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

[Hartmut]

Follow-up Comment #6, bug #56796 (project octave):

Using a grayscale version of the attached image file in comment #0, I can
reproduce a brightness difference when resacling this image with imtransform.
The input image has an average brigthnessof 225, the rescaled image with
bicubic interpolation has also 225 mean brightness, but the rescaled image
with the (default) bilinear interpolation method has 230 mean brightness in my
case. (It is amazing how slight brightness differences the human eye can still
percive.)

This might hint to a problem in the bilinear interpolation method used by
imtransform. But imtransform uses the interp2 function from core Octave for
interpolation. And without further information I don't see a good way forward
to further point down this behavior.

So I agree, let's CLOSE this bug report for now.

    _______________________________________________________

Reply to this item at:

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

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/