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Item Template-Based Volume Viewing(Blackwell Science Ltd and the Eurographics Association, 1992) Yagel, Roni; Kaufman, ArieWe present an efficient three-phase algorithm for volume viewing that is based on exploiting coherency between rays in parallel projection. The algorithm starts by building a ray-template and determining a special plane for projection - the base-plane. Parallel rays are cast into the volume from within the projected region of the volume on the base-plane, by repeating the sequence of steps specified in the ray-template. We carefully choose the type of line to be employed and the way the template is being placed on the base-plane in order to assure uniform sampling of the volume by the discrete rays. We conclude by describing an optimized software implementation of our algorithm and reporting its performance.Item Building a Full Scale VLSI-Based Volume Visualization System(The Eurographics Association, 1990) Bakalash, Reuven; Kaufman, Arie; Xu, Zhong; Richard Grimsdale and Arie KaufmanThe hardware realization of an advanced prototype of the Cube volume visualization system, Cube-3, is presented. The primary hardware component of Cube is a viewing and rendering multiprocessor with distributed 3D voxel memory. Cube-3 design is based on our experience with two earlier prototypes: Cube-1 realized in hard ware using printed circuit board technology and Cube-2 our first custom-designed VLSI implementation. Both prototypes are of reduced-size resolution (163 ) and can generate only orthographic views. Cube-3 is the next generation prototype of a full-scale resolution of 2563 voxels. It has been functionally extended to generate non-orthographic projec tions, 3D real-time transformations, and shading. The ability to project and manipulate volumetric images in real-time is attributed to a unique skewed memory organization, a generalized skewed mapping, a special ray projection bus, a congradient shading tech nique, and a new barrel-shifting mechanism. This paper specifically describes the latter mechanism.Item Cube-4 Implementations on the Teramac Custom Computing Machine(The Eurographics Association, 1996) Kanus, Urs; Meißner, Michael; Straßer, Wolfgang; Pfister, Hanspeter; Kaufman, Arie; Amerson, Rick; Carter, Richard J.; Culbertson, Bruce; Kuekes, Phil; Snider, Greg; Bengt-Olaf Schneider and Andreas SchillingWe present two implementations of the Cube-4 volume rendering architecture on the Teramac custom computing machine. Cube-4 uses a slice parallel ray-casting algorithm that allows for a paral lel and pipelined implementation of ray-casting with tri-linear interpolation and surface normal estimation from interpolated samples. Shading, classification and compositing are part of rendering pipeline. With the partitioning schemes introduced in this paper, Cube-4 is capable of rendering large datasets with a limited number of pipelines. The Teramac hardware simulator at the Hewlett-Packard research laboratories, Palo Alto, CA, on which Cube-4 was implemented, belongs to the new class of custom computing machines. Teramac combines the speed of special-purpose hardware with the flexibility of general-purpose computel's. With Teramac as a development tool we were able to implement in just five weeks working Cube-4 prototypes, capable of rendering for example datasets of 1283 voxels in 0.65 seconds at 0,96 MHz processing frequency. The performance results from these implementations indicate real-time performance for high-resolution data-sets.Item Three Architectures for Volume Rendering(Blackwell Science Ltd and the Eurographics Association, 1995) Hesser, Jurgen; Manner, Reinhard; Knittel, Gunter; Strasser, Wolfgang; Pfister, Hanspeter; Kaufman, ArieVolume rendering is a key technique in scientific visualization that lends itself to significant exploitable parallelism. The high computational demands of real-time volume rendering and continued technological advances in the area of VLSl give impetus to the development of special-purpose volume rendering architectures. This paper presents and characterizes three recently developed volume rendering engines which are based on the ray-casting method. A taxonomy of the algorithmic variants of ray-casting and details of each ray-casting architecture are discussed. The paper then compares the machinefeatures and provides an outlook onfuture developments in the area of volume rendering hardware.Item Hybrid Volume and Polygon Rendering with Cube Hardware(The Eurographics Association, 1999) Kreeger, Kevin; Kaufman, Arie; A. Kaufmann and W. Strasser and S. Molnar and B.- O. SchneiderWe present two methods which connect today s polygon graphics hardware accelerators to Cube-5 volume rendering hardware, the successor to Cube4 The proposed methods allow mixing of both opaque and translucent polygons with volumes on PC class machines, while ensuring the correct compositing order of all objects. Both implementations connect the two hardware acceleration subsystems at the frame buffer. One shares a common DRAM buffer and one run-length encodes images of thin slabs of polygonal data and then combines them in the Cube composite buffer In both realizations, we take advantage of the predictable ordered access to frame buffer storage that is utilized by Cube-5 and the rest of the family of volume rendering accelerators based on the Cube design.Item PAVLOV: A Programmable Architecture for Volume Processing(The Eurographics Association, 1998) Kreeger, Kevin; Kaufman, Arie; S. N. SpencerWe present a parallel 2D mesh connected architecture with SIMD processing elements. The design allows for real-time volume rendering as well as interactive 30 segmentation and 1D feature extraction. This is possible because the SIMD processing elements are programmable, a feature which also allows the use of many different rendering algorithms. We present an algorithm which, with the addition of hardware resources, provides conflict free access to volume slices along any of the three major axes. The volume access conflict has been the main reason why previous similar architectures could not perform real-time volume rendering. We present the performance of preliminary algorithms on a software simulator of the architecture design.Item High-Quality Volume Rendering Using Texture Mapping Hardware(The Eurographics Association, 1998) Dachille, Frank; Kreeger, Kevin; Chen, Baoquan; Bitter, Ingmar; Kaufman, Arie; S. N. SpencerWe present a method Jor volume rendering of regular grids which takes advantage of 3D texture mapping hardware currently, available on graphics workstations. Our method products accurate shading for arbitrary and dynamically changing directional lights, viewing parameters, and transfer functions. This is achieved by hardware interpolating the data values and gradients before software classification and shading. The method works equally well for parallel and perspective projections. We present two approaches for OUT method: one which takes advantage of software ray casting optimizations and another which takes advantage of hardware blending acceleration.Item A Ray-Slice-Sweep Volume Rendering Engine(The Eurographics Association, 1997) Bitter, Ingmar; Kaufman, Arie; A. Kaufmann and W. Strasser and S. Molnar and B.-O. SchneiderRay-slice-sweeping is a plane sweep algorithm for volume rendering, The compositing buffer sweeps through the volume and combines the accumulated image with the new slice of just-projected voxels. The image combination is guided by sight rays from the view point through every voxel of the new slice. Cube-4L is a volume rendering architecture which employs a ray-slice-sweeping algorithm. It improves the Cube-4 architecture in three ways. First, during perspective projection all voxels of the dataset contribute to the rendering. Second, it computes gradients at the voxel positions which improves accuracy and allows a more compact implementation, Third, Cube-AL has less control overhead than Cube-4.Item Sheared Interpolation and Gradient Estimation for Real-Time Volume Rendering(The Eurographics Association, 1994) Pfister, Hanspeter; Wessels, Frank; Kaufman, Arie; W. StrasserIn this paper we present a technique for the interactive control and display of static and dynamic 3D datasets. We describe novel ways of tri-linear interpolation and gradient estimation for a real-time volume rendering system, using coherency between rays. We show simu lation results that compare the proposed methods to tra ditional algorithms and present them in the cantezt of Cube-B, a special-purpose architecture capable afrender ing 5123 16-bit per vozel datasets at over 20 frames per second.Item Real-time Biomechanically-based Muscle Volume Deformation using FEM(Blackwell Publishers Ltd and the Eurographics Association, 1998) Zhu, Qing-hong; Chen, Yan; Kaufman, ArieThis paper presents a voxel-based biomechanical model for muscle deformation using finite element method (FEM) and volume graphics. Hierarchical voxel meshes are reconstructed from filtered segmented muscle images followed by FEM simulation and volume rendering. Physiological muscle force is considered and linear elastic muscle models for both static and dynamic cases are simulated by FEM. Voxel-based wireframe, polygon surface rendering, and volume rendering techniques are applied to show real-time muscle deformation processes as well as realistic animations.