Influence of Noise on the Results of Rigid Registration of Segmented Ovarian Volumes Using Spherical Correlation in Frequency Domain

The influence of noise on the results of rigid registration of segmented ultrasound volumes is studied in this paper. Binary volumes result from a segmentation of ovarian ultrasound volumes. Rigid registration is preformed in frequency domain, where the rotation and translation can be calculated separately. The calculation of rotation is done using the amplitude spectrum and sphere correlation. The method was tested on pairs of synthetic volumes where ovarian follicles in one volume were altered and, thus, simulated different kinds of noise (non-rigid changes) characteristic for segmented volumes. We systematically assessed the performance of our registration algorithm by changing the number of follicles, their position, orientation and size. Hundred volume pairs were involved in each experiment. The method proved sensitive to the change of follicle size but resistive to all other kinds of destruction we simulated. Key-Words: image registration, rigid registration in frequency domain, spherical correlation