The CLEAN algorithm is a computational algorithm to perform a
deconvolution
In mathematics, deconvolution is the operation inverse to convolution. Both operations are used in signal processing and image processing. For example, it may be possible to recover the original signal after a filter (convolution) by using a deco ...
on images created in
radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation comin ...
. It was published by
Jan Högbom in 1974 and several variations have been proposed since then.
The family of CLEAN algorithms
a chapter from the ''MAPPING'' software manual
The algorithm assumes that the image consists of a number of point sources. It will iteratively find the highest value in the image and subtract a small gain of this point source convolved with the point spread function ("dirty beam") of the observation, until the highest value is smaller than some threshold.
Astronomer T. J. Cornwell writes, "The impact of CLEAN on radio astronomy has been immense", both directly in enabling greater speed and efficiency in observations, and indirectly by encouraging "a wave of innovation in synthesis processing that continues to this day." It has also been applied in other areas of astronomy and many other fields of science.
The CLEAN algorithm and its variations are still extensively used in radio astronomy, for example in the first imaging of the M87 central supermassive black hole by the Event Horizon Telescope
The Event Horizon Telescope (EHT) is a large Astronomical interferometer, telescope array consisting of a global network of radio telescopes. The EHT project combines data from several very-long-baseline interferometry (VLBI) stations around Ear ...
.
References
Radio astronomy
Computational astronomy
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