The whiskbroom scanners consist of a single detector and a rotating mirror. In order to produce pictures in a large number of small spectral bands spanning the visible to middle infrared sections of the spectrum, the mirror is angled in such a way that when it completes a revolution, the detector sweeps throughout the field of vision between 90° and 120°. The scanner’s total Field of View (IFOV) refers to the whole area covered by the oscillating sensor. The sensor’s optical head is always positioned at a certain dimension known as the Instantaneous Field of View while scanning the whole field (IFOV).
(a) In a whiskbroom scanner, a single mirror is used to reflect light onto a single detector. The mirror moves back and forth to collect measurements from one pixel in the image at a time, whereas, in a push broom scanner, a line of detectors is arranged perpendicular to the flight direction. The image is collected one line at a time, with all of the pixels in a line measured simultaneously.
(b) A push broom scanner receives a stronger signal than a whiskbroom scanner because it looks at each pixel area for a long time.
(c) Push broom scanner is more sensitive than whiskbroom scanner. So it is needed to calibrate perfectly.
