1pfstmo_fattal02(1)          General Commands Manual         pfstmo_fattal02(1)
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NAME

6       pfstmo_fattal02 - Gradient domain high dynamic range compression
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SYNOPSIS

9       pfstmo_fattal02  [--alpha  <val>]  [--beta  <val>] [--saturation <val>]
10       [--noise <val>] [--verbose] [--help]
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DESCRIPTION

13       This command implements a tone mapping operator as described in:
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15       Gradient Domain High Dynamic Range Compression R. Fattal,  D.  Lischin‐
16       ski, and M. Werman In ACM Transactions on Graphics, 2002.
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18       With  respect  to  the original paper, this program provides additional
19       parameter which limits the amplification of noise. The noise  is  often
20       starkly  amplified  because of division by zero in one of the equations
21       in the paper. Extension contributed by Przemyslaw Bazarnik.
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23       Results of this TMO can be improved by using a gamma correction.
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OPTIONS

26       --alpha <val>, -a <val>
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28              Set alpha parameter. <val> defines the threshold gradient  value
29              (luminance differents of adjacent pixels) below which the gradi‐
30              ents are amplified (detail enhancement) and above which the gra‐
31              dients are attenuated (global contrast reduction).
32               Suggested  range  is  1  to  0.0001. It is reasonable to change
33              parameters by orders of magnitude, so for instance  trying  0.1,
34              0.01, 0.001 etc.  (see paper for details).
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36       --beta <val>, -b <val>
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38              Set  beta  parameter. <val> sets the strength of gradient (local
39              contrast) modification.  Suggested range is  0.8  to  0.96  (see
40              paper  for details).  Value of 1 does not change contrasts, val‐
41              ues above 1 reverse the effect: global contrast is stretched and
42              details  are  attenuated.   Values below 0.5 lead to very strong
43              amplification of  small  contrast,  so  consider  using  --noise
44              parameter close to 'alpha' value to prevent noise.
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46       --saturation <val>, -s <val>
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48              Amount  of  color  saturation.  Suggested  range  is 0.4 to 0.8.
49              Default value: 0.6.
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51       --noise <val>, -n <val>
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53              Reduces gradient amplification value for gradients  close  to  0
54              and  reduces  noise  in the result. <val> defines gradient value
55              (luminance differents of adjacent pixels) which  is  treated  as
56              noise.  Suggested  range  is  0.0 to the value of alpha. Default
57              value calculated based on alpha: 0.001*alpha.
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59       --verbose
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61              Print additional information during program execution.
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63       --help
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65              Print list of command line options.
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EXAMPLES

68       pfsin memorial.hdr | pfstmo_fattal02 -v |  pfsgamma  -g  2.2  |  pfsout
69       memorial.png
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71              Tone map image and save it in png format.
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SEE ALSO

74       pfsin(1) pfsout(1) pfsview(1)
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BUGS

77       Please  report bugs and comments on implementation to Grzegorz Krawczyk
78       <krawczyk@mpi-sb.mpg.de>.
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82                                                            pfstmo_fattal02(1)