defocus


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defocus

(de-fo'kus) [L. de, away from, + focus, hearth]
The blurring of a visual image caused by spherical aberration, chromatic aberration, or diffraction. Also called optical defocus. Synonym: optical defocus

optical defocus

Defocus.
Medical Dictionary, © 2009 Farlex and Partners

defocus

To put or go out of focus.
hyperopic defocus State of the eye in which the retinal image is focused behind the retina. It may occur when placing a negative lens in front of an emmetropic presbyopic eye; in an uncorrected presbyopic hyperope; in a high hyperope unable to overcome the ametropia by accommodating; or as an accommodative lag in an uncorrected or corrected myope, as well as in an emmetrope viewing a near object. See lag of accommodation; over-correction.
myopic defocus State of the eye in which the retinal image is focused in front of the retina. It may occur when placing a positive lens in front of an emmetropic eye; in an uncorrected or undercorrected myopic eye; or if there is a lead of accommodation, as is the case in some individuals viewing a distant object. See lead of accommodation; under-correction.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
We also compared the defocus curves of the dominant and nondominant eyes uniocularly at the last visit.
In Liu et al.'s method, a knife was used to bisect the detecting laser beam for bidirectional defocus detection.
where d is the full defocus map, [??] is the vector forms of the sparse defocus map, L is the matting Laplacian matrix, and D is diagonal matrix whose element [D.sub.ii] is 1 at edge regions and 0 otherwise and [lambda] is a parameter which balances fidelity to the sparse depth map and smoothness of interpolation.
Caption: FIGURE 4: Focus criteria values measured for defocus of 390 (a) Std, (b) entropy, (c) FFT, and (d) gradient.
where [DELTA][f.sub.p] is defocus of focal length caused by atmospheric pressure change; p is atmospheric pressure at certain altitude; [p.sub.0] is atmospheric pressure when camera is assembled on the ground; [n.sub.a] is refractive index of air; [n.sub.g] is refractive index of glass.
The slider on the right side of the screen will allow users to adjust the level of defocus either horizontally or vertically.
(2) As industry's first commercialization of DFD (depth from defocus) technology for cameras, as of February 7, 2014, according to Panasonic survey
Besides the above, we defined the laser output power as P, welding speed as V, side-blow shielding gas flow rate as [U.sub.f], defocus amount as [DELTA]Z, the cap width as [W.sub.u], the root width as [W.sub.b], and the weld penetration as [H.sub.p], respectively.
AN AZIMUTH VELOCITY ESTIMATOR BASED ON SYMMETRIC DEFOCUS FILTER BANK
The camera features the world's first 1.0-type Exmor CMOS sensor with a resolution of 20.2 effective megapixels and a bright F1.8 lens making it the perfect fit for a compact, pocket-sized second camera for enthusiasts who want to capture stills with defocus effect and Full HD video.
The focusing predicted by ray theory generally agrees with the experiment, although initially these rays defocus as they are caught in the dipole.