Zero Mean Normalized Cross Correlation in Einstein Notation

I try to formulate the Zero-Mean Normalized Cross-Correlation in Einstein Notation. Thus without the Sigma's and with indices. I came up with the following but im not sure if the is correct and readable for others. What do you think?

$$C_{nm} = \frac{(I_{ij}-\hat I)(T_{i+n,j+m}-\hat T)}{\sqrt{(I_{ij}-\hat I)^2}(T_{i+n,j+m}-\hat T)^2}$$

with Image $$I_{ij}$$, Template $$T_{ij}$$, Image mean $$\hat I$$ and template mean $$\hat T$$