dcmscale(1)                       OFFIS DCMTK                      dcmscale(1)

NAME
       dcmscale - Scale DICOM images


SYNOPSIS
       dcmscale [options] dcmfile-in dcmfile-out

DESCRIPTION
       The  dcmscale  utility  reads a DICOM image, scales it according to the
       command line settings and writes back the  DICOM  image.  This  utility
       only supports uncompressed and RLE compressed DICOM images.

PARAMETERS
       dcmfile-in   DICOM input filename to be scaled ("-" for stdin)

       dcmfile-out  DICOM output filename to be written ("-" for stdout)

OPTIONS
   general options
         -h    --help
                 print this help text and exit

               --version
                 print version information and exit

               --arguments
                 print expanded command line arguments

         -q    --quiet
                 quiet mode, print no warnings and errors

         -v    --verbose
                 verbose mode, print processing details

         -d    --debug
                 debug mode, print debug information

         -ll   --log-level  [l]evel: string constant
                 (fatal, error, warn, info, debug, trace)
                 use level l for the logger

         -lc   --log-config  [f]ilename: string
                 use config file f for the logger

   input options
       input file format:

         +f    --read-file
                 read file format or data set (default)

         +fo   --read-file-only
                 read file format only

         -f    --read-dataset
                 read data set without file meta information

       input transfer syntax:

         -t=   --read-xfer-auto
                 use TS recognition (default)

         -td   --read-xfer-detect
                 ignore TS specified in the file meta header

         -te   --read-xfer-little
                 read with explicit VR little endian TS

         -tb   --read-xfer-big
                 read with explicit VR big endian TS

         -ti   --read-xfer-implicit
                 read with implicit VR little endian TS

   image processing and encoding options
       scaling:

         +a    --recognize-aspect
                 recognize pixel aspect ratio when scaling (default)

         -a    --ignore-aspect
                 ignore pixel aspect ratio when scaling

         +i    --interpolate  [n]umber of algorithm: integer
                 use interpolation when scaling (1..4, default: 1)

         -i    --no-interpolation
                 no interpolation when scaling

         -S    --no-scaling
                 no scaling, ignore pixel aspect ratio (default)

         +Sxf  --scale-x-factor  [f]actor: float
                 scale x axis by factor, auto-compute y axis

         +Syf  --scale-y-factor  [f]actor: float
                 scale y axis by factor, auto-compute x axis

         +Sxv  --scale-x-size  [n]umber: integer
                 scale x axis to n pixels, auto-compute y axis

         +Syv  --scale-y-size  [n]umber: integer
                 scale y axis to n pixels, auto-compute x axis

       other transformations:

         +C    --clip-region  [l]eft [t]op [w]idth [h]eight: integer
                 clip rectangular image region (l, t, w, h)

       SOP Instance UID:

         +ua   --uid-always
                 always assign new SOP Instance UID (default)

         +un   --uid-never
                 never assign new SOP Instance UID

   output options
       output file format:

         +F    --write-file
                 write file format (default)

         -F    --write-dataset
                 write data set without file meta information

       output transfer syntax:

         +t=   --write-xfer-same
                 write with same TS as input (default)

         +te   --write-xfer-little
                 write with explicit VR little endian TS

         +tb   --write-xfer-big
                 write with explicit VR big endian TS

         +ti   --write-xfer-implicit
                 write with implicit VR little endian TS

       post-1993 value representations:

         +u    --enable-new-vr
                 enable support for new VRs (UN/UT) (default)

         -u    --disable-new-vr
                 disable support for new VRs, convert to OB

       group length encoding:

         +g=   --group-length-recalc
                 recalculate group lengths if present (default)

         +g    --group-length-create
                 always write with group length elements

         -g    --group-length-remove
                 always write without group length elements

       length encoding in sequences and items:

         +e    --length-explicit
                 write with explicit lengths (default)

         -e    --length-undefined
                 write with undefined lengths

       data set trailing padding (not with --write-dataset):

         -p=   --padding-retain
                 do not change padding
                 (default if not --write-dataset)

         -p    --padding-off
                 no padding (implicit if --write-dataset)

         +p    --padding-create  [f]ile-pad [i]tem-pad: integer
                 align file on multiple of f bytes and items on
                 multiple of i bytes

NOTES
       The  following preferred interpolation algorithms can be selected using
       the --interpolate option:

       • 1 = free scaling algorithm with interpolation from pbmplus toolkit

       • 2 = free scaling algorithm with interpolation from c't magazine

       • 3 = magnification algorithm with bilinear interpolation  from  Eduard
         Stanescu

       • 4  =  magnification  algorithm with bicubic interpolation from Eduard
         Stanescu

LOGGING
       The level of logging output of  the  various  command  line  tools  and
       underlying  libraries  can  be  specified by the user. By default, only
       errors and warnings are written to the  standard  error  stream.  Using
       option  --verbose  also  informational messages like processing details
       are reported. Option --debug can be used to get  more  details  on  the
       internal  activity,  e.g.  for debugging purposes. Other logging levels
       can be selected using option --log-level. In --quiet  mode  only  fatal
       errors  are reported. In such very severe error events, the application
       will usually terminate. For  more  details  on  the  different  logging
       levels, see documentation of module 'oflog'.

       In  case  the logging output should be written to file (optionally with
       logfile rotation), to syslog (Unix) or the event log  (Windows)  option
       --log-config  can  be  used.  This  configuration  file also allows for
       directing only certain messages to a particular output stream  and  for
       filtering  certain  messages  based  on the module or application where
       they are generated.  An  example  configuration  file  is  provided  in
       <etcdir>/logger.cfg.

COMMAND LINE
       All  command  line  tools  use  the  following notation for parameters:
       square brackets enclose optional  values  (0-1),  three  trailing  dots
       indicate  that multiple values are allowed (1-n), a combination of both
       means 0 to n values.

       Command line options are distinguished from parameters by a leading '+'
       or '-' sign, respectively. Usually, order and position of command  line
       options  are  arbitrary  (i.e.  they  can appear anywhere). However, if
       options are mutually exclusive the rightmost appearance is  used.  This
       behavior  conforms  to  the  standard  evaluation  rules of common Unix
       shells.

       In addition, one or more command files can be specified  using  an  '@'
       sign  as  a  prefix to the filename (e.g. @command.txt). Such a command
       argument is replaced by the content  of  the  corresponding  text  file
       (multiple  whitespaces  are  treated  as a single separator unless they
       appear between two quotation marks) prior to  any  further  evaluation.
       Please  note  that  a command file cannot contain another command file.
       This simple but effective  approach  allows  one  to  summarize  common
       combinations  of  options/parameters  and  avoids longish and confusing
       command lines (an example is provided in file <datadir>/dumppat.txt).

ENVIRONMENT
       The dcmscale utility will  attempt  to  load  DICOM  data  dictionaries
       specified  in the DCMDICTPATH environment variable. By default, i.e. if
       the  DCMDICTPATH  environment   variable   is   not   set,   the   file
       <datadir>/dicom.dic  will be loaded unless the dictionary is built into
       the application (default for Windows).

       The  default  behavior  should  be  preferred   and   the   DCMDICTPATH
       environment  variable  only used when alternative data dictionaries are
       required. The DCMDICTPATH environment variable has the same  format  as
       the  Unix  shell PATH variable in that a colon (':') separates entries.
       On Windows systems, a semicolon (';') is used as a separator. The  data
       dictionary  code  will  attempt  to  load  each  file  specified in the
       DCMDICTPATH environment variable. It is an error if no data  dictionary
       can be loaded.

COPYRIGHT
       Copyright  (C)  2002-2025  by OFFIS e.V., Escherweg 2, 26121 Oldenburg,
       Germany.

Version 3.7.0                   Mon Dec 15 2025                    dcmscale(1)
