The Future of Volume Graphics in Medical Virtual Reality

Lecture Notes in Computer Science, 2007

Volumetric data rendering has become an important tool in various medical procedures as it allows the unbiased visualization of fine details of volumetric medical data (CT, MRI, fMRI). However, due to the large amount of computation involved, the rendering time increases dramatically as the size of the data set grows. This paper presents several acceleration techniques of volume rendering using general-purpose GPU. Some techniques enhance the rendering speed of software ray casting based on voxels' opacity information, while the others improve traditional hardware-accelerated object-order volume rendering. Remarkable speedups are observed using the proposed GPU-based algorithm from experiments on routine medical data sets.

Advances in Water Resources, 2010

We describe a system for volume rendering via ray casting, targeted at medical data and clinicians. We discuss the benefits of server vs client rendering, and of GPU vs CPU rendering, and show how we combine these two advantages using nVidia's Tesla hardware and CUDA toolkit. The resulting system allows hopsital-acquired data to be visualized on-demand and in real-time by multiple simultaneous users, with low latency even on low bandwidth networks and on thin clients. Each GPU serves multiple clients, and our system scales to many GPUs, with data distribution and load balancing, to create a fully scalable system for commercial deployment. To optimize rendering performance, we present our novel solution for empty space skipping, which improves on previous techniques used with CUDA. To demonstrate the flexibility of our system, we show several new visualization techniques, including assisted interaction through automatic organ detection and the ability to toggle visibility of pre-segmented organs. These visualizations have been deemed by clinicians to be highly useful for diagnostic purposes. Our performance results indicate that our system may be the best-value option for hospitals to provide ubiquitous access to state-of-the-art 3D visualizations.

We present a method for fast volume rendering using graphics hardware (GPU). To our knowledge, it is the first implementation on the GPU. Based on the Shear-Warp algorithm, our GPU-based method provides real-time frame rates and outperforms the CPU-based implementation. When the number of slices is not sufficient, we add in-between slices computed by interpolation. This improves then the quality of the rendered images. We have also implemented the ray marching algorithm on the GPU. The results generated by the three algorithms (CPU-based and GPU-based Shear-Warp, GPU-based Ray Marching) for two test models has proved that the ray marching algorithm outperforms the shear-warp methods in terms of speed up and image quality.

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.

Computers & Graphics, 2012

This article presents an innovative GPU-based solution for visualization of perfusion abnormalities detected in dynamic brain perfusion computer tomography (dpCT) maps in an augmented-reality environment. This new graphic algorithm is a vital part of a complex system called DMD (detection measure and description), which was recently proposed by the authors. The benefit of this algorithm over previous versions is its ability to operate in real time to satisfy the needs of augmented reality simulation. The performance speed (in frames per second) of six volume-rendering algorithms was determined for models with and without semi-transparent pixels.

2008 Fifth International Conference BioMedical Visualization: Information Visualization in Medical and Biomedical Informatics, 2008

This paper describes the Medical Visualizer, a real-time visualization system for analyzing medical volumetric data in various virtual environments, such as autostereoscopic displays, dual-projector screens and immersive environments such as the CAVE. Direct volume rendering is used for visualizing the details of medical volumetric data sets without intermediate geometric representations. By interactively manipulating the color and transparency functions through the friendly user interface, radiologists can either inspect the data set as a whole or focus on a specific region. In our system, 3D texture hardware is employed to accelerate the rendering process. The system is designed to be platform independent, as all virtual reality functions are separated from kernel functions. Due to its modular design, our system can be easily extended to other virtual environments, and new functions can be incorporated rapidly.

2004

This paper reports on a new approach for visualizing multi-field MRI or CT datasets in an immersive environment with medical applications. Multi-field datasets combine multiple scanning modalities into a single 3D, multivalued, dataset. In our approach, they are classified and rendered using real-time hardware accelerated volume rendering, and displayed in a hybrid work environment, consisting of a dual power wall and a desktop PC. For practical reasons in this environment, the design and use of the transfer functions is subdivided into two steps, classification and exploration. The classification step is done at the desktop, taking advantage of the 2D mouse as a high accuracy input device. The exploration process takes place on the powerwall. We present our new approach, describe the underlying implementation issues, report on our experiences with different immersive environments, and suggest ways it can be used for collaborative medical diagnosis and treatment planning.

Computers & Graphics, 1995

Architecture and applications of a massively parallel system currently developed are described, which allows real-time visualization using volume oriented visualization algorithms. Volumes of 256 x 256 x 128 voxels can be visualized with a frame rate of 10 Hz. The system is scalable and modular, and will allow a multi-user access over high-speed networks. 3D-rotation around arbitrary rotation axis, perspective, zooming and arbitrary grey value mapping are provided in real-time. A volume oriented algorithm is used that is tailored to the requirements in medicine [H.-I'. Meinzer et d., IEEE Comp. Graph. Appl., 34 (Nov. 1991)]. With this algorithm, small structures without defined surfaces, e.g., tumours, can be visualized as well as semi-transparent objects. One planned application of the system is heart surgery.

Medical Imaging 2001: Visualization, Display, and Image-Guided Procedures, 2001

There are various 3D visualization methods such as volume rendering and surface renderingS The volume rendering (VR) is a useful tool to visualize 3D medical images. However, a requirement of large computation amount makes it difficult for the VR to be used in real-time medical applications. In order to overcome the large computation amount of the VR, we have developed a progressive VR (PVR) method that can perform the low-resolution VR for fast and intuitive processing and use the depth information from the low-resolution VR to generate the full-resolution VR image with a reduced computation time. The developed algorithm can be applicable to the real-time applications of the YR. Le., the low-resolution VR is performed interactively according to change of view direction, and the full-resolution VR is performed once we fix the view direction In this paper its computation complexity and image quality are analyzed Also an extension of its progressive refinement is introduced.

Citeseer

Cardiovascular diseases are the the leading cause of death and disability in the world. Non-invasive tecniques are required to reduce the number of deaths as well as the patients quality of life. These techniques usually rely on 3D visualization of MRI or CT data. In this work we describe how improved volume rendering techniques, combined with graphics cards programming can provide interactive visualization of the heart internal structures. Our main focus here is to provide doctors with high-performance 3D images for evaluating patient heart anatomy and performance. Our idea is to take full advantage of the triangle-rendering hardware to provide interactive frame rates.