solved: misunderstand -threshold IM 6.4.4.-4
Posted: 2008-10-11T17:50:26-07:00
IM 6.4.4.-4 Q16 Mac OSX Tiger
I am having a problem getting a b/w only image (no color showing) when thresholding a single channel image. Either there is a bug or I do not understand something. Please correct me about my misconception if this is not a bug.
These two give a pure b/w only result:
convert rose: -threshold 50% rose_thresh50.png
convert rose: -colorspace gray -threshold 50% rose_gray_thresh50.png
But these two results still show some color in them and are not pure b/w:
convert rose: -channel G -separate -threshold 50% rose_green_thresh50.png
convert rose: -channel G -separate -colorspace gray -threshold 50% rose_green_gray_thresh50.png
Am I doing something wrong? How do I go about separating one channel from an image and thresholding it?
OK. I solved it. I need to turn back on all the channels as in:
convert rose: -channel G -separate -channel RGB -threshold 50% rose_green_rgb_thresh50.png
I am having a problem getting a b/w only image (no color showing) when thresholding a single channel image. Either there is a bug or I do not understand something. Please correct me about my misconception if this is not a bug.
These two give a pure b/w only result:
convert rose: -threshold 50% rose_thresh50.png
convert rose: -colorspace gray -threshold 50% rose_gray_thresh50.png
But these two results still show some color in them and are not pure b/w:
convert rose: -channel G -separate -threshold 50% rose_green_thresh50.png
convert rose: -channel G -separate -colorspace gray -threshold 50% rose_green_gray_thresh50.png
Am I doing something wrong? How do I go about separating one channel from an image and thresholding it?
OK. I solved it. I need to turn back on all the channels as in:
convert rose: -channel G -separate -channel RGB -threshold 50% rose_green_rgb_thresh50.png