55 KB892 KB38 KB200020242005Tohka, Jussištevilka:111 straniletnik:24str. 9-19ISSN:1580-3139COBISSID:20442841URN:URN:NBN:SI:doc-6RI6CT83enDruštvo za stereologijo in kvantitativno analizo slike, Medicinska fakultetaImage analysis and stereologyImage Processing, Computer-Assistedobdelava slikSlika, obdelava z računalnikomtomografijaTomografija emisijska-računalniškaTomography, Emission-ComputedGlobal deformable surface optimization using adaptive constraints and penalties|Deformable models are able to solve surface extraction problems challenged by image noise because imageindependent constraints are used to regularize the shape of the extracted surface. However, this ability of deformable models is shadowed by their application specificity, initialization sensitivity and the difficulty of the selection of proper values for user definable parameters. Toovercome these problems restricting the automation of surface extraction, wepresent a new algorithm, named AdaCoP, for the global minimization of the energy of deformable surfaces. It iteratively performs constrained local minimizations of the energy. It avoids the detection of the same local minimummultiple times by constraining the local optimizations in an adaptive manner. AdaCoP escapes from local minima by imposing an adaptive penalty energy to it. These constraints and penalties prevent the convergence to the local minima already found. The performance of the AdaCoP algorithm is relatively independent on the nature of the underlying image as well as the shape of the surface to be extracted. The performance of the algorithm is evaluated by extracting surfaces from synthetic images. Moreover, the good properties of the algorithm are demonstrated by considering applications within the automated analysis of positron emission tomography images. AlthoughAdaCoP cannot be proven to converge to the global minimum, it is insensitive to its initialization and it therefore provides a way to automate surface extraction problems within medical image analysisTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaDruštvo za stereologijo in kvantitativno analizo slike