pamsistoaglyph man page on Pidora

Man page or keyword search:  
man Server   31170 pages
apropos Keyword Search (all sections)
Output format
Pidora logo
[printable version]

Pamsistoaglyph User Manual(0)			 Pamsistoaglyph User Manual(0)

NAME
       pamsistoaglyph  -  convert  a  single-image  stereogram	to  a red/cyan
       anaglyphic image

SYNOPSIS
       pamsistoaglyph [--invert] [--sep=number] [--minsep=number] [--gray=num‐
       ber] [in_netpbmfile

       All options can be abbreviated to their shortest unique prefix. You may
       use either white space or an equals sign between an option name and its
       value.

DESCRIPTION
       This program is part of Netpbm(1).

       pamsistoaglyph  reads  a	 Netpbm	 image	as input and produces a Netpbm
       image as output.

       pamsistoaglyph takes a single-image stereogram (SIS) such as those pro‐
       duced	by   <a	  href=	  "http://netpbm.sourceforge.net/doc/pamstere‐
       ogram.html">pamstereogram</a> and converts it to a red/cyan  anaglyphic
       image  such  as	those  produced by ppm3d(1).  Many people have trouble
       tricking their eyes into focusing beyond the image in front of them and
       are  therefore unable to perceive the 3-D shape hidden within a single-
       image stereogram.  Anaglyphic stereograms are easier to perceive in 3-D
       but  require  a	pair  of  red/cyan glasses such as those often used to
       watch 3-D movies. The goal of pamsistoaglyph is to help people who have
       trouble viewing single-image stereograms see the intriguing 3-D effect.

       pamsistoaglyph can convert single-image random-dot stereograms (SIRDS),
       wallpaper stereograms, and even dual-image  stereograms	to  anaglyphic
       images.

OPTIONS
       For most images, no command-line options need to be specified. The fol‐
       lowing options are available, however, for unusual circumstances:

       --invert
	      Swap the left- and right-eye
		  images. pamsistoaglyph assumes that its input
		  represents  a	 wall-eyed  stereogram	 and   generates   the
	      anaglyphic
		  image	 accordingly. If the generated image appears to recede
	      into
		  the page where it should pop	out  of	 the  page  (and  vice
	      versa),
		  this typically implies that the input image represents a
		  cross-eyed stereogram. Use --invert to correct
		  the image depth.

       --sep=number
	      Specify the distance in pixels between the left- and right-eye
		  images.   Essentially,  this	corresponds  to	 the  distance
	      between
		  repetitions of the background pattern.  The --sep
		  option should rarely be necessary
		  as pamsistoaglyph is fairly good at determining
		  automatically the eye-separation distance.

       --minsep=number
	      This option is similar to --sep but
		  constrains pamsistoaglyph only to
		  a minimum eye-separation distance. Any distance larger
		  than number is acceptable.  The --minsep
		  option should rarely be necessary
		  as pamsistoaglyph is fairly good at determining
		  automatically	 the  eye-separation  distance.	  The  default
	      value for
		  the  minimum	eye-separation	distance  is  10% of the image
	      width;
		  this value seems to work well in practice.

       --gray=number
	      Limit the number of gray levels to use when searching for the
		  optimal eye-separation
		  distance.  Because pamsistoaglyph looks for
		  repeated patterns, it is vulnerable  to  being  confused  by
	      slight
		  variations  in  color.   By  reducing	 the  input  image  to
	      grayscale and
		  capping the number of gray levels,
		  pamsistoaglyph ameliorates the effects of
		  unintentional color variations (such as those caused by con‐
	      version
		  from	a low-quality JPEG image, for example). The default of
	      63
		  seems to work well so the --gray option should
		  rarely be necessary.

NOTES
       The registration algorithm used by pamsistoaglyph was developed specif‐
       ically  for  this  program.  As	far  as the author knows, there are no
       existing algorithms for converting stereograms to anaglyphs.  The algo‐
       rithm works as follows:

       ·      Convert  the image to grayscale to increase the ability to iden‐
	      tify
		  matches.

       ·      Count the number of pixels that match N pixels ahead in the
		  image for all N in [1, width/2].

       ·      Maintain a running mean (μ) and standard deviation  (σ)
	      of
		  the number of matched pixels.

       ·      Store the N corresponding to each spike in the number of
		  matched  pixels.  A spike is defined as a tally that exceeds
	      the
		  mean plus one, two, or three standard deviations.  Only  the
	      first
		  spike of a given standard-deviation multiplier is stored.

       ·      If  a  tally  greater than μ+3σ was encountered, return
	      the
		  corresponding N. If not, then if a tally greater than
		  μ+2σ was encountered, return the
		  corresponding N. If not, then if a tally greater than
		  μ+σ was encountered, return the
		  corresponding N. If not, then return the N that
		  produces the minimum average distance between matched pixels
		  (i.e., #matches divided by #pixels). If no
		  such N exceeds the minimum allowable eye-separation value,
		  return zero to indicate failure.

       ·      If the algorithm returned zero,  rerun  the  algorithm  indepen‐
	      dently
		  on each row of the input image and return the median of
		  all N that exceed the minimum allowable eye-separation
		  value. If no such N exists, abort with an error
		  message.

HISTORY
       Scott  Pakin  wrote pamsistoaglyph in April 2009.  It first appeared in
       Netpbm in Release 10.47 (June 2009).

AUTHOR
       Copyright (C) 2009 Scott Pakin, scott+pbm@pakin.org.

SEE ALSO
       ·

	      pamstereogram(1)

       ·

	      ppm3d(1),

       ·

	      http://en.wikipedia.org/wiki/Stereogram
	      ⟨http://en.wikipedia.org/wiki/Stereogram⟩

netpbm documentation		 5 April 2009	 Pamsistoaglyph User Manual(0)
[top]

List of man pages available for Pidora

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net