如何在MATLAB中获取非零元素的边界框? [英] How to get the bounding box of non-zero elements in MATLAB?

问题描述

假设我有一个矩阵(通过 imread )作为以下:

Let's say, I have a matrix (by imread) as following:

A = [0 0 1 0 0; 
     0 0 1 0 0; 
     0 1 1 1 0; 
     0 0 1 0 0; 
     0 0 0 0 0];

我想得到非零元素的边界框

I would like to get the bounding box of non-zero elements as

BB = show_me_the_bounding_box(A);
BB = [1, 2, 4, 4]; % y0, x0, y1, x0

我应该使用什么功能?

推荐答案

要获得所需的结果，请使用:

To get the result you want, please use:

[y,x] = ind2sub(size(A), find(A))
coord = [y, x]
[min(coord) max(coord)] % [1 2 4 4]

但是请注意，使用正确的约定，边界框为:

Note however that, with the correct conventions, the bounding box is:

[y,x] = ind2sub(size(A), find(A))
coord = [x, y]
mc = min(coord)-0.5
Mc = max(coord)+0.5
[mc Mc-mc] % [1.5 0.5 3 4]

产生与以下结果相同的结果:

which yields the same result as:

stats = regionprops(A, 'BoundingBox')
BB = stats.BoundingBox % [1.5 0.5 3 4]

通过使用以下代码，可以轻松地将代码适应3D图像:

The code can easily be adapted to 3D images, by using:

[y,x,z] = ind2sub(size(A), find(A));
coord = [x, y, z];
mc = min(coord)-0.5;
Mc = max(coord)+0.5;
[mc Mc-mc]

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