bugGNU Octave - Bugs: bug #56796, [octave forge] (image) imtransform...

 
 

bug #56796: [octave forge] (image) imtransform changes the contrast of image when using bilinear interpolation

Submitted by:  None
Submitted on:  Thu 22 Aug 2019 11:09:55 PM UTC  
 
Category:  Octave Forge Package Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Need Info Assigned to:  None
Originator Name:  Originator Email:  -email is unavailable-
Open/Closed:  Open Release:  5.1.0
Operating System:  Microsoft Windows

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Sat 31 Aug 2019 06:49:49 PM UTC, comment #3: 

Could you also please explain what problem you see in your result image (b), generated with Octave's 'bilinear' interpolation method?

Hartmut <hardy>
Sat 31 Aug 2019 05:49:45 PM UTC, comment #2: 

To OP:
Can upload the image you haver used, your implementation of bilinear and the calling sequence to imtransform?

Thanks.

Avinoam Kalma <avinoam>
Project Member
Sat 31 Aug 2019 11:09:48 AM UTC, comment #1: 

Adding pkg maintainers

Avinoam Kalma <avinoam>
Project Member
Thu 22 Aug 2019 11:09:55 PM UTC, original submission:  

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.

Anonymous

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

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Attached Files
file #47384:  interpolation.jpg added by None (57KiB - image/jpeg)

 

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    Follow 6 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-09-09 avinoam StatusNone => Need Info
    2019-08-31 avinoam Carbon-Copy- => Added carandraug
        Carbon-Copy- => Added hardy
    2019-08-23 mtmiller CategoryOctave Function => Octave Forge Package
        Summaryimtransform changes the contrast of image when using bilinear interpolation => [octave forge] (image) imtransform changes the contrast of image when using bilinear interpolation
    2019-08-22 None Attached File- => Added interpolation.jpg, #47384

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