Sobel function documentation

I am looking for more documentation around the Sobel function arguments but I have been unable to find. Here is what I am after: This tutorial http://docs.opencv.org/2.4/doc/tutorials/imgproc/imgtrans/sobel_derivatives/sobel_derivatives.html calls : Sobel( src_gray, grad_x, ddepth, 1, 0, 3, scale, delta, BORDER_DEFAULT ); I understand src_gray, grad_x . What is ddepth for . What are the arguments 1,0, 3. What is scale and delta and BORDER_DEFAULT. I am unable to find this in the documentation anywhere.