Results of a User Study on 2D Hurricane Visualization

We present the results from a user study looking at the ability of observers to mentally integrate wind direction and magnitude over a vector field. The data set chosen for the study is an MM5 (PSU/NCAR Mesoscale Model) simulation of Hurricane Lili over the Gulf of Mexico as it approaches the southeastern United States. Nine observers participated in the study. This study investigates the effect of layering on the observer's ability to determine the magnitude and direction of a vector field. We found a tendency for observers to underestimate the magnitude of the vectors and a counter‐clockwise bias when determining the average direction of a vector field. We completed an additional study with two observers to try to uncover the source of the counter‐clockwise bias. These results have direct implications to atmospheric scientists, but may also be able to be applied to other fields that use 2D vector fields.     

Continuous Levels‐of‐Detail and Visual Abstraction for Seamless Molecular Visualization

Molecular visualization is often challenged with rendering of large molecular structures in real time. We introduce a novel approach that enables us to show even large protein complexes. Our method is based on the level‐of‐detail concept, where we exploit three different abstractions combined in one visualization. Firstly, molecular surface abstraction exploits three different surfaces, solvent‐excluded surface (SES), Gaussian kernels and van der Waals spheres, combined as one surface by linear interpolation. Secondly, we introduce three shading abstraction levels and a method for creating seamless transitions between these representations. The SES representation with full shading and added contours stands in focus while on the other side a sphere representation of a cluster of atoms with constant shading and without contours provide the context. Thirdly, we propose a hierarchical abstraction based on a set of clusters formed on molecular atoms. All three abstraction models are driven by one importance function classifying the scene into the near‐, mid‐ and far‐field. Moreover, we introduce a methodology to render the entire molecule directly using the A‐buffer technique, which further improves the performance. The rendering performance is evaluated on series of molecules of varying atom counts.     

Scalable Symmetry Detection for Urban Scenes

In this paper, we present a novel method for detecting partial symmetries in very large point clouds of 3D city scans. Unlike previous work, which has only been demonstrated on data sets of a few hundred megabytes maximum, our method scales to very large scenes: We map the detection problem to a nearest‐neighbour problem in a low‐dimensional feature space, and follow this with a cascade of tests for geometric clustering of potential matches. Our algorithm robustly handles noisy real‐world scanner data, obtaining a recognition performance comparable to that of state‐of‐the‐art methods. In practice, it scales linearly with scene size and achieves a high absolute throughput, processing half a terabyte of scanner data overnight on a dual socket commodity PC.     

Relativistic Effects for Time‐Resolved Light Transport

We present a real‐time framework which allows interactive visualization of relativistic effects for time‐resolved light transport. We leverage data from two different sources: real‐world data acquired with an effective exposure time of less than 2 picoseconds, using an ultra‐fast imaging technique termed femto‐photography, and a transient renderer based on ray‐tracing. We explore the effects of time dilation, light aberration, frequency shift and radiance accumulation by modifying existing models of these relativistic effects to take into account the time‐resolved nature of light propagation. Unlike previous works, we do not impose limiting constraints in the visualization, allowing the virtual camera to explore freely a reconstructed 3D scene depicting dynamic illumination. Moreover, we consider not only linear motion, but also acceleration and rotation of the camera. We further introduce, for the first time, a pinhole camera model into our relativistic rendering framework, and account for subsequent changes in focal length and field of view as the camera moves through the scene.     

如何开发新颖的图文报表

重点介绍如何将Ｏｒａｃｌｅ Ｒｅｐｏｒｔｓ和Ｏｒａｃｌｅ Ｇｒａｐｈｉｃｓ开发的报表应用和图形应用集成起来，以便在报表中动态地自动生成图形，这样在一张报表中既有精确的数学说明，也有形象，直观的图形表示，图形和文字互为补充说明，使报表更具说服力和吸引力。     

Simulating Gaseous Fluids with Low and High Speeds

Gaseous fluids may move slowly, as smoke does, or at high speed, such as occurs with explosions. High‐speed gas flow is always accompanied by low‐speed gas flow, which produces rich visual details in the fluid motion. Realistic visualization involves a complex dynamic flow field with both low and high speed fluid behavior. In computer graphics, algorithms to simulate gaseous fluids address either the low speed case or the high speed case, but no algorithm handles both efficiently. With the aim of providing visually pleasing results, we present a hybrid algorithm that efficiently captures the essential physics of both low‐ and high‐speed gaseous fluids. We model the low speed gaseous fluids by a grid approach and use a particle approach for the high speed gaseous fluids. In addition, we propose a physically sound method to connect the particle model to the grid model. By exploiting complementary strengths and avoiding weaknesses of the grid and particle approaches, we produce some animation examples and analyze their computational performance to demonstrate the effectiveness of the new hybrid method.     

Perceptually‐motivated Real‐time Temporal Upsampling of 3D Content for High‐refresh‐rate Displays

High‐refresh‐rate displays (e. g., 120 Hz) have recently become available on the consumer market and quickly gain on popularity. One of their aims is to reduce the perceived blur created by moving objects that are tracked by the human eye. However, an improvement is only achieved if the video stream is produced at the same high refresh rate (i. e. 120 Hz). Some devices, such as LCD TVs, solve this problem by converting low‐refresh‐rate content (i. e. 50 Hz PAL) into a higher temporal resolution (i. e. 200 Hz) based on two‐dimensional optical flow. In our approach, we will show how rendered three‐dimensional images produced by recent graphics hardware can be up‐sampled more efficiently resulting in higher quality at the same time. Our algorithm relies on several perceptual findings and preserves the naturalness of the original sequence. A psychophysical study validates our approach and illustrates that temporally up‐sampled video streams are preferred over the standard low‐rate input by the majority of users. We show that our solution improves task performance on high‐refresh‐rate displays.     

3D Slit Scanning with Planar Constraints★

We present a planarity constraint and a novel three‐dimensional (3D) point reconstruction algorithm for a multiview laser range slit scanner. The constraint is based on the fact that all observed points on a projected laser line lie on the same plane of laser light in 3D. The parameters of the plane of laser light linearly parametrize a homography between a pair of images of the laser points. This homography can be recovered from point correspondences derived from epipolar geometry. The use of the planar constraint reduces outliers in the reconstruction and allows for the reconstruction of points seen in only one view. We derive an optimal reconstruction of points subject to the planar constraint and compare the accuracy to the suboptimal approach in prior work. We also construct a catadioptric stereo rig with high quality optical components to remove error due to camera synchronization and non‐uniform laser projection. The reconstruction results are compared to prior work that uses inexpensive optics and two cameras.     

Oracle＊Forms与Oracle＊Graphics的集成技术

本文将研究Oracle*Forms与Oracle*Graphics集成的作用和机制,并结合典型实例着重介绍使用OG．PLL集成Oracle*Forms与Oracle*Graphics的方法和步骤。     

ARSC: Augmented reality student card

Augmented Reality (AR) is the technology of adding virtual objects to real scenes through enabling the addition of missing information in real life. As the lack of resources is a problem that can be solved through AR, this paper presents and explains the usage of AR technology we introduce Augmented Reality Student Card (ARSC) as an application of AR in the field of education. ARSC uses single static markers combined in one card for assigning different objects, while leaving the choice to the computer application for minimizing the tracking process. ARSC is designed to be a useful low cost solution for serving the education field. ARSC can represent any lesson in a 3D format that helps students to visualize different learning objects, interact with theories and deal with the information in a totally new, effective, and interactive way. ARSC can be used in offline, online and game applications with seven markers, four of them are used as a joystick game controller. One of the novelties in this paper is that experimental tests had been made for the ARTag marker set for sorting them according to their efficiency. The results of those tests were used in this research to choose the most efficient markers for ARSC, and can be used for further research. The experimental work in this paper also shows the constraints for marker creation for an AR application. As we need to work in both online and offline application, merging of toolkits and libraries has been made, as presented in this paper. ARSC was examined by a number of students of both genders with average age between 10 and 17 years and it found great acceptance among them.