OpenCV Error: Image step is wrong (The matrix is not continuous, thus its number

 of rows can not be changed) in unknown function,

According to the documentation the signature is

Mat Mat::reshape(int cn, int rows=) const

With the following meaning of the arguments:

• cn – New number of channels. If the parameter is 0, the number of channels remains the same.
• rows – New number of rows. If the parameter is 0, the number of rows remains the same.

Note that the number of columns is implicit -- it's calculated from the existing matrix properties and the two parameters.

According to this, the code

data = mu.reshape(, );

creates a 5-channel matrix of 5 rows and 1 column.

In order to reshape you matrix to a single channel 5x5 matrix, you have to do the following:

data = mu.reshape(, );

Alternately, since the input matrix is already single channel, you can also use

data = mu.reshape(, );

Besides:

there are 3 cases, where you'd get non-continuous Mat's.

• it's a roi
• bmp images and the like sometimes come padded
• you made a mat from a pixel pointer ( i.e some non-opencv capture device ) and that might be padded, too

since you have to reorder the memory in all those cases, checking for continuity and a clone() acll will solve it.

if ( ! mat.isContinuous() )

{

    mat = mat.clone();

}