fiducial marks


fiducial marks
Any marker built into an aerial camera that registers its image on an aerial photograph as a fixed reference mark in the form of an image is called a fiducial mark. These are usually four fiducial marks on a photograph and are used to define the principal point of the photograph. Their appearance on the image permits various calibrations, such as determination of the degree of enlargement needed to fit the picture to the rectification grids. Fiducial marks are also marks in any instrument that define the axes whose intersection fixes the principal point of a photograph and fulfills the requirements of interior orientation. These are also usually four in number. See collimating marks.

Aviation dictionary. 2014.

Look at other dictionaries:

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  • Fiduciary marker — A fiduciary marker or fiducial is an object used in the field of view of an imaging system which appears in the image produced, for use as a point of reference or a measure. It may be either something placed into or on the imaging subject, or a… …   Wikipedia

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