Method of registering images, algorithm for carrying out the method of registering images, a program for registering images using the said algorithm and a method of treating biomedical images to reduce imaging artefacts caused by object movement

摘要

In a method for registering biomedical images such as at least a first and a second digital or digitalized image or set of cross-sectional images of the same object, within the first image or set of images a certain number of landmarks, so called features are individuated by selecting a certain number of pixels or voxels. The position of each pixel or voxel selected as a feature is tracked from the first to the second image or set of images by determining the optical flow vector from the first to the second image or set of images for each pixel or voxel selected as a feature. Registration of the first and second images or set of images is carried out by applying the inverse optical flow to the pixels or voxels of the second image or set of images. The invention provides for an automatic trackable landmark selection step consisting in defining a pixel or voxel neighbourhood around each pixel or voxel of the first image or first set of cross-sectional images; for each target pixel or voxel determining one or more characteristic parameters which are calculated as a function of the parameters describing the appearance of the said target pixel or voxel and of each or a part of the pixels or voxels of the window and as a function of one or more characteristic parameters of either the numerical matrix or of a transformation of the said numerical matrix representing the pixels or voxels of the said window. The pixels or voxels coinciding with validly trackable landmarks are determined as a function of the said characteristic parameters of the target pixels or voxels.