[Octave-bug-tracker] [bug #51264] imread incorrect results (vs python matlab results)

[mac cordel]

URL:
  <http://savannah.gnu.org/bugs/?51264>

                 Summary: imread incorrect results (vs python matlab results)
                 Project: GNU Octave
            Submitted by: markiko
            Submitted on: Mon 19 Jun 2017 11:47:47 AM UTC
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: markiko
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.0.0
        Operating System: GNU/Linux

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Details:

I noticed the problem when processing large amount of images using octave. A
very few of my images (3 so far out of 500) are read by Octave (via imread) as
grayscale images (i.e. mxn) whereas I'm expecting all images as RGB images
(i.e. mxnx3). It does not flag an error so I was not aware until I encounter
some matrix dimension error in my post processing. I traced the root cause and
found out indeed some images are read as grayscale images. I never encountered
this error when I was using python and matlab so I tried to investigate for
hours. Until now, I have no idea why Octave reads it as grayscale. 

I verified again the dimension of these images using Python and Matlab, and
they are indeed read as RGB images. I am attaching the actual image (0594.jpg)
if you want to replicate my findings. Also some screenshots (output.pdf) to
give you my results.



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File Attachments:


-------------------------------------------------------
Date: Mon 19 Jun 2017 11:47:47 AM UTC  Name: 0594.jpg  Size: 64kB   By:
markiko
I added additional file &quot;0081.jpg&quot; for additional test data
<http://savannah.gnu.org/bugs/download.php?file_id=40935>
-------------------------------------------------------
Date: Mon 19 Jun 2017 11:47:47 AM UTC  Name: 0081.jpg  Size: 114kB   By:
markiko
I added additional file &quot;0081.jpg&quot; for additional test data
<http://savannah.gnu.org/bugs/download.php?file_id=40936>
-------------------------------------------------------
Date: Mon 19 Jun 2017 11:47:47 AM UTC  Name: output.pdf  Size: 794kB   By:
markiko
I added additional file &quot;0081.jpg&quot; for additional test data
<http://savannah.gnu.org/bugs/download.php?file_id=40937>

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