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NoiseChisel - detect signal in a noisy image



NoiseChisel - detect signal in a noisy image


astnoisechisel [ OPTION...] ASTRdata


NoiseChisel is part of GNU Astronomy Utilities 0.4. NoiseChisel Detects and segments signal that is deeply burried in noise. It employs a noise-based detection and segmentation method enabling it to be very resilient to the rich diversity of shapes in astronomical targets.
For more information, please run any of the following commands. In particular the second contains a very comprehensive explanation of NoiseChisel's invocation: expected input(s), output(s), and a full description of all the options.
All options and their values:
$ astnoisechisel -P
Inputs/Outputs and options:
$ info astnoisechisel
Full section in manual/book:
$ info NoiseChisel
Full Gnuastro manual/book:
$ info gnuastro
If you couldn't find your answer in the manual, you can get direct help from experienced Gnuastro users and developers. For more information, please run:
$ info help-gnuastro
NoiseChisel options:
-B, --minskyfrac=FLT
Min. fraction of undetected area in tile.
-E, --skysubtracted
Input is Sky subtracted (for error estimation).
-h, --hdu=STR/INT
Extension name or number of input data.
-k, --kernel=STR
Filename of Kernel to convolve with input
HDU containing Kernel image.
Minimum number for S/N estimation.
Tessellation (tile grid):
Tile IDs in an image, the size of input.
-F, --remainderfrac=FLT
Fraction of remainder to split last tile.
No. of neighbors to use for interpolation.
Only interpolate over the blank tiles.
-L, --largetilesize=INT[,INT]
Sim. to --tilesize, but for larger tiles.
-M, --numchannels=INT[,..] No. of channels in dim.s (FITS order).
Only display 1 element/tile, not full input res.
Work (not tile) over channel edges.
-Z, --tilesize=INT[,INT]
Regular tile size on dim.s (FITS order).
-D, --dontdelete
Don't delete output if it exists.
Save grown clumps instead of original.
-K, --keepinputdir
Keep input directory for automatic output.
Stop at the end of detection.
-o, --output=STR
Output name.
`txt', `fits-ascii', `fits-binary'.
Save all the detection steps to a file.
Save Sky value estimation for pseudo-dets.
Save pseudo-detection S/N values to a file.
Save quantile threshold estimation in file.
-c, --detquant=FLT
Quantile in pseudo-det. to define true.
Final sky and its STD steps in a file.
Remove small S/N dilated objects.
-d, --dilate=INT
Number of times to dilate true detections.
4 or 8 connectivity in final dilation.
-e, --erode=INT
Number of erosions after thresholding.
4 or 8 connectivity in erosion.
-i, --detsnminarea=INT
Min. pseudo-detection area for S/N dist.
Quantile for no erosion.
4 or 8 connectivity in opening.
-p, --opening=INT
Depth of opening after erosion.
-Q, --modmedqdiff=FLT
Max. mode and median quant diff. per tile.
-r, --mirrordist=FLT
Max. dist. (error multip.) to find mode.
-R, --dthresh=FLT
Sigma threshold for Pseudo-detections.
Flat kernel width to smooth interpolated.
-s, --sigmaclip=FLT,FLT
Sigma multiple and, tolerance or number.
-t, --qthresh=FLT
Quantile threshold on convolved image.
Save Sky clump S/N values into a file.
Store segmentation steps in a file.
-g, --segquant=FLT
S/N Quantile of true sky clumps.
-G, --gthresh=FLT
Multiple of STD to stop growing clumps.
-m, --segsnminarea=INT
Minimum area of clumps for S/N estimation.
-O, --objbordersn=FLT
Min. S/N for grown clumps as one object.
-v, --keepmaxnearriver
Keep clumps with peak touching a river.
-y, --minriverlength=INT
Minimum len of useful grown clump rivers.
Operating modes:
-?, --help
give this help list
BibTeX citation for this program.
Read configuration file STR immediately.
-C, --continueaftercheck
Continue processing after checks.
Do not parse any more configuration files.
Information about output(s) in a log file.
Minimum bytes in array to not use ram RAM.
-N, --numthreads=INT
Number of CPU threads to use.
Only run if the program version is STR.
-P, --printparams
Print parameter values to be used and abort.
-q, --quiet
Only report errors, remain quiet about steps.
-S, --setdirconf
Set default values for this directory and abort.
give a short usage message
-U, --setusrconf
Set default values for this user and abort.
-V, --version
print program version
Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options.
GNU Astronomy Utilities home page:


Report bugs to Copyright © 2015-2017, Free Software Foundation, Inc. License GPLv3+: GNU General public license version 3 or later.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
Written/developed by Mohammad Akhlaghi


The full documentation for NoiseChisel is maintained as a Texinfo manual. If the info and NoiseChisel programs are properly installed at your site, the command
info NoiseChisel
should give you access to the complete manual.
September 2017 GNU Astronomy Utilities 0.4