分割出其中有孔的对象 [英] Segment out those objects that have holes in it

问题描述

我有一个二进制图像，其中有圆圈和正方形.

I have a binary image, that has circles and squares in it.

imA = imread('blocks1.png');

A = im2bw(imA);

figure,imshow(A);title('Input Image - Blocks');
imBinInv = ~A;
figure(2); imshow(imBinInv); title('Inverted Binarized Original Image');

某些圆形和正方形在其中具有小孔，因此，我必须生成一个图像，该图像仅包含其中具有孔/缺失点的那些圆形和正方形.我该如何编码?

Some circles and squares have small holes in them based on which, I have to generate an image which has only those circles and squares that have holes/missing point in them. How can I code that?

目的:稍后，在MATLAB中使用regionprops，我将从这些对象中提取出多少个圆和正方形的信息.

PURPOSE: Later on, using regionprops in MATLAB, I will extract the information that from those objects, how many are circles and squares.

推荐答案

您应该使用Euler特性.这是一个拓扑不变量，它描述了2D情况下对象中的孔数量.您也可以使用regionprops来计算它:

You should use the Euler characteristic. It's a topological invariant which describes the amount of holes in a object in the 2D case. You can calculate it using regionprops too:

STATS = regionprops(L, 'EulerNumber');

任何不带孔的单个对象的欧拉特征为1，任何带1个孔的单个对象的欧拉特征为0，两个孔-> -1等.因此，您可以用EC <; 1.计算也非常快.

Any single object with no holes will have an Euler characteristic of 1, any single object with 1 hole will have an Euler characteristic of 0, two holes -> -1 etc. So you can segment out all the objects with EC < 1. It's pretty fast to calculate too.

imA = imread('blocks1.png');

A = logical(imA);
L = bwlabel(A); %just for visualizing, you can call regionprops straight on A

STATS = regionprops(L, 'EulerNumber');

holeIndices = find( [STATS.EulerNumber] < 1 ); 

holeL = false(size(A));
for i = holeIndices
    holeL( L == i ) = true;
end

输出孔L:

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