"Calculates the first, second, third or mixed image derivatives using an extended Sobel operator"
"image"=cv_sobel("img","ddepth","xorder","yorder","ksize","mode")
"Input image"
"order of the derivative x"
"order of the derivative y"
"size of the extended Sobel kernel; it must be 1, 3, 5, or 7"
"It is used to set output image depth. If it is 1 then output image depth is cv2.CV_16S else if it is 2 then its cv2.CV_64F"
"Output image"
"Sobel"
"Calculates the first, second, third, or mixed image derivatives using an extended Sobel operator that convolves the image with the appropriate kernel."