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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 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 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 An Algorithm for 3D Scan-Conversion of Polygons(Eurographics Association, 1987) Kaufman, ArieA three-dimensional (3D) scan-conversion algorithm, that scanconverts 3D planar polygons into their discrete voxel-map representation within a Cubic Frame Buffer (CFB), is presented. The algorithm, which is a variation of a 2D scan-line filling algorithm, is incremental and uses only simple operations like additions and testy inside the inner loops. The algorithm performs scan-conversion with computational complexity which is linear in the number of voxels written to the CFB. The paper also presents an algorithm that scan-converts polygons clipped to the CFB boundaries with no added time complexity. An all-integer decision mechanism which makes the inner-most loop of the algorithm more efficient is discussed too. All the algorithms guarantee lack of 6-connected "tunnels" in the converted polygons. The algorithms have been implemented as part of the 3D geometry processor of the CUBE Architecture, which is a voxel-based system for 3D graphics. These algorithms allow the' CUBE system to generate the essential primitive polygon within the CFB from a 3D geometric model.