Public visualization of high quality medical information has been wildly available since the creation of the Visible
Human Project in the late 90´s. We discuss the extraction of information from 3D volumes along curved slices with
emphasis on those that can be displayed on the plane without deformation. Special attention is given to a dental volume
containing the sixteen teeth of the upper human jaw. We review several approaches to display information along curved
slices contained within the 3D data set.
In the present work an automatic brain tumor segmentation procedure based on mathematical morphology is proposed. The approach considers sequences of eight multi-echo MR T2-weighted images. The relaxation time T2 characterizes the relaxation of water protons in the brain tissue: white matter, gray matter, cerebrospinal fluid (CSF) or pathological tissue. Image data is initially regularized by the application of a log-convex filter in order to adjust its geometrical properties to those of noiseless data, which exhibits monotonously decreasing convex behavior. Finally the regularized data is analyzed by means of an 8-dimensional morphological eccentricity filter. In a first stage, the filter was used for the spatial homogenization of the tissues in the image, replacing each pixel by the most representative pixel within its structuring element, i.e. the one which exhibits the minimum total distance to all members in the structuring element. On the filtered images, the relaxation time T2 is estimated by means of least square regression algorithm and the histogram of T2 is determined. The T2 histogram was partitioned using the watershed morphological operator; relaxation time classes were established and used for tissue classification and segmentation of the image. The method was validated on 15 sets of MRI data with excellent results.
It is shown how to construct G2-continuous spline with arcs of cubics. Each arc is a piece of the oval of a cubic and it is controlled locally by a triangle tangent to the arc at both endpoints. Formulas for mixed interpolation of further points and tangents are given in terms of geometrically meaningful shape parameters. It is shown that under certain restrictions, the numerical values of the curvatures may be prescribed at the joints. Some new shape handles are developed for the local control of each arc of the spline. Intersection problems are easily handled. The main advantage of algebraic splines is that they are completely parametrization free.