how to find sub matrixes in large one

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xuan hau nguyen 2017-4-14

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评论： xuan hau nguyen 2017-4-17

I try to find sub matrixes in large one. I read documents a lot, but didnt find functions support for this one please help me

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Stephen23 2017-4-14

编辑：Stephen23 2017-4-14

Basically loop over the indices and check the match using your chosen difference metric. There is no magic solution.

Image Analyst 2017-4-14

Well it might not be magic, but it might cut down on the number of lines if you use normxcorr2() and look for the max value, as I show in my demo below.

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Image Analyst 2017-4-14

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normxcorr2_demo.m

If you have the Image Processing Toolbox, you can use normxcorr2(). Demo m-file is attached below the image.

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Image Analyst 2017-4-15

在 MATLAB Online 中打开

I'm sure you've already tried it and proven it to yourself by now, but for what it's worth, here is my demo with your data:

% Read in data
data = csvread('data.txt');
subplot(2, 1, 1);
imshow(data, []);
[rows, columns] = size(data);
% Data is 28 x 721
% Create a 8 by 4 template
template = [...     % Will be found at data(6:13, 3:6)
     0    52    52     0
     0     0    52     0
     0     0     0    52
     0    52    52     0
    52    52     1     0
     0    52     0     0
     0     0    75     0
     0     0     0     0]
[rowsT, columnsT] = size(template);
% Now we have our large matrix and our template and we can begin:
% Find the normalized cross correlation.
c = normxcorr2(template, data); % c is 35 by 724
subplot(2, 1, 2);
imshow(c, []);
% Extract middle 28 x 721
c = c(rowsT:rowsT+rows-1, columnsT:columnsT+columns-1);
% Find where template occurs in data
[matchingRows, matchingColumns] = find(abs(c - 1) < 0.00001)
message = sprintf('That pattern shows up at row=%d, column = %d\nof the larger matrix', matchingRows, matchingColumns);
uiwait(helpdlg(message));