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

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References in periodicals archive

The basic idea is to create a non-reversal pattern with two or three fiducial marks on the board or panel.

What makes a good fiducial? It all comes down to contrast and positional accuracy

Five EM-tracked fiducial marks were placed on the phantom or patient in order to create the "patient-space." In patients, the fiducial markers were placed on the patients' skin outside of the sterile field.

Application of Real-Time 3D Navigation System in CT-Guided Percutaneous Interventional Procedures: A Feasibility Study

Also, on the left and right margin of scanned aerial photographs, fiducial marks must be clearly visible.

Scanning aerial photos using a non-professional scanner

Up to three fiducial marks are selected in a learning procedure.

Optical-aligning selective soldering

This low error probability system based in application of hyperbolic wavelet transforms and integrated circuits photo masks fiducial marks geometric moment features.

The integrated circuits photo masks images alignment for automated optical inspection system

The chorobates was an elongated wooden platform, sometimes with a water-filled longitudinal groove, having plumb bobs on each end that were aligned with fiducial marks on the structure.

Finite elements, roman-style: a very professional corps of ancient engineers made a lasting contribution to Western civilization

Sampling for calculations of the average friction is restricted to the middle portions of each cycle, as indicated by fiducial marks. The peak is taken at the start of the first cycle.

New rubber friction testing machine

ONE OF THE handy aspects of getting boards assembled at Screaming Circuits is we don't require fiducial marks for standard process boards.

Fiducials and odd boards: not all boards need fiducials, but they do come in handy on challenging boards

PR enables a wire bonder to easily identify fiducial marks and other alignment features.

The benefits of good 'PR': teaching the wirebonder pattern recognition