Physics:Push broom scanner
A push broom scanner, also known as an along-track scanner, is a device for obtaining images with spectroscopic sensors. The scanners are regularly used for passive remote sensing from space, and in spectral analysis on production lines, for example with near-infrared spectroscopy used to identify contaminated food and feed.[1] 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 arrays (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,[2] Lunar Reconnaissance Orbiter Camera NAC,[3][4] Mars Global Surveyor's Mars Orbiter Camera WAC,[2] and the Multi-angle Imaging SpectroRadiometer on board the Terra satellite.[2]
See also
References
- ↑ Vincent Baeten; Philippe Vermeulen; Juan Antonio Fernández Pierna; Pierre Dardenne (June 2014). "From targeted to untargeted detection of contaminants and foreign bodies in food and feed using NIR spectroscopy". New Food magazine: pp. 18–23. http://www.newfoodmagazine.com/14111/new-food-magazine/digital-issues/issue-3-2014-digital-edition/. Retrieved 26 June 2014.
- ↑ 2.0 2.1 2.2 Hoekzema, Nick. "Planetary & Cometary Exploration Cameras on Orbiters and Landers". Archived from the original on 2014-02-19. https://web.archive.org/web/20140219073935/http://www.solar-system-school.de/lectures/space_instrumentation/11.ppt. Retrieved 2 February 2014.
- ↑ Neal-Jones, Nancy (2014-01-29). "NASA's LRO Snaps a Picture of NASA's LADEE Spacecraft". NASA. http://www.nasa.gov/content/goddard/nasas-lro-snaps-a-picture-of-nasas-ladee-spacecraft/. Retrieved 2 February 2014.
- ↑ "Digital Elevation Models and Derived Products from LROC NAC STEREO observations". International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B4, 2012 XXII ISPRS Congress. 25 August 2012. p. 483. http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XXXIX-B4/483/2012/isprsarchives-XXXIX-B4-483-2012.pdf. Retrieved 2 February 2014.
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
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