Analog image processing is the use of an
optical computer
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultravio ...
to process physical,
optical images formed by light waves coming from an object, as opposed to the
digital image processing
Digital image processing is the use of a digital computer to process digital images through an algorithm. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing. It allo ...
and its use of
digital computers to process pixelated,
digital images
A digital image is an image composed of picture elements, also known as pixels, each with '' finite'', '' discrete quantities'' of numeric representation for its intensity or gray level that is an output from its two-dimensional functions f ...
. Correspondingly, a range of digital image processing techniques possess direct physical analogs. For example,
fast Fourier transform algorithms are commonly implemented in digital
phase correlation
Phase correlation is an approach to estimate the relative Translation (geometry), translative offset between two similar images (digital image correlation) or other data sets. It is commonly used in image registration and relies on a frequency-doma ...
and other digital image processing techniques. These digital
Fourier transforms
In mathematics, the Fourier transform (FT) is an integral transform that takes a function (mathematics), function as input then outputs another function that describes the extent to which various Frequency, frequencies are present in the origin ...
can be considered to be the digitized approximation of methods utilizing
Fourier transforming properties of an ideal lens.
References
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