打印图像与imagemagick不同的像素值?

让我们制作两张图片,宽3倍,高1倍:

convert xc:red xc:lime xc:blue +append 1.png

convert 1.png -flop 2.png

如果我们执行以下操作,可以使两幅图像中相同的任何像素变为透明:

convert {1,2}.png -compose changemask -composite mask.png     # Note that {1,2}.png is just bash shorthand for "1.png" "2.png"

如果我们重新排列输入图像:

convert {2,1}.png -compose changemask -composite mask.png     # Note that {2,1}.png is just bash shorthand for "2.png" "1.png"

convert {1,2}.png -compose changemask -composite txt: | grep -v ",0)"

输出

# ImageMagick pixel enumeration: 3,1,65535,srgba
0,0: (65535,0,0,65535)  #FF0000FF  red
2,0: (0,0,65535,65535)  #0000FFFF  blue

注意,如果您想允许图像之间有一点差异,可以添加一些 -fuzz 5 在命令开始时。

在Imagemagick 6中,可以执行以下操作列出两幅图像不同的坐标:

convert image1 image2 -compose difference -composite -threshold 0 txt: | tail -n +2 | grep "white" | awk '{print $1}' | sed 's/://g'

如果使用Imagemagick 7,请将convert更改为magick

如果需要两个图像中的一个同时包含坐标和颜色,则假设该图像没有完美的黑色像素,可以执行以下操作:

convert image1 image2 \
\( -clone 0,1 -compose difference -composite -threshold 0 \) \
-delete 1 \
-compose multiply -composite txt: |\
 tail -n +2 | grep -v "black" | awk '{print $1,$4}'

例如,我取lena图像,在左上角放置一个蓝色正方形来生成第二个图像。

输入:

convert lena.png \( -clone 0 -size 5x5 xc:blue -composite \) \
\( -clone 0,1 -compose difference -composite -threshold 0 \) \
-delete 1 \
-compose multiply -composite txt: |\
 tail -n +2 | grep -v "black" | awk '{print $1,$4}'

结果:

0,0: srgb(226,137,124)
1,0: srgb(224,137,130)
2,0: srgb(225,135,121)
3,0: srgb(228,134,121)
4,0: srgb(227,138,125)
0,1: srgb(226,137,124)
1,1: srgb(224,137,131)
2,1: srgb(225,135,121)
3,1: srgb(228,134,121)
4,1: srgb(227,138,126)
0,2: srgb(226,138,124)
1,2: srgb(224,136,127)
2,2: srgb(225,135,120)
3,2: srgb(228,134,121)
4,2: srgb(227,137,121)
0,3: srgb(228,137,122)
1,3: srgb(225,134,114)
2,3: srgb(225,134,118)
3,3: srgb(229,132,112)
4,3: srgb(227,133,113)
0,4: srgb(224,130,109)
1,4: srgb(223,132,110)
2,4: srgb(224,132,116)
3,4: srgb(226,131,112)
4,4: srgb(226,134,117)

convert image1 image2 \
\( -clone 0,1 -compose difference -composite -threshold 0 \) \
-delete 1 \
-alpha off -compose copy_opacity -composite \
-background black -alpha background txt: |\
 tail -n +2 | grep -v "none" | awk '{print $1,$4}'

例如:

convert lena.png \( -clone 0 -size 5x5 xc:blue -composite \) \
\( -clone 0,1 -compose difference -composite -threshold 0 \) \
-delete 1 \
-alpha off -compose copy_opacity -composite \
-background black -alpha background txt: |\
 tail -n +2 | grep -v "none" | awk '{print $1,$4}'

结果:

0,0: srgba(226,137,124,1)
1,0: srgba(224,137,130,1)
2,0: srgba(225,135,121,1)
3,0: srgba(228,134,121,1)
4,0: srgba(227,138,125,1)
0,1: srgba(226,137,124,1)
1,1: srgba(224,137,131,1)
2,1: srgba(225,135,121,1)
3,1: srgba(228,134,121,1)
4,1: srgba(227,138,126,1)
0,2: srgba(226,138,124,1)
1,2: srgba(224,136,127,1)
2,2: srgba(225,135,120,1)
3,2: srgba(228,134,121,1)
4,2: srgba(227,137,121,1)
0,3: srgba(228,137,122,1)
1,3: srgba(225,134,114,1)
2,3: srgba(225,134,118,1)
3,3: srgba(229,132,112,1)
4,3: srgba(227,133,113,1)
0,4: srgba(224,130,109,1)
1,4: srgba(223,132,110,1)
2,4: srgba(224,132,116,1)
3,4: srgba(226,131,112,1)
4,4: srgba(226,134,117,1)