Sobel Edge Detection Filter

[indierektmusick]

Hey, i do have a question... the sobel mask is: 1 |0| -1 , 2 |0| -2, 1 |0| -1, but why the number 2 , 1 or 0?? The same effect appears with this mask: 7 |0| -7, 12 |0| -12, 7 |0| -7, (numbers just for example) right?? or has it anything to do with gradients? hope you right back. greets