Scroll to navigation

dcm2pnm(1) OFFIS DCMTK dcm2pnm(1)


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


dcm2pnm [options] dcmfile-in [bitmap-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 PGM/PPM (portable gray map / portable pix map), PNG, TIFF or Windows 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
bitmap-out  output filename to be written (default: stdout)


general options

-h --help
print this help text and exit
print version information and exit
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 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 rotation:
+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) flipping:
+Lh --flip-horizontally
flip image horizontally
+Lv --flip-vertically
flip image vertically
+Lhv --flip-both-axes
flip image horizontally and vertically 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 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
+Wfl --linear-function
set VOI LUT function to LINEAR
+Wfs --sigmoid-function
set VOI LUT function to SIGMOID presentation LUT transformation:
+Pid --identity-shape
set presentation LUT shape to IDENTITY
+Piv --inverse-shape
set presentation LUT shape to INVERSE
+Pod --lin-od-shape
set presentation LUT shape to LIN OD overlay:
-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:
+Ma --accept-acr-nema
accept ACR-NEMA images without photometric
+Mp --accept-palettes
accept incorrect palette attribute tags
(0028,111x) and (0028,121x)
+Mc --check-lut-depth
check 3rd value of the LUT descriptor, compare
with expected bit depth based on LUT data
+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 format:
+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 format:
+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 color image to grayscale (monochrome)
+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


-im --image-info
print image details (requires verbose mode)
-o --no-output
do not create any output (useful with -im) filename generation (only with --frame-range or --all-frames):
+Fc --use-frame-counter
use 0-based counter for filenames (default)
+Fn --use-frame-number
use absolute frame number for filenames image format:
+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
+obr --write-32-bit-bmp
write 32-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
+on2 --write-16-bit-png
write 16-bit (monochrome) or 48-bit (color) PNG


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

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.

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


dcm2pnm supports the following transfer syntaxes for input (dcmfile-in):

LittleEndianImplicitTransferSyntax             1.2.840.10008.1.2
LittleEndianExplicitTransferSyntax             1.2.840.10008.1.2.1
DeflatedExplicitVRLittleEndianTransferSyntax   1.2.840.10008. (*)
BigEndianExplicitTransferSyntax                1.2.840.10008.1.2.2
RLELosslessTransferSyntax                      1.2.840.10008.1.2.5

(*) if compiled with zlib support enabled


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.


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).


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 <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.


<datadir>/camera.lut - sample characteristics file of a camera
<datadir>/monitor.lut - sample characteristics file of a monitor
<datadir>/printer.lut - sample characteristics file of a printer
<datadir>/scanner.lut - sample characteristics file of a scanner


dcmj2pnm(1), img2dcm(1)


Copyright (C) 1998-2022 by OFFIS e.V., Escherweg 2, 26121 Oldenburg, Germany.

Fri Apr 22 2022 Version 3.6.7