如何使用 linux 控制台在图像中搜索子图像?

本文介绍了如何使用 linux 控制台在图像中搜索子图像?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我必须使用控制台在较大的图像中搜索较小图像的出现.结果我想接收它的图像坐标.有哪些可能的解决方案?

I have to search for the occurrence of a smaller image in a larger one using the console. As result I want to receive it`s image coordinates. What solutions are possible?

我听说过 ImageMagick，但并不真正了解它是如何工作的.如果它足够了，那么我会很感激一个示例命令.

I heard about ImageMagick, but not really understand how it works. If it`s enough, then I would appreciate an example command.

谢谢.

推荐答案

这里有一个小例子，你可以看看它是如何工作的......

Here's a little example so you can see how it works...

首先，我们的针头图像

现在做一个干草堆，绿色和蓝色 - 非常时尚:-)

Now make a haystack, green and blue - very stylish :-)

convert -size 256x256 gradient:lime-blue haystack.png

现在在大海捞针中隐藏两根针，一次一根，没什么花哨的:

Now hide two needles in the haystack, one at a time, nothing fancy:

convert haystack.png needle.png -geometry +30+5 -composite haystack.png
convert haystack.png needle.png -geometry +100+150 -composite haystack.png

现在在大海捞针中搜索，会产生两个输出文件，locations-0.png和locations-1.png

Now search for the needles in the haystack, two output files will be produced, locations-0.png and locations-1.png

compare -metric RMSE -subimage-search haystack.png needle.png locations.png > /dev/null 2>&1

这是第二个更有用的输出文件locations-1.png.在 IM 确定没有匹配项的情况下，它是黑色的，并且随着 ImageMagick 越确定存在匹配项，它会逐渐接近白色.

This is the second, more useful output file locations-1.png. It is black where IM is sure there is no match and progressively nearer to white the more certain ImageMagick is that there is a match.

现在查找 IM 95+% 确定匹配的位置，并将所有像素转换为文本，以便我们可以搜索单词 white.

Now look for locations where IM is 95+% certain there is a match and convert all pixels to text so we can search for the word white.

convert locations-1.png -threshold 95% txt: | grep white

输出是这样的，这意味着 ImageMagick 在 30,5 和 100,150 处找到了针——正是我们将它们藏起来的地方！告诉过你这是魔法！

The output is this, meaning ImageMagick has found the needles at 30,5 and 100,150 - exactly where we hid them! Told you it was Magic!

30,5: (255,255,255)  #FFFFFF  white
100,150: (255,255,255)  #FFFFFF  white

这是整个脚本，因此您可以运行它并使用它:

Here is the entire script so you can run it and play with it:

#!/bin/bash
convert -size 256x256 gradient:lime-blue haystack.png                      # make our haystack
convert haystack.png needle.png -geometry +30+5 -composite haystack.png    # hide our needle near top-left
convert haystack.png needle.png -geometry +100+150 -composite haystack.png # hide a second needle lower down

# Now search for the needles in the haystack...
# ... two output files will be produced, "locations-0.png" and "locations-1.png"
compare -metric RMSE -subimage-search haystack.png needle.png locations.png > /dev/null 2>&1

# Now look for locations where IM is 95% certain there is a match
convert locations-1.png -threshold 95% txt: | grep white

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Haystack