pincushion distortion

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pincushion distortion

irregular image produced when axial magnification is greater than peripheral magnification. See: Petzval surface.

pincushion distortion

1 inward bowing of gridded straight lines in an image as a result of lens distortion.
2 the image of a square object thus resembling a pincushion or pillow.
3 a distortion of a fluoroscopic image associated with the use of image intensifier tubes. See also barrel distortion.

pin·cush·i·on dis·tor·tion

(pin'kush-ŭn dis-tōr'shŭn)
Irregular image produced when axial magnification is greater than peripheral magnification.
See: Petzval surface

distortion

Aberration of an optical system resulting in an image which does not conform to the shape of the object, somewhat resembling the image viewed through a cylindrical lens. This is due to an unequal magnification of the image. Distortion can be barrel-shaped (barrel-shaped distortion) in which the corners of the image of a square are closer to the centre than the middle part of the sides; or pincushion (pincushion distortion) in which the corners of the image of a square are farther from the centre than the middle part of the sides (Fig. D10). Example of barrel-shaped distortion: a square object seen through an uncorrected negative spectacle lens. Example of pincushion distortion: a square object seen through an uncorrected positive spectacle lens. See correction; fisheye lens; sine condition.
Fig. D10 Distortion (O, object; A, pincushion distortion; B, barrel-shaped distortion)enlarge picture
Fig. D10 Distortion (O, object; A, pincushion distortion; B, barrel-shaped distortion)
References in periodicals archive ?
The author acquired a second pincushion from an auction in Alabama, reportedly the property of an estate in Savannah, Georgia.
He's also taken to creating his own--cross-pollinating flowers to come up with pincushion hybrids, and grafting proteas he likes onto more vigorous rootstocks.
They've stood the test of time, having been cultivated in Britain since the 16th century, and have been fondly labelled with names such as Hattie's pincushion, great masterwort and melancholy gentlemen.
Its pretty, pincushion flowers are pink at first, but change gradually to a soft green before eventually fading to biscuit shades.
And yet, the idea is one that's positively thrilling, and Finnegan's 10-in-1 Circus Sideshow promises everything that makes that idea of sideshows exciting: a human pincushion, burlesque, a "Dragon Man" (whom one imagines breathes fire), a "Man-Eating Chicken" and - perhaps most importantly - a night of "magic and pizzazz," the idea that the world is stranger and cooler than we often notice.
Spent far too much money but then the Business Manager (Mrs P) collects porcelain pincushion dolls, or half dolls as they are often termed, so I was able to treat her.
As well as appealing to pincushion collectors, pigs in any shape or form are always popular items at auction.
Examining the Nikon we noted no astigmatism, curvature of field, rolling distortion, or pincushion distortion.
Lifto, pierced more than a pincushion, lifts heavy objects from said piercings, namely earlobes and nipples.
Look at how the roughened texture of The Ten Thousand Things, 1972, creates an optical pincushion, or how the pretty gray and pink undergrid of Where the Gods Reside, Per I-Per IV, 1968, is allowed to peek through the not-quite-joined patches of surface impasto.
Viewers will sit fascinated--especially those too young to remember the shows that exhibited them--as the Human Pincushion, Lobster Boy and Alligator Man, Seal Etta the Seal Girl, Zip the Pinheaded Man, and a panoply of Siamese twins, tattooed men, fat ladies, giants, and bearded women fill the screen.
When MS was added to her plate in 1991, "I was already a human pincushion," she laughed.