defocus


Also found in: Dictionary, Medical, Wikipedia.

defocus

[dē′fō·kəs]
(engineering)
To make a beam of x-rays, electrons, light, or other radiation deviate from an accurate focus at the intended viewing or working surface.
References in periodicals archive ?
Figure 3(a) shows the binocular uncorrected and distance-corrected defocus curves under photopic conditions.
Distinguished from the image-based methods, optic-based autofocus methods adopt auxiliary optical paths for defocus detection, which have also been widely researched [6-11].
With its wide F1.8 aperture, it can produce impressive, exceptionally sharp portraits with soft background defocus that take advantage of its 85mm focal length and wide F1.8 maximum aperture.
The estimated blur amounts from the edge regions are propagated to other nonedge regions to form a defocus map.
(a) At Image plane, (b) defocus of 400 [micro]m, and (c) defocus of -400 [micro]m.
where [DELTA][f.sub.t] is defocus of the focal length caused by temperature change; f is focal length of the lens; [DELTA]T is temperature variation; [n.sub.g] is refractive index of glass; [[eta].sub.g] is [n.sub.g] variation under each Celsius; [[eta].sub.a] is refractive index of air variation under each Celsius.
Most of the high-end smartphones launched have the background defocus feature to give a DSLR style depth of focus effect.
The new lens allows photographers to capture snapshots with beautiful defocus features produced by F1.7 high speed.
This camera is the first in the industry(*2) to feature DFD (Depth from Defocus), a unique spatial perception technology that instantaneously detects distance according to the level of lens blur (defocus property), to improve auto focus performance in both speed and precision.
The employed parameters were optimized based on our experimental work; that is, laser output power was varied between 1kW and 3.5 kW, laser beam scanning velocity varied between 0.9 m/min and 3 m/min, and direction of the side-blow shielding gas was pointed to the opposite welding direction, with an angle of 35[degrees] to the horizon plane, flow rate of side-blow shielding gas of 5-25 L/min, and defocus amount of -3-2 mm.
The problem of catadioptric omnidirectional imaging defocus blur, which is caused by lens aperture and mirror curvature, becomes more severe when high resolution sensors and large apertures are used.
In regard to what BDI say, analyst Zidas Daskalovski believes that may be an attempt by BDI to attribute to themselves greater relevance but may also be an attempt to defocus the public from what is really going on behind closed doors.