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At least 91 records · Page 5

Instructor and student pilots' subjective evaluation of a general aviation simulator with a terrain visual system

Ten student pilots were given a 1 hour training session in the NASA Langley Research Center's General Aviation Simulator by a certified flight instructor and a follow-up flight evaluation was performed by the student's own flight instructor, who has also flown the simulator. The students and instructors generally felt that the simulator session had a positive effect on the students. They recommended that a simulator with a visual scene and a motion base would be useful in performing such maneuvers as: landing approaches, level flight, climbs, dives, turns, instrument work, and radio navigation, recommending that the simulator would be an efficient means of introducing the student to new maneuvers before doing them in flight. The students and instructors estimated that about 8 hours of simulator time could be profitably devoted to the private pilot training.

Kiteley, G. W.↗

A computer graphics system for visualizing spacecraft in orbit

To carry out unanticipated operations with resources already in space is part of the rationale for a permanently manned space station in Earth orbit. The astronauts aboard a space station will require an on-board, spatial display tool to assist the planning and rehearsal of upcoming operations. Such a tool can also help astronauts to monitor and control such operations as they occur, especially in cases where first-hand visibility is not possible. A computer graphics visualization system designed for such an application and currently implemented as part of a ground-based simulation is described. The visualization system presents to the user the spatial information available in the spacecraft's computers by drawing a dynamic picture containing the planet Earth, the Sun, a star field, and up to two spacecraft. The point of view within the picture can be controlled by the user to obtain a number of specific visualization functions. The elements of the display, the methods used to control the display's point of view, and some of the ways in which the system can be used are described.

Eyles, Don E.↗

A VR-based volumetric medical image segmentation and visualization system with natural human interaction

Volume rendering produces informative two-dimensional (2D) images from a 3-dimensional (3D) volume. It highlights the region of interest and facilitates a good comprehension of the entire data set. However, volume rendering faces a few challenges. First, a high-dimensional transfer function is usually required to differentiate the target from its neighboring objects with subtle variance. Unfortunately, designing such a transfer function is a strenuously trial-and-error process. Second, manipulating/visualizing a 3D volume with a traditional 2D input/output device suffers dimensional limitations. To address all the challenges, we design NUI-VR 2 , a natural user interface-enabled volume rendering system in the virtual reality space. NUI-VR 2 marries volume rendering and interactive image segmentation. It transforms the original volume into a probability map with image segmentation. A simple linear transfer function will highlight the target well in the probability map. More importantly, we set the entire image segmentation and volume rendering pipeline in an immersive virtual reality environment with a natural user interface. NUI-VR 2 eliminates the dimensional limitations in manipulating and perceiving 3D volumes and dramatically improves the user experience.

42 ENGINEERING↗

Multifunctionality of chiton biomineralized armor with an integrated visual system

Nature provides a multitude of examples of multifunctional structural materials. There are often trade-offs in these materials because few of them are equally well suited for multiple tasks. One such example is the biomineralized armor of the chiton Acanthopleura granulata, which incorporates an integrated sensory system that includes hundreds of eyes with aragonite-based lens. Here, we used optical experiments to demonstrate directly, for the first time, that these microscopic, mineralized lenses are able to form images. Furthermore, our experiments revealed that the optical performance of these polycrystalline lenses is enhanced by the reduction of spherical aberration through the shape of the lens and that birefringence scattering is minimized by the use of relatively large, co-aligned grains (~10 μm as compared to ~1 μm in the non-eye regions). Additionally, we used multi-scale mechanical testing techniques to show that A. granulata’s lenses are an integral component of its biomineralized armor, but that both the intrinsic and overall mechanical properties of the lenses are compromised as compared to the primary solid regions of the armor plates. Our results demonstrate that as the size, complexity, and functionality of the integrated sensory elements increases, the local mechanical performance of the armor decreases. But, A. granulata has evolved several strategies to compensate for its local mechanical vulnerabilities to form a multifunctional system with co-optimized overall optical and structural functions.

36 MATERIALS SCIENCE↗

New versions of old flow visualization systems

A small, modified Mach-Zehnder interferometer placed in series with a much larger schlieren optical system spanning the test section is examined. In one arm of the interferometer, light from the schlieren is focused through a pinhole and recollimating lens to produce a reference beam which interferes with the remaining object beam from the other arm. The object and reference beams are separated only over a small interval following the test section, and differential vibrations are greatly reduced. Color schlieren has technical, as well as aesthetic, advantages over black-and-white schlieren. Since each color is associated with a specific amount of refraction, quantitative evaluation of certain refractive-index fields becomes possible using very simple equations derived from ray trace theory. Rainbow schlieren of an acetylene flame, and the evaluated refractive index distribution are shown. Root-mean-square refractive index fluctuations in homogeneous, isotropic turbulence were determined using the rainbow schlieren, since these fluctuations determine the root-mean-square refraction, which is indicated by the overall color of the image.

Howes, W. L.↗

Visual Systems for Remotely Controlled Vehicles

The Variable Acuity Remote Viewing System is discussed. It was conceived as a technique for resolving the field of view/resolution/ bandwidth tradeoffs that exist in remote viewing systems. This system is based on the fact that integration of the human eye acuity function shows only about 130,000 pixels are required to fully support the human vision. This quantity is well within the capabilities of conventional video systems. The technique utilizes a non-linear optical system in both the sensing and display equipment. The non-linearity is achieved by a special lens which translates a uniform pixel array on its image plane into the object field as a variable angular array. This lens will record the same angular detail the eye would see when viewing the same scene and compress this detail into a uniform matrix of equal sized picture elements on its image plane. This image can be scanned with a broadcast quality tv having a 525 line raster scan. Conventional transmission equipment can then also be used to send the image information to a remote location. When received, the image is projected by a light valve projector onto a hemispherical screen by an identical non-linear lens.

Rezek, T.↗

The helmet-mounted visual system in flight simulation

An account is given of the application of fiber-optic helmet-mounted display systems to flight simulation tasks for complex combat mission scenarios involving numerous external aircraft, audible communications, and various types of threats. Such helmets, which although custom-made for each pilot are far less expensive than image-projection systems, consist of two 3-in. diameter 'optical pancake windows' mounted in front of the pilot's eyes to which images are transferred through fiber-optic cables from four high-brightness light-valve projectors. Head-position information is provided by an optical tracking system. The pancake window displays are semitransparent and allow cockpit controls and displays to be viewed normally.

Cook, Anthony M.↗

A 3D visualization system for molecular structures

The properties of molecules derive in part from their structures. Because of the importance of understanding molecular structures various methodologies, ranging from first principles to empirical technique, were developed for computing the structure of molecules. For large molecules such as polymer model compounds, the structural information is difficult to comprehend by examining tabulated data. Therefore, a molecular graphics display system, called MOLDS, was developed to help interpret the data. MOLDS is a menu-driven program developed to run on the LADC SNS computer systems. This program can read a data file generated by the modeling programs or data can be entered using the keyboard. MOLDS has the following capabilities: draws the 3-D representation of a molecule using stick, ball and ball, or space filled model from Cartesian coordinates, draws different perspective views of the molecule; rotates the molecule on the X, Y, Z axis or about some arbitrary line in space, zooms in on a small area of the molecule in order to obtain a better view of a specific region; and makes hard copy representation of molecules on a graphic printer. In addition, MOLDS can be easily updated and readily adapted to run on most computer systems.

Green, Terry J.↗

Science information systems: Visualization

Future programs in earth science, planetary science, and astrophysics will involve complex instruments that produce data at unprecedented rates and volumes. Current methods for data display, exploration, and discovery are inadequate. Visualization technology offers a means for the user to comprehend, explore, and examine complex data sets. The goal of this program is to increase the effectiveness and efficiency of scientists in extracting scientific information from large volumes of instrument data.

Wall, Ray J.↗

ISERV Pathfinder. The ISS SERVIR Environmental Research and Visualization System

SERVIR integrates Earth observations (e.g., space imagery), predictive models, and in situ data to provide timely information products to support environmental decision makers. ISERV propoesed development -- ISERV-W: Internal Visible/Near-Infrared (VNIR), attached to ISS via Window Observational Research Facility (WORF), ISERV-E: External Visible/Broad-Infrared (V/IR) and ISERV-PM: External Passive Microwave.

Howell, Burgess↗

Visual Alert System

A visual alert system resulted from circuitry developed by Applied Cybernetics Systems for Langley as part of a space related telemetry system. James Campman, Applied Cybernetics president, left the company and founded Grace Industries, Inc. to manufacture security devices based on the Langley technology. His visual alert system combines visual and audible alerts for hearing impaired people. The company also manufactures an arson detection device called the electronic nose, and is currently researching additional applications of the NASA technology.

Source record↗

Ascent/abort training in the Shuttle Mission Simulator

The Shuttle Mission Simulator is the primary tool employed in the training of orbiter flight crews in ascent and abort flight techniques at the Johnson Space Center. The simulator uses a motion system, visual systems, and a high-fidelity cockpit to enhance accuracy of training. A team concept is utilized to train flight crews and controllers for each mission to ensure a complete understanding in both orbiter systems and mission specific flight profiles. Thus, each flight crew and flight control team is prepared for the actual flight by practicing repeatedly both the nominal ascent and each type of possible abort situation for that Shuttle mission.

Sims, John T.↗

Overview of research in progress at the Center of Excellence

The Center of Excellence (COE) was created nine years ago to facilitate active collaboration between the scientists at Ames Research Center and the Stanford Psychology Department. Significant interchange of ideas and personnel continues between Stanford and participating groups at NASA-Ames; the COE serves its function well. This progress report is organized into sections divided by project. Each section contains a list of investigators, a background statement, progress report, and a proposal for work during the coming year. The projects are: Algorithms for development and calibration of visual systems, Visually optimized image compression, Evaluation of advanced piloting displays, Spectral representations of color, Perception of motion in man and machine, Automation and decision making, and Motion information used for navigation and control.

Wandell, Brian A.↗

Helicopter visual aid system

The helicopter visual aid system has been built and flight tested in situations representative of actual flight missions. The mechanisms discussed contributed greatly to the successful performance of the system throughout the 160 hours of flight testing. It has demonstrated that the visual aid concept can provide improved daytime visual capability, greatly improved nighttime capability, surveillance from greater distances and/or altitudes, covert operation at night through the use of the IR searchlight, and a photographic recording at the scene being viewed.

Baisley, R. L.↗