GradientFilter

GradientFilter[data,r] gives the magnitude of the gradient of data, computed using discrete derivatives of a Gaussian of sample radius r.

GradientFilter[data,{r,σ}] uses a Gaussian with standard deviation σ.

GradientFilter[data,{{r1,r2,…},…}] uses a Gaussian with radius ri at level i in data.

Please visit the official Wolfram Language Reference for more details and examples on core symbols.