[Octave-bug-tracker] [bug #63560] [octave forge] (image) imresize gives inaccurate result

[Raghavan]

Follow-up Comment #4, bug #63560 (project octave):

I verified that the problem is not visible by setting "antialiasing" as false.
 I was not able to compare pixel values numerically with an earlier version
since this option is not available in a previous version (octave:6.4.0,
image:2.12.0).

Since antialiasing is used only when down-sizing, I tried resizing to
[200,200] (up-sizing) instead of [100,100].  The stripe artifact was not seen
in both the older and newer (octave: 7.3.0, image: 2.14.0) versions.
In 7.3.0, I also verified that for [200,200] output size, the output was the
same with and without setting the "antialiasing" option as false.  This is as
expected.

One note however: While no visual difference was found between outputs for
6.4.0 and 7.3.0 for output size [200,200], there was a difference of up to 33
in pixel values when I took an image difference.  This may or may not be
another problem with bilinear interpolation.

Overall, I would agree that the original problem that I reported is due to a
bug in anti-aliasing, which seems to be reported already.


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