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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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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

A discrepancy within primate spatial vision and its bearing on the definition of edge detection processes in machine vision

The visual perception of form information is considered to be based on the functioning of simple and complex neurons in the primate striate cortex. However, a review of the physiological data on these brain cells cannot be harmonized with either the perceptual spatial frequency performance of primates or the performance which is necessary for form perception in humans. This discrepancy together with recent interest in cortical-like and perceptual-like processing in image coding and machine vision prompted a series of image processing experiments intended to provide some definition of the selection of image operators. The experiments were aimed at determining operators which could be used to detect edges in a computational manner consistent with the visual perception of structure in images. Fundamental issues were the selection of size (peak spatial frequency) and circular versus oriented operators (or some combination). In a previous study, circular difference-of-Gaussian (DOG) operators, with peak spatial frequency responses at about 11 and 33 cyc/deg were found to capture the primary structural information in images. Here larger scale circular DOG operators were explored and led to severe loss of image structure and introduced spatial dislocations (due to blur) in structure which is not consistent with visual perception. Orientation sensitive operators (akin to one class of simple cortical neurons) introduced ambiguities of edge extent regardless of the scale of the operator. For machine vision schemes which are functionally similar to natural vision form perception, two circularly symmetric very high spatial frequency channels appear to be necessary and sufficient for a wide range of natural images. Such a machine vision scheme is most similar to the physiological performance of the primate lateral geniculate nucleus rather than the striate cortex.

Jobson, Daniel J.↗
NASA NTRS1996

Gravitational acceleration as a cue for absolute size and distance?

When an object's motion is influenced by gravity, as in the rise and fall of a thrown ball, the vertical component of acceleration is roughly constant at 9.8 m/sec2. In principle, an observer could use this information to estimate the absolute size and distance of the object (Saxberg, 1987a; Watson, Banks, von Hofsten, & Royden, 1992). In five experiments, we examined people's ability to utilize the size and distance information provided by gravitational acceleration. Observers viewed computer simulations of an object rising and falling on a trajectory aligned with the gravitational vector. The simulated objects were balls of different diameters presented across a wide range of simulated distances. Observers were asked to identify the ball that was presented and to estimate its distance. The results showed that observers were much more sensitive to average velocity than to the gravitational acceleration pattern. Likewise, verticality of the motion and visibility of the trajectory's apex had negligible effects on the accuracy of size and distance judgments.

NASA Discipline Space Human Factors↗
NASA NTRS2002

Ideomotor compatibility in the psychological refractory period effect: 29 years of oversimplification

Four experiments examined whether the psychological refractory period (PRP) effect can be eliminated with ideomotor compatible (IM) but not stimulus-response compatible (SR) tasks, as reported by A. G. Greenwald and H. G. Shulman (1973). Their tasks were used: a left or right movement to a left- or right-pointing arrow (IM) or to the word left or right (SR) for Task 1; saying "A" or "B" (IM) or "1" or "2" (SR) to an auditory A or B for Task 2. The stimulus onset asynchronies were 0, 100, 200, 300, 500, and 1,000 ms in Experiment 1, and only 0, 100, 200, and 1,000 ms in Experiments 2-4. The arrow was in the center of the screen in Experiments 1-3 and to the left or right in Experiment 4. As in Greenwald and Shulman's Experiment 2, the instructions stated that most often the 2 stimuli would be presented simultaneously. A PRP effect was obtained in all conditions, most likely because response-selection decisions are required even for IM tasks.

Refractory Period, Psychological↗
NASA NTRS1998

Two memories for geographical slant: separation and interdependence of action and awareness

The present study extended previous findings of geographical slant perception, in which verbal judgments of the incline of hills were greatly overestimated but motoric (haptic) adjustments were much more accurate. In judging slant from memory following a brief or extended time delay, subjects' verbal judgments were greater than those given when viewing hills. Motoric estimates differed depending on the length of the delay and place of response. With a short delay, motoric adjustments made in the proximity of the hill did not differ from those evoked during perception. When given a longer delay or when taken away from the hill, subjects' motoric responses increased along with the increase in verbal reports. These results suggest two different memorial influences on action. With a short delay at the hill, memory for visual guidance is separate from the explicit memory informing the conscious response. With short or long delays away from the hill, short-term visual guidance memory no longer persists, and both motor and verbal responses are driven by an explicit representation. These results support recent research involving visual guidance from memory, where actions become influenced by conscious awareness, and provide evidence for communication between the "what" and "how" visual processing systems.

NASA Discipline Space Human Factors↗
NASA NTRS1931

Effect of stabilizing forces on turbulence

The appearance of expressed discontinuity layers in the free atmosphere, where a warm air mass flows over a cold mass without perceptible intermingling forms the basis of the present report. In these experiments an air stream is to be blown between a water-cooled and a vapor-heated plate. According to what preceded it is anticipated that the exchange will be enhanced. Because these experiments had to be made at relatively low air speeds so as to let the lifting forces become effective, it first required a study of the test methods, and so we have not yet proceeded beyond the preliminary tests on the most suitable hot-wire connections and thermocouples for recording speed and temperature.

PRANDTL L↗
NASA NTRS2003

Modeling of Depth Cue Integration in Manual Control Tasks

Psychophysical research has demonstrated that human observers utilize a variety of visual cues to form a perception of three-dimensional depth. However, most of these studies have utilized a passive judgement paradigm, and failed to consider depth-cue integration as a dynamic and task-specific process. In the current study, we developed and experimentally validated a model of manual control of depth that examines how two potential cues (stereo disparity and relative size) are utilized in both first- and second-order active depth control tasks. We found that stereo disparity plays the dominate role for determining depth position, while relative size dominates perception of depth velocity. Stereo disparity also plays a reduced role when made less salient (i.e., when viewing distance is increased). Manual control models predict that position information is sufficient for first-order control tasks, while velocity information is required to perform a second-order control task. Thus, the rules for depth-cue integration in active control tasks are dependent on both task demands and cue quality.

Sweet, Barbara T.↗
NASA NTRS2002

Repetition blindness has a perceptual locus: evidence from online processing of targets in RSVP streams

Four experiments tested whether repetition blindness (RB; reduced accuracy reporting repetitions of briefly displayed items) is a perceptual or a memory-recall phenomenon. RB was measured in rapid serial visual presentation (RSVP) streams, with the task altered to reduce memory demands. In Experiment 1 only the number of targets (1 vs. 2) was reported, eliminating the need to remember target identities. Experiment 2 segregated repeated and nonrepeated targets into separate blocks to reduce bias against repeated targets. Experiments 3 and 4 required immediate "online" buttonpress responses to targets as they occurred. All 4 experiments showed very strong RB. Furthermore, the online response data showed clearly that the 2nd of the repeated targets is the one missed. The present results show that in the RSVP paradigm, RB occurs online during initial stimulus encoding and decision making. The authors argue that RB is indeed a perceptual phenomenon.

Form Perception↗
NASA NTRS2001

Demonstration of prominent actin filaments in the root columella

The distribution of actin filaments within the gravity-sensing columella cells of plant roots remains poorly understood, with studies over numerous years providing inconsistent descriptions of actin organization in these cells. This uncertainty in actin organization, and thus in actin's role in graviperception and gravisignaling, has led us to investigate actin arrangements in the columella cells of Zea mays L., Medicago truncatula Gaertn., Linum usitatissiilium L. and Nicotianla benthamiana Domin. Actin organization was examined using a combination of optimized immunofluorescence techniques, and an improved fluorochrome-conjugated phalloidin labeling method reliant on 3-maleimidobenzoyl-N-hydroxy-succinimide ester (MBS) cross-linking combined with glycerol permeabilization. Confocal microscopy of root sections labeled with anti-actin antibodies revealed patterns suggestive of actin throughout the columella region. These patterns included short and fragmented actin bundles, fluorescent rings around amyloplasts and intense fluorescence originating from the nucleus. Additionally, confocal microscopy of MBS-stabilized and Alexa Fluor-phalloidin-labeled root sections revealed a previously undetected state of actin organization in the columella. Discrete actin structures surrounded the amyloplasts and prominent actin cables radiated from the nuclear surface toward the cell periphery. Furthermore, the cortex of the columella cells contained fine actin bundles (or single filaments) that had a predominant transverse orientation. We also used confocal microscopy of plant roots expressing endoplasmic reticulum (ER)-targeted green fluorescent protein to demonstrate rapid ER movements within the columella cells, suggesting that the imaged actin network is functional. The successful identification of discrete actin structures in the root columella cells forms the perception and signaling.

Non-NASA Center↗
NASA NTRS2000

Context-specific adaptation of pursuit initiation in humans

PURPOSE: To determine if multiple states for the initiation of pursuit, as assessed by acceleration in the "open-loop" period, can be learned and gated by context. METHODS: Four normal subjects were studied. A modified step-ramp paradigm for horizontal pursuit was used to induce adaptation. In an increasing paradigm, target velocity doubled 230 msec after onset; in a decreasing paradigm, it was halved. In the first experiment, vertical eye position (+/-5 degrees ) was used as the context cue, and the training paradigm (increasing or decreasing) changed with vertical eye position. In the second experiment, with vertical position constant, when the target was red, training was decreasing, and when green, increasing. The average eye acceleration in the first 100 msec of tracking was the index of open-loop pursuit performance. RESULTS: With vertical position as the cue, pursuit adaptation differed between up and down gaze. In some cases, the direction of adaptation was in exact accord with the training stimuli. In others, acceleration increased or decreased for both up and down gaze but always in correct relative proportion to the training stimuli. In contrast, multiple adaptive states were not induced with color as the cue. CONCLUSIONS: Multiple values for the relationship between the average eye acceleration during the initiation of pursuit and target velocity could be learned and gated by context. Vertical position was an effective contextual cue but not target color, implying that useful contextual cues must be similar to those occurring naturally, for example, orbital position with eye muscle weakness.

NASA Discipline Neuroscience↗
NASA NTRS1990

Mueller-Lyer decrement: practice or prolonged inspection?

Noting the similarity between the illusion decrement and selective adaptation paradigms, Long has challenged the view that illusion decrement effects reflect a strategic--as opposed to a structural--underlying mechanism, and has called for further research on this issue. To investigate the confound between prolonged free inspection and repeated trials in the standard decrement procedure, the effects of three inspection conditions (continuous, intermittent, and immediate) on the magnitude of the overestimation Mueller-Lyer illusion have been assessed under two levels of trials (a total of two or six judgments). Significant illusion decline was found only under conditions of repeated trials, with either continuous or intermittent inspection. These findings do not support the predictions of purely structural theories (including neural adaptation and efferent readiness theories), according to which degree of decrement should be determined solely by viewing time. Instead, the data demonstrate that illusion decrement is a product of practice, providing converging evidence for the view of decrement as involving a cognitive 'recalibration' or learning process.

Form Perception↗
NASA NTRS1989

Effect of structured visual environments on apparent eye level

Each of 12 subjects set a binocularly viewed target to apparent eye level; the target was projected on the rear wall of an open box, the floor of which was horizontal or pitched up and down at angles of 7.5 degrees and 15 degrees. Settings of the target were systematically biased by 60% of the pitch angle when the interior of the box was illuminated, but by only 5% when the interior of the box was darkened. Within-subjects variability of the settings was less under illuminated viewing conditions than in the dark, but was independent of box pitch angle. In a second experiment, 11 subjects were tested with an illuminated pitched box, yielding biases of 53% and 49% for binocular and monocular viewing conditions, respectively. The results are discussed in terms of individual and interactive effects of optical, gravitational, and extraretinal eye-position information in determining judgements of eye level.

NASA Center ARC↗
NASA NTRS1989

Does the identification of simple features require serial processing?

Several recent studies have shown performance decrements with increasing display size when background texture elements are present in a same-different feature discrimination task--a result that challenges the traditional notion that the identities of simple visual features are processed in parallel, preattentively. Four experiments are reported that explore the implications of these results. Experiment 1 replicates the recent studies but limits the generalizability of the results to small target numbers. Experiments 2 and 3 show that the observed performance decrements are not due to a serial or even limited-capacity, parallel process. Experiment 4 suggests that decision factors idiosyncratic to the use of texture elements in a same-different task are responsible for the effect. It is concluded that the identification of simple visual features proceeds in parallel, with unlimited capacity (i.e., preattentively).

Pattern Recognition, Visual↗
NASA NTRS1991

Pictorial communication in virtual and real environments

Papers about the communication between human users and machines in real and synthetic environments are presented. Individual topics addressed include: pictorial communication, distortions in memory for visual displays, cartography and map displays, efficiency of graphical perception, volumetric visualization of 3D data, spatial displays to increase pilot situational awareness, teleoperation of land vehicles, computer graphics system for visualizing spacecraft in orbit, visual display aid for orbital maneuvering, multiaxis control in telemanipulation and vehicle guidance, visual enhancements in pick-and-place tasks, target axis effects under transformed visual-motor mappings, adapting to variable prismatic displacement. Also discussed are: spatial vision within egocentric and exocentric frames of reference, sensory conflict in motion sickness, interactions of form and orientation, perception of geometrical structure from congruence, prediction of three-dimensionality across continuous surfaces, effects of viewpoint in the virtual space of pictures, visual slant underestimation, spatial constraints of stereopsis in video displays, stereoscopic stance perception, paradoxical monocular stereopsis and perspective vergence. (No individual items are abstracted in this volume)

Ellis, Stephen R.↗
NASA NTRS2000

Lay and Expert Perceptions of Planetary Protection

As space scientists and engineers plan new missions to Mars and other planets in our solar system, they will face critical questions about the potential for biological contamination of planetary surfaces. In a society that places ever-increasing importance on the role of public involvement in science and technology policy, questions about risks of biological contamination will be examined and debated in the media, and will lead to the formation of public perceptions of planetary-contamination risks. These perceptions will, over time, form an important input to the development of space policy. Previous research in public and expert perceptions of technological risks and hazards has shown that many of the problems faced by risk-management organizations are the result of differing perceptions of risk (and risk management) between the general public and scientific and technical experts. These differences manifest themselves both as disagreements about the definition (and level) of risk associated with a scientific, technological or industrial enterprise, and as distrust about the ability of risk-management organizations (both public and private) to adequately protect people's health and safety. This report presents the results of a set of survey studies designed to reveal perceptions of planetary exploration and protection from a wide range of respondents, including both members of the general public and experts in the life sciences. The potential value of this research lies in what it reveals about perceptions of risk and benefit that could improve risk-management policies and practices. For example, efforts to communicate with the public about Mars sample return missions could benefit from an understanding of the specific concerns that nonscientists have about such a mission by suggesting areas of potential improvement in public education and information. Assessment of both public and expert perceptions of risk can also be used to provide an advanced signal of aspects of planetary exploration and protection that may be particularly sensitive or controversial and that could prove problematic from a risk-management standpoint, perhaps warranting a more stringent risk-management approach than would otherwise be the case based on technical considerations alone. The design of the study compares perceptions and attitudes about space exploration relevant to a Mars sample return mission between three respondent groups: (1) members of The Planetary Society, a group representing individuals with a strong interest in space-related issues, (2) a group of university-aged students, representing a population relatively sensitive to environmental hazards, and (3) a group of life scientists outside of the space research community. Members of The Planetary Society received the survey as part of a special issue of The Planetary Report on planetary protection, which contained a number of background articles on planetary protection and related topics. A synopsis of the issue was prepared as an introduction to the survey for the other two groups.

Race, Margaret S.↗
NASA NTRS1999

Electroencephalographic imaging of higher brain function

High temporal resolution is necessary to resolve the rapidly changing patterns of brain activity that underlie mental function. Electroencephalography (EEG) provides temporal resolution in the millisecond range. However, traditional EEG technology and practice provide insufficient spatial detail to identify relationships between brain electrical events and structures and functions visualized by magnetic resonance imaging or positron emission tomography. Recent advances help to overcome this problem by recording EEGs from more electrodes, by registering EEG data with anatomical images, and by correcting the distortion caused by volume conduction of EEG signals through the skull and scalp. In addition, statistical measurements of sub-second interdependences between EEG time-series recorded from different locations can help to generate hypotheses about the instantaneous functional networks that form between different cortical regions during perception, thought and action. Example applications are presented from studies of language, attention and working memory. Along with its unique ability to monitor brain function as people perform everyday activities in the real world, these advances make modern EEG an invaluable complement to other functional neuroimaging modalities.

Non-NASA Center↗
NASA NTRS1972

Mapping an operator's perception of a parameter space

Operators monitored the output of two versions of the crossover model having a common random input. Their task was to make discrete, real-time adjustments of the parameters k and tau of one of the models to make its output time history converge to that of the other, fixed model. A plot was obtained of the direction of parameter change as a function of position in the (tau, k) parameter space relative to the nominal value. The plot has a great deal of structure and serves as one form of representation of the operator's perception of the parameter space.

Pew, R. W.↗
NASA NTRS1990

Human motion perception: Higher-order organization

An overview is given of higher-order motion perception and organization. It is argued that motion is sufficient to fully specify a number of environmental properties, including: depth order, three-dimensional form, object displacement, and dynamics. A grammar of motion perception is proposed; applications of this work for display design are discussed.

Kaiser, Mary K.↗
NASA NTRS2020

Evaluation of Low Cost, User-Centered Alerting Devices for the Mitigation of Flight Crew Spatial Disorientation

The National Aeronautics and Space Administration (NASA) is conducting research into technologies which have the potential to reduce flight crew Spatial Disorientation (SD). While flight deck technology has advanced rapidly over the past fifty (50) years, the reported occurrences of flight crew SD have not decreased. The Cost-Effective Devices for Alerting Research (CEDAR) effort has focused on the identification and development of low cost, user-centered alerting solutions for the purpose of mitigating the occurrence of flight crew SD. This effort seeks to evaluate both existing technologies as well as new and emerging technologies which have a viable path to implementation in commercial aviation within the next five (5) years. This research is intended to develop a proof-of-concept for real-time SD mitigation which could eventually be utilized to improve safety in future air transport operations. NASA has partnered with the United States Naval Aeromedical Research Unit in Dayton, OH (NAMRU-D) to conduct flight crew SD research utilizing their Disorientation Research Device (DRD), dubbed “The Kraken”. This high-tech simulator features never-before-seen capabilities for side-by-side commercial aviation flight crew SD research, and is capable of re-creating the forces necessary to induce SD illusions in a safe and repeatable manner. Prototype SD mitigation solutions were incorporated into this simulator for scenario-based testing and evaluation using airline pilots within a contextually representative operational environment. SD mitigation technology prototypes designed to provide haptic feedback for both alerting and guidance, as well as innovative visual and aural alerting displays were evaluated. In December 2014, as a result of analyzing eighteen (18) loss-of-control events, the Commercial Aviation Safety Team (CAST) recommended research into flight deck technologies that have potential to mitigate the problems and contributing factors that lead to flight crew loss of airplane state awareness (ASA) and conditions likely to produce SD. The aviation community (government, industry and academia) have been charged with conducting research into cost-effective, user-centered flight deck alerting systems to alert flight crews; especially for the two conditions that produced SD (sub-threshold rolls and the somatogravic illusion). Somatogravic illusions are defined as illusions in which “there is a false perception of attitude on exposure to a force vector that differs in direction and/or magnitude from the normal gravitational force”. The sub-threshold roll illusion (aka the “leans” illusion) is a false sensation of roll attitude. A prolonged roll of less than two degrees becomes physiologically imperceptible to the pilot, and can lead to an incorrect perception of aircraft orientation. The sub-threshold roll illusion forms the entry point for the “graveyard spiral”, a maneuver in which the pilot’s corrective action (based on their false perception of aircraft orientation) causes the aircraft to spiral down into the ground. In both of these SD illusions, it is when the pilot attempts to correct the aircraft’s attitude (based on a false perception of its state) that problems arise, sometimes with lethal consequences.

Ronald J Daiker↗