EM 1110-2-2907
1 October 2003
Reflected energy peak
Wavelength (0.5 m) at which maximum amount of energy is reflected
from the earth's surface.
Reflected IR
Electromagnetic energy of wavelengths from 0.7 m to about 3 m that
consists primarily of reflected solar radiation.
Reflectivity
Ability of a surface to reflect incident energy.
Bending of electromagnetic rays as they pass from one medium into
another when each medium has a different index of refraction.
Registration
Process of superposing two or more images or photographs so that
equivalent geographic points coincide.
Relief
Vertical irregularities of a surface.
Relief displacement
Geometric distortion on vertical aerial photographs. The tops of objects
appear in the photograph to be radially displaced from their bases
outward from the photograph's center point.
Remote sensing
Collection and interpretation of information about an object without
being in physical contact with the object.
Resampling
The calculation of new DN for pixels created during geometric
correction of a digital scene, based on the values in the local area
around the uncorrected pixels.
Reseau marks
Pattern of small crosses added to photographs.
Resolution
Ability to separate closely spaced objects on an image or photograph.
Resolution is commonly expressed as the most closely spaced line-
pairs per unit distance that can be distinguished. Also called spatial
resolution.
Resolution target
Series of regularly spaced alternating light and dark bars used to
evaluate the resolution of images or photographs.
Resolving power
A measure of the ability of individual components. And of remote
sensing systems, to separate closely spaced targets.
Reststrahlen band
In the IR region, refers to absorption of energy as a function of silica
content.
Return
In radar, a pulse of microwave energy reflected by the terrain and
received at the radar antenna. The strength of a return is referred to as
return intensity.
Return-beam vidicon
A system in which images are formed on the photosensitive surface o
(RBV)
a vacuum tube; the image is scanned with an electron beam and
transmitted or recorded. Landsat 3 used a pair of RBV's to acquire
images.
Ringing
Fringe-like artifacts produced at edges by some forms of spatial-
frequency filtering.
Rods
The receptors in the retina that are sensitive to brightness variations.
Roll
Rotation of an aircraft that causes a wing-up or wing-down attitude.
Roll compensation system
Component of an airborne scanner system that measures and records
the roll of the aircraft. This information is used to correct the imagery for
distortion due to roll.
Rough criterion
In radar, the relationship between surface roughness, depression
angle, and wavelength that determines whether a surface will scatter
the incident radar pulse in a rough or intermediate fashion.
Roughness
In radar, the average vertical relief of a small-scale irregularities of the
terrain surface. Also called surface roughness
RMSE (Root Mean
The RMSE statistic is used to describe accuracy encompassing both
Square Error)
random and systematic errors. The square of the difference between a
true test point and an interpolated test point divided by the total number
of test points in the arithmetic mean. The square root of this value is the
root mean square error.
S
SAMII
Stratospheric Aerosol Measurement experiment, carried by Nimbus-7.
Glossary-25
Previous Page
