bugGNU Octave - Bugs: bug #35846, Imwrite inaccurate

 
 

bug #35846: Imwrite inaccurate

Submitted by:  None
Submitted on:  Thu 15 Mar 2012 08:12:22 AM UTC  
 
Category: InterpreterSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Inaccurate Result
Status: Works For MeAssigned to: None
Originator Name: Vladimir VasilievOriginator Email: -unavailable-
Open/Closed: ClosedRelease: 3.6.1
Operating System: GNU/Linux

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Thu 14 Mar 2013 05:40:52 PM UTC, comment #2:

Sorry, I accidently have missed your comment.

I have checked today on tip, nothing changed for me.

I attach copy of session; you can see configuration from it.

(file #27603)

Anonymous
Wed 11 Jul 2012 09:14:53 AM UTC, comment #1:

You code works(sum(sum(img-img2)) is zero) for me on a current tip(f71108f20a18) build on 11.Jul.2012

libgraphicsmagick++1 version is 1.3.16-1, Debian GNU/Linux testing (wheezy)

I have also opened the saved test.pgm in gimp, picked a color and checked that the graylevel on the diagonal equals to 50.

Also gm identify -verbose shows:

Andreas Weber <andy1978>
Project Member
Thu 15 Mar 2012 08:12:22 AM UTC, original submission:

Seems to be the same as bugs #29359 and #33317, but they point to MS Windows as os and old octave. Grayscale images are not saved well in such formats, as pgm, png or tiff.

I think the test in bug #33317 isn't very good because of one-dimension of img (it works well for me).

This code does not work in octave 3.6.1, GNU/Linux (graphicsmagick 1.3.14). Also tested in old octave 3.2.4 under windows - same result.

After saving I viewed image 'test.pgm' in xnview, using "Display color information" option and noticed, that pixels on diagonal have intencity 49, not 50.

I have also tried testing graphicsmagick with various grayscale images and did not notice any inaccuracy (i used 'gm convert input.pgm input.png' and 'gm compare -metric mse input.pgm input.png').

Anonymous

 

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Attached Files
file #27603:  octave-bug-imwrite.txt added by None (12KiB - text/plain - Log with configutation of my system.)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by rik5 (Updated the item)
  • -unavailable- added by andy1978 (Posted a comment)
  • -unavailable- added by None (Submitted the item)
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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Thu 14 Mar 2013 05:40:52 PM UTCNoneAttached File-=>Added octave-bug-imwrite.txt, #27603
    Thu 14 Mar 2013 03:29:11 AM UTCrik5StatusNone=>Works For Me
      Open/ClosedOpen=>Closed

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