Whiskbroom scanner
Also called: Across-track scanner · Topic: Remote Sensing, GIS and GNSS · NCERT: Class 11, Ch 6 "Introduction to Remote Sensing"
Meaning
A whiskbroom scanner, also called an across-track scanner, is a multispectral scanner that uses a rotating mirror and a single detector. The mirror sweeps from side to side across the satellite's path, like a broom sweeping a floor. One full sweep covers 90° to 120°, which is called the total field of view (TFOV). At any one moment the detector sees only a small patch, called the instantaneous field of view (IFOV). The IFOV fixes the size of each ground cell. The image is built cell by cell and line by line.
Example
The scanners on the early US Landsat satellites, such as the Multispectral Scanner (MSS, 80 m), built their images with a sweeping mirror in this way.
Don't confuse with
- Pushbroom scanner: uses a straight line of many detectors, one for each ground cell, and records a whole line at once with no sweeping mirror. Examples are SPOT HRV and the IRS LISS cameras.
Related concepts
- Sensor
- Photographic sensor
- Multispectral scanner
- Swath
- Instantaneous field of view
- Pushbroom scanner
- Passive and active remote sensing
- Radar
- Synthetic aperture radar
- LiDAR