How to convert matrix to 1-D array and back to matrix form?

I have a matrix of size say, W X H, i have to convert the matrix into a 1-D array and perform some operations(bitxor) and again retrieve back my image in the same dimension ie W X H. How to do it? Thanks in advance.

Answer 1

[Stephen23]

Use reshape to do both of these:

>> A = [1,2,3,4;5,6,7,8]
A =
     1     2     3     4
     5     6     7     8
>> B = reshape(A,1,[]) % columnwise
B =
     1     5     2     6     3     7     4     8
>> B = reshape(A.',1,[]) % rowwise
B =
     1     2     3     4     5     6     7     8
>> reshape(B,size(A))
ans =
     1     3     5     7
     2     4     6     8

Note how one can use the transpose operator to select between columnwise and rowwise conversion from the matrix to the vector.

[j john]

Thanks @Stephen.. but what to do if the size of my 1-D array is changed?

[Stephen23]

If the number of elements has changed then you will have to decide yourself how this should be dealt with. You have many choices, such as:

• define a new size based on the new number of elements
• removing some values
• padding
• subsampling
• interpolating
• extrapolating
• etc

What do you want to do?

[j john]

okay... Thanks Stephen for helping me. I think i have to remove some elements to keep the number of elements same.