[Octave-bug-tracker] [bug #56796] imtransform changes the contrast of image when using bilinear interpolation

[anonymous]

URL:
  <https://savannah.gnu.org/bugs/?56796>

                 Summary: imtransform changes the contrast of image when using
bilinear interpolation
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Thu 22 Aug 2019 11:09:55 PM UTC
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 5.1.0
        Operating System: Microsoft Windows

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Details:

When transforming images with "imtransform" I noticed that the result with
bilinear interpolation did not give the expected result, but a brighter
image.
The attached image shows the transformed image with interpolation set to:
a) nearest neighbor ('nearest')
b) bilinear (default)
c) my own implementation of bilinear
d) bicubic
The interpolation option was the only parameter varied, and Octave's bilinear
result seems wrong.



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File Attachments:


-------------------------------------------------------
Date: Thu 22 Aug 2019 11:09:55 PM UTC  Name: interpolation.jpg  Size: 57KiB  
By: None

<http://savannah.gnu.org/bugs/download.php?file_id=47384>

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