Question Regarding Covariance/Information Matrix

[magicbycalvin]

Greetings,

I had a question about estimating the Covariance/Information matrix of the resulting transform in order to use the ICP algorithm as a front end for graph SLAM. I noticed the value being computed in the prepare_system function. However that is a scalar value and I believe that I am looking for a 3x3 information matrix for graph SLAM in SE(2) (x and y positions along with heading angle theta).

I have come across a few methods suggesting that computing the Hessian of the error function should be able to provide me with the matrix I am looking for, but I wanted to check and see whether that is the appropriate method and whether the provided icp.ipynb notebook already computes it somewhere I am not seeing.

Thank you for your time!