1Pamstereogram User Manual(0) Pamstereogram User Manual(0)
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6 Table Of Contents ⟨#contents⟩
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12 pamstereogram - create a single-image stereogram from a PAM height map
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16 pamstereogram [-help] [-verbose] [-blackandwhite | -grayscale | -color]
17 [-maxval=value] [-patfile=pamfile] [-xshift=pixels] [-yshift=pixels]
18 [-magnifypat=scale] [-guidesize=pixels] [-dpi=resolution] [-crosseyed]
19 [-makemask] [-eyesep=inches] [-depth=fraction] [-randomseed=integer]
20 [infile]
21
27 This program is part of Netpbm(1).
28 pamstereogram inputs a height map (a map of the distances from your eye
30 of the points in a scene) and outputs a single-image stereogram (SIS).
31 A SIS is a 2-D image specially designed to appear three dimensional
32 when viewed with relaxed, slightly unfocused eyes. What's exciting
33 about single-image stereograms is that they don't require special
34 glasses to view, although it does require a bit of practice to train
35 your eyes to unfocus properly. The pamstereogram program provides a
36 wealth of control over how the stereogram is generated, including the
37 following:
38 · black and white, grayscale, or color output
42 · single-image random-dot stereograms (SIRDS) or single-image
45 stereograms (SIS) using a tiled image
46 · images targeting a given device resolution and eye separation
49 · optional guide boxes to assist in focusing
52 · the ability to trade off depth levels for easier viewing
55 · choice of wall-eyed or cross-eyed stereograms
58 The output is a PAM image on standard output. Options control the
62 exact format of the PAM. If you want a PNM (PBM, PGM, or PPM) image,
63 use pamtopnm on the output. There is no need to convert if you will
64 use the image as input to a current Netpbm program, but many other pro‐
65 grams don't know what a PAM is.
66 To make a red/green type of stereogram (that you view with 3-D glasses)
68 instead, see ppm3d.
69
73 You may use either single or double hyphens to denote options. You may
74 use either whitespace or an equals sign to separate an option name from
75 its value.
76 -verbose
81 Display messages about image sizes and formats and properties of
82 the stereogram being generated.
83 -blackandwhite
86 Produce a single-image random-dot black-and-white stereogram.
87 This is the default.
88 -grayscale
91 Produce a single-image random-dot grayscale stereogram.
92 -color Produce a single-image random-dot color stereogram.
95 -maxval=value
98 Designate the maximum value of each gray/color component, i.e.
99 the color resolution. Smaller values make the output image have
100 smaller numbers of unique grays/colors. If you don't specify
101 -maxval, pamstereogram uses the maxval of the input image. This
102 option has no effect with -blackandwhite.
103 -patfile=pnmfile
106 Specify an image to use as a repeated background pattern for the
107 stereogram instead of a random-dot pattern. Intricate images
108 generally produce a crisper 3-D effect that simpler images. The
109 output file will have the same maxval and format (black and
110 white, grayscale or color) as the pattern file. You cannot spec‐
111 ify the -patfile option along with -blackandwhite, -grayscale,
112 -color, or -maxval.
113 -xshift=pixels
116 Shift the pattern image (designated by -patfile) to the right by
117 pixels pixels (default: 0). <!-- -xshift is helpful when creat‐
118 ing "true-color" stereograms. --> This option is valid only
119 along with -patfile.
120 -yshift pixels
123 Shift the pattern image (designated by -patfile) downwards by
124 pixels pixels (default: 0). This option is valid only along with
125 -patfile.
126 -magnifypat=scale
129 Magnify each pixel in the pattern file or each random dot by
130 integral scaling factor scale. Note that pamstereogram applies
131 the pattern magnification after pattern shifting (-xshift and
132 -yshift).
133 -guidesize=pixels
136 Draw a pair of pixels by pixels black squares on a white back‐
137 ground underneath the stereogram proper. These squares help you
138 guide your eyes into proper focus to view the 3-D image. The
139 trick is to focus your eyes some distance behind the image,
140 causing you to see four black squares, then continue altering
141 your focus distance until the middle two black squares fuse into
142 a single black square. At that point, a crisp, 3-D image will
143 appear.
144 If pixels is negative, pamstereogram will draw the guide squares
146 above the stereogram instead of below it. If pixels is zero (the
147 default), pamstereogram will draw no guide squares.
148 -dpi=resolution
152 Specify the resolution of the output device in dots per inch.
153 The default is 96 DPI, which represents a fairly crisp screen
154 resolution.
155 -crosseyed
158 Invert the gray levels in the height map (input image) so that
159 the 3-D image pops out of the page where it would otherwise sink
160 into the page and vice versa. Some people are unable to diverge
161 their eyes and can only cross them. The -crosseyed option
162 enables such people to see the 3-D image as intended.
163 -makemask
166 Instead of a stereogram, output a PAM mask image showing color‐
167 ing constraints. New pixels will be taken from the pattern file
168 where the mask is black. Copies of existing pixels will be taken
169 from the pattern file where the mask is white. The -makemask
170 option can be used to help create more sophisticated pattern
171 files (to use with -patfile) Note that -makemask ignores -magni‐
172 fypat; it always produces masks that assume a pattern magnifica‐
173 tion of 1.
174 -eyesep=inches
177 Specify the separation in inches between your eyes. The default,
178 2.5 inches (6.4 cm), should be sufficient for most people and
179 probably doesn't need to be changed.
180 -depth=fraction
183 Specify the output image's depth of field. That is, fraction
184 represents the fractional distance of the near plane from the
185 far plane. Smaller numbers make the 3-D image easier to perceive
186 but flatter. Larger numbers make the 3-D image more difficult to
187 perceive but deeper. The default, 0.3333, generally works fairly
188 well.
189 -randomseed=integer
192 Specify a seed to be used for the random number generator. The
193 default is to use a seed based on the time of day, to one second
194 granularity.
195 It is useful to specify the seed if you want to create repro‐
197 ducible results. With the same random seed, you should get
198 identical results every time you run pamstereogram.
199 This is irrelevant if you use a pattern file (-patfile option),
201 because there is no random element to pamstereogram's behavior.
202 This option was new in Netpbm 10.32 (Februrary 2006).
204
210 The only parameter, infile, is the name of an input file that is a
211 height map image. If you don't specify infile, the input is from stan‐
212 dard input.
213 The input is a PAM image of depth 1. Each sample represents the dis‐
215 tance from the eye that the 3-D image at that location should be.
216 Higher numbers mean further from the eye.
217 pamstereogram pays no attention the the image's tuple type and ignores
219 all planes other than plane 0.
220 Like any Netpbm program, pamstereogram will accept PNM input as if it
222 were the PAM equivalent.
223 A good initial test is to input an image consisting of a solid shape of
225 distance 0 within a large field of maximum distance (e.g., a black
226 square on a white background).
227
232 Generate a SIRDS out of small, brightly colored squares and prepare it
233 for display on an 87 DPI monitor:
234 pamstereogram heightmap.pam -dpi 87 -verbose -color -maxval 1 -magnifypat 3 >3d.pam
235 Generate a SIS by tiling a PPM file (a prior run with -verbose indi‐
237 cates how wide the pattern file should be for seamless tiling, although
238 any width is acceptable for producing SISes):
239 pamstereogram myheights.pam -patfile mypattern.ppm >mysis.pam
240
244 ·
245 pam(1)
247 ·
250 ppm3d(1)
252 · Harold W. Thimbleby, Stuart Inglis, and Ian H. Witten. Display‐
255 ing 3D Images: Algorithms for Single Image Random Dot Stere‐
256 ograms. In IEEE Computer, 27(10):38-48, October 1994. DOI
257 10.1109/2.318576 ⟨http://dx.doi.org/10.1109/2.318576⟩ .
258
264 pamstereogram was new in Netpbm 10.22 (April 2004), but probably broken
265 beyond usability until Netpbm 10.32 (Februrary 2006) and Netpbm
266 10.26.23 (January 2006).
267
271 Copyright (C) 2006 Scott Pakin, scott+pbm@pakin.org.
272
274 ·
275 SYNOPSIS ⟨#synopsis⟩
277 ·
279 DESCRIPTION ⟨#description⟩
281 ·
283 OPTIONS ⟨#options⟩
285 ·
287 PARAMETERS ⟨#parameters⟩
289 ·
291 EXAMPLES ⟨#examples⟩
293 ·
295 SEE ALSO ⟨#seealso⟩
297 ·
299 HISTORY ⟨#history⟩
301 ·
303 AUTHOR ⟨#author⟩
305netpbm documentation 6 January 2006 Pamstereogram User Manual(0)