Documentation - Matlab API - MISC - VL_GRAD

[IX,IY] = VL_GRAD(I) returns the finite gradient components IX,IY of the grayscale image I. I must be a two-dimensional matrix. The function uses central differences for all but the boundary pixels, for which it uses forward/backward differences as appropriate.

The function accepts the following options:

Type Central

Use either 'central', 'forward', or 'backward' differences for all but the boundary pixels.

See also: GRADIENT(), VL_HELP().