We present an efficient three-phase algorithm for volume viewing that is based on exploit- - t ing coherency between rays in parallel projection. The algorithm starts by building a ray emplate and determining a special plane for projection -- the base-plane. Parallel rays are cast t into the volume from within the projected region of the volume on the base-plane, by repeating he sequence of steps specified in the ray-template. We carefully choose the type of line to be s employed and the way the template is being placed on the base-plane in order to assure uniform ampling of the volume by the discrete rays. We conclude by describing an optimized software K implementation of our algorithm and reporting its performance. eywords: volume rendering, ray casting, template, parallel projection 1. Introduction Volume visualization is the process of converting complex volume data to a format that is p amenable to human understanding while maintaining the integrity and accuracy of the data. Th...

....................................................................................................... vi Chapter 1: Representation and Appearance .................................................. 1 1-1. Representation for Problem Solving ............................................... 1 1-2. Representing Appearance ................................................................ 3 1-3. The Asp: A Continuous, Viewer-centered Object Representation ................................................................................. 4 Chapter 2: The Aspect Representation .......................................................... 9 2-1. Introduction ...................................................................................... 9 2-2. The Asp under Orthographic Projection ......................................... 10 2-2.1. Representing Asps ................................................................ 16 2-2.2. Asps and Visibility .....................................................

We introduce an algorithm for reconstructing a solid model given a series of planar cross-sections. The main contribution of this work is the use of knowledge obtained during the interpolation of neighboring layers while attempting to interpolate a particular layer. This knowledge is used to reconstruct a surface in which consecutive layers are connected smoothly. In most previous work, each layer is interpolated independently of what happened or will happen in the other layers. We also discuss various objective functions which aim to optimize the reconstruction, and present an evaluation of the different objective functions by using various criteria. Keywords: reconstruction, interpolation, triangulation. 1 INTRODUCTION The reconstruction of an object from a series of crosssections has been an intriguing problem during the last couple of decades. Main motivations for this problem come from applications such as medical imaging, digitization of objects, and GIS systems. Data obtained ...

This report focuses at the application of volume modeling and visualization to the research, the diagnosis and the treatment of pathologies related with the brain. Neurological studies and Neurosurgery simulations require the analysis of anatomical information as well as functional data. This information is provided by different registration devices, each one based on its own physical principles. Each type of data is a measure of a different property, either anatomical or functional. It is registered at a specific spatial resolution and scale, with a given intensity precision and within a range of capture error. The integration of different data in a common medical imaging application presents various problems. It is currently an active reseach field. The purpose of this report is to analyze the current methods of data integration in Computer-Assisted Neurosurgery applications. Neurological studies require the integration of anatomical data registered with CT Computed Tomography,