Matlab：获取图像的子集 [英] Matlab: getting a subset of an image

问题描述

我试图从4个点获得图像的子集。遵循此处中给出的解决方案我找到了点并根据最大和最小x，y值对它们进行了排序。之后我做了：

I am trying to get a subset of an image from 4 points. Following the solution given in here I located the points and sorted them in terms of maximum and minimum x,y values. After that I did:

subim = image(x_min:x_max,y_min:y_max,:);

以获取由 x_min中包含的矩形形成的子图像：x_max，y_min：y_max ，但这不起作用。

in order to obtain a sub-image formed by the rectangle contained in x_min:x_max,y_min:y_max, but this didn't work.

我做错了什么？

推荐答案

喜欢@Divakar回答你，

Like @Divakar answer you,

matlab image 适用于行和列属性，如图1中的帮助所示。

matlab image works with row and columns attribute as you can see in figure 1 on this help.

在图2中，它们显示了如何（x，y） ）轴是定义的。如您所见， y 是行轴， x 列。

And in figure 2, they show how ( x , y ) axis are define. As you can see, y is the rows axis and x the columns.

因此当您使用 imshow 或 imtool 时得到一个图上的坐标，它显示在（x，y）而不是（row，col）。只需反转您的坐标，您就可以获得所需。

So when you are using imshow or imtool to get coordinate on a figure, it's show in (x,y) instead of (row,col). Just by inverting your coordinate, you'll get what you need.

请注意，并非所有库或langague都使用相同的顺序，例如python中的Numpy与Matlab相同，但OpenCV是反向的。

Be aware not all library or langague use the same order, like Numpy in python is same as Matlab but OpenCV is the inverse.

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