Provided by: pfstools_2.1.0-5build3_amd64 bug

NAME

       pfshdrcalibrate  -  Create  an  HDR  image  or  calibrate  a  response curve from a set of
       differently exposed images supplied in PFS stream.

SYNOPSIS

       pfshdrcalibrate [--response <type>] [--calibration <type>]  [--gauss  <val>]  [--response-
       file  <filename.m>]  [--save-response  <filename.m>]  [--multiplier  <val>]  [--bpp <val>]
       [--luminance] [--samples <val>] [--help] [--verbose]

DESCRIPTION

       Create an HDR image or calibrate a response curve from a set of differently exposed images
       supplied in PFS stream.

       When  used  with  8bit images, luminance in the output HDR image corresponds to real world
       values in [cd/m^2] provided that hdrgen script contained correct information  on  exposure
       time,  aperture  and iso speed. Note that sometimes ISO speed indicated by camera does not
       correspond to standard (ISO-100 is in fact ISO-125).

       The accuracy of absolute calibration has not been thoroughly tested with different  camera
       models, however one can expect the relative measurement error below 8%. Use pfsabsolute in
       case of systematic error.

OPTIONS

       --response <type>, -r <type>

              Allows one to choose from predefined response curves. This can be  used  either  to
              apply  this response or use it as an initialization for automatic self-calibration.
              Predefined response curves are: "linear", "gamma", "log". Default is "linear". This
              option can be used only with Robertson method.

       --calibration <type>, -c <type>

              Type  of  automatic self-calibration method used for recovery of the response curve
              and/or type of method used for HDR merging. Accepted  types  include:  "robertson",
              "mitsunaga".  "robertson" is the default and recommended algorithm (see commends in
              the Bugs section below). More information on the algorithms can be found in:

              M.A. Robertson,  S. Borman and R.L. Stevenson
              Dynamic range improvement through multiple exposures
              In: Proc. of International Conference  on  Image  Processing  1999  (ICIP  99),  pp
              159-163 vol.3

              and

              T. Mitsunaga and S. K. Nayar
              Radiometric Self Calibration
              In: Proc on IEEE Conf. on Computer Vision and Pattern Recognition (CVPR'99). Volume
              1, p. 1374

       --gauss <val>, -g <val>

              Sigma value for the Gaussian used as a  weighting  function  (in  the  range  0-1).
              Applies to Robertson02 algorithm. Default value: 0.2

       --response-file <filename.m>, -f <filename.m>

              Use  response  curve  saved  in  the  matlab format file. Turns off automatic self-
              calibration. Uses Robertson02 or Mitsunaga99 model to apply the response curve (see
              -c option).

       --save-response <filename.m>, -s <filename.m>

              Saves  the  response  curve calculated during automatic self-calibration stage in a
              matlab format file. Can be later reused for  set  of  images  captured  with  given
              camera. Also works fine for plotting with gnuplot.

       --multiplier <val>, -m <val>

              Input  multiplier  value.  Can be used to manipulate the range of source exposures.
              Default value for Robertson method is 256 since LDR images are by default scaled to
              0..1. This value is set to 1.0 for Mitsunaga method.

       --bpp <val>, -b <val>

              Number of bits per pixel in input data from the camera. Default value is 8.

       --samples <val>, -p <val>

              Number  of samples used during the self-calibration in Mitsunaga algorithm. Default
              is 50000.

       --deghosting, -d

              EXPERIMENTAL. Try to use a simple rejection criterion to reduce ghosting  artifacts
              due  to  movement  in dynamic scenes. This is currently not well implemented to the
              results can be disappointing.

       --luminance, -Y

              Recovery of response curve will be performed for luminance channel only.

       --verbose

              Print additional information during program execution.

       --help

              Print list of command line options.

EXAMPLES

       pfsinme *.JPG | pfshdrcalibrate -v -s response.m | pfsview

              Recover the response curve from set of all JPEG files in the current directory  and
              save  it  to  response.m  file.  To  view  the  response curve, use pfsplotresponse
              command.

       pfsinme *.CR2 | pfssize  --maxx 1200 | pfshdrcalibrate -r linear  -v  --bpp  16  |  pfsout
       result.exr

              Read  Camera  RAW images (from Canon), resize them so that the image width is equal
              or less 1200 pixels, merge them into an HDR image using all 16 bits and save as  an
              Open EXR image.

       pfsinhdrgen sample.hdrgen | pfshdrcalibrate -x -f response.m | pfsview

              Create  an  HDR  image  from  exposures defined in sample.hdrgen using the response
              curve "response.m" and view  it.  Fix  the  problem  with  black  values  given  to
              overexposed pixels.

       pfsinhdrgen sample.hdrgen | pfshdrcalibrate | pfsview

              Create an HDR image from exposures defined in sample.hdrgen using the default self-
              calibration method and view it.

       pfsinhdrgen sample_dcraw.hdrgen | pfshdrcalibrate -b 16 -r linear -c none | pfsview

              Given  that  the  script  sample_dcraw.hdrgen  refers  to  camera  RAW  files  (see
              pfsindcraw), this example will generate an HDR image assuming a linear response.

       pfsinhdrgen sample.hdrgen | pfshdrcalibrate | pfsview

              Create an HDR image from exposures defined in sample.hdrgen using the default self-
              calibration method and view it.

       pfsinhdrgen  sample.hdrgen   |   pfshdrcalibrate   -c   mitsunaga   -samples   100000   -s
       resp_mitsunaga.m >/dev/null

              Create  an  HDR  image  from exposures defined in sample.hdrgen using the mitsunaga
              self-calibration method with 100000 samples and save it to "resp_mitsunaga.m".

SEE ALSO

       pfsplotresponse(1) pfsinhdrgen(1) jpeg2hdrgen(1) pfsview(1)  pfsindcraw(1)  pfsabsolute(1)
       pfsglview(1)

BUGS

       Currently  Mitsunaga  and Nayar's method does not produce reliable camera response curves.
       Robertson's method should be used instead.

       Robertson's method may banding or wrong  colors  in  strongly  over-saturated  and  under-
       saturated  areas.  For  best results, there should be a sufficient numbers of exposures in
       which no pixels is over- or under-saturated in all the exposures. It is  possible  to  fix
       these issues with some heuristics (as most HDR merging software does), but it is currently
       not done in this release. pfscalibration was meant to be used for  research  purposes  and
       getting  accurate  result  is  more  important  than  generating  good looking images. The
       heuristics could hide the well visible artifacts, but would also introduce  error  to  the
       measurements.

       For  any  other issues please report bugs and comments on implementation to the discussion
       group http://groups.google.com/group/pfstools

                                                                               pfshdrcalibrate(1)