Function describe_corners 

pub fn describe_corners(
    img: &[u8],
    w: usize,
    h: usize,
    radius: u32,
    corners: Vec<Corner>,
    method: OrientationMethod,
) -> Vec<CornerDescriptor>

Convert raw corner candidates into full descriptors by sampling the source image and running the chosen OrientationMethod at each corner.

Orientation and polarity follow the conventions documented on CornerDescriptor. When method is OrientationMethod::DiskFit and the candidate count exceeds an internal cap, only the strongest candidates run the full-disk estimator; the rest fall back to ring-fit transparently.