remote sensing scanners

cross-track scanners

• rotation or “back and forth” motion of the foreoptics (mirror)

• scans each ground resolution cell (pixel) one by one

along-track scanners

• multiple cross track scanners (no scanning motion)

• dwell time increase

• now dwell time = down pixel size/orbital velocity

• large arrays are more difficult to fabricate

• failure of one element means a loss/calibration error of an entire column of data

whisk-broom scanner

• mix of a cross track and push broom scanner

• scan with a small line array of detectors

• same wavelength for detectors

• longer dwell time

• different response sensitivities in each detector can cause striping

push-whisk scanner

• scanner with multiple spectral bands

• add cross track scanning with a line array

• scanning performed with a line array of detectors at different wavelengths

• short dwell time