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Satellite Optical Imagery
Published in Victor Raizer, Optical Remote Sensing of Ocean Hydrodynamics, 2019
Spectral resolution describes the ability of a sensor to define fine wavelength intervals. Optical MS and HS systems record energy over several separate wavelength ranges at various spectral resolutions. High spectral resolution facilitates fine discrimination between different targets based on their spectral response in each of the narrow bands. Spectral band is usually defined in terms of a “central” wavelength λc and a “bandwidth” Δλ. The bandwidth is defined by lower λ1 and upper λ2 cutoff wavelengths. The spectral resolution Δλ is given by Δλ = λ2 −λ1. Thus, the spectral resolution of an image is inversely proportional to its band width. The narrow the band, the greater the spectral resolution. Additionally, smallest separation in the wavelength that can still be distinguished by a sensor is given as fraction Δλ/λc (defined by certain % criteria).
Digital Image Processing and Visual Perception
Published in Scott E. Umbaugh, Digital Image Processing and Analysis, 2017
The visible light energy corresponds to an electromagnetic wave that falls into the wavelength range from about 380 nm for ultraviolet to about 780 nm for infrared, although above 700 nm the response is minimal. In young adults, wavelengths as high as 1000 nm or down to 300 nm may be seen, but the standard range for human vision is typically given as 400–700 nm (see Figure 2.2-1 for the electromagnetic spectrum). In imaging systems, the spectrum is often divided into various spectral bands, where each band is defined by a range on the wavelengths (or frequency). For example, it is typical to divide the visible spectrum into roughly three bands corresponding to “blue” (400–500 nm), “green” (500–600 nm), and “red” (600–700 nm). In Figure 7.2-2, we see the visible wavelengths of light and their corresponding colors, and how these relate to the standard separation into RGB color bands.
Airborne Radiometers to Measure Electromagnetic Radiation in the Earth’s Atmosphere: Mature and Emerging Technologies
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Spectral radiometers (also called spectroradiometers) measure radiometric quantities in narrow spectral bands as function of wavelength. In this way, spectroradiometers allow more detailed insights into the nature of solar radiation as can be achieved by broadband radiometers.
Land use and land cover change detection by using principal component analysis and morphological operations in remote sensing applications
Published in International Journal of Computers and Applications, 2021
There exist hundreds of remote sensing applications, which are used in agriculture, geology, oceanography, meteorology, glaciology, forest management, disaster management, the military, environmental planning, oil and mineral exploration, urban studies, climate studies, and weather forecasting. Remote sensing refers to observing or acquiring information regarding the characteristics of distant objects without direct contact. Remote sensing can be broadly defined as the collection and interpretation of information regarding an object or area without being in physical contact with the object or area. Aerial photography in the visible portion of the electromagnetic (EM) spectrum was the original form of remote sensing. However, technological developments have enabled the acquisition of information at other wavelengths, including the near-infrared, thermal infrared, and microwave wavelengths. The radiation is measured in the form of spectral bands.