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Name

ccddiffract - smoothing/diffracting an image

Synopsis

ccddiffract in=image out=image [parameter=value]

Description

ccddiffract will smooth and/or add diffraction patterns an image to make it look "pretty". It can also add some quasi poissonian noise.

In the current version a fraction of light is kept in the main gaussian beam, whereas another fraction is dispersed in the diffraction spikes.

Parameters

The following parameters are recognized in any order if the keyword is also given:
in=in-file
input file, in Image(5) format [no default]
out=out-file
output file, will be in Image(5) format [no default]
gauss=value
Beam size (FWHM, note FWHM = 2*sqrt(2*ln(2) ) = 2.355 * sigma) of a gaussian smoothing kernel. ignored [default: 0.05].
fraction=
Fraction of signal that is diffracted. The remainder is smoothed using a gaussian beam. [default: 0.1].
cutoff=
Signal below which no diffraction spikes are added.
spike=
The width of the spike. For the spike, a sqr(sinc(x)) is used, where the width is the distance to the first null. No signal beyond the first null is added. [default: 0.1].
noise=
Amount of noise. [default: 0].
bad=bad_value
Input pixel value which to skip in smoothing. [Default: not used]

Caveats

Should look at the code in STARLAB/src/star/rdc/make_ccd.C

See Also

ccdsmooth(1NEMO) , ccdfill(1NEMO) , snapccd(1NEMO) , snapgrid(1NEMO) , image(5NEMO)

Author

Peter Teuben

Files


src/image/trans         ccddiffract.c 

Update History


9-may-01    V0.1: Created from CCDSMOOTH    PJT


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