... Pergamon Press plc NATURE AND ORIGINS OF VIRTUAL ENVIRONMENTS: A BIBLIOGRAPHICAL ESSAY SR ELL... more ... Pergamon Press plc NATURE AND ORIGINS OF VIRTUAL ENVIRONMENTS: A BIBLIOGRAPHICAL ESSAY SR ELLIS NASA Ames Research Center, Moffett Field, CA 94035, USA and University of California, Berkeley, CA 94270, USA (Received 30 May 1991) Abstract-- ...
The authors review virtual environment technology and its application to the aerospace industry. ... more The authors review virtual environment technology and its application to the aerospace industry. Virtual environment systems have three components: sensors, effectors, and interlinkage hardware and software. Virtual environment tools used by the aerospace industry include the Multi-dimensional, User-oriented, Synthetic Environment (MUSE); Cave Automatic Virtual Environment (CAVE); and Immersadesk. Engineering applications include design and manufacture of aerospace systems, maintenance, and repair.
As virtual and augmented reality hardware and software have grown more mature over the past decad... more As virtual and augmented reality hardware and software have grown more mature over the past decade, the focus of the field is shifting away from the basic engineering technology, and towards the science and applications of VR and AR techniques. Increasingly, virtual and augmented reality researchers are conducting human-subject experiments, both to understand the way humans perceive, manipulate, and cognate with VR and AR information, and to quantify the utility of VR and AR in different application contexts. This tutorial is for researchers and engineers, working in the field of VR and AR, who wish to conduct a human-subject experiment. It will cover (1) the basic principles of experimental design and analysis, with an emphasis on human-subject experiments in VR and AR (Swan); (2) a "journalistic approach" to measuring human performance that organizes the activity around questions such as "Who? What? When? Where? How? and Why?" (Ellis); and (3) the basic principals and techniques of psychophysics, along with examples of how they have successfully examined human perceptual performance in virtual environments (Adelstein). To illustrate the discussed principals and techniques, the course will include illustrative case studies of actual human-subject experiments conducted with VR and AR systems.
Proceedings of the 1st Symposium on Applied perception in graphics and visualization - APGV '04, 2004
System latency (time delay) and its visible consequences are fundamental virtual environment (VE)... more System latency (time delay) and its visible consequences are fundamental virtual environment (VE) deficiencies that can hamper user perception and performance. The aim of this research is to quantify the role of VE scene content and resultant relative object motion on perceptual sensitivity to VE latency. Latency detection was examined by presenting observers in a head-tracked, stereoscopic head mounted display with environments having differing levels of complexity ranging from simple geometrical objects to a radiosity-rendered scene of two interconnected rooms. Latency discrimination was compared with results from a previous study in which only simple geometrical objects, without radiosity rendering or a 'real-world' setting, were used. From the results of these two studies, it can be inferred that the Just Noticeable Difference (JND) for latency discrimination by trained observers averages ~15 ms or less, independent of scene complexity and real-world meaning. Such knowledge will help elucidate latency perception mechanisms and, in turn, guide VE designers in the development of latency countermeasures.
Proceedings of the 2009 13th Ieee Acm International Symposium on Distributed Simulation and Real Time Applications, 2009
System rendering latency has been recognized by senior researchers, such as Professor Fredrick Br... more System rendering latency has been recognized by senior researchers, such as Professor Fredrick Brooks of UNC (Turing Award 1999), as a major factor limiting the realism and utility of head-referenced displays systems. Latency has been shown to reduce the user's sense of immersion within a virtual environment, disturb user interaction with virtual objects, and to contribute to motion sickness during some simulation tasks.
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
The Misalignment Effect Function (MEF) describes the decrement in manual performance associated w... more The Misalignment Effect Function (MEF) describes the decrement in manual performance associated with a rotation between a person's visual display frame of reference and that of their manual control. It now has been empirically determined for rotation axes oblique to canonical body axes and is compared with the MEF previously measured for rotations about canonical axes. A targeting rule based on these earlier measurements is derived from a hypothetical process and shown to describe some of the data from three previous experiments. We call it the Secant Rule. It appears to explain the motion trajectories determined for rotations less than 65° purely in kinematic terms without a need to appeal to a process of mental rotation. Further analysis of this rule in three dimensions applied to oblique rotation axes leads to a somewhat surprising expectation that the difficulty posed by rotational misalignment should get harder as the required movement is shorter. This prediction is confirmed. Geometry underlying this rule also suggests analytic extensions for predicting more generally the difficulty of making movements in arbitrary directions subject to arbitrary misalignments.
A spatial instrument is defined as a display device which has been either geometrically or symbol... more A spatial instrument is defined as a display device which has been either geometrically or symbolically enhanced to better enable a user to accomplish a particular task. Research conducted over the past several years on 3-D spatial instruments has shown that perspective displays, even when viewed from the correct viewpoint, are subject to systematic viewer biases. These biases interfere with correct spatial judgements of the presented pictorial information. It is also found that deliberate, appropriate geometric distortion of the perspective projection of an image can improve user performance. These two findings raise intriguing questions concerning the design of head-mounted spatial instruments. The design of such instruments may not only require the introduction of compensatory distortions to remove the neutrally occurring biases but also may significantly benefit from the introduction of artificial distortions which enhance performance. These image manipulations, however, can cau...
Kinesthetic feedback was shown to significantly improve the accuracy of teleoperations subject to... more Kinesthetic feedback was shown to significantly improve the accuracy of teleoperations subject to rotational misalignments between the image source and the operator even without explicit training. Rotational misalignments are often encountered in teleoperation and telerobotics when a remote image sensor (usually a camera) is oriented so that the resulting display coordinates are rotated with respect to the coordinates in which the user is operating. In the past, users have had to learn to compensate for this misalignment through practice, camera adjustment, or the use of multiple camera images. A new compensation technique is proposed in which the hand not used for control is utilized to provide a kinesthetic cue to the camera orientation. This cue greatly reduces the difficulty operators have had in compensating for control-display misalignment. The cueing hand, which is positioned to copy the attitude of the viewing camera, provides a kinesthetic reference for the movement of othe...
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
In previous reports we measured and analyzed the Misalignment Effect Function, a function describ... more In previous reports we measured and analyzed the Misalignment Effect Function, a function describing the decrement in human performance due to rotation between operators’ display and control axes. This prior work allowed us to determine difficulty-matched sets of rotations for a generalized 3D Fitts-like movement task. We consequently are now able to study the interaction of system latency and movement difficulty in a highly generalized way in a virtual telerobotic environment using wide variety of conditions and targets. Our targets are located on a spherical shell near our participants’ starting point in a high dynamic fidelity virtual environment. Analysis of participants’ ability to make movements to these targets has revealed a purely multiplicative interaction between control latency and task difficulty. Interestingly, we show that this the observed interaction supports work on Fitts’ Law by E.R. Hoffmann and that it depends upon accounting for an internal human processing lat...
Human Vision, Visual Processing, and Digital Display III
Pictorial display aids represent synthetic environments within which users interact with symbolic... more Pictorial display aids represent synthetic environments within which users interact with symbolic elements representing objects and processes in the real world. The design of these environments challenge researchers to understand the elements of the physical environment that make them predicable and understandable. By incorporating these aspects of the physical world, useful representation aids can improve the naturalness of their symbolic representation, geometric structure, and dynamic response.
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
A perspective format for a “Tunnel-in-the-Sky” primary flight display was evaluated in a part-tas... more A perspective format for a “Tunnel-in-the-Sky” primary flight display was evaluated in a part-task experiment to determine if it provided improved spatial situation awareness compared to a conventional electronic attitude director indicator. Body referenced visual direction to targets on the ground was used to measure spatial situation awareness. Underestimation of visual direction previously observed in laboratory conditions was replicated in the part-task environment. Conditions under which the the “Tunnel” display could provide less biased and more accurate situation awareness were also investigated.
Proceedings. ICCON IEEE International Conference on Control and Applications
An interactive, graphical proximity operations planning system has been developed which allows on... more An interactive, graphical proximity operations planning system has been developed which allows on-site design of efficient, complex, multiburn maneuvers in the dynamic multispacecraft environment about the space station. Maneuvering takes place in, as well as out of, the orbital plane. The difficulty in planning such missions results from the unusual and counterintuitive character of relative orbital motion trajectories and complex operational constraints, which are both time-varying and highly dependent on the mission scenario. This difficulty is greatly overcome by visualizing the relative trajectories and the relevant constraints in an easily interpretable, graphical format, which provides the operator with immediate feedback on design actions. The display shows a perspective bird's-eye view of the space station and co-orbiting spacecraft on the background of the station's orbital plane. The operator has control over two modes of operation: (1) a viewing system mode, which enables him or her to "explore" the spatial situation about the space station and thus choose and frame in on areas of interest; and (2) a trajectory design mode, which allows the interactive "editing" of a series of way-points and maneuvering burns to obtain a trajectory which complies with all operational constraints. Through a graphical interactive process, the operator will continue to modify the trajectory design until all operational constraints are met. The effectiveness of this display format in complex trajectory design is presently being evaluated in an ongoing experimental program.
The Misalignment Effect Function (MEF) describes the decrement in manual performance due to rotat... more The Misalignment Effect Function (MEF) describes the decrement in manual performance due to rotation between the users' visual display frame of reference and that of their manual control. A targeting process, called the Secant Rule is proposed to explain this function for rotation angles less than 65°. This rule describes data from three previous experiments without a need for hypothetical user mental rotation. Analysis of its three-dimensional generalization leads to an unexpected conclusion that difficulties due to rotational misalignment should get harder as the required movement is shorter. This prediction is confirmed, an approach for generalizing the analysis to larger rotations is considered, and a connection with Crossman and Goodeve's explanation of Fitts's Law is examined.
Proceedings of the SIGGRAPH 2003 conference on Sketches & applications in conjunction with the 30th annual conference on Computer graphics and interactive techniques - GRAPH '03
In order to determine the required visual frame rate (FR) for minimizing prediction errors with o... more In order to determine the required visual frame rate (FR) for minimizing prediction errors with out-the-window video displays at remote/virtual airport towers, thirteen active air traffic controllers viewed high dynamic fidelity simulations of landing aircraft and decided whether aircraft would stop as if to be able to make a turnoff or whether a runway excursion would be expected. The viewing conditions and simulation dynamics replicated visual rates and environments of transport aircraft landing at small commercial airports. The required frame rate was estimated from the FR-extrapolation of event probabilities conditional on predictions (stop, no-stop), and from a model fit to the perceptual discriminability A (average area under all proper ROC-curves) as dependent on FR. Decision errors are biased towards preference of overshoot and appear due to illusionary increase in speed at low frames rates. Both extrapolations yield a framerate requirement FR min of 35 < FR min < 40 Hz which is compared with published results [12] on shooter game scores. Definitive recommendations require further experiments with FR > 30 Hz.
Visual motion and other visual cues are used by tower controllers to provide important support fo... more Visual motion and other visual cues are used by tower controllers to provide important support for their control tasks at and near airports. These cues are particularly important for anticipated separation. Some of them, which we call visual features, have been identified from structured interviews and discussions with 24 active air traffic controllers or supervisors. The visual information that these features provide has been analyzed with respect to possible ways it could be presented at a remote tower that does not allow a direct view of the airport. Two types of remote towers are possible. One could be based on a plan-view, map-like computergenerated display of the airport and its immediate surroundings. An alternative would present a composite perspective view of the airport and its surroundings, possibly provided by an array of radially mounted cameras positioned at the airport in lieu of a tower. An initial more detailed analyses of one of the specific landing cues identified by the controllers, landing deceleration, is provided as a basis for evaluating how controllers might detect and use it. Understanding other such cues will help identify the information that may be degraded or lost in a remote or virtual tower not located at the airport. Suggestions are made regarding how some of the lost visual information may be displayed. Many of the cues considered involve visual motion, though some important static cues are also discussed.
The conference proceedings topics are divided into two main areas: (1) issues of spatial and pict... more The conference proceedings topics are divided into two main areas: (1) issues of spatial and picture perception raised by graphical electronic displays of spatial information; and (2) design questions raised by the practical experience of designers actually defining new spatial instruments for use in new aircraft and spacecraft. Each topic is considered from both a theoretical and an applied direction. Emphasis is placed on discussion of phenomena and determination of design principles.
The quality of visual registration achievable with an optical see-through head mounted display (H... more The quality of visual registration achievable with an optical see-through head mounted display (HMD) ultimately depends on the user's targeting precision. This paper presents design guidelines for calibration procedures based on measurements of users' head stability during visual alignment with reference targets. Targeting data was collected from 12 standing subjects who aligned a head fixed cursor presented in a see-through HMD with background targets that varied in azimuth (0°, ±30°, ±60°) and elevation (0°, ±10°). Their data showed that: 1) Both position and orientation data will need to be used to establish calibrations based on nearby reference targets since eliminating body sway effects can improve calibration precision by a factor of 16 and eliminate apparent angular anisotropies. 2) Compensation for body sway can speed the calibration by removing the need to wait for the body sway to abate, and 3) calibration precision can be less than 2 arcmin even for head directions rotated up to 60° with respect to the user's torso provided body sway is corrected. Users of Augmented Reality (AR) applications overlooking large distances may avoid the need to correct for body sway by boresighting on markers at relatively long distances, >> 10 m. These recommendations contrast with those for heads up displays using real images as discussed in previous papers.
This guide instructs users in the operation of a Proximity Operations Planning System. This syste... more This guide instructs users in the operation of a Proximity Operations Planning System. This system uses an interactive graphical method for planning fuel-efficient rendezvous trajectories in the multi-spacecraft environment of the space station and allows the operator to compose a multi-burn transfer trajectory between orbit initial chaser and target trajectories. The available task time (window) of the mission is predetermined and the maneuver is subject to various operational constraints, such as departure, arrival, spatial, plume impingement, and en route passage constraints. The maneuvers are described in terms of the relative motion experienced in a space station centered coordinate system. Both in-orbital plane as well as out-of-orbital plane maneuvering is considered. A number of visual optimization aids are used for assisting the operator in reaching fuel-efficient solutions. These optimization aids are based on the Primer Vector theory. The visual feedback of trajectory shapes, operational constraints, and optimization functions, provided by user-transparent and continuously active background computations, allows the operator to make fast, iterative design changes that rapidly converge to fuel-efficient solutions. The planning tool is an example of operator-assisted optimization of nonlinear cost functions.
... Pergamon Press plc NATURE AND ORIGINS OF VIRTUAL ENVIRONMENTS: A BIBLIOGRAPHICAL ESSAY SR ELL... more ... Pergamon Press plc NATURE AND ORIGINS OF VIRTUAL ENVIRONMENTS: A BIBLIOGRAPHICAL ESSAY SR ELLIS NASA Ames Research Center, Moffett Field, CA 94035, USA and University of California, Berkeley, CA 94270, USA (Received 30 May 1991) Abstract-- ...
The authors review virtual environment technology and its application to the aerospace industry. ... more The authors review virtual environment technology and its application to the aerospace industry. Virtual environment systems have three components: sensors, effectors, and interlinkage hardware and software. Virtual environment tools used by the aerospace industry include the Multi-dimensional, User-oriented, Synthetic Environment (MUSE); Cave Automatic Virtual Environment (CAVE); and Immersadesk. Engineering applications include design and manufacture of aerospace systems, maintenance, and repair.
As virtual and augmented reality hardware and software have grown more mature over the past decad... more As virtual and augmented reality hardware and software have grown more mature over the past decade, the focus of the field is shifting away from the basic engineering technology, and towards the science and applications of VR and AR techniques. Increasingly, virtual and augmented reality researchers are conducting human-subject experiments, both to understand the way humans perceive, manipulate, and cognate with VR and AR information, and to quantify the utility of VR and AR in different application contexts. This tutorial is for researchers and engineers, working in the field of VR and AR, who wish to conduct a human-subject experiment. It will cover (1) the basic principles of experimental design and analysis, with an emphasis on human-subject experiments in VR and AR (Swan); (2) a "journalistic approach" to measuring human performance that organizes the activity around questions such as "Who? What? When? Where? How? and Why?" (Ellis); and (3) the basic principals and techniques of psychophysics, along with examples of how they have successfully examined human perceptual performance in virtual environments (Adelstein). To illustrate the discussed principals and techniques, the course will include illustrative case studies of actual human-subject experiments conducted with VR and AR systems.
Proceedings of the 1st Symposium on Applied perception in graphics and visualization - APGV '04, 2004
System latency (time delay) and its visible consequences are fundamental virtual environment (VE)... more System latency (time delay) and its visible consequences are fundamental virtual environment (VE) deficiencies that can hamper user perception and performance. The aim of this research is to quantify the role of VE scene content and resultant relative object motion on perceptual sensitivity to VE latency. Latency detection was examined by presenting observers in a head-tracked, stereoscopic head mounted display with environments having differing levels of complexity ranging from simple geometrical objects to a radiosity-rendered scene of two interconnected rooms. Latency discrimination was compared with results from a previous study in which only simple geometrical objects, without radiosity rendering or a 'real-world' setting, were used. From the results of these two studies, it can be inferred that the Just Noticeable Difference (JND) for latency discrimination by trained observers averages ~15 ms or less, independent of scene complexity and real-world meaning. Such knowledge will help elucidate latency perception mechanisms and, in turn, guide VE designers in the development of latency countermeasures.
Proceedings of the 2009 13th Ieee Acm International Symposium on Distributed Simulation and Real Time Applications, 2009
System rendering latency has been recognized by senior researchers, such as Professor Fredrick Br... more System rendering latency has been recognized by senior researchers, such as Professor Fredrick Brooks of UNC (Turing Award 1999), as a major factor limiting the realism and utility of head-referenced displays systems. Latency has been shown to reduce the user's sense of immersion within a virtual environment, disturb user interaction with virtual objects, and to contribute to motion sickness during some simulation tasks.
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
The Misalignment Effect Function (MEF) describes the decrement in manual performance associated w... more The Misalignment Effect Function (MEF) describes the decrement in manual performance associated with a rotation between a person's visual display frame of reference and that of their manual control. It now has been empirically determined for rotation axes oblique to canonical body axes and is compared with the MEF previously measured for rotations about canonical axes. A targeting rule based on these earlier measurements is derived from a hypothetical process and shown to describe some of the data from three previous experiments. We call it the Secant Rule. It appears to explain the motion trajectories determined for rotations less than 65° purely in kinematic terms without a need to appeal to a process of mental rotation. Further analysis of this rule in three dimensions applied to oblique rotation axes leads to a somewhat surprising expectation that the difficulty posed by rotational misalignment should get harder as the required movement is shorter. This prediction is confirmed. Geometry underlying this rule also suggests analytic extensions for predicting more generally the difficulty of making movements in arbitrary directions subject to arbitrary misalignments.
A spatial instrument is defined as a display device which has been either geometrically or symbol... more A spatial instrument is defined as a display device which has been either geometrically or symbolically enhanced to better enable a user to accomplish a particular task. Research conducted over the past several years on 3-D spatial instruments has shown that perspective displays, even when viewed from the correct viewpoint, are subject to systematic viewer biases. These biases interfere with correct spatial judgements of the presented pictorial information. It is also found that deliberate, appropriate geometric distortion of the perspective projection of an image can improve user performance. These two findings raise intriguing questions concerning the design of head-mounted spatial instruments. The design of such instruments may not only require the introduction of compensatory distortions to remove the neutrally occurring biases but also may significantly benefit from the introduction of artificial distortions which enhance performance. These image manipulations, however, can cau...
Kinesthetic feedback was shown to significantly improve the accuracy of teleoperations subject to... more Kinesthetic feedback was shown to significantly improve the accuracy of teleoperations subject to rotational misalignments between the image source and the operator even without explicit training. Rotational misalignments are often encountered in teleoperation and telerobotics when a remote image sensor (usually a camera) is oriented so that the resulting display coordinates are rotated with respect to the coordinates in which the user is operating. In the past, users have had to learn to compensate for this misalignment through practice, camera adjustment, or the use of multiple camera images. A new compensation technique is proposed in which the hand not used for control is utilized to provide a kinesthetic cue to the camera orientation. This cue greatly reduces the difficulty operators have had in compensating for control-display misalignment. The cueing hand, which is positioned to copy the attitude of the viewing camera, provides a kinesthetic reference for the movement of othe...
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
In previous reports we measured and analyzed the Misalignment Effect Function, a function describ... more In previous reports we measured and analyzed the Misalignment Effect Function, a function describing the decrement in human performance due to rotation between operators’ display and control axes. This prior work allowed us to determine difficulty-matched sets of rotations for a generalized 3D Fitts-like movement task. We consequently are now able to study the interaction of system latency and movement difficulty in a highly generalized way in a virtual telerobotic environment using wide variety of conditions and targets. Our targets are located on a spherical shell near our participants’ starting point in a high dynamic fidelity virtual environment. Analysis of participants’ ability to make movements to these targets has revealed a purely multiplicative interaction between control latency and task difficulty. Interestingly, we show that this the observed interaction supports work on Fitts’ Law by E.R. Hoffmann and that it depends upon accounting for an internal human processing lat...
Human Vision, Visual Processing, and Digital Display III
Pictorial display aids represent synthetic environments within which users interact with symbolic... more Pictorial display aids represent synthetic environments within which users interact with symbolic elements representing objects and processes in the real world. The design of these environments challenge researchers to understand the elements of the physical environment that make them predicable and understandable. By incorporating these aspects of the physical world, useful representation aids can improve the naturalness of their symbolic representation, geometric structure, and dynamic response.
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
A perspective format for a “Tunnel-in-the-Sky” primary flight display was evaluated in a part-tas... more A perspective format for a “Tunnel-in-the-Sky” primary flight display was evaluated in a part-task experiment to determine if it provided improved spatial situation awareness compared to a conventional electronic attitude director indicator. Body referenced visual direction to targets on the ground was used to measure spatial situation awareness. Underestimation of visual direction previously observed in laboratory conditions was replicated in the part-task environment. Conditions under which the the “Tunnel” display could provide less biased and more accurate situation awareness were also investigated.
Proceedings. ICCON IEEE International Conference on Control and Applications
An interactive, graphical proximity operations planning system has been developed which allows on... more An interactive, graphical proximity operations planning system has been developed which allows on-site design of efficient, complex, multiburn maneuvers in the dynamic multispacecraft environment about the space station. Maneuvering takes place in, as well as out of, the orbital plane. The difficulty in planning such missions results from the unusual and counterintuitive character of relative orbital motion trajectories and complex operational constraints, which are both time-varying and highly dependent on the mission scenario. This difficulty is greatly overcome by visualizing the relative trajectories and the relevant constraints in an easily interpretable, graphical format, which provides the operator with immediate feedback on design actions. The display shows a perspective bird's-eye view of the space station and co-orbiting spacecraft on the background of the station's orbital plane. The operator has control over two modes of operation: (1) a viewing system mode, which enables him or her to "explore" the spatial situation about the space station and thus choose and frame in on areas of interest; and (2) a trajectory design mode, which allows the interactive "editing" of a series of way-points and maneuvering burns to obtain a trajectory which complies with all operational constraints. Through a graphical interactive process, the operator will continue to modify the trajectory design until all operational constraints are met. The effectiveness of this display format in complex trajectory design is presently being evaluated in an ongoing experimental program.
The Misalignment Effect Function (MEF) describes the decrement in manual performance due to rotat... more The Misalignment Effect Function (MEF) describes the decrement in manual performance due to rotation between the users' visual display frame of reference and that of their manual control. A targeting process, called the Secant Rule is proposed to explain this function for rotation angles less than 65°. This rule describes data from three previous experiments without a need for hypothetical user mental rotation. Analysis of its three-dimensional generalization leads to an unexpected conclusion that difficulties due to rotational misalignment should get harder as the required movement is shorter. This prediction is confirmed, an approach for generalizing the analysis to larger rotations is considered, and a connection with Crossman and Goodeve's explanation of Fitts's Law is examined.
Proceedings of the SIGGRAPH 2003 conference on Sketches & applications in conjunction with the 30th annual conference on Computer graphics and interactive techniques - GRAPH '03
In order to determine the required visual frame rate (FR) for minimizing prediction errors with o... more In order to determine the required visual frame rate (FR) for minimizing prediction errors with out-the-window video displays at remote/virtual airport towers, thirteen active air traffic controllers viewed high dynamic fidelity simulations of landing aircraft and decided whether aircraft would stop as if to be able to make a turnoff or whether a runway excursion would be expected. The viewing conditions and simulation dynamics replicated visual rates and environments of transport aircraft landing at small commercial airports. The required frame rate was estimated from the FR-extrapolation of event probabilities conditional on predictions (stop, no-stop), and from a model fit to the perceptual discriminability A (average area under all proper ROC-curves) as dependent on FR. Decision errors are biased towards preference of overshoot and appear due to illusionary increase in speed at low frames rates. Both extrapolations yield a framerate requirement FR min of 35 < FR min < 40 Hz which is compared with published results [12] on shooter game scores. Definitive recommendations require further experiments with FR > 30 Hz.
Visual motion and other visual cues are used by tower controllers to provide important support fo... more Visual motion and other visual cues are used by tower controllers to provide important support for their control tasks at and near airports. These cues are particularly important for anticipated separation. Some of them, which we call visual features, have been identified from structured interviews and discussions with 24 active air traffic controllers or supervisors. The visual information that these features provide has been analyzed with respect to possible ways it could be presented at a remote tower that does not allow a direct view of the airport. Two types of remote towers are possible. One could be based on a plan-view, map-like computergenerated display of the airport and its immediate surroundings. An alternative would present a composite perspective view of the airport and its surroundings, possibly provided by an array of radially mounted cameras positioned at the airport in lieu of a tower. An initial more detailed analyses of one of the specific landing cues identified by the controllers, landing deceleration, is provided as a basis for evaluating how controllers might detect and use it. Understanding other such cues will help identify the information that may be degraded or lost in a remote or virtual tower not located at the airport. Suggestions are made regarding how some of the lost visual information may be displayed. Many of the cues considered involve visual motion, though some important static cues are also discussed.
The conference proceedings topics are divided into two main areas: (1) issues of spatial and pict... more The conference proceedings topics are divided into two main areas: (1) issues of spatial and picture perception raised by graphical electronic displays of spatial information; and (2) design questions raised by the practical experience of designers actually defining new spatial instruments for use in new aircraft and spacecraft. Each topic is considered from both a theoretical and an applied direction. Emphasis is placed on discussion of phenomena and determination of design principles.
The quality of visual registration achievable with an optical see-through head mounted display (H... more The quality of visual registration achievable with an optical see-through head mounted display (HMD) ultimately depends on the user's targeting precision. This paper presents design guidelines for calibration procedures based on measurements of users' head stability during visual alignment with reference targets. Targeting data was collected from 12 standing subjects who aligned a head fixed cursor presented in a see-through HMD with background targets that varied in azimuth (0°, ±30°, ±60°) and elevation (0°, ±10°). Their data showed that: 1) Both position and orientation data will need to be used to establish calibrations based on nearby reference targets since eliminating body sway effects can improve calibration precision by a factor of 16 and eliminate apparent angular anisotropies. 2) Compensation for body sway can speed the calibration by removing the need to wait for the body sway to abate, and 3) calibration precision can be less than 2 arcmin even for head directions rotated up to 60° with respect to the user's torso provided body sway is corrected. Users of Augmented Reality (AR) applications overlooking large distances may avoid the need to correct for body sway by boresighting on markers at relatively long distances, >> 10 m. These recommendations contrast with those for heads up displays using real images as discussed in previous papers.
This guide instructs users in the operation of a Proximity Operations Planning System. This syste... more This guide instructs users in the operation of a Proximity Operations Planning System. This system uses an interactive graphical method for planning fuel-efficient rendezvous trajectories in the multi-spacecraft environment of the space station and allows the operator to compose a multi-burn transfer trajectory between orbit initial chaser and target trajectories. The available task time (window) of the mission is predetermined and the maneuver is subject to various operational constraints, such as departure, arrival, spatial, plume impingement, and en route passage constraints. The maneuvers are described in terms of the relative motion experienced in a space station centered coordinate system. Both in-orbital plane as well as out-of-orbital plane maneuvering is considered. A number of visual optimization aids are used for assisting the operator in reaching fuel-efficient solutions. These optimization aids are based on the Primer Vector theory. The visual feedback of trajectory shapes, operational constraints, and optimization functions, provided by user-transparent and continuously active background computations, allows the operator to make fast, iterative design changes that rapidly converge to fuel-efficient solutions. The planning tool is an example of operator-assisted optimization of nonlinear cost functions.
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Papers by Stephen Ellis