[magick-users] Need help covering up misalignment of RGB channels

[Fred Weinhaus]

try

convert example_rgb_gap.jpg -separate example_rgb_gap_%d.png
convert example_rgb_gap_0.png example_rgb_gap_1.png \
	-compose darken -composite example_rgb_gap_01.png
convert example_rgb_gap_2.png example_rgb_gap_01.png \
	-compose darken -composite -threshold 1 example_rgb_gap_mask.png
convert example_rgb_gap.jpg example_rgb_gap_mask.png \
	-compose multiply -composite example_rgb_gap_proc.jpg




>The attachment on my last post didn't go through.  An example of what 
>I am describing can be found here:
>
>http://www.magicpancakes.com/example_rgb_gap.jpg
>
>Hello all,
>I'm writing with what should be a relatively simple task.  I've never 
>tried to do anything beyond simple conversions, resizing, composites, 
>etc. using IM, so I'm sort of a newbie.
>I am starting with three individual images, representing R G and B 
>bands that I combine into a single RGB image.  In the resulting 
>image, the individual bands do not line up properly (an issue 
>inherent in the individual bands, not anything that I can control).  
>I've attached a small section as an example.
>I want to set the entire region to 0 while preserving the surrounding 
>areas where the RGB pixel value is correct.  In other words, if the 
>value is 0 on an individual band, it should be 0 in the final image.  
>I have been playing with fx statements, but I'm having trouble with 
>syntax, and it is SLOW.
>I know there must be a simple and FAST solution.  Perhaps creating a 
>mask from the individual bands and then applying it over the RGB 
>image?  I need to run this as a step in a script to process many of 
>these images (~11 mb each).
>Thanks for any suggestions.