We introduced a lifting scheme for quaternion signals on that unifies graph construction, node partitioning, and prediction weights through a single geometric quantity—the geodesic correlation , the radial coordinate of the foliation of . Spherical shell sectors in the relative-rotation domain group coarse neighbors that share similar rotation magnitude and direction, and a tensor-product cubic B-spline kernel weights them by three-dimensional geometric proximity. Prediction is fully intrinsic—angles averaged as scalars, axes as unit vectors on , and the result reconstructed via the exact axis-angle formula, with no log/exp maps or Euclidean normalization.
Sasan Sepehrirad (Tue,) studied this question.
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