Morph_files has 'discontinuities' in output

I tried to use morph_files to interpolate some 2D data. It works really well but there are discontinuities between the interpolated and actual frames.

To reproduce the issue

git clone gmic morph · GitHub
cd 10efd4aec866c6fc13eb3c9d9bec493c
chmod +x ./run.sh && ./run.sh

Looking at the output frames in frames (8-12):

8

9

10

11

12

It’s maybe not so visible by looking at the images in this forum but when looking at them in an animation the discontinuity becomes quite obvious and disturbing.

I’m not sure what’s actually causing this. Does anyone know of a way around this to make the sequence appear to be smooth?

I had a quick look, but I don’t think I see something disturbing. I’ll give a closer look later today.

Let me try another way to illustrate the issue:

These are the mean grey values (as reported by identify -verbose), based on the example data in the gist:

This is when running it on a longer series:

The peaks correspond to the original frames. In an animated sequence they show up as sort of flickering.

Ah, that’s interesting, and that would explain why I haven’t noticed this before, as I’ve always looked at the generated frames using the G’MIC image viewer that indeed normalizes image values.