characteristics of electromagnetic radiation in remote sensing

Electromagnetic Radiation Source of Remote Sensing data. Remote sensing technologies rely on a variety of electromagnetic energy. Answer 2: Using the equation for the relationship between wavelength and frequency, let's calculate the wavelength of radiation of a frequency of 500,000 GHz. Most sensors record the EMR in this range, e.g., bands of IRS P6 LISS IV sensor are in optical range of EMR. Active remote sensing systems emit radiation on the study object and measure the reflected amount of radiation. Electromagnetic Radiation. Sensors detect and measure electromagnetic energy in different portions of the spectrum. These devices are sensitive to the wavelengths ranging from 300 nm to 3000 nm. Active sensors, provide their own source of energy to illuminate the objects they observe. Different The physics of electromagnetic radiation is electrodynamics, a subfield of electromagnetism. Wavelength is usually represented by the Greek letter lambda (λ). High-pitched sounds have short wavelengths and high frequencies. Assume the speed of light to be 3x108 m/s. Frequency refers to the number of cycles of a wave passing a fixed point per unit of time. 7. There are other types of light which are invisible to us...but more about that later. %PDF-1.5 %���� Characteristics as Wave motion: EMR can be considered as a transverse wave with an electric field and a magnetic field, located at right angles to each other. In addition, the use of drones is emerging due to the high-resolution data that can be collected in a short time for real-time monitoring. Both have the same amplitude at the same time. Hospitals use imaging technology, including CAT scans, magnetic resonance imaging (3-D imaging of soft tissue), and x-rays for examining our bodies. Both these fields travel at the speed of light (c). Chapter 2 of Campbell (2007) delves into the scientific principles of electromagnetic radiation that are fundamental to remote sensing. What is the obvious source of electromagnetic energy that you can think of? Print. h�b```a``�a�``0abf@ afV�,�7 ������AS��ܙ�g,dH����|Ό��{=TMD�+���}K����ÆC?V�Dĭ���>&��9���֏w$�..H�ؒ������h�� ���������V�V� �Ѐ� ˜AP9�. Next we will be examining the way in which we categorize electromagnetic radiation for just that purpose. Principles of remote sensing Detection and discrimination of objects or surface features means detecting and recording of radiant energy reflected or emitted by objects or surface material. Electromagnetic radiation is generated whenever the electrical charge is accelerated. This same principle (applied to light) is used by astronomers to see how quickly stars are moving away from us (the Red shift). Passive remote sensing systemsmeasure existing radiation such as the reflected solar radiation from the earth’s surface. The longer the wavelength, the lower the frequency. The sensor is merely a passive observer collecting electromagnetic radiation. are several regions of the electromagnetic spectrum which are useful for remote sensing. Optical remote sensing devices operate in the visible, near infrared, middle infrared and short wave infrared portion of the electromagnetic spectrum. These sensors measure land and sea surface temperature, vegetation properties, cloud and aerosol properties, and other physical properties. In particular, microwave remote sensing uses electromagnetic radiation with a wavelength between 1 cm and 1 m (commonly referred to as microwaves) as a measurement tool. This radiation is just beyond the violet portion of the visible wavelengths, hence its name. The vital concepts of spatial resolution and detection are explained using the eye as an example of remote sensing system. The remote sensing device that we humans use to detect radiation from the sun is our eyes. Low sounds are the opposite. The major regions of interest in satellite sensing are visible light, reflected and emitted infrared, and the microwave regions. Fundamentals of Remote Sensing 1.2 Electromagnetic Radiation As was noted in the previous section, the first requirement for remote sensing is to have an energy source to illuminate the target (unless the sensed energy is being emitted by the target). Thermal IR (3 µm - 35 µm) is the radiation emitted from earth’s surface in the form of heat and used for remote sensing. We will look at each of these characteristics in turn 1] Stages All electromagnetic radiation has fundamental properties and behaves in predictable ways according to the basics of wave theory. In remote sensing, we are most interested in measuring the radiation reflected from targets. A sensor is a device comprising of optical component or system and a detector with electronic circuit. • The foundation of remote sensing technology is based on the measurement and interpretation of the patterns of EMR. This involves the detection and measurement of radiation of different wavelengths reflected or emitted from distant objects or materials, by which they may be … Section 1.2 Electromagnetic Radiation EMR transmit cross space in the wave form and in the speed of light. The wavelength and frequency are the two important characteristics of this electromagnetic radiation. Some Earth surface Remote sensing technologies can be satellite- or aircraft-based and are able to detect and classify objects and characteristics of the Earth system through propagated signals (e.g. An active sensor emits radiation in the direction of the target to be investigated. 597 0 obj <> endobj 618 0 obj <>stream As a train or race car advances towards us, our ears tend to hear progressively lower sounds or frequencies (shorter wavelengths) until it reaches us, the original frequency of the object when it is broadside, then even lower frequencies as it moves further away. These are the wavelength and frequency. Remote sensing is the part of geospatial technologies that deals with the detection of electromagnetic radiation to determine characteristics without direct contact. What "remote sensing device" do you personally use to detect this energy? We refer to two types of reflection, which represent the two extreme ends of the way in which energy is reflected from a target: specular reflection and diffuse reflection . Understanding the characteristics of electromagnetic radiation in terms of their wavelength and frequency is crucial to understanding the information to be extracted from remote sensing data. As was noted in the previous section, the first requirement for remote sensing is to have an energy source to illuminate the target (unless the sensed energy is being emitted by the target). The wavelength is the length of one wave cycle, which can be measured as the distance between successive wave crests. Remote sensing is the science and art of identifying, observing, and measuring an object without coming into direct contact with it. However, in remote sensing the most useful regions are the visible (0.4-0.7 µm), the reflected IR (0.7-3 µm), the thermal IR (3-5 & 8-14 µm) and the microwave region varies from 0.3-300 cm. 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