函数相加

void addWeighted(InputArray src1, double alpha, InputArray src2, double beta, double gamma, OutputArray
dst, int dtype=-1)

Parameters
src1 – First source array.
alpha – Weight for the first array elements.
src2 – Second source array of the same size and channel number as src1 .
beta – Weight for the second array elements.
dst – Destination array that has the same size and number of channels as the input arrays.
gamma – Scalar added to each sum.
dtype – Optional depth of the destination array. When both input arrays have the same
depth, dtype can be set to -1, which will be equivalent to src1.depth().
The function addWeighted calculates the weighted sum of two arrays as follows:
dst(I) = saturate(src1(I)  alpha + src2(I)  beta + gamma)
where I is a multi-dimensional index of array elements. In case of multi-channel arrays, each channel is processed
independently.
The function can be replaced with a matrix expression:
dst = src1*alpha + src2*beta + gamma;