Performs the matrix transformation of every array element

dst = cv.transform(src, mtx)

Input

• src Source array that must have as many channels (1 to 4) as columns of mtx or columns-1 of mtx
• mtx floating-point transformation matrix.

Output

• dst Destination array of the same row/column size and depth as src. It has as many channels as rows of mtx

The function cv.transform performs the matrix transformation of every element of the array src and stores the results in dst:

• when columns of mtx equal channels of src:

  dst(I) = mtx * src(I)
  

• when columns of mtx equal channels+1 of src:

  dst(I) = mtx * [src(I); 1]
  

Every element of the N-channel array src is interpreted as N-element vector that is transformed using the MxN or Mx(N+1) matrix mtx to M-element vector - the corresponding element of the destination array dst.

The function may be used for geometrical transformation of N-dimensional points, arbitrary linear color space transformation (such as various kinds of RGB to YUV transforms), shuffling the image channels, and so forth.

Example

This function is equivalent to the following MATLAB code:

function dst = my_transform(src, mtx)
    % check sizes
    [I,J,N] = size(src);
    [MM,NN] = size(mtx);
    assert(N==1 || N==2 || N==3 || N==4, '1 to 4 channels');
    assert(N==NN || (N+1)==NN, 'Wrong dimensions');
    if N ~= NN, src(:,:,end+1) = 1; end

    % transform
    dst = zeros([I,J,MM], class(src));
    for i=1:I
        for j=1:J
            dst(i,j,:) = mtx * squeeze(src(i,j,:));
        end
    end
end