Itseez/opencv — pull request #490 by mschoeler (2013-02-14 12:37:27+00:00)
Title: Added two kernels to existing SVM framework 

Histogram intersection kernel (accessible by using SVM::INTER in CV namespace as kernel_type)
Exponential chi2 kernel (accessible by using SVM::CHI2 in CV namespace as kernel_type)

Formulas:
Exp-CHI2
k(x,y) = exp(-gamma * CHI2(x,y))
CHI2(x,y) = 1- 2* SUM_i[(xi-yi)²/(xi+yi)]

Intersection
k(x,y) = SUM_i[min(xi,yi)]