Direct volume rendering of multiple scalar fields

IEEE Computer Graphics and Applications, 1992

A combination of segmentation tools and fast volume renderers that provides an interactive exploration environment for volume visualization is discussed. The tools and renderers include mechanisms that distribute volume data across multiple processors, as well as image compositing techniques and solutions to representation problems in the selection and display of subregions within bounding volumes. A volume visualization technique using the interactive control of images rendered directly from volume data coupled with a user-controlled semantic classification tool is described. The variations of parallel volume rendering being explored on the Pixel-Planes 5 system and the region-of-interest selection methods and the interactive tools used by the system are presented. The flexibility and power of combining volume rendering with region-of-interest selection techniques are demonstrated using examples of medical imaging applications.>

1993

Volume rendering is a title often ambiguously used in science. One meaning often quoted is:`to render any three volume dimensional data set'; however, within this categorisation \surface rendering" is contained. Surface rendering is a technique for visualising a geometric representation of a surface from a three dimensional volume data set. A more correct de nition of Volume Rendering would only incorporate the direct visualisation of volumes, without the use of intermediate surface geometry representations. Hence we state:`Volume Rendering is the Direct Visualisation of any three dimensional Volume data set; without the use of an intermediate geometric representation for isosurfaces';`Surface Rendering is the Visualisation of a surface, from a geometric approximation of an isosurface, within a Volume data set'; where an isosurface is a surface formed from a cross connection of data points, within a volume, of equal value or density. This paper is an overview of both Surface Rendering and Volume Rendering techniques. Surface Rendering mainly consists of contouring lines over data points and triangulations between contours. Volume rendering methods consist of ray casting techniques that allow the ray to be cast from the viewing plane into the object and the transparency, opacity and colour calculated for each cell; the rays are often cast until an opaque object is`hit' or the ray exits the volume.

Proceedings of the 1990 workshop on Volume visualization - VVS '90, 1990

Direct volume rendering can visualize sampled 3D scala r data as a continuous medium or extract features. However , it is generally slow. Furthermore, most algorithms fo r direct volume rendering have assumed rectilinear gridde d data. This paper discusses methods for using direct volum e rendering when the original volume is curvilinear, i .e. , is divided into six-sided cells which are not necessaril y equilateral hexahedra. One approach is to ray-cast suc h volumes directly. An alternative approach is to interpolat e the sample volumes to a rectilinear grid, and use this regula r volume for rendering. Advantages and disadvantages of th e two approaches in terms of speed and image quality are explored. Permission w copy utihont fee all or pall of this material is granted provided that the copie s are no made or distributed for direct commercial ads ;ttage, the ACM copyright notice and th e tide of the publication and its date appear, and notice is given that eapying is by permission of the Association for Computing Machinery. To copy-ulhunsise, or to republish, requires a fe e andior specific perntissioa .

Proceedings of GRAPP, 2008

Direct Volume Rendering is a popular method for displaying volumetric data sets without generating intermediate representations. The technique is most frequently applied to scalar data and few specialized techniques exist for visualizing higher-order data, such as tensor fields, directly. This is a serious limitation because progress in medical imaging, satellite technology and numerical simulations has made higher-order and multifield data sets a common entity in medicine, science and engineering. In this paper we present a framework for the interactive exploration of complex data sets using direct volume rendering. This is achieved by applying sophisticated Software Engineering (SE) to modularize the direct volume rendering pipeline and by exploiting the latest advances in graphics hardware and shading languages to modify rendering effects and to compute derived data sets at runtime. We discuss how the framework can be used to mimic the latest specialized direct volume rendering algorithms and to interactively explore and gain new insight into high-order and multifield data sets. The capabilities of the framework are demonstrated by three case studies and the efficiency and effectiveness of the framework is evaluated.

ACM Transactions on Applied Perception, 2009

The display of space filling data is still a challenge for the community of visualization. Direct Volume Rendering (DVR) is one of the most important techniques developed to achieve direct perception of such volumetric data. It is based on semi-transparent representations, where the data are accumulated in a depth-dependent order. However, it produces images that may be difficult to understand, and thus several techniques have been proposed so as to improve its effectiveness, using for instance lighting models or simpler representations (e.g. Maximum Intensity Projection). In this paper we present two perceptual studies that question how DVR meets its goals, in either static or dynamic context. We show that a static representation is highly ambiguous, even in simple cases, but this can be counterbalanced by use of dynamic cues, i.e. motion parallax, provided that the rendering parameters are correctly tuned.

1993

In this paper various algorithms for rendering gaseous phenomena are reviewed. In computer graphics such algorithms are used to model natural scenes containing clouds, fog, flames and so on. On the other hand displaying three dimensional scalar datasets as cloudy objects has become an important technique in scientific visualization. Our emphasis is on this latter subject of so-called direct volume rendering. All algorithms will be discussed within the framework of linear transport theory. The equation of transfer is derived. This equation is suitable to describe the radiation field in a participating medium where absorption, emission, and scattering of light can occur. Almost all volume rendering algorithms can be shown to solve special cases of the equation of transfer. Related problems like the mapping from data values to model parameters or possible parallelization strategies will be discussed as well.

In this paper various algorithms for rendering gaseous phenomena are reviewed. In computer graphics such algorithms are used to model natural scenes containing clouds, fog, ames and so on. On the other hand displaying three dimensional scalar datasets as cloudy objects has become an important technique in scienti c visualization. Our emphasis is on this latter subject of so-called direct volume rendering. All algorithms will be discussed within the framework of linear transport theory. The equation of transfer is derived. This equation is suitable to describe the radiation eld in a participating medium where absorption, emission, and scattering of light can occur. Almost all volume rendering algorithms can beshown to solve special cases of the equation of transfer. Related problems like the mapping from data values to model parameters or possible parallelization strategies will be discussed as well.

Proceedings Visualization '92

The VolVis system has been developed to satisfv the diverse requirements of the volume visualization community by co@ortably housing numerous visualization algorithms and methods within a consistent and well organized framavork. The VoNis system is supported by a generalized abstract model which provides for both geometric and volumetric constructs. VolVis contains several rendering algorithms that span the speed versus accuracy continuum. A fmt volume rendering algorithm has been dcveloped, which is capable of exploiting existing graphics hardware without placing any viewing restrictwns or compromising accuracy. In addition, VoNis includes a volumetn'c navigm'on facility, key-pame animation generator, quantitative analysis tools, and a generalized protocol for commm'cating with 30 input devices.

1993

In this paper various algorithms for rendering gaseous phenomena are reviewed. In computer graphics such algorithms are used to model natural scenes containing clouds, fog, ames and so on. On the other hand displaying three dimensional scalar datasets as cloudy objects has become an important technique in scienti c visualization. Our emphasis is on this latter subject of so-called direct volume rendering. All algorithms will be discussed within the framework of linear transport theory. The equation of transfer is derived. This equation is suitable to describe the radiation eld in a participating medium where absorption, emission, and scattering of light can occur. Almost all volume rendering algorithms can beshown to solve special cases of the equation of transfer. Related problems like the mapping from data values to model parameters or possible parallelization strategies will be discussed as well.

The Journal of Visualization and Computer Animation, 1992

Most of the available algorithms for scalar volume visualization offer predefined techniques such as display of volumetric regions defined by scalar threshold values. The regions can usually be drawn opaque or transparent or appear in combinations. This paper presents an implementation of a volume visualization concept where several modelling and rendering techniques can be applied in any combination, mainly bounded by the creativity of the user,