In OpenCV, what's the difference between CV_8U and CV_8UC1?

Question

In OpenCV, is there a difference between CV_8U and CV_8UC1? Do they both refer to an 8-bit unsigned type with one channel? If so, why are there two names? If not, what\'s the di

Answer 1

They should be the same. For me, I prefer to use CV_8UC1 since it makes my code more clear that how many number of channels I am working with.

However, if you are dealing with a matrix that has 10 channels or more, you need to specify the number of channels.

You may want to experiment with the number of channels using the code snippet below.

#define CV_MAT_ELEM_CN( mat, elemtype, row, col ) \
    (*(elemtype*)((mat).data.ptr + (size_t)(mat).step*(row) + sizeof(elemtype)*(col)))

...

CvMat *M = cvCreateMat(4, 4, CV_32FC(10));
for(int ch = 0; ch < 10; ch++) {
  for(int i = 0; i < 4; i++) {
    for(int j = 0; j < 4; j++) {
      CV_MAT_ELEM_CN(*M, float, i, j * CV_MAT_CN(M->type) + ch) = 0.0;
      cout << CV_MAT_ELEM_CN(*M, float, i, j * CV_MAT_CN(M->type) + ch) << " ";        
    }
  }
  cout << endl << endl;
}
cvReleaseMat(&M);

credit: http://note.sonots.com/OpenCV/MatrixOperations.html