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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 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 A 3-D CELLULAR FRAME BUFFER(The Eurographics Association, 1985) Kaufman, Arie; Bakalash, Reuven; C.E. VandoniA new architecture for storing and processing of threedimensional (3-D) graphics is described, The 3-D objects are discretized and stored in a full 3-D cellular memory of voxels. A 3-D graphics processor scan-converts 3-D geometric objects into the cellular representation. A 3-D frame buffer processor manipulates 3-D cellular sub-boxes and controls 3-D interaction. Displaying 2-D orthographic projections from a given view position and direction is accomplished by a 3-D viewing processor. With this new architecture, there is neither a need for repeatedly scan-converting modified geometric objects nor a need for removing hidden-surfaces.Item A Two-Dimensional Frame Buffer Processor(The Eurographics Association, 1987) Kaufman, Arie; Fons Kuijk and Wolfgang StrasserThe two-dimensional Frame Buffer Processor (FBP) is part of a proposed raster graphics computer architecture. It is a hardware-oriented organisation of a variation of a bitblt engine with a much richer repertoire. In addition, the FBP gives support to window management, transformations, and assists in some image operations ordinarily performed in software. The introduction of the FBP as a co-processor to geometry and video processors would increase efficiency and speed of graphics systems and bitmap workstations. A special skewed frame-buffer organisation, which allows parallel memory access, further improves system performance.Item Forest of Quadtrees: An Object Representation for 3D Graphics(Eurographics Association, 1989) Kaufman, Arie; Bandopadhay, AmitA forest of quadtrees is proposed as an alternative data structure for representing and manipulating 3D and 2.5D graphics. A data representation of a forest offers space savings over common quadtrees by concentrating the vital information and discarding unused pointers. Several properties of the forest of quadtrees and the basic operations for display and elementary transformations like rotation, reflection, enlargement, reduction, and translation are investigated. Specifically, the temporary memory requirements and duplication time of the algorithms are analyzed.Item The voxblt Engine: A Voxel Frame Buffer Processor(The Eurographics Association, 1988) Kaufman, Arie; A. A. M.KuijkThe voxblt Engine (vE) is a 3D frame-buffer processor which manipulates and processes ''3~ bitmaps"" (voxel maps) stored in a cubic frame buffer of voxels. The vE is the 3D counterpart of the 20 frame buffer processor, which is an extended version of the 20 bitbl/ and RasterOps engines.The primitives of the vE are subcubes of the cubic frame buffer and are of three kinds: rooms (3D windows), jacks (3D cursors), and figurines (3D ,cons). In addition to manipUlating these primitives, the vE also serves as a monitor for interaction, as an interfaoe for 3D input devices, and as a channel for inputling into the cubic frame buffer 3D voxel images from either 3D scanners or a voxel image database. The vE has been developed as part of the CUBE system, In which it operates as an Independent processor executing its own commands stored in a 3D frame-buffer display list. A room manager, which is the 3D counterpart of the 20 Window manager, has been implemented on top cf the vEItem 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 Memory Organization for a Cubic Frame Buffer(The Eurographics Association, 1986) Kaufman, Arie; A.A.G. RequichaA special memory organization of a cubic voxel-based frame buffer is presented. The memory of voxels is divided into n modules of voxels each. The k-th module groups together all the principal diagonal planes within the cubic frame buffer, that their sequential index is k mod (n ). This organization guarantees that all the n voxels which constitute a row in any direction parallel to the axes reside in different modules, permitting the retrieval of all the voxels of a row simultaneously. This memory layout is the heart of a voxel-based CUBE Architecture for three-dimensional graphics. The architecture employs three processors which access the memory, to input, manipulate, and view the image within the memory. The unique memory organization enables these processors and the entire system to cope with real-time constraints.Item Towards a Scalable Architecture for Real-Time Volume Rendering(The Eurographics Association, 1995) Pfister, Hanspeter; Kaufman, Arie; Wessels, Frank; W. StrasserIn this paper we present our research efforts towards a scalable volume rendering architecture for the real-time visualization of dynamically changing high-resolution datasets. Using a linearly skewed memory interleav ing we were able to develop a parallel dataflow model that leads to local, fixed-bandwidth interconnections be tween processing elements. This parallel dataflow model differs from previous work in that it requires no global communication of data except at the pixel level. Us ing this dataflow model we are developing Cube-4, an architecture that is scalable to very high performances and allows for modular and extensible hardware imple mentations.