How do i vectorize an image?

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Prashanna Jain 2015-10-14

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评论： Walter Roberson 2015-10-15

I am trying to break a square matrix of an image and create another vector which contains its column vector sub-blocks. I used the following code for it and getting an error

for i=1:50 a(i)=A(:,i)

The error says 'In an assignment A(I) = B, the number of elements in B and I must be the same.'

Please help me how i can solve my problem.

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Prashanna Jain 2015-10-15

i want to write an algorithm to find the KL Transform of the image, for which i need to vectorize the image to find the mean and covariance. converting it to grayscale and double will lead to loss in data..so i might have to use the coloured version.

Walter Roberson 2015-10-15

mean(Array) gives a vector of column means, you do not need to split it up. Likewise with std()

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回答（2 个）

Walter Roberson 2015-10-14

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https://ww2.mathworks.cn/matlabcentral/answers/248532-how-do-i-vectorize-an-image#answer_195924

在 MATLAB Online 中打开

a = mat2cell(A, size(A,1), ones(1,size(A,2)));

Now a{K} will be the column vector corresponding to A(:,K)

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Walter Roberson 2015-10-14

在 MATLAB Online 中打开

For RGB one solution would be

a = mat2cell(A, size(A,1), ones(1,size(A,2)), size(A,3));

This would create a{k} as being an N x 3 matrix, rather than creating the vectors that were asked for. Or you could use

a = mat2cell(A, size(A,1), ones(1,size(A,2)), ones(1,size(A,3)));

which would create a as an N x 3 cell array, each entry of which is a column vector.

Prashanna Jain 2015-10-15

but this is easy to implement for a 3x3 matrix..i will have to apply it on an image of about 100x100..writing it for the entire thing would be tedious no?

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