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Basic Information on sigest
Task: sigest
Purpose: Estimate the rms level in an image.
Categories: map analysis
SIGEST is a Miriad task which attempts to estimate the rms noise
level in an image. It does this by determining statistics of a
clipped version of the image data. Based on the statistics of
clipped Gaussian noise, the rms is then estimated. This
assumes that the image pixels, after clipping, are dominated by noise.
SIGEST will work poorly on images containing significant sidelobes.
Key: in
The input image dataset. No default.
Key: clip
The clip level to use. Pixels are excluded from the calculation
if their absolute value is greater than the clip value. Ideally
the clip should be about 2 to 3 times the rms noise level.
The default uses an initial estimate of the rms to set the clip
at 2.5 times the rms.
Key: region
The standard image region of interest of the input. See the help
on region for more information. The default is the entire image.