Chi-square Distance

Classical Chi-square Formula
$\hspace{8mm}\chi^2{(I,M)} = \sum_{j=1}^n \frac{(I_j - M_j)^2}{I_i+M_j + eps}$

Weighted Chi-square Formula
$\hspace{8mm}\chi^2{(I,M)} = \sum_{j=1}^n \frac{w_j(I_j - M_j)^2}{I_i+M_j + eps}\\ \hspace{12mm}其中: \\ \hspace{16mm} w可以通过学习得到$