@inproceedings{PietrzykPalmBeyer, author = {Pietrzyk, Uwe and Palm, Christoph and Beyer, Thomas}, title = {Investigation of fusion strategies of multi-modality images}, series = {IEEE Nuclear Science Symposium Conference Record}, volume = {4}, booktitle = {IEEE Nuclear Science Symposium Conference Record}, doi = {10.1109/NSSMIC.2004.1462740}, pages = {2399 -- 2401}, abstract = {Presenting images from different modalities seems to be a trivial task considering the challenges to obtain registered images as a pre-requisite for image fusion. In combined tomographs like PET/CT, image registration is intrinsic. However, informative image fusion mandates careful preparation owing to the large amount of information that is presented to the observer. In complex imaging situations it is required to provide tools that are easy to handle and still powerful enough to help the observer discriminating important details from background patterns. We investigated several options for color tables applied to brain and non-brain images obtained with PET, MRI and CT.}, language = {en} } @inproceedings{PalmPietrzyk, author = {Palm, Christoph and Pietrzyk, Uwe}, title = {Time-Dependent Joint Probability Speed Function for Level-Set Segmentation of Rat-Brain Slices}, series = {Proceedings of the SPIE Medical Imaging 6914: Image Processing 69143U}, booktitle = {Proceedings of the SPIE Medical Imaging 6914: Image Processing 69143U}, number = {6914}, doi = {10.1117/12.770673}, pages = {69143U-1 -- 69143U-8}, abstract = {The segmentation of rat brain slices suffers from illumination inhomogeneities and staining effects. State-of-the-art level-set methods model slice and background with intensity mixture densities defining the speed function as difference between the respective probabilites. Nevertheless, the overlap of these distributions causes an inaccurate stopping at the slice border. In this work, we propose the characterisation of the border area with intensity pairs for inside and outside estimating joint intensity probabilities. Method - In contrast to global object and background models, we focus on the object border characterised by a joint mixture density. This specifies the probability of the occurance of an inside and an outside value in direct adjacency. These values are not known beforehand, because inside and outside depend on the level-set evolution and change during time. Therefore, the speed function is computed time-dependently at the position of the current zero level-set. Along this zero level-set curve, the inside and outside values are derived as mean along the curvature normal directing inside and outside the object. Advantage of the joint probability distribution is to resolve the distribution overlaps, because these are assumed to be not located at the same border position. Results - The novel time-dependent joint probability based speed function is compared expermimentally with single probability based speed functions. Two rat brains with about 40 slices are segmented and the results analysed using manual segmentations and the Tanimoto overlap measure. Improved results are recognised for both data sets.}, subject = {Kernspintomografie}, language = {en} }