IFOV: Instantaneous Field of View.
Illuminance: Photometric measure of amount of light radiated onto
a surface. Radiometric equivalent is irradiance. Standard measurement unit
lm ft^-2 .
Image: (1) The counterpart of an object produced by the reflection
or refraction of light when focused by a lens or mirror. (2) The recorded
representation (commonly as a photo-image) of an object produced by optical,
electro-optical, optical mechanical, or electronic means. It is generally
used when the electromagnetic radiation emitted or reflected from a scene
is not directly recorded on film.
Image compression: Operation that reduces the amount of image data
and the time needed to transmit an image while preserving all or most of
the information in the image.
Image enhancement: Any one of a group of operations that improve
the detectability of the targets or categories, such as contrast improvement,
edge enhancement, spatial filtering, noise suppression, image smoothing,
and image sharpening.
Image processing (IP): Encompasses all the various operations that
can be applied to photographic or image data, such as image compression,
image restoration, image enhancement, preprocessing quantisation, spatial
filtering and other image pattern recognition techniques.
Image processing system: Any optical, electro-optical, or electronic
system capable of manipulating photographic or digital images and extracting
information from those images.
Image registration: Alignment process by which two images of the
same scene are positioned coincident with respect to each other so that
corresponding elements of the same ground appear in the same position on
the registered images.
Image restoration: Operation that restores a degraded image to its
original condition.
Image segmentation: Operation to determine which regions or areas
in an image constitute objects or patterns of interest.
Image striping: A defect produced in line-scanner imaging devices,
produced by non-uniform response of a single detector, or amongst a bank
of detectors.
Image transformation: Operation that takes an image as input and
produces an image with modified values as output.
Incidence angle: See angle of incidence.
Incident light: Light falling on an object. The colour of an object
is perceived as a function of the wavelengths of incident light reflected
or absorbed by it.
Incident radiation: Radiation impinging on a surface.
Infrared: Pertaining to energy in the 0.7-15.0 µm wavelength
region of the electromagnetic spectrum. For remote sensing, the infrared
wavelengths are often subdivided into near infrared (0.7-1.3 µm),
middle infrared (1.3-3.0 µm), and far infrared (7.0-15.0 µm).
Far infrared is sometimes referred to as thermal or emissive infrared.
Infrared, photographic: Pertaining to or designating the portion
of the EM spectrum with wavelengths just beyond the red end of the visible
spectrum; generally defined as from 700 to about 1100 nm, or the useful
limits of film sensitivities.
Inkjet plotter: A plotter which forms images by firing dots of ink
onto paper or transparent film.
Input: The process of entering data into a computer.
Input image: Image data file(s) which are input to a processing system.
Insolation: Incident solar energy.
Instantaneous field of view (IFOV): A term specifically denoting
the narrow field of view designed into detectors, particularly scanning
radiometer systems, so that, while as much as 120° may be under scan,
only radiation from a small area is being recorded at any one instant. (See
pixel, field of view).
Integration: Process of combining data in different formats from
various sources to a common geometrically registered base.
Intensity: (1) A measure of the energy reflected or emitted by an
object. (2) Amount of energy in all wavelengths of a colour; also called
value.
Interactive image processing: The use of an operator or analyst at
a console that provides the means of assessing, preprocessing, feature extracting,
classifying, identifying, and displaying the original imagery or the processed
imagery for his/her subjective evaluations and further interactions.
Interface: The junction between the components of a data processing
system.
Internet: Global computer network.
IR: Infrared.
Irradiance (E): Total energy radiated onto an object of unit area
per unit time. Standard measurement unit W m^-2.
Irradiation: The impinging of radiation on an object or surface.
Iterative: Repetitive. Often used when each succeeding 'iteration'
or repetition of a procedure comes closer to the desired result.