Emulation
Bokeh can be simulated by convolving the image with a kernel that corresponds to the image of an out-of-focus point source taken with a real camera. Unlike conventional convolution, this convolution has a kernel that depends on the distance of each image point and – at least in principle – has to include image points that are occluded by objects in the foreground. Also, bokeh is not just any blur. To a first approximation, defocus blur is convolution by a uniform disk, a more computationally intensive operation than the "standard" Gaussian blur; the former produces sharp circles around highlights whereas the latter is a much softer effect. Diffraction may alter the effective shape of the blur. Some graphics editors have a filter to do this, usually called "Lens Blur."
An alternative mechanical mechanism has been proposed for generating bokeh in small aperture cameras such as compacts or cellphone cameras, called image destabilisation, in which both the lens and sensor are moved in order to maintain focus at one focal plane, while defocusing nearby ones. This effect currently generates blur in only one axis.
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Famous quotes containing the word emulation:
“Our children will not survive our habits of thinking, our failures of the spirit, our wreck of the universe into which we bring new life as blithely as we do. Mostly, our children will resemble our own misery and spite and anger, because we give them no choice about it. In the name of motherhood and fatherhood and education and good manners, we threaten and suffocate and bind and ensnare and bribe and trick children into wholesale emulation of our ways.”
—June Jordan (b. 1939)