3 * 3 Sobel Matrix | |||||||||||
NE-SW | E-W | NW-SE | N-S | ||||||||
0 | 1 | 2 | −1 | 0 | 1 | 2 | 1 | 2 | 1 | 2 | 1 |
−1 | 0 | 1 | −2 | 0 | 2 | 1 | 0 | −1 | 0 | 0 | 0 |
−2 | −1 | 0 | −1 | 0 | 1 | 0 | −1 | −2 | −1 | −2 | −1 |