Oblique photograph: A photograph taken with the camera axis intentionally
directed between the horizontal and the vertical. A high-oblique photograph
is one in which the apparent horizon is included within the field of view,
whereas a low-oblique does not include the apparent horizon within the field
of view.
Ocean Colour Scanner (OCS): Airborne scanner developed by DSTO which
is being modified and further developed by COSSA.; principally for water
mapping.
OCS: Ocean Colour Scanner.
Opponents colour theory: A theory of colour which uses three axes
in colour space, white-black, blue-yellow, and red-green. It corresponds
to the coding of signals from the retina to the brain, and to the method
of transmitting colour television signals. It is sometimes known as Taylor
colour space.
Orbit: (1) The path of a body or particle under the influence of
a gravitational or other force. For instance, the orbit of a celestial body
is its path relative to another body around which it revolves. (2) To go
around the Earth or other body in an orbit.
Orientation: Direction or arrangement with respect to other detail
or the direction in which a photograph is turned with respect to an observer
or map. A single photograph is best oriented for study when turned so that
the shadows are cast toward the observer.
Orthophotograph: Photograph having the properties of an orthographic
projection. It is derived from a conventional perspective photograph by
simple or differential rectification so that image displacements caused
by the camera tilt and terrain relief are removed.
Output: Information transferred from the internal storage of a computer
to external storage. This is usually a visible product, such as a classification
map for the user's evaluation and/or use (see also hardcopy) but may also
be a digital image which will be used for further processing.
Output image: Contains modified image values after processing.
Oversampling: (1) Image scanning process which results in the image
optical pixel size being larger than the geometric pixel size. (2) Rewriting
image geometry such that the output image contains a greater number of pixels
than the input image.