1 .\" RCSid "$Id: falsecolor.1,v 1.8 2010/10/05 01:07:16 greg Exp $"

     2 .TH FALSECOLOR 1 11/15/93 RADIANCE

     3 .SH NAME

     4 falsecolor - make a false color RADIANCE picture

     5 .SH SYNOPSIS

     6 .B falsecolor

     7 [

     8 .B "\-i input"

     9 ][

    10 .B "\-p picture"

    11 ][

    12 .B "\-cb | \-cl"

    13 ][

    14 .B \-e

    15 ][

    16 .B "\-s scale"

    17 ][

    18 .B "\-l label"

    19 ][

    20 .B "\-n ndivs"

    21 ][

    22 .B "\-lw lwidth"

    23 ][

    24 .B "\-lh lheight"

    25 ][

    26 .B "\-log decades"

    27 ][

    28 .B "\-m mult"

    29 ][

    30 .B "\-pal palette"

    31 ][

    32 .B "\-r redv"

    33 ][

    34 .B "\-g grnv"

    35 ][

    36 .B "\-b bluv"

    37 ]

    38 .SH DESCRIPTION

    39 .I Falsecolor

    40 produces a false color picture for lighting analysis.

    41 Input is a rendered Radiance picture.

    42 .PP

    43 By default, luminance is displayed on a linear scale from 0 to 1000 nits, where

    44 dark areas are blue and brighter areas move through the spectrum to red.

    45 A different scale can be given with the

    46 .I \-s

    47 option.

    48 If the argument given to

    49 .I \-s

    50 begins with an "a" for "auto," then the maximum is used for scaling the result.

    51 The default multiplier is 179, which converts from radiance or irradiance

    52 to luminance or illuminance, respectively.

    53 A different multiplier can be given with

    54 .I \-m

    55 to get daylight factors or whatever.

    56 For a logarithmic rather than a linear mapping, the

    57 .I \-log

    58 option can be used, where

    59 .I decades

    60 is the number of decades below the maximum scale desired.

    61 .PP

    62 A legend is produced for the new image with a label given by the

    63 .I \-l

    64 option.

    65 The default label is "Nits", which is appropriate for standard Radiance

    66 images.

    67 If the

    68 .I -i

    69 option of

    70 .I rpict(1)

    71 was used to produce the image, then the appropriate label would be "Lux".

    72 .PP

    73 If contour lines are desired rather than just false color, the

    74 .I \-cl

    75 option can be used.

    76 These lines can be placed over another Radiance picture using the

    77 .I -p

    78 option.

    79 If the input picture is given with

    80 .I \-ip

    81 instead of

    82 .I \-i,

    83 then it will be used both as the source of values and as the picture

    84 to overlay with contours.

    85 The

    86 .I \-cb

    87 option produces contour bands instead of lines, where the thickness of

    88 the bands is related to the rate of change in the image.

    89 The

    90 .I \-n

    91 option can be used to change the number of contours (and corresponding

    92 legend entries) from the default value of 8.

    93 The

    94 .I \-lw

    95 and

    96 .I \-lh

    97 options may be used to change the legend dimensions from the default width

    98 and height of 100x200.

    99 A value of zero in either eliminates the legend in the output.

   100 .PP

   101 The

   102 .I \-e

   103 option causes extrema points to be printed on the brightest and

   104 darkest pixels of the input picture.

   105 .PP

   106 The

   107 .I "\-pal"

   108 option provides different color palettes for

   109 .I falsecolor.

   110 The current choices are

   111 .I spec

   112 for the old spectral mapping,

   113 .I hot

   114 for a thermal scale, and

   115 .I pm3d

   116 for a variation of the default mapping,

   117 .I def.

   118 The remaining options,

   119 .I "\-r, \-g,"

   120 and

   121 .I \-b

   122 are for changing the mapping of values to colors.

   123 These are expressions of the variable 

   124 .I v,

   125 where

   126 .I v

   127 varies from 0 to 1.

   128 These options are not recommended for the casual user.

   129 .PP

   130 If no

   131 .I \-i

   132 or

   133 .I \-ip

   134 option is used, input is taken from the standard input.

   135 The output image is always written to standard output, which should

   136 be redirected.

   137 .SH EXAMPLES

   138 To create a false color image directly from

   139 .I rpict(1):

   140 .IP "" .2i

   141 rpict \-vf default.vp scene.oct | falsecolor > scene.hdr

   142 .PP

   143 To create a logarithmic contour plot of illuminance values on a

   144 Radiance image:

   145 .IP "" .2i

   146 rpict \-i \-vf default.vp scene.oct > irrad.hdr

   147 .br

   148 rpict \-vf default.vp scene.oct > rad.hdr

   149 .br

   150 falsecolor \-i irrad.hdr \-p rad.hdr \-cl \-log 2 \-l Lux > lux.hdr

   151 .SH AUTHOR

   152 Greg Ward

   153 .br

   154 Axel Jacobs (Perl translation and -pal options)

   155 .SH ACKNOWLEDGEMENT

   156 Work on this program was initiated and sponsored by the LESO

   157 group at EPFL in Switzerland.

   158 .SH "SEE ALSO"

   159 getinfo(1), pcomb(1), pcompos(1), pextrem(1), pfilt(1), pflip(1), protate(1),

   160 psign(1), rpict(1), ximage(1)