This creates a circularly symmetric, Gaussian shapped kernel.
G is the orignal image with the gausing kernel applied.
This is only a problem when sharpening, for blurring the result is mathematically equivalent to the non-separable kernel and much faster. The kernel weights always sum to one and the clamping attribute is set on this kernel so no change in the input range of values will be effected by the application of this kernel. Creates a separable kernel with the specified sharpness and radius . The sharpness typically ranges from -1 for maximum blur, to 0 for no effect, to positive values up to about 10 for various degrees of sharpening. The radius can be any non-negative value.