indices of intersection points of two logical arrays

Question

Amani 2013-1-18

1
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/59236-indices-of-intersection-points-of-two-logical-arrays

评论： Azzi Abdelmalek 2013-11-10

采纳的回答： Image Analyst

在 MATLAB Online 中打开

how can I find the indices of the intersection points of a binary image with a logical array

this is the code

//////////////////

f2= imread('anyBinaryImage');
norm2 = normalization(f2,128,128); % normalization function
f3= zeros(size(norm2));
a = ones(2,80);
f3(10:11,1:80) = a;
[g, k, c]= intersect(norm2,f3,'rows');

////////////////

but I got empty matrix, even though there are lots of intersection points between the image and the array

g =
   Empty matrix: 0-by-128
k =
   Empty matrix: 0-by-1
c =
   Empty matrix: 0-by-1

what should I do ?

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Walter Roberson 2013-1-19

The f3 you construct is not a logical array. zeros() and ones() create numeric arrays, not logical arrays. Initialize with false(size(norm2)) instead of zeros()

Amani 2013-1-21

thank you soooooo much for clarifying

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Answer 1

Image Analyst 2013-1-19

1
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https://ww2.mathworks.cn/matlabcentral/answers/59236-indices-of-intersection-points-of-two-logical-arrays#answer_71706

在 MATLAB Online 中打开

Try it this way:

% Find pixels in both binary images:
intersectionImage = f2 & f3;
% Now get the rows and columns of the intersecting pixels
% (for some unknown, unspecified, and probably unnecessary reason):
[rows columns] = find(intersectionImage);

Are you sure you really need the rows and columns of the intersections? I'd say that most likely you don't need them at all. The intersectionImage is enough to do whatever you're going to do.