emitted from a body in Watts m-2 can be calculated as M = T4 where is a constant (5.6697 x 10-8) and T4 is the temperature in degrees Kelvin *Know this formula
Degrees Kelvin = Degrees C (centigrade) + 273 M = T4 where is a constant (5.6697 x 10-8) and T4 is the temperature in degrees Kelvin
Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission
Planck’s formula** • Spectral emittance – S() S() = 2 h c2 / [5 (ech / kT – 1)] Where h is Planck’s constant And k is the Stephan-Boltzman constant **you don’t have to know this formula
Planck’s formula gives basic shape of emittance curves Stephan Boltzman Law predicts how much total energy is emitted Note how total energy drops dramatically as temperature decreases Note how the wavelength where maximum emittance occurs increases as temperature decreases
Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission