An algorithm for correcting the geometric distortions in the echo planar images and diffusion weighted images is described. In this method the geometric distortion in the echo planar imaging (EPI) data is corrected by non-rigid registration to conventional fast-spin echo (FSE) images. The registration is based on a variant of the Demon's algorithm [10] with consistency enforced by an improved bijectivity scheme. Quantitative metrics based on the forward similarity and inverse consistency measures, calculated from the closest point distances of the image contours, are used to evaluate the performance of nonlinear registration algorithms. The experimental results demonstrated that the proposed nonlinear registration algorithm is able to correct large distortion in the EPI and diffusion weighted images (DWI) while preserving the topology of brain structure.

This paper presents the development of regularized optical flow computation methods and an evaluation of their performance in the extraction of quantitative motion information from video recordings of neonatal seizures. A general formulation of optical flow computation is presented and a mathematical framework for the development of practical tools for computing optical flow is outlined. In addition, this paper proposes an alternative formulation of the optical flow problem that relies on a discrete approximation of a family of quadratic functionals. These regularized optical flow computation methods are used to extract motion strength signals from video recordings of neonatal seizures.

The paper presents a procedure developed to extract quantitative information from video recordings of neonatal seizures in the form of temporal motion strength signals. These signals are obtained by applying nonlinear filtering, segmentation, and morphological filtering on the differences between adjacent frames. The experiments indicate that temporal motion strength signals constitute an effective representation of videotaped clinical events and can be used for seizure recognition and characterization.