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

[Fred Weinhaus]

Actually there is a simpler way, thanks to Anthony Thyssen:

convert example_rgb_gap.jpg \
	\( +clone -separate -compose darken -flatten -threshold 1 \) \
	-compose multiply -composite example_rgb_gap_proc3.jpg





>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.