Function init_intrinsics 

pub fn init_intrinsics(
    homographies: &[Matrix3<f64>],
    width: u32,
    height: u32,
) -> Option<InitialIntrinsics>

Estimate initial intrinsics from per-view homographies and the image size.

Returns None if there are too few views or the focal-length solution is non-physical (non-positive squared focal length).