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gdcmconv

Langue: en

Version: 329626 (ubuntu - 24/10/10)

Section: 1 (Commandes utilisateur)

NAME

gdcmconv - .TH "gdcmconv" 1 "Thu Sep 16 2010" "Version 2.0.15" "GDCM"

NAME

gdcmconv - .SH "SYNOPSIS"
 
 gdcmconv [options] file-in file-out
 

DESCRIPTION

The gdcmconv command line program takes as input a DICOM file (file-in) and process it to generate an output DICOM file (file-out). The command line option dictate the type of operation(s) gdcmconv will use to generate the output file.

PARAMETERS

 
 file-in   DICOM input filename
 
 file-out  DICOM output filename
 

OPTIONS

PARAMETERS

 
   -i --input      DICOM filename
   -o --output     DICOM filename
 

OPTIONS

 
   -X --explicit            Change Transfer Syntax to explicit.
   -M --implicit            Change Transfer Syntax to implicit.
   -U --use-dict            Use dict for VR (only public by default).
      --with-private-dict   Use private dict for VR (advanced user only).
   -C --check-meta          Check File Meta Information (advanced user only).
      --root-uid            Root UID.
      --remove-gl           Remove group length (deprecated in DICOM 2008).
      --remove-private-tags Remove private tags.
      --remove-retired      Remove retired tags.
 

image options

 
   -l --apply-lut                      Apply LUT (non-standard, advanced user only).
   -P --photometric-interpretation %s  Change Photometric Interpretation (when possible).
   -w --raw                            Decompress image.
   -d --deflated                       Compress using deflated (gzip).
   -J --jpeg                           Compress image in jpeg.
   -K --j2k                            Compress image in j2k.
   -L --jpegls                         Compress image in jpeg-ls.
   -R --rle                            Compress image in rle (lossless only).
   -F --force                          Force decompression/merging before recompression/splitting.
      --compress-icon                  Decide whether icon follows main TransferSyntax or remains uncompressed.
      --planar-configuration [01]      Change planar configuration.
   -Y --lossy                          Use the lossy (if possible) compressor.
   -S --split %d                       Write 2D image with multiple fragments (using max size)
 

JPEG options

 
   -q --quality %*f           set quality.
 

JPEG-LS options

 
   -e --lossy-error %*i       set error.
 

J2K options

 
   -r --rate    %*f           set rate.
   -q --quality %*f           set quality.
   -t --tile %d,%d            set tile size.
   -n --number-resolution %d  set number of resolution.
      --irreversible          set irreversible.
 

general options

 
   -h   --help
          print this help text and exit
 
   -v   --version
          print version information and exit
 
   -V   --verbose
          verbose mode (warning+error).
 
   -W   --warning
          warning mode, print warning information
 
   -E   --error
          error mode, print error information
 
   -D   --debug
          debug mode, print debug information
 

special options

 
   -I --ignore-errors   convert even if file is corrupted (advanced users only, see disclaimers).
 

environment variable

 
   GDCM_ROOT_UID Root UID
 

Simple usage

gdcmconv is a great tool to convert broken DICOM implementation into properly parsable DICOM file. Usage is simply:

 
 gdcmconv input.dcm output.dcm
 

or if you prefer being explicit:

 
 gdcmconv -i input.dcm -o output.dcm
 

Eventhough gdcmconv can overwrite directly on the same file (input.dcm = output.dcm), it is recommended that user should first convert into a different file to make sure the bug is properly handled by GDCM.

Typical cases where you would want to use gdcmconv in its simple form:

convert non-cp246 conforming file into conforming cp246,
convert implicit little endian transfer syntax file meta header into proper explicit little endian transfer syntax,
convert the GE-13 bytes bug,
convert dual syntax file: implicit/explicit,
convert Philips dual Little Endian/Big Endian file,
convert GDCM 1.2.0 broken UN-2-bytes fields,
&...
All other broken files listed in the supported section.

When no option other is used, only the dataset is inspected. So encapsulated Pixel Data, for instance, is not inspected for well known bugs.

When doing this kind of work, this is usually a good idea to perform some kind of quality control, see gdcmconv Quality Control section (down below).

Typical usage

File Meta Header

Running

gdcmconv input.dcm output.dcm

Is not enough to recompute file meta header, when input file is buggy. You may want to use: --check-meta

 
 $ gdcmconv --check-meta input.dcm output.dcm
 

See typical cases such as: GE_DLX-8-MONO2-PrivateSyntax.dcm or PICKER-16-MONO2-No_DicomV3_Preamble.dcm from gdcmData.

Conversion to Explicit Transfer Syntax

To convert a file that was written using Implicit Transfer Syntax into Explicit Transfer Syntax simply use:
 
 $ gdcmconv --explicit uncompressed.dcm compressed.dcm
 

Compressing to lossless JPEG

To compress an uncompressed DICOM file to a JPEG Lossless encapsulated format:
 
 $ gdcmconv --jpeg uncompressed.dcm compressed.dcm
 

Compressing to lossy JPEG

To compress an uncompressed DICOM file to a JPEG Lossy encapsulated format:
 
 $ gdcmconv --lossy --jpeg -q 90 uncompressed.dcm compressed.dcm
 

Note:

-q is just one of the many way to specify lossy quality, you need to inspect the other cmd line flag to specify lossyness properties.

Compressing to lossless JPEG-LS

To compress an uncompressed DICOM file to a JPEG-LS Lossless encapsulated format:
 
 $ gdcmconv --jpegls uncompressed.dcm compressed.dcm
 

Compressing to lossy JPEG-LS

To compress an uncompressed DICOM file to a JPEG-LS Lossy encapsulated format:
 
 $ gdcmconv --lossy --jpegls -e 2 uncompressed.dcm lossy_compressed.dcm
 

Note:

-e (or --lossy-error) means that the maximum tolerate error is 2 for each pixel value

Compressing to lossless J2K

To compress an uncompressed DICOM file to a JPEG-2000 Lossless encapsulated format:
 
 $ gdcmconv --j2k uncompressed.dcm compressed.dcm
 

Compressing to lossy J2K

To compress an uncompressed DICOM file to a JPEG-2000 Lossy encapsulated format:
 
 $ gdcmconv --lossy -q 55,50,45 --j2k uncompressed.dcm lossy_compressed.dcm
 

Note:

-q is just one of the many way to specify lossy quality, you need to inspect the other cmd line flag to specify lossyness properties.

Compressing to lossless RLE

To compress an uncompressed DICOM file to a RLE Lossless encapsulated format:
 
 $ gdcmconv --rle uncompressed.dcm compressed.dcm
 

There is no such thing as lossy RLE compression.

Forcing (re)compression

Sometime it is necessary to use the --force option. By default when user specify --j2k and input file is already in JPEG 2000 encapsulated DICOM format then no operation takes places. By using --force you make sure that (re)compression operation takes places.

Real life example of why you would use --force:

When Pixel Data is missing data / is padded with junk
When you would like to make sure GDCM can handle decompression & recompression cycle

Decompressing a Compressed DICOM

 
 $ gdcmconv --raw compressed.dcm uncompressed.dcm
 

Changing the planar Configuration

Often RLE files are compressed using a different Planar Comnfiguration (RRR ... GGG... BBB...) instead of the usual triplet (RGB ... RGB ... RGB ). So upon decompression the Planar Configuration is 1. This is perfectly legal in DICOM, however this is unconventional, and thus it may be a good idea to also change the planar configuration and set it to the default :
 
 $ gdcmconv --raw --planar-configuration 0 compressed.dcm uncompressed1.dcm
 

To reinvert the planar configuration of file 'uncompressed1.dcm', simply do:

 
 $ gdcmconv --raw --planar-configuration 1 uncompressed1.dcm uncompressed2.dcm
 

Lossless Conversion

When talking about lossless conversion, there is an ambiguity that need to be understood. To achieve higher compression ratio, the RGB color space is usually not used, in favor of a YBR one. Changing from one color space to the other is (bit level) not lossless.

For more detail, see what are the true lossless transformations as described:

http://sourceforge.net/apps/mediawiki/gdcm/index.php?title=Color_Space_Transformations

Quality Control

One important part when using gdcmconv it to have a way to quality control the output.

You can use 3rd party tool to check the output of gdcmconv is correct.

DCMTK / dicom3tools

Using another DICOM implementation such as the one from DCMTK or dicom3tools can be a good process to check the output of gdcmconv.
For DCMTK use: dcmdump
For dicom3tools use: dcdump

VIM: vimdiff

You can setup your favorite editor to compare the output, for instance in vim:
 autocmd BufReadPre *.dcm set ro
 autocmd BufReadPost *.dcm silent %!dcmdump -M +uc '%'
 

then simply do:

 $ vimdiff input.dcm output.dcm
 

vbindiff

On unix you can visually compare binary file using the vbindiff command:
 $ vbindiff input.dcm output.dcm
 

SEE ALSO

gdcmdump(1), gdcmraw(1), gdcminfo(1)

Copyright (c) 2006-2010 Mathieu Malaterre

Un peu de science éloigne de Dieu, mais beaucoup y ramène.
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