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A mark or shape used as a standard of reference for measurement, position or location. Fiducial images are used for alignment, tracking or identification. These images are typically simple geometric shapes of specific size and dimension and unique from any natural image features.…
See Digital file
File format
Set of structural conventions that define a wrapper, formatted data, and embedded metadata, and that can be followed to represent images, audiovisual waveforms, texts, etc., in a digital object. The wrapper component on its own is often colloquially called a file format. The formatted data may consist of one or more…
See Also Wrapper; Bitstream; Encoding; Digital file; Object (PREMIS term)
A skirty or wide spreading of light. In photography and imaging, the term "lens flare" is frequently encountered and refers to generally unwanted light scattered by internal reflections and lack of homogeneity in the lens. …
Flat fielding
Process that corrects for irregularities in pixel values caused by variations in pixel sensitivity in the camera sensor, dust or damage on a lens, uneven lighting, or distortions in the optical path to produce an image of uniform brightness. Flat fielding software can reduce non-uniformity in images. Lenses designed specifically for digital flat field imaging…
Focus stacking
A digital imaging process that combines multiple images focused on different distances at parallel planes on a three-dimensional object to produce an image with a greater depth of field than could be achieved with a single image. The technique is most commonly used in macro photography and photo microscopy.…
See Also File format; Encoding
Frequency response (audio)
This concept applies to any waveform, ranging from radio spectrum frequencies to earthquakes. The focus for this definition is sound, where the term is usually referenced to electronic amplifiers, microphones, loudspeakers, or other elements in a recording system. Frequency response is the measure of any system's output to an input signal of varying frequency (but…