The problem of robust registration in the case of anisotropic scaling has been investigated. Registration of two images using corresponding sets of fiducial points is sensitive to inaccuracies in point placement due to poor image quality or non-rigid distortions, including possible out-of-plane rotations. An approach aimed at the detection of the most unreliable points has been developed. It is based on the a priori knowledge of the sequential ordering of rotation and scaling. A measure of guilt derived from the anomalous geometric relationships is introduced. A heuristic decision rule allowing for deletion of the most guilty points is proposed. The approach allows for more precise evaluation of the translation vector. It has been tested on phantom images with known parameters and has shown satisfactory results.
Georgi J. Gluhchev,
"Robust registration in case of different scaling", Proc. SPIE 1898, Medical Imaging 1993: Image Processing, (14 September 1993); doi: 10.1117/12.154497; https://doi.org/10.1117/12.154497