Displays for seeing without looking.
Peripheral vision displays for dynamic tracking information during difficult flight control tasks improve operator performance
HUMAN PERFORMANCE↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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From following edges to pursuing objects
Primates can generate accurate, smooth eye-movement responses to moving target objects of arbitrary shape and size, even in the presence of complex backgrounds and/or the extraneous motion of non-target objects. Most previous studies of pursuit have simply used a spot moving over a featureless background as the target and have thus neglected critical issues associated with the general problem of recovering object motion. Visual psychophysicists and theoreticians have shown that, for arbitrary objects with multiple features at multiple orientations, object-motion estimation for perception is a complex, multi-staged, time-consuming process. To examine the temporal evolution of the motion signal driving pursuit, we recorded the tracking eye movements of human observers to moving line-figure diamonds. We found that pursuit is initially biased in the direction of the vector average of the motions of the diamond's line segments and gradually converges to the true object-motion direction with a time constant of approximately 90 ms. Furthermore, transient blanking of the target during steady-state pursuit induces a decrease in tracking speed, which, unlike pursuit initiation, is subsequently corrected without an initial direction bias. These results are inconsistent with current models in which pursuit is driven by retinal-slip error correction. They demonstrate that pursuit models must be revised to include a more complete visual afferent pathway, which computes, and to some extent latches on to, an accurate estimate of object direction over the first hundred milliseconds or so of motion.
NASA Discipline Neuroscience↗
Distinct Pattern of Oculomotor Impairment Associated with Acute Sleep Loss and Circadian Misalignment
Sleep loss and circadianmisalignment have long been known to impair human cognitive and motor performance with significant societal and health consequences. It is well known that human reaction time to a visual cue is impaired following sleep loss and circadian misalignment, but it has remained unclear how more complex visuomotor control behaviour is altered under these conditions. In this study, we measured 14 parameters of the voluntary ocular tracking response of 12 human participants (six females) to systematically examine the effects of sleep loss and circadianmisalignment using a constant routine 24 h acute sleep-deprivation paradigm. The combination of state-of-the-art oculometric and sleep-research methodologies allowed us to document, for the first time, large changes in many components of pursuit, saccades and visual motion processing as a function of time awake and circadian phase. Further, we observed a pattern of impairment across our set of oculometric measures that is qualitatively different from that observed previously with other mild neural impairments. We conclude that dynamic vision and visuomotor control exhibit a distinct pattern of impairment linked with time awake and circadian phase. Therefore, a sufficiently broad set of oculometric measures could provide a sensitive and specific behavioural biomarker of acute sleep loss and circadian misalignment. We foresee potential applications of such oculometric biomarkers assisting in the assessment of readiness-to-perform higher risk tasks and in the characterization of sub-clinical neural impairment in the face of a multiplicity of potential risk factors, including disrupted sleep and circadian rhythms.
Stone, Leland S.↗
Construction and testing of a Scanning Laser Radar (SLR), phase 2
The scanning laser radar overall system is described. Block diagrams and photographs of the hardware are included with the system description. Detailed descriptions of all the subsystems that make up the scanning laser radar system are included. Block diagrams, photographs, and detailed optical and electronic schematics are used to help describe such subsystem hardware as the laser, beam steerer, receiver optics and detector, control and processing electronics, visual data displays, and the equipment used on the target. Tests were performed on the scanning laser radar to determine its acquisition and tracking performance and to determine its range and angle accuracies while tracking a moving target. The tests and test results are described.
Flom, T.↗
Proceedings, 13th Annual Conference on Manual Control
Theoretical aspects of manual control theory are discussed. Specific topics covered include: tracking; performance, attention allocation, and mental load; surface vehicle control; monitoring behavior and supervisory control; manipulators and prosthetics; aerospace vehicle control; motion and visual cues; and displays and controls.
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An experimental evaluation of head-up display formats
Three types of head-up display format are investigated. Type 1 is an unreferenced (conventional) flight director, type 2 is a ground referenced flight path display, and type 3 is a ground referenced director. Formats are generated by computer and presented by reflecting collimation against a simulated forward view in flight. Pilots, holding commercial licenses, fly approaches in the instrument flight mode and in a combined instrument and visual flight mode. The approaches are in wind shear with varied conditions of visibility, offset, and turbulence. The displays are equivalent in pure tracking but there is a slight advantage for the unreferenced director in poor conditions. Flight path displays are better for tracking in the combined flight mode, possibly because of poor director control laws and the division of attention between superimposed fields. Workloads is better for the type 2 displays. The flight path and referenced director displays are criticized for effects of symbol motion and field limiting. In the subjective judgment of pilots familiar with the director displays, they are rated clearly better than path displays, with a preference for the unreferenced director. There is a fair division of attention between superimposed fields.
Naish, J. M.↗
A simulation study of the flight dynamics of elastic aircraft. Volume 1: Experiment, results and analysis
The simulation experiment described addresses the effects of structural flexibility on the dynamic characteristics of a generic family of aircraft. The simulation was performed using the NASA Langley VMS simulation facility. The vehicle models were obtained as part of this research. The simulation results include complete response data and subjective pilot ratings and comments and so allow a variety of analyses. The subjective ratings and analysis of the time histories indicate that increased flexibility can lead to increased tracking errors, degraded handling qualities, and changes in the frequency content of the pilot inputs. These results, furthermore, are significantly affected by the visual cues available to the pilot.
Waszak, Martin R.↗
A simulation study of the flight dynamics of elastic aircraft. Volume 2: Data
The simulation experiment described addresses the effects of structural flexibility on the dynamic characteristics of a generic family of aircraft. The simulation was performed using the NASA Langley VMS simulation facility. The vehicle models were obtained as part of this research project. The simulation results include complete response data and subjective pilot ratings and comments and so allow a variety of analyses. The subjective ratings and analysis of the time histories indicate that increased flexibility can lead to increased tracking errors, degraded handling qualities, and changes in the frequency content of the pilot inputs. These results, furthermore, are significantly affected by the visual cues available to the pilot.
Waszak, Martin R.↗
Visual scanning with or without spatial uncertainty and time-sharing performance
An experiment is reported that examines the pattern of task interference between visual scanning as a sequential and selective attention process and other concurrent spatial or verbal processing tasks. A distinction is proposed between visual scanning with or without spatial uncertainty regarding the possible differential effects of these two types of scanning on interference with other concurrent processes. The experiment required the subject to perform a simulated primary tracking task, which was time-shared with a secondary spatial or verbal decision task. The relevant information that was needed to perform the decision tasks were displayed with or without spatial uncertainty. The experiment employed a 2 x 2 x 2 design with types of scanning (with or without spatial uncertainty), expected scanning distance (low/high), and codes of concurrent processing (spatial/verbal) as the three experimental factors. The results provide strong evidence that visual scanning as a spatial exploratory activity produces greater task interference with concurrent spatial tasks than with concurrent verbal tasks. Furthermore, spatial uncertainty in visual scanning is identified to be the crucial factor in producing this differential effect.
Liu, Yili↗
Adaptation of the phase of the human linear vestibulo-ocular reflex (LVOR) and effects on the oculomotor neural integrator
The phase of the translational linear VOR (LVOR) can be adaptively modified by exposure to a visual-vestibular mismatch. We extend here our earlier work on LVOR phase adaptation, and discuss the role of the oculomotor neural integrator. Ten subjects were oscillated laterally at 0.5 Hz, 0.3 g peak acceleration, while sitting upright on a linear sled. LVOR was assessed before and after adaptation with subjects tracking the remembered location of a target at 1 m in the dark. Phase and gain were measured by fitting sine waves to the desaccaded eye movements, and comparing sled and eye position. To adapt LVOR phase, the subject viewed a computer-generated stereoscopic visual display, at a virtual distance of 1 m, that moved so as to require either a phase lead or a phase lag of 53 deg. Adaptation lasted 20 min, during which subjects were oscillated at 0.5 Hz/0.3 g. Four of five subjects produced an adaptive change in the lag condition (range 4-45 deg), and each of five produced a change in the lead condition (range 19-56 deg), as requested. Changes in drift on eccentric gaze suggest that the oculomotor velocity-to-position integrator may be involved in the phase changes.
Non-NASA Center↗
Visualizing characteristics of ocean data collected during the Shuttle Imaging Radar-B experiment
Topographic measurements of sea surface elevation collected by the Surface Contour Radar (SCR) during NASA's Shuttle Imaging Radar (SIR-B) experiment are plotted as three dimensional surface plots to observe wave height variance along the track of a P-3 aircraft. Ocean wave spectra were computed from rotating altimeter measurements acquired by the Radar Ocean Wave Spectrometer (ROWS). Fourier power spectra computed from SIR-B synthetic aperture radar (SAR) images of the ocean are compared to ROWS surface wave spectra. Fourier inversion of SAR spectra, after subtraction of spectral noise and modeling of wave height modulation, yields topography similar to direct measurements made by SCR. Visual perspectives on the SCR and SAR ocean data are compared. Threshold distinctions between surface elevation and texture modulations of SAR data are considered within the context of a dynamic statistical model of rough surface scattering. The result of these endeavors is insight as to the physical mechanism governing the imaging of ocean waves with SAR.
Tilley, David G.↗
A study to determine the characteristic shapes of helicopter visual approach profiles
On previous helicopter instrument approach studies, pilot comments frequently indicated that the deceleration profiles were characterized by 'unnatural cues', and it was found that the pilots were comparing the motion and attitude cues with those obtained during visual approaches. Prior to this study, the characteristic shape of visual approach profiles had not been formally documented. Over 200 visual approaches were flown using different helicopter types, test subjects, and initial conditions, and the altitude and groundspeed profiles were measured by a precision tracking radar. The data from each approach were then processed, and the characteristic shape of the altitude, groundspeed, and deceleration profiles was determined for each set of initial conditions. These flight data were processed further using graphical analysis techniques and parameterization, which, in turn, led to developing closed-form equations that accurately describe the characteristic groundspeed and deceleration profiles. Results from this study can be used to select instrument approach profiles, to develop instrument approach control laws, and to define the corresponding hardware requirements.
Moen, G. C.↗
Lightweight Surveillance and Target Acquisition Radar Characterization For High Density Vertiplex Beyond Visual Line of Sight Operations
With the growth of the National Aeronautics and Space Administration (NASA) National Campaign, it is becoming increasingly important for government and enforcement agencies to be able to monitor and safely track urban air traffic that will take place in the coming years. The performance of the Lightweight Surveillance and Target Acquisition Radar (LSTAR) is investigated and statistically characterized. The compact LSTAR is mounted on a building at NASA Langley Research Center (LaRC) and operated to track a SR-22 aircraft. Performance data of the LSTAR tracking is presented by comparing the LSTAR-tracked flight against the onboard flight records and statistical characteristics are presented. Implications of findings to operations within High Density Vertiplex (HDV) at LaRC are discussed. The LSTAR ultimately proves to be a compact method to safely track and monitor small aircraft and other unmanned aerial vehicles.
Nicholas M. Gaug↗
A laboratory simulation of a single-axis dual-level precision pointing system
The laboratory simulation of a scaled single-axis dual-level control system for a large space telescope is demonstrated. The dual-level control system consists of a coarse-body-pointing system and a fine-pointing system, which uses an image motion compensator, an image dissector tube, and digital electronics. The results of the simulation indicate that the dual-level system can be used to provide tracking capability within one-tenth of a diffraction-limited image diameter of a 3-meter f/100 telescope for stars up to a +12.3 visual magnitude.
Bullock, G. F.↗
Manual and automatic control of surface effect ships
A recent investigation of crew performance in the motion environment of a large generic high speed surface effect ship by means of a motion base simulation addressed some of the helmsman's control task with an external forward visual field of the seascape and navigation and steering displays in the pilot house. In addition to the primary steering control task, a subcritical speed tracking task provided a secondary surrogate for trimming the water speed of the craft. The results of helsmen's steering describing function measurements are presented, and some suggestions for their interpretation are offered. The likely steering loop closures comprise heading and lateral displacement for the course keeping task investigated. Also discussed is the manner in which these loop closures were implemented for automatic steering of the surface effect ship. Regardless of the influence of workload, steering technique, water speed and sea state, the helmsmen apparently adopted a disturbance regulation bandwidth of about 0.2 rad/sec for lateral displacement.
Clement, W. F.↗
The effect of attention loading on the inhibition of choice reaction time to visual motion by concurrent rotary motion
This study investigates the influence of attention loading on the established intersensory effects of passive bodily rotation on choice reaction time (RT) to visual motion. Subjects sat at the center of rotation in an enclosed rotating chamber and observed an oscilloscope on which were, in the center, a tracking display and, 10 deg left of center, a RT line. Three tracking tasks and a no-tracking control condition were presented to all subjects in combination with the RT task, which occurred with and without concurrent cab rotations. Choice RT to line motions was inhibited (probability less than .001) both when there was simultaneous vestibular stimulation and when there was a tracking task; response latencies lengthened progressively with increased similarity between the RT and tracking tasks. However, the attention conditions did not affect the intersensory effect; the significance of this for the nature of the sensory interaction is discussed.
Looper, M.↗
The determination of measures of software reliability
Measurement of software reliability was carried out during the development of data base software for a multi-sensor tracking system. The failure ratio and failure rate were found to be consistent measures. Trend lines could be established from these measurements that provide good visualization of the progress on the job as a whole as well as on individual modules. Over one-half of the observed failures were due to factors associated with the individual run submission rather than with the code proper. Possible application of these findings for line management, project managers, functional management, and regulatory agencies is discussed. Steps for simplifying the measurement process and for use of these data in predicting operational software reliability are outlined.
Maxwell, F. D.↗
STS-114: Discovery Return to Flight Imagery Briefing
George Diller, from NASA Public Affairs, introduces Bob Page who is the chairman of the NASA Intercenter Photo Working Group. Page discusses the purpose of the group which is to perform an analysis of all imagery captured of spacecraft launches. He presents charts to discuss return to flight optics. The charts consist of: 1) Overall Shuttle Imagery Plan; 2) Baseline Configuration Imagery; 3) Upgraded Operational Television (OTV) Cameras; 4) Mobile Launch Platform Cameras; 5) Fixed Service Structure Cameras; 6) Kimeto Tracking Mount (KMT); 7) MOTS (Mobile Optical Tracking System); 8) Intermediate Focal Length Optical Tracker (IFLOT); 9) Distant Object Attitude Measurement System (DOAMS); 10) Advanced Transportable Optical Tracking System (ATOTS); 11) STS-114 Pad Fixed Tracker Camera Configuration; 12) STS-114 Camera Medium and Long Range Tracker Configuration; 13) WB-57 Ascent Visualization Experiment (WAVE); 14) WAVE Profile, Plan View, CAD Flight Training, and Test Flight; 15) Minimum STS-114 Flight Cameras Configuration; 16) External Tank (ET) Separation Cameras; 17) ET Imagery; Umbilical and Handheld; 18) On-Orbit Imagery; and 19) Imagery Data Distribution Plan. The presentation ends with a brief question and answer period.
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