European Facility For Airborne Research April 4, 2025, 16:33
radiance: Measure of the energy radiated by an object. In general, radiance is a function of viewing angle and spectral wavelength and is expressed as energy per solid angle.
radiation: The process by which electromagnetic energy is propagated through any medium by virtue of wave motion variations in electric and magnetic fields.
radiometric calibration: Radiometric calibration consists in linking pixels intensities to a physical parameter.
radiometric resolution: The smallest difference in radiance that can be detected. Describes how precisely radiance is depicted in a set of data, as a result of both the sensor and subsequent data transformations such as analogue-to-digital conversion.
radiometric response: Radiometric response (the same as gain/slope/calibration coefficient) is a ratio between the input and output signals.
radiometric stability: Change of end-to-end instrument response between calibration cycles at a constant at-sensor radiance level.
raster: Refers to the two-dimensional array of pixels in an image.
real-time: The actual time during which something takes place [acc. to Meriam-Webster]. Characteristic in case of data transfers is a negligible time-delay between the data gathering and transmission.
rectification: Process by which a tilted or oblique image is projected onto a horizontal reference plane, the angular relation between the image and the plane being determined by ground reconnaissance.
red edge: Spectral region at the limit of the red and near-infrared wavelengths characterized by a sharp rise in the plant reflectance.
reflectance: The ratio of amount of electromagnetic energy reflected by a surface to amount of energy incident on the surface.
remote sensing: The measurement or acquisition of information of some property of an object or phenomenon, by a recording device that is not in physical or intimate contact with the object or phenomenon under study.
resampling: Rearrangement of the resolution of cells of each scanned line of an image into geometrically equal terrain elements.
research infrastructure: Refers to facilities, resources and related services used by the scientific community for leading edge research.
resolution: A measure of the ability to separate observable quantities.
roll: The rotation of an aircraft or spacecraft about its longitudinal axis (in the along-track direction) so as to cause a side-up or side-down attitude.