The values within the 1D derivative filter is determined by the scale factor applied to $f(x+1)$ (1), $f(x)$ (0), and $f(x-1)$ (-1). Note that it is convention to ignore the denominator when computing the derivative filter.
The values within the 1D derivative filter is determined by the scale factor applied to $f(x+1)$ (1), $f(x)$ (0), and $f(x-1)$ (-1). Note that it is convention to ignore the denominator when computing the derivative filter.