Overview of Computer Graphics and Algorithms

Journal of Digital Imaging, 2010

With the increasing availability of high-resolution isotropic three-or four-dimensional medical datasets from sources such as magnetic resonance imaging, computed tomography, and ultrasound, volumetric image visualization techniques have increased in importance. Over the past two decades, a number of new algorithms and improvements have been developed for practical clinical image display. More recently, further efficiencies have been attained by designing and implementing volumerendering algorithms on graphics processing units (GPUs). In this paper, we review volumetric image visualization pipelines, algorithms, and medical applications. We also illustrate our algorithm implementation and evaluation results, and address the advantages and drawbacks of each algorithm in terms of image quality and efficiency. Within the outlined literature review, we have integrated our research results relating to new visualization, classification, enhancement, and multimodal data dynamic rendering. Finally, we illustrate issues related to modern GPU working pipelines, and their applications in volume visualization domain.

International Journal of Online and Biomedical Engineering (iJOE)

One of the most valuable medical imaging visualizations or computer-aided diagnosis is Volume rendering (VR). This survey’s objective is reviewing and comparing between several methods and techniques of VR, for a better and more comprehensive reading and learning of both pros and cons of each method, and their use cases.

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.

Computers & Graphics

This paper is a survey ofvolume graphics. It includes an introduction to volumetric data and to volume modeling techniques, such as voxelization, texture mapping, amorphous phenomena, block operations, constructive solid modeling, and volume sculpting. Acomparison between surface graphics and volume graphics is given, along with a consideration of volume graphics advantages and weaknesses. The paper concludes with a discussion on special-purpose volume rendering hardware.

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.

This paper presents Direct Volume Rendering (DVR) improvement strategies, which provide new opportunities for scientific and medical visualization which are not available in due measure in analogues: 1) multi-volume rendering in a single space of up to 3 volumetric datasets determined in different coordinate systems and having sizes as big as up to 512x512x512 16-bit values; 2) performing the above process in real time on a middle class GPU, e. g. nVidia GeForce GTS 250 512 M B; 3) a custom bounding mesh for more accurate selection of the desired region in addition to the clipping bounding box; 4) simultaneous usage of a number of visualization techniques including the shaded Direct Volume Rendering via the 1D-or 2D-transfer functions, multiple semi-transparent discrete iso-surfaces visualization, M IP, and M IDA. The paper discusses how the new properties affect the implementation of the DVR. In the DVR implementation we use such optimization strategies as the early ray termination and the empty space skipping. The clipping ability is also used as the empty space skipping approach to the rendering performance improvement. We use the random ray start position generation and the further frame accumulation in order to reduce the rendering artifacts. The rendering quality can be also improved by the onthe-fly tri-cubic filtering during the rendering process. Our framework supports 4 different stereoscopic visualization modes. Finally we outline the visualization performance in terms of the frame rates for different visualization techniques on different graphic cards.

CRC Press eBooks, 1991

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.

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.

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.