Research On Application Of Distance Transformation And Medial Axis Transformation To Morphing

This paper summaries the researches on the application of the technology of image analysis, distance transformation and medial axis transformation, to the field of computer graphics. Based on the tool of distance transformation, we deeply discuss the distance transformation and the generation of skeleton and apply them to the shape interpolation, where skeleton works as a bridge among them. Meanwhile, the technology of morphing between object shapes is applied to the interpolation among image slice with different sampling resolution in different direction so that the three dimension reconstruction of medical image can performed successfully. And it is worked over to some extent.Starting from the pioneering stage of image analysis and computer graphics, we indicate the inevitability and feasibility of the application of the technology of image analysis to that of computer graphics. Under the background of the trend that the methods in image and in graphics seep into each other at present, a necessary account of import works is rendered about several fields, such as distance transformation, skeletonization, morphing technology and 3D reconstruction of medical image. These different fields can connected organically by some means.Distance transformation is an important method of vision analysis and is a basic tool for ,further study in this paper. So, an overview is given, including several popular definitions and all kinds of typical fast algorithms.Skeletonization is a concept related closely to distance transformation. Skeleton is an efficient representation of object shapes since it reflects the topological structure of the original shape in a simpler manner, so that it can offer an effective method to control its topological change. Skeleton of shapes is a main thread of this paper. Methods based on distance transformation can generate skeletons with accurate position, but connectivity of the skeleton branches must be carefully checked. It is difficult to check the connectivity when the structures of the skeleton are very complicated. In this paper, a dynamic skeleton algorithm is present for binary images by combining with thinning method and Snake model technique. The initial skeleton is computed based on thinning technology of which the connectivity and the topologyof the skeleton can be kept well. Then the initial skeleton can be led to its accurate locations in distance field based on Snake model technique. The skeletons generated by this method are not only locating at accurate positions, but also with correct connectivity and topology.Because of the validity of topological representation of shapes, an algorithm for shape interpolation is presented by applying skeletal representation to control topological structure. Morphing or Metamorphosis, is a fluid transformation and gradual interpolation from one shape to another. It has received much attention in recent years because of its wide application to movie and television, computer animation, computer graphics and industrial design. In this paper a novel framework is presented for 2-D shape interpolation using the intrinsic shape parameters of a piecewise linear curve based on skeleton. Feature graphs, linear forms of skeletons, are introduced to guide the construction of intermediate skeleton. If the topologies of the source object and the target one are different, their feature graphs will be automatically extended with equivalent topologies. Then the technique of intrinsic shape parameters is applied to the smooth transition of the extended feature graphs, which will guide the metamorphosis of the skeletons. Not only can the new approach be capable of morphing between objects with different topological genus, but also the topologies and the shapes of the intermediate objects can be controlled efficiently. We will show its feasibility via the smooth transformation of distance fields driven by metamorphosis from the skeleton of the source object to that of the target one.The above method combines the context of transformation with th...