dcm2pnm: Convert DICOM images to PPM/PGM, PNG, TIFF or BMP


dcm2pnm [options] dcmfile-in [pnmfile-out]


The dcm2pnm utility reads a DICOM image, converts the pixel data according to the selected image processing options and writes back an image in the well-known PPM/PGM file format (portable pix map / portable gray map), PNG, TIFF or BMP format. This utility only supports uncompressed and RLE compressed DICOM images. The command line tool dcmj2pnm also supports a number of JPEG compression schemes.


dcmfile-in   DICOM input filename to be converted

pnmfile-out  output filename to be written (default: stdout)


general options

  -h    --help
          print this help text and exit

          print version information and exit

  -v    --verbose
          verbose mode, print processing details

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

  -d    --debug
          debug mode, print debug information

  -im   --image-info
          info mode, print image details

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

processing options

frame selection:

  +F    --frame  [n]umber : integer
          select specified frame (default: 1)

  +Fr   --frame-range  [n]umber [c]ount : integer
          select c frames beginning with frame n

  +Fa   --all-frames
          select all frames


  +Rl   --rotate-left
          rotate image left (-90 degrees)

  +Rr   --rotate-right
          rotate image right (+90 degrees)

  +Rtd  --rotate-top-down
          rotate image top-down (180 degrees)


  +Lh   --flip-horizontally
          flip image horizontally

  +Lv   --flip-vertically
          flip image vertically

  +Lhv  --flip-both-axes
          flip image horizontally and vertically


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

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

  +i    --interpolate  [n]umber of algorithm : integer
          use interpolation when scaling (1..2, 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

modality LUT transformation:

  -M    --no-modality
          ignore stored modality LUT transformation

  +M    --use-modality
          use modality LUT transformation (default)

VOI LUT transformation:

  -W    --no-windowing
          no VOI windowing (default)

  +Wi   --use-window  [n]umber : integer
          use the n-th VOI window from image file

  +Wl   --use-voi-lut  [n]umber : integer
          use the n-th VOI look up table from image file

  +Wm   --min-max-window
          compute VOI window using min-max algorithm

  +Wn   --min-max-window-n
          compute VOI window using min-max algorithm,
          ignoring extreme values

  +Wr   --roi-min-max-window  [l]eft [t]op [w]idth [h]eight : integer
          compute ROI window using min-max algorithm,
          region of interest is specified by l,t,w,h

  +Wh   --histogram-window  [n]umber : integer
          compute VOI window using Histogram algorithm,
          ignoring n percent

  +Ww   --set-window  [c]enter [w]idth : float
          compute VOI window using center c and width w

presentation LUT transformation:

  +Pid  --identity-shape
          presentation LUT shape IDENTITY

  +Piv  --inverse-shape
          presentation LUT shape INVERSE

  +Pod  --lin-od-shape
          presentation LUT shape LIN OD


  -O    --no-overlays
          do not display overlays

  +O    --display-overlay  [n]umber : integer
          display overlay n (0..16, 0=all, default: +O 0)

  +Omr  --ovl-replace
          use overlay mode "Replace"
          (default for Graphic overlays)

  +Omt  --ovl-threshold
          use overlay mode "Threshold Replace"

  +Omc  --ovl-complement
          use overlay mode "Complement"

  +Omv  --ovl-invert
          use overlay mode "Invert Bitmap"

  +Omi  --ovl-roi
          use overlay mode "Region of Interest"
          (default for ROI overlays)

  +Osf  --set-foreground  [d]ensity : float
          set overlay foreground density (0..1, default: 1)

  +Ost  --set-threshold  [d]ensity : float
          set overlay threshold density (0..1, default: 0.5)

display LUT transformation:

  +Dm   --monitor-file  [f]ilename : string
          calibrate output according to monitor characteristics
          defined in f

  +Dp   --printer-file  [f]ilename : string
          calibrate output according to printer characteristics
          defined in f

  +Da   --ambient-light  [a]mbient light : float
          ambient light value (cd/m^2, default: file f)

  +Di   --illumination  [i]llumination : float
          illumination value (cd/m^2, default: file f)

  +Dn   --min-density  [m]inimum optical density : float
          Dmin value (default: off, only with +Dp)

  +Dx   --max-density  [m]aximum optical density : float
          Dmax value (default: off, only with +Dp)

  +Dg   --gsd-function
          use GSDF for calibration (default for +Dm/+Dp)

  +Dc   --cielab-function
          use CIELAB function for calibration

compatibility options:

  +Ma   --accept-acr-nema
          accept ACR-NEMA images without photometric

  +Mp   --accept-palettes
          accept incorrect palette attribute tags
          (0028,111x) and (0028,121x)

  +Mm   --ignore-mlut-depth
          ignore 3rd value of the modality LUT descriptor,
          determine bits per table entry automatically

  +Mv   --ignore-vlut-depth
          ignore 3rd value of the VOI LUT descriptor,
          determine bits per table entry automatically

TIFF options:

  +Tl   --compr-lzw
          LZW compression (default)

  +Tr   --compr-rle
          RLE compression

  +Tn   --compr-none

  +Pd   --predictor-default
          no LZW predictor (default)

  +Pn   --predictor-none
          LZW predictor 1 (no prediction)

  +Ph   --predictor-horz
          LZW predictor 2 (horizontal differencing)

  +Rs   --rows-per-strip  [r]ows : integer (default: 0)
          rows per strip, default 8K per strip

PNG options:

  +il   --interlace
          create interlaced file (default)

  -il   --nointerlace
          create non-interlaced file

  +mf   --meta-file
          create PNG file meta information (default)

  -mf   --meta-none
          no PNG file meta information

other transformations:

  +G    --grayscale
          convert to grayscale if necessary

  +P    --change-polarity
          change polarity (invert pixel output)

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

output options

  -o    --no-output
          do not create any output (useful with -im)

  +op   --write-raw-pnm
          write 8-bit binary PGM/PPM (default for files)

  +opb  --write-8-bit-pnm
          write 8-bit ASCII PGM/PPM (default for stdout)

  +opw  --write-16-bit-pnm
          write 16-bit ASCII PGM/PPM

  +opn  --write-n-bit-pnm  [n]umber : integer
          write n-bit ASCII PGM/PPM (1..32)

  +ob   --write-bmp
          write 8-bit (monochrome) or 24-bit (color) BMP

  +obp  --write-8-bit-bmp
          write 8-bit palette BMP (monochrome only)

  +obt  --write-24-bit-bmp
          write 24-bit truecolor BMP

  +ot   --write-tiff
          write 8-bit (monochrome) or 24-bit (color) TIFF

  +on   --write-png
          write 8-bit (monochrome) or 24-bit (color) PNG


The --write-tiff option is only available when DCMTK has been configured and compiled with support for the external libtiff TIFF library. The availability of the TIFF compression options depends on the libtiff configuration. In particular, the patented LZW algorithm may not be available.

The --write-png option is only available when DCMTK has been configured and compiled with support for the external libpng PNG library. Interlace enables progressive image view while loading the PNG file. Only a few applications take care of the metainfo (TEXT) in a png file.

Sample monitor and printer characteristics files are available in the data folder.


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 behaviour 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) prior to any further evaluation. Please note that a command file cannot contain another command file. This simple but effective approach allows to summarize common combinations of options/parameters and avoids longish and confusing command lines (an example is provided in file share/data/dumppat.txt).


The dcm2pnm 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 <PREFIX>/lib/dicom.dic will be loaded unless the dictionary is built into the application (default for Windows).

The default behaviour 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. 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.


share/data/camera.lut - sample characteristics file of a camera
share/data/monitor.lut - sample characteristics file of a monitor
share/data/printer.lut - sample characteristics file of a printer
share/data/scanner.lut - sample characteristics file of a scanner




Copyright (C) 1998-2005 by Kuratorium OFFIS e.V., Escherweg 2, 26121 Oldenburg, Germany.

Generated on 20 Dec 2005 for OFFIS DCMTK Version 3.5.4 by Doxygen 1.4.5