1. A method of segmenting tubular structures in digital images, comprising the steps of: providing a digitized image comprising a plurality of intensities corresponding to a domain of points on a 3-dimensional grid; selecting a point within a tubular object in said image, wherein said object is to be segmented; defining an initial state of said selected point of said object; initializing measurement weights, a conditional probability distribution and a prior probability distribution of a feature space of said initial state; sampling said feature space from said prior probability distribution; estimating a posterior probability distribution by summing sample measurements weighted by said measurement weights, and segmenting a cross section of said tubular object from said posterior probability distribution.