Interactive volume cutting of medical data

IEEE Transactions on Visualization and Computer Graphics, 2003

We propose clipping methods that are capable of using complex geometries for volume clipping. The clipping tests exploit per-fragment operations on the graphics hardware to achieve high frame rates. In combination with texture-based volume rendering, these techniques enable the user to interactively select and explore regions of the data set. We present depth-based clipping techniques that analyze the depth structure of the boundary representation of the clip geometry to decide which parts of the volume have to be clipped. In another approach, a voxelized clip object is used to identify the clipped regions. Furthermore, the combination of volume clipping and volume shading is considered. An optical model is introduced to merge aspects of surface-based and volumebased illumination in order to achieve a consistent shading of the clipping surface. It is demonstrated how this model can be efficiently incorporated in the aforementioned clipping techniques.

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.

2003

For volume rendering of regular grids the display of view-plane aligned slices has proven to yield both good quality and performance. In this paper we demonstrate how to merge the most important extensions of the original 3D slicing approach, namely the pre-integration technique, volumetric clipping, and advanced lighting. Our approach allows the suppression of clipping artifacts and achieves high quality while offering the flexibility to explore volume data sets interactively with arbitrary clip objects. We also outline how to utilize the proposed volumetric clipping approach for the display of segmented data sets. Moreover, we increase the rendering quality by implementing efficient over-sampling with the pixel shader of consumer graphics accelerators. We give prove that at least 4times over-sampling is needed to reconstruct the ray integral with sufficient accuracy even with pre-integration. As an alternative to this brute-force over-sampling approach we propose a hardware-accelerated ray caster which is able to perform over-sampling only where needed and which is able to gain additional speed by early ray termination and space leaping. CR Category: I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism.

2004

We developed a direct volume rendering technique, that supports low latency real time visual feedback in parallel with physical simulation on commodity graphics platforms. In our approach, a fast approximation of the diffuse shading equation is computed on the fly by the graphics pipeline directly from the scalar data. We do this by exploiting the possibilities offered by multi-texturing with the register combiner OpenGL extension, that provides a configurable means to determine per-pixel fragment coloring. The effectiveness of our approach, that supports a full decoupling of simulation and rendering, is demonstrated in a training system for temporal bone surgery.

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.

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.

Medical Imaging 2004: Visualization, Image-Guided Procedures, and Display, 2004

This work presents a set of tools developed to provide 3D visualization and interaction with large volumetric data that relies on recent programmable capabilities of consumer-level graphics cards. We are exploiting the programmable control of calculations performed by the graphics hardware for generating the appearance of each pixel on the screen to develop real-time, interactive volume manipulation tools. These tools allow real-time modification of visualization parameters, such as color and opacity classification or the selection of a volume of interest, extending the benefit of hardware acceleration beyond display, namely for computation of voxel visibility. Three interactive tools are proposed: a cutting tool that allows the selection of a convex volume of interest, an eraser-like tool to eliminate non-relevant parts of the image and a digger-like tool that allows the user to eliminate layers of a 3D image. To interactively apply the proposed tools on a volume, we are making use of some so known user interaction techniques, as the ones used in 2D painting systems. Our strategy is to minimize the user entrainment efforts involved in the tools learning. Finally, we illustrate the potential application of the conceived tools for preoperative planning of liver surgery and for liver vascular anatomy study. Preliminary results concerning the system performance and the images quality and resolution are presented and discussed.

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.

Biological and Medical Physics, Biomedical Engineering, 2011

International Journal of Imaging Systems and Technology, 2000

With the advent of high-powered, commodity volume visualization hardware comes a new challenge: effectively harnessing the visualization power to enable greater understanding of data through dynamic interaction. We examine Cube-4/VolumePro as the latest advance in real-time volume visualization hardware. We describe tools to utilize this hardware including a software developers' kit, called the Cube Toolkit (CTK). We show how the CTK supports algorithms such as perspective rendering, overlapping volumes, and geometry mixing within volumes. We examine a case study of a virtual colonoscopy application developed using the CTK.