Function extract_fpfh_features 

pub fn extract_fpfh_features(
    cloud: &PointCloud<Point3f>,
) -> Result<Vec<Vec<f32>>>

Extract FPFH features from a plain point cloud, estimating normals first.

Normals are estimated using k = 10 nearest neighbours. For better control, pre-compute normals with crate::normals::estimate_normals and call extract_fpfh_features_with_normals directly.

Returns a 33-element Vec<f32> descriptor per point.