Forty years ago, the first General Purpose Raster graphics Processor made the transition from research project to commercial product. This is the story of the creation of a new graphics system and the startup company ...
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Forty years ago, the first General Purpose Raster graphics Processor made the transition from research project to commercial product. This is the story of the creation of a new graphics system and the startup company that produced it in the early days of raster computer graphics.
We describe the first known algorithm for efficiently maintaining a Binary Space Partition (BSP) for n continuously moving segments in the plane, whose interiors remain disjoint throughout the motion. Under reasonable...
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We describe the first known algorithm for efficiently maintaining a Binary Space Partition (BSP) for n continuously moving segments in the plane, whose interiors remain disjoint throughout the motion. Under reasonable assumptions on the motion, we show that the total number of times this BSP changes is O(n(2)), and that we can update the BSP in O(log n) expected time per change. Throughout the motion, the expected size of the BSP is O(n log n). We also consider the problem of constructing a BSP for n static triangles with pairwise-disjoint interiors in R-3. We present a randomized algorithm that constructs a BSP of size O(n(2)) in O(n(2) log(2) n) expected time. We also describe a deterministic algorithm that constructs a BSP of size O((n + k) log(2) n) and height O(log n) in O((n + k) log(3) n) time, where k is the number of intersection points between the edges of the projections of the triangles onto the xy-plane. This is the first known algorithm that constructs a BSP of O(log n) height for disjoint triangles in R-3. (C) 2000 Elsevier Science B.V. All rights reserved.
Transitioning from bespoke, single-purpose public displays to generic, multipurpose ones entails a number of research challenges. One such challenge is understanding how to group and present available applications to ...
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Transitioning from bespoke, single-purpose public displays to generic, multipurpose ones entails a number of research challenges. One such challenge is understanding how to group and present available applications to users and what effect this grouping has on application use. This study of an iterative, longitudinal deployment of a multipurpose public display examines two mechanisms that help users find the available applications: a quick-launch menu and a browsable application directory. Using the measures of relative and absolute utility, the study reveals these mechanisms' complex effects on application usage. It also addresses whether a public display should promote popular or unpopular applications. [ABSTRACT FROM AUTHOR]
In the Industrie 4.0 vision, the creation of leading-edge options for interaction between people and technology occupies a key role. In this context, augmented reality (AR) is one of the most suitable solutions. Howev...
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In the Industrie 4.0 vision, the creation of leading-edge options for interaction between people and technology occupies a key role. In this context, augmented reality (AR) is one of the most suitable solutions. However, it is still not ready to be effectively used in industry. A crucial problem is the legibility of text seen through AR head-worn displays (HWDs). AR interface designers have no standard guidelines to follow, especially for these devices. Literature and anecdotal evidence suggest that legibility depends mainly on background, display technology (that is, see-through optical or video HWDs), and text style (for example, plain text, outline, or billboard). Furthermore, there are constraints to consider in industrial environments, such as standard color-coding practices and workplace lighting. The authors examine aspects affecting text legibility with an emphasis on deriving guidelines to support AR interface designers. Their results suggest that enhancing text contrast via software, along with using the outline or billboard style, is an effective practice to improve legibility in many situations. If one text style is needed for both types of HWD, their results suggest that colored billboards (with neutral white text) are effective. When color coding is not mandatory, white text and blue billboard are more effective than other styles tested. [ABSTRACT FROM AUTHOR]
This paper presents a new data hiding scheme via steganographic image transformation, which is different from conventional data hiding techniques. The transformation is achieved in the frequency domain and the concept...
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This paper presents a new data hiding scheme via steganographic image transformation, which is different from conventional data hiding techniques. The transformation is achieved in the frequency domain and the concept of Fourier filtering method is used. An input image is transformed into a fractal image, which can be used in computer Graphic (CG) applications. One of the main advantages of this scheme is the amount of data to be hidden (embedded) is equal to that of the host signal (generated fractal image) while it is in general limited in the conventional data hiding schemes. Also both the opened fractal image and the hidden original one can be properly used depending on the situation. Unauthorized users will not notice the "secret" original image behind the Fractal image, but even if they know that there is a hidden image it will be difficult for them to estimate the original image from the transformed image. Only authorized users who know the proper keys can regenerate the original image. The proposed method is applicable not only as a security tool for multimedia contents on web pages but also as a steganographic secret communication method through fractal images.
Structure from Motion (SfM) is a computer vision technique used to reconstruct three-dimensional (3D) structures from a series of two-dimensional (2D) images or video frames. However, SfM tools struggle with transpare...
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Structure from Motion (SfM) is a computer vision technique used to reconstruct three-dimensional (3D) structures from a series of two-dimensional (2D) images or video frames. However, SfM tools struggle with transparent objects, reflective surfaces, and low-resolution frames. In such situations, image-based interactive 3D modeling software packages are employed to model 3D objects and measure dimensions. Our contributions to this work are twofold. First, we have introduced new tools to improve 3D modeling software packages;such tools are aimed at easing the workload for users. Second, we have conducted a comprehensive user study to evaluate the efficacy of popular 3d modeling software packages. The task is to measure certain dimensions for which ground truth measurements are already known. A relative error is calculated for every measurement. The evaluation of each software tool is done through survey form, event logs, and measurement relative error. The results of this user study clearly show that our approach to 3D modeling using multiple images has a lower relative error and produces higher quality 3D models than other software packages. In addition, it shows our new tools reduce the required time for completing a task.
A new visualization system analyzes multidimensional surgical performance databases of information collected via emerging surgical robot and simulator technologies. In particular, it has visualized force, position, ro...
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A new visualization system analyzes multidimensional surgical performance databases of information collected via emerging surgical robot and simulator technologies. In particular, it has visualized force, position, rotation, and synchronized video data from 300 bimanual laparoscopic surgery tasks performed by more than 50 surgeons. To explore data, the system uses a multiple-coordinated-views framework. It provides techniques to select and filter multivariate time series data, visualize animated force plots in conjunction with contextual videos, encode multivariate bimanual tool trace data in 3D visualizations, and link visualizations to a database management system via a new generalizable data model. Insights and feedback from an interdisciplinary iterative design process and use case studies support the utility of visualization in this emerging area of data-driven surgical training. [ABSTRACT FROM PUBLISHER]
The sum and difference of two random variables with same variances are decorrelated and define the principal axes of their associated joint probability function. Therefore, sum and difference histograms are introduced...
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The sum and difference of two random variables with same variances are decorrelated and define the principal axes of their associated joint probability function. Therefore, sum and difference histograms are introduced as an alternative to the usual co-occurrence matrices used for texture analysis. Two maximum likelihood texture classifiers are presented depending on the type of object used for texture characterization (sum and difference histograms or some associated global measures). Experimental results indicate that sum and difference histograms used conjointly are nearly as powerful as cooccurrence matrices for texture discrimination. The advantage of the proposed texture analysis method over the conventional spatial gray level dependence method is the decrease in computation time and memory storage.
Designers of computer graphics hardware have used increasing device counts available from IC manufacturers to increase parallelism using techniques such as putting a longer pipeline of data path elements on integrated...
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Designers of computer graphics hardware have used increasing device counts available from IC manufacturers to increase parallelism using techniques such as putting a longer pipeline of data path elements on integrated circuits, or developing designs which use an array of processors. Pixel-Planes 1-5 and PixelFlow are examples of architectures which use an array of pixel processors for rasterization. Early generations of Pixel-Planes attempted to make these arrays as large as the display providing one processor for each display pixel. Later generations improved performance by grouping processors into multiple smaller arrays, subdividing the screen into sections of a corresponding size and having the arrays independently process the screen subdivisions. This paper describes simulations which were performed to determine the optimum size subdivision for a graphicscomputer which uses Pixel-Planes type parallelism, i.e. static two dimensional screen subdivision parallel polygon rasterization. We then develop a mathematical approach to determining the optimal subdivision size and show that it agrees well with the experimental data. For special purpose architectures we show that the optimal size depends not only on the polygon size but also on the silicon area consumed by the rasterizer overhead. The mathematical approach can be directly applied to special purpose architectures, and we show how it can be modified for use in analyzing algorithms developed for general purpose architectures such as the Intel Touchstone or Paragon, or the Thinking Machines CM-5. (C) 1997 Elsevier Science Ltd.
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