Although mature technologies exist for acquiring images, geometry, and normals of small objects, they remain cumbersome and time-consuming for non-experts to employ on a large scale. In an archaeological setting, a practical acquisition system for routine use on every artifact and fragment would open new possibilities for archiving, analysis, and dissemination. We present an inexpensive system for acquiring all three types of information, and associated metadata, for small objects such as fragments of wall paintings. The acquisition system requires minimal supervision, so that a single, non-expert user can scan at least 10 fragments per hour. To achieve this performance, we introduce new algorithms to robustly and automatically align range scans, register 2-D scans to 3-D geometry, and compute normals from 2-D scans. As an illustrative application, we present a novel 3-D matching algorithm that efficiently searches for matching fragments using the scanned geometry.

In 3D renderings of complex scenes, objects of interest may be occluded by those of secondary importance. Cutaway renderings address this problem by omitting portions of secondary objects so as to expose the objects of interest. This paper introduces a method for generating cutaway renderings of polygonal scenes at interactive frame rates, using illustrative and non-photorealistic rendering cues to expose objects of interest in the context of surrounding objects. We describe a method for creating a view-dependent cutaway shape along with modifications to the polygonal rendering pipeline to create cutaway renderings. Applications for this technique include architectural modeling, path planning, and computer games.

Dense clinical data like 3D Computed Tomography (CT) scans can be visualized together with real-time imaging for a number of medical intervention applications. However, it is difficult to provide a fused visualization that allows sufficient spatial perception of the anatomy of interest, as derived from the rich pre-operative scan, while not occluding the real-time image displayed embedded within the volume. We propose an importance-driven approach that presents the embedded data such that it is clearly visible along with its spatial relation to the surrounding volumetric material. To support this, we present and integrate novel techniques for importance specification, feature emphasis, and contextual cutaway generation. We show results in a clinical context where a pre-operative CT scan is visualized alongside a tracked ultrasound image, such that the important vasculature is depicted between the viewpoint and the ultrasound image, while a more opaque representation of the anatomy is exposed in the surrounding area.

In fields ranging from technical illustration to mapmaking, artists have developed distinctive visual styles designed to convey both detail and overall shape as clearly as possible. We investigate a non-photorealistic shading model, inspired by techniques for carto-graphic terrain relief, based on dynamically adjusting the effective light position for different areas of the surface. It reveals detail regardless of surface orientation and, by operating at multiple scales, is designed to convey detail at all frequencies simultaneously.

Renderings of volumetric data have become an important data analysis tool for applications ranging from medicine to scientific simulation. We propose a volumetric drawing system that directly extracts sparse linear features, such as silhouettes and suggestive contours, using a temporally coherent seed-and-traverse framework. In contrast to previous methods based on isosurfaces or nonrefractive transparency, producing these drawings requires examining an asymptotically smaller subset of the data, leading to efficiency on large data sets. In addition, the resulting imagery is often more comprehensible than standard rendering styles, since it focuses attention on important features in the data. We test our algorithms on datasets up to 512 3 , demonstrating interactive extraction and rendering of line drawings in a variety of drawing styles.

Finding the minimum column multiplicity for a bound set of variables is an important problem in Curtis decomposi-tion. To investigate this problem, we compared two graph-coloring programs: one exact, and another one based on heuristics which can give, however, provably exact results on some types of graphs. These programs were incorporated into the multi-valued decomposer MVGUD. We proved that the exact graph coloring is not necessary for high-quality functional decomposers. Thus we improved by orders of magnitude the speed of the column multiplicity problem, with very little or no sacrifice of decomposition quality. Comparison of our experimental results with competing de-composers shows that for nearly all benchmarks our solu-tions are best and time is usually not too high.

Commercial design verification is a complex activity involving many abstraction levels (such as architectural, register transfer, gate, switch, circuit, fabrication), many different aspects of design (such as timing, speed, functional, power, reliability and manufacturability) and many different design styles (such as ASIC, full custom, semi-custom, memory, cores, and asynchronous). We present a representative design flow and methodology that is common to many commercial integrated circuit design environments and that concentrates on functional validation using informal verification (e.g., simulation, emulation and ATPG) and formal verification (e.g., logic checking and sequential verification).