MEDICAL IMAGE SEGMENTATION TECHNIQUES FOR VIRTUAL ENDOSCOPY

摘要

Virtual endoscopes give internal views of the human body without penetrating it, based on a set of parallel cross-sections produced with any computer tomography method. This paper presents some ideas concerning the design and implementation of a software system, which acts like a virtual endoscope. It takes into account the general requirements of the system, gives a solution that uses a multi-step algorithm, and finally shows the resulting 3-D images. Most of the algorithmic steps have several possible solutions. Our virtual endoscope establishes 3-D internal views based on sets of 2-D slices, which originate from magnetic resonance imaging devices. The chain of the applied image processing methods consists of the followings: (1) Adequate pre-filtering to eliminate the low-frequency intensity non-uniformity (INU) artifact, and high-frequency "salt-and-pepper" disturbances; (2) Segmentation of the stack of MRI slices using an enhanced fuzzy C-means algorithm; (3) 3-D surface recovery algorithm based on level set methods and fast marching methods; (4) Interactive visualization using modern computer graphics technologies, providing the possibility to measure distances, areas, volumes as well. The quality of service provided by the chosen method mainly depends on the resolution of input images.