Legacy ImageMagick Discussions Archive

I want to convert RGB stereo pairs to gray anaglyph.
composite -stereo needs rgb images, so I need to convert color RGB to gray RGB. How?

In IM 6, grayscale images should still work, since IM replicates the gray image 3 times. Internally to IM, grayscale images have 3 channels. But I do not know if -stereo will work properly on 3 equal grayscale channels, since I have not tested that. So go ahead and try it.

Thanks much. Yes,
composite -stereo 0 rgt.jpg -colorspace gray lft.jpg -colorspace gray anagg.jpg
works "like Magick".

If the images are already grayscale, then you do not need -colorspace gray. This should work in IM 6. It won't work in IM 7, since in IM 7 grayscale images are single channel. So you would have to -combine 3 copies of the grayscale image to format as RGB.

The images are rgb to begin with. But gray anaglyph is usually better for checking stereo alignment.

Ideally, the -stereo operator should automatically convert a single channel image to 3 channel.