Quote: "In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy."
A discussion of the laws of radiation and how they apply to remote sensing, such as how objects emit and absorb radiation, and the principles of blackbody radiation and emissivity.
Electromagnetic Spectrum: Understanding the electromagnetic spectrum is crucial as it forms the basis for remote sensing technology. One needs to know the different types of electromagnetic radiation and their characteristics.
Radiation and Matter Interaction: This topic covers how electromagnetic radiation interacts with matter, including reflection, absorption, and transmission.
Remote Sensing Platforms: One needs to understand the different types of remote sensing platforms, such as satellites, aircraft, and ground-based sensors.
Remote Sensing Data Types: This topic explores the different types of remote sensing data, including optical, thermal, and radar.
Radiometric Calibration: Radiometric calibration refers to the process of converting raw remote sensing data into calibrated data that can be used for analysis.
Image Enhancement Techniques: Image enhancement techniques are used to improve the visual quality of remote sensing images to extract more information.
Image Classification Techniques: Image classification techniques involve categorizing remote sensing images into different thematic classes, such as land cover classes.
Digital Image Processing: This is a broad topic that encompasses all the techniques used to analyze and manipulate digital images.
Geometric Correction: Geometric correction refers to the process of removing distortions from remote sensing images, such as those caused by the curvature of the Earth.
Radiometric Correction: Radiometric correction refers to the process of removing atmospheric effects from remote sensing images, allowing for more accurate analysis.
Feature Extraction Techniques: Feature extraction techniques are used to identify and extract specific features or objects from remote sensing images.
Spatial and Temporal Resolution: Spatial and temporal resolution determines the level of detail and frequency of remote sensing images, and are key considerations when selecting remote sensing data.
Data Fusion: Data fusion involves combining data from multiple sensors to improve the accuracy and detail of remote sensing images.
Applications of Remote Sensing: Lastly, understanding the applications of remote sensing in various fields such as agriculture, forestry, ecology, mining, geology, and oceanography is essential.
Electromagnetic radiation: This is the most commonly used form of radiation in remote sensing. It includes a wide range of wavelengths from radio waves to gamma rays. It is used to gather information about the Earth's surface by measuring the reflection, emission, and transmission of this type of radiation.
Thermal radiation: This type of radiation is emitted from the Earth's surface as heat. It is used to measure the temperature of the Earth's surface and the atmosphere.
Spectral radiation: This type of radiation is measured by its wavelength, and it is used to identify the chemical composition of the Earth's surface or its atmosphere.
Active radiation: This type of radiation is generated and sent from the sensor directly to the Earth's surface. It is used in technologies like radar and lidar.
Passive radiation: This type of radiation is measured as it naturally occurs on the Earth's surface. It includes things like sunlight and the heat emitted by the Earth's surface.
Scattered radiation: This type of radiation is scattered by the atmosphere, and it is used to measure things like aerosols and cloud cover.
Reflected radiation: This type of radiation is reflected off the Earth's surface, and it is used to measure things like vegetation coverage and water content.
Absorbed radiation: This type of radiation is absorbed by the Earth's surface or the atmosphere, and it is used to measure things like the concentration of gases in the air or the moisture content of soil.
Penetrating radiation: This type of radiation can penetrate the Earth's surface, and it is used to measure things like the depth of soil moisture or the thickness of ice.
Quote: "Types of EMR include radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays."
Quote: "In a vacuum, electromagnetic waves travel at the speed of light, commonly denoted c."
Quote: "In homogeneous, isotropic media, the oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy and wave propagation, forming a transverse wave."
Quote: "The position of an electromagnetic wave within the electromagnetic spectrum can be characterized by either its frequency of oscillation or its wavelength."
Quote: "In order of increasing frequency and decreasing wavelength these are: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays."
Quote: "Electromagnetic waves are emitted by electrically charged particles undergoing acceleration."
Quote: "EM waves carry energy, momentum and angular momentum away from their source particle and can impart those quantities to matter with which they interact."
Quote: "EMR is sometimes referred to as the far field, as it is associated with those EM waves that are free to propagate themselves ('radiate') without the continuing influence of the moving charges that produced them."
Quote: "In this language, the near field refers to EM fields near the charges and current that directly produced them, specifically electromagnetic induction and electrostatic induction phenomena."
Quote: "In quantum mechanics, an alternate way of viewing EMR is that it consists of photons, uncharged elementary particles with zero rest mass which are the quanta of the electromagnetic field, responsible for all electromagnetic interactions."
Quote: "Quantum electrodynamics is the theory of how EMR interacts with matter on an atomic level."
Quote: "Quantum effects provide additional sources of EMR, such as the transition of electrons to lower energy levels in an atom and black-body radiation."
Quote: "The energy of an individual photon is quantized and is greater for photons of higher frequency. This relationship is given by Planck's equation E = hf."
Quote: "A single gamma ray photon, for example, might carry ~100,000 times the energy of a single photon of visible light."
Quote: "The effects of EMR upon chemical compounds and biological organisms depend both upon the radiation's power and its frequency."
Quote: "EMR of visible or lower frequencies (i.e., visible light, infrared, microwaves, and radio waves) is called non-ionizing radiation."
Quote: "The effects of these radiations on chemical systems and living tissue are caused primarily by heating effects from the combined energy transfer of many photons."
Quote: "High frequency ultraviolet, X-rays, and gamma rays are called ionizing radiation since individual photons of such high frequency have enough energy to ionize molecules or break chemical bonds."
Quote: "These radiations have the ability to cause chemical reactions and damage living cells beyond that resulting from simple heating, and can be a health hazard."