4 ms·
W.r.t. running the edge detection twice. Is there a name for this operation? Finding points that are near an edge but not on the edge?
by TheLoneWolfling 11y ago
W.r.t. running the edge detection twice. Is there a name for this operation? Finding points that are near an edge but not on the edge?
- a_e_k 11y agoThe Laplacian.
- TheLoneWolfling 11y agoWeird. I hadn't made the connection with Physics there. I suppose it is a general mathematical operator. Thanks!
- a_e_k 11y agoYes, it's not exactly equivalent here but it's pretty close. Basically, Sobel kernels are analogous to the 1st derivative and the Laplacian is analogous to the 2nd. You'll also often see the Laplacian combined with a Gaussian (the "LoG" operator) for pre-smoothing since it tends to be particularly sensitive to any noise.
- TheLoneWolfling 11y agoBeing a second derivative, I suppose it would be. So does that mean that there are other kernels that approximate derivatives "better"? Like with finite differences?