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A push broom scanner, also known as an along-track scanner, is a device for obtaining images with 
In orbital push broom sensors, a line of sensors arranged perpendicular to the flight direction of the spacecraft is used. Different areas of the surface are imaged as the spacecraft flies forward. A push broom scanner can gather more light than a whisk broom scanner because it looks at a particular area for a longer time, like a long exposure on a camera. One drawback of push broom sensors is the varying sensitivity of the individual detectors. Another drawback is that the resolution is lower than a whisk broom scanner because the entire image is captured at once.
Examples of spacecraft cameras using push broom imagers include Mars Express's High Resolution Stereo Camera,
Earth Observing-1
(NASA), with animated whisk broom and push broom illustrations
Airborne Pushbroom Line Scan
(PDF) – overview article
Linear Pushbroom Cameras
(PDF) – detailed modelling theory Spectrometers Image sensors {{technology-stub
spectroscopic
Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter ...
sensors. The scanners are regularly used for passive remote sensing
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Ear ...
from space, and in spectral analysis on production lines, for example with near-infrared spectroscopy
Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum (from 780 nm to 2500 nm). Typical applications include medical and physiological diagnostics and research inc ...
used to identify contaminated food and feed. The moving scanner line in a traditional photocopier (or a scanner or facsimile machine) is also a familiar, everyday example of a push broom scanner. Push broom scanners and the whisk broom scanners variant (also known as across-track scanners) are often contrasted with staring array
A staring array, also known as staring-plane array or focal-plane array (FPA), is an image sensor consisting of an array (typically rectangular) of light-sensing pixels at the focal plane of a lens. FPAs are used most commonly for imaging purp ...
s (such as in a digital camera), which image objects without scanning, and are more familiar to most people.
In orbital push broom sensors, a line of sensors arranged perpendicular to the flight direction of the spacecraft is used. Different areas of the surface are imaged as the spacecraft flies forward. A push broom scanner can gather more light than a whisk broom scanner because it looks at a particular area for a longer time, like a long exposure on a camera. One drawback of push broom sensors is the varying sensitivity of the individual detectors. Another drawback is that the resolution is lower than a whisk broom scanner because the entire image is captured at once.
Examples of spacecraft cameras using push broom imagers include Mars Express's High Resolution Stereo Camera, Lunar Reconnaissance Orbiter
The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic missions to ...
Camera NAC, Mars Global Surveyor's Mars Orbiter Camera WAC, and the Multi-angle Imaging SpectroRadiometer on board the Terra satellite.
See also
* Time delay and integration * Whisk broom scannerReferences
External links
Earth Observing-1
(NASA), with animated whisk broom and push broom illustrations
Airborne Pushbroom Line Scan
(PDF) – overview article
Linear Pushbroom Cameras
(PDF) – detailed modelling theory Spectrometers Image sensors {{technology-stub