Whisk broom scanner on:
[Wikipedia]
[Google]
[Amazon]
A whisk broom or spotlight sensor, also known as an across-track scanner, is a technology for obtaining 
The moving parts make this type of sensor expensive and more prone to wearing out, such as in the Landsat 7. Whisk broom scanners have the effect of stopping the scan, and focusing the detector on one part of the
Earth Observing-1
(NASA), with animated whisk broom and push broom illustrations Image sensors
satellite image
Satellite images (also Earth observation imagery, spaceborne photography, or simply satellite photo) are images of Earth collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell ima ...
s with optical camera
A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), ...
s. It is used for passive remote sensing from space. In a whisk broom sensor, a mirror scans across the satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
’s path (ground track
A ground track or ground trace is the path on the surface of a planet directly below an aircraft's or satellite's trajectory. In the case of satellites, it is also known as a suborbital track, and is the vertical projection of the satellite's or ...
), reflecting light into a single detector
A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon.
In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...
which collects data one pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device.
In most digital display devices, pixels are the smal ...
at a time.
The moving parts make this type of sensor expensive and more prone to wearing out, such as in the Landsat 7. Whisk broom scanners have the effect of stopping the scan, and focusing the detector on one part of the swath width
A swathe (; rhymes with "bathe") or swath (; rhymes with "cloth") is the width of a scythe stroke or a mowing-machine blade, the path of this width made in mowing or the mown grass or grain lying on such a path.
The mower with a scythe moves alon ...
. Because the detector is only focused on a subsection of the full swath at any time, it typically has a higher resolution than a push broom design for the same size of scan swath.
All sensors aboard the Landsat
The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On 23 July 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to Lan ...
series of satellites used the whisk broom design until Landsat 8
Landsat 8 is an American Earth observation satellite launched on 11 February 2013. It is the eighth satellite in the Landsat program; the seventh to reach orbit successfully. Originally called the Landsat Data Continuity Mission (LDCM), it is a ...
.
See also
*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 exampl ...
References
{{ReflistExternal links
Earth Observing-1
(NASA), with animated whisk broom and push broom illustrations Image sensors