func Subtract(src1, src2, dst *IplImage) {
	SubtractWithMask(src1, src2, dst, nil)
}
func Subtract(src1, src2, dst *IplImage) {
	SubtractWithMask(src1, src2, dst, nil)
}
func Subtract ( src1 , src2 , dst * IplImage ) { SubtractWithMask ( src1 , src2 , dst , nil ) }
// Calculates the per-element difference between two arrays.
//   dst = src1 - src2
Calculates the per - element difference between two arrays . dst = src1 - src2