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pfshdrcalibrate(1)	    General Commands Manual	    pfshdrcalibrate(1)

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 differ-
       ently exposed images supplied in	PFS stream.

       When used with 8bit images, luminance in	the output  HDR	 image	corre-
       sponds  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 mea-
       surement	error below 8%.	Use pfsabsolute	in case	of systematic error.

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

	      Allows to	choose from predefined response	curves.	 This  can  be
	      used  either  to apply this response or use it as	an initializa-
	      tion for automatic self-calibration. Predefined response	curves
	      are: "linear", "gamma", "log". Default is	"linear".

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

	      Type  of	automatic self-calibration method used for recovery of
	      the response curve. Accepted types include: "none", "robertson",
	      "mitsunaga". Default is "robertson". In case "none" is chosen, a
	      predefined response will be used,	without	self-calibration. More
	      infomation 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  Recogni-
	      tion (CVPR'99). Volume 1,	p. 1374

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

	      Sigma  value  for	the Gaussian used as a weighting function. Ap-
	      plies to Robertson02 algorithm. Default value: 16.0f

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

	      Use response curve saved in the matlab format  file.  Turns  off
	      automatic	 self-calibration. Uses	Robertson02 model to apply the
	      response curve.

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

	      Saves the	response curve calculated during automatic  self-cali-
	      bration  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 is 256 since LDR images  are  by
	      default scaled to	0..1.

       --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	sample pixels used in inverse response computations in
	      Mitsunaga	algorithm. Default is 50000.

       --fix-saturated,	-x

	      Use  this	 option	if you see black pixels	in overexposed / satu-
	      rated areas. The black pixels are	visible	if all exposures  con-
	      tain pixel values	that are outside reliable range	(are under- or
	      over-exposed). This flag gives non-zero weight for the brightest
	      and the darkest pixels, thus avoiding zero-weighted pixels. Note
	      that the calculated luminance values for these  pixels  are  not
	      reliable.

       --luminance, -Y

	      Recovery of response curve will be performed for luminance chan-
	      nel only.

       --verbose

	      Print additional information during program execution.

       --help

	      Print list of commandline	options.

EXAMPLES
       pfsinhdrgen sample.hdrgen | pfshdrcalibrate -v -s response.m

	      Recover the response curve from set of exposures defined in sam-
	      ple.hdrgen  and save it to response.m file. To view the response
	      curve, run gnuplot and write 'plot "response.m"'.

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

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

       pfsinhdrgen  sample.hdrgen  |  pfshdrcalibrate  -c  mitsunaga  -samples
       100000 |	pfsglview

	      Create an	HDR image from exposures defined in sample.hdrgen  us-
	      ing  the	mitsunaga  self-calibration method with	100000 samples
	      and view it in pfsglview.

SEE ALSO
       pfsinhdrgen(1) jpeg2hdrgen(1) pfsview(1)	 pfsindcraw(1)	pfsabsolute(1)
       pfsglview(1)

BUGS
       Please  report bugs and comments	on implementation to Grzegorz Krawczyk
       <gkrawczyk@users.sourceforge.net>.

							    pfshdrcalibrate(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | SEE ALSO | BUGS

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