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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Physiologic adaptation of man in space; Proceedings of the Seventh International Man in Space Symposium, Houston, TX, Feb. 10-13, 1986

Topics discussed in this volume include space motion sickness, cardiovascular adaptation, fluid shifts, extravehicular activity, general physiology, perception, vestibular response modifications, vestibular physiology, and pharmacology. Papers are presented on the clinical characterization and etiology of space motion sickness, ultrasound techniques in space medicine, fluid shifts in weightlessness, Space Shuttle inflight and postflight fluid shifts measured by leg volume changes, and the probability of oxygen toxicity in an 8-psi space suit. Consideration is also given to the metabolic and hormonal status of crewmembers in short-term space flights, adaptive changes in perception of body orientation and mental image rotation in microgravity, the effects of a visual-vestibular stimulus on the vestibulo-ocular reflex, rotation tests in the weightless phase of parabolic flight, and the mechanisms of antimotion sickness drugs.

Holland, Albert W.↗
NASA NTRS1989

The power of shadows - Shadow stereopsis

It is demonstrated that retinal images with no parallax disparity but with different shadows are fused stereoscopically, imparting depth perception to the imaged scene. Shadows are shown to be an important, hitherto undescribed, stereoscopic cue for depth perception.

Puerta, Antonio Medina↗
NASA NTRS1988

Information processing

Theoretical models of sensory-information processing by the human brain are reviewed from a human-factors perspective, with a focus on their implications for aircraft and avionics design. The topics addressed include perception (signal detection and selection), linguistic factors in perception (context provision, logical reversals, absence of cues, and order reversals), mental models, and working and long-term memory. Particular attention is given to decision-making problems such as situation assessment, decision formulation, decision quality, selection of action, the speed-accuracy tradeoff, stimulus-response compatibility, stimulus sequencing, dual-task performance, task difficulty and structure, and factors affecting multiple task performance (processing modalities, codes, and stages).

Wickens, Christopher D.↗
NASA NTRS1989

Ambler - An autonomous rover for planetary exploration

The authors are building a prototype legged rover, called the Ambler (loosely an acronym for autonomous mobile exploration robot) and testing it on full-scale, rugged terrain of the sort that might be encountered on the Martian surface. They present an overview of their research program, focusing on locomotion, perception, planning, and control. They summarize some of the most important goals and requirements of a rover design and describe how locomotion, perception, and planning systems can satisfy these requirements. Since the program is relatively young (one year old at the time of writing) they identify issues and approaches and describe work in progress rather than report results. It is expected that many of the technologies developed will be applicable to other planetary bodies and to terrestrial concerns such as hazardous waste assessment and remediation, ocean floor exploration, and mining.

Bares, John↗
NASA NTRS1989

How to detect when cells in space perceive gravity

It is useful to be able to measure when and whether cells detect gravity during spaceflights. For studying gravitational physiology, gravity perception is the response the experimentalist needs to measure. Also, for growing plants in space, plant cells may have a non-directional requirement for gravity as a development cue. The main goals of spaceflight experiments in which gravity perception would be measured are to determine the properties of the gravity receptor and how it is activated, and to determine fundamental characteristics of the signal generated. The main practical difficulty with measuring gravity sensing in space is that gravity sensing cannot be measured with certainty on earth. Almost all experiments measure gravitropic curvature. Reciprocity and intermittent stimulation are measurements which were made to some degree on earth using clinostatting, but which would provide clearer results if done with microgravity rather than clinostatting. These would be important uses of the space laboratory for determining the nature of gravity sensing in plants. Those techniques which do not use gravitropic curvature to measure gravity sensing are electrophysiological. The vibrating probe would be somewhat easier to adapt to space conditions than the intracellular microelectrode because it can be positioned with less precision. Ideally, a non-invasive technique would be best suited if an appropriate measure could be developed. Thus, the effect of microgravity on cultured cells is more likely to be by large-scale physical events than gravity sensing in the culture cells. It is not expected that it will be necessary to determine whether individual cultured cells perceive gravity unless cells grow abnormally even after the obvious microgravity effects on the culture as a whole can be ruled out as the cause.

Bjoerkman, Thomas↗
NASA NTRS1989

Isolating contour information from arbitrary images

Aspects of natural vision (physiological and perceptual) serve as a basis for attempting the development of a general processing scheme for contour extraction. Contour information is assumed to be central to visual recognition skills. While the scheme must be regarded as highly preliminary, initial results do compare favorably with the visual perception of structure. The scheme pays special attention to the construction of a smallest scale circular difference-of-Gaussian (DOG) convolution, calibration of multiscale edge detection thresholds with the visual perception of grayscale boundaries, and contour/texture discrimination methods derived from fundamental assumptions of connectivity and the characteristics of printed text. Contour information is required to fall between a minimum connectivity limit and maximum regional spatial density limit at each scale. Results support the idea that contour information, in images possessing good image quality, is (centered at about 10 cyc/deg and 30 cyc/deg). Further, lower spatial frequency channels appear to play a major role only in contour extraction from images with serious global image defects.

Jobson, Daniel J.↗
NASA NTRS1990

Vision science and technology for supervised intelligent space robots

The focus of recent work in robotic vision for application in intelligent space robots such as the Extravehicular Activity (EVA) Retriever is in visual function, that is, how information about the space world is derived and then conveyed to cognition. The goal of this work in visual function is first to understand how the relevant structure of the surrounding world is evidenced by regularities among the pixels of images, then to understand how these regularities are mapped on the premises that form the primitive elements of cognition, and then to apply these understandings with the elements of visual processing (algorithms) and visual mechanism (machine organization) to intelligent space robot simulations and test beds. Since visual perception is the process of recognizing regularities in images that are known on the basis of a model of the world to be reliable related to causal structure in the environment (because perception attaches meaning to the link between a conception of the environment and the objective environment), the work involves understanding generic, generally applicable models of world structure (not merely objects) and how that structure evidences itself in images.

Erickson, Jon D.↗
NASA NTRS1989

Distortions in memory for visual displays

Systematic errors in perception and memory present a challenge to theories of perception and memory and to applied psychologists interested in overcoming them as well. A number of systematic errors in memory for maps and graphs are reviewed, and they are accounted for by an analysis of the perceptual processing presumed to occur in comprehension of maps and graphs. Visual stimuli, like verbal stimuli, are organized in comprehension and memory. For visual stimuli, the organization is a consequence of perceptual processing, which is bottom-up or data-driven in its earlier stages, but top-down and affected by conceptual knowledge later on. Segregation of figure from ground is an early process, and figure recognition later; for both, symmetry is a rapidly detected and ecologically valid cue. Once isolated, figures are organized relative to one another and relative to a frame of reference. Both perceptual (e.g., salience) and conceptual factors (e.g., significance) seem likely to affect selection of a reference frame. Consistent with the analysis, subjects perceived and remembered curves in graphs and rivers in maps as more symmetric than they actually were. Symmetry, useful for detecting and recognizing figures, distorts map and graph figures alike. Top-down processes also seem to operate in that calling attention to the symmetry vs. asymmetry of a slightly asymmetric curve yielded memory errors in the direction of the description. Conceptual frame of reference effects were demonstrated in memory for lines embedded in graphs. In earlier work, the orientation of map figures was distorted in memory toward horizontal or vertical. In recent work, graph lines, but not map lines, were remembered as closer to an imaginary 45 deg line than they had been. Reference frames are determined by both perceptual and conceptual factors, leading to selection of the canonical axes as a reference frame in maps, but selection of the imaginary 45 deg as a reference frame in graphs.

Tversky, Barbara↗
NASA NTRS1989

Effect of low air velocities on thermal homeostasis and comfort during exercise at space station operational temperature and humidity

The effectiveness of different low air velocities in maintaining thermal comfort and homeostasis during exercise at space station operational temperature and humidity was investigated. Five male subjects exercised on a treadmill for successive ten minute periods at 60, 71, and 83 percent of maximum oxygen consumption at each of four air velocities, 30, 50, 80, and 120 ft/min, at 22 C and 62 percent relative humidity. No consistent trends or statistically significant differences between air velocities were found in body weight loss, sweat accumulation, or changes in rectal, skin, and body temperatures. Occurrence of the smallest body weight loss at 120 ft/min, the largest sweat accumulation at 30 ft/min, and the smallest rise in rectal temperature and the greatest drop in skin temperature at 120 ft/min all suggested more efficient evaporative cooling at the highest velocity. Heat storage at all velocities was evidenced by increased rectal and body temperatures; skin temperatures declined or increased only slightly. Body and rectal temperature increases corresponded with increased perception of warmth and slight thermal discomfort as exercise progressed. At all air velocities, mean thermal perception never exceeded warm and mean discomfort, greatest at 30 ft/min, was categorized at worst as uncomfortable; sensation of thermal neutrality and comfort returned rapidly after cessation of exercise. Suggestions for further elucidation of the effects of low air velocities on thermal comfort and homeostasis include larger numbers of subjects, more extensive skin temperature measurements and more rigorous analysis of the data from this study.

Beumer, Ronald J.↗
NASA NTRS1989

Building an environment model using depth information

Modeling the environment is one of the most crucial issues for the development and research of autonomous robot and tele-perception. Though the physical robot operates (navigates and performs various tasks) in the real world, any type of reasoning, such as situation assessment, planning or reasoning about action, is performed based on information in its internal world. Hence, the robot's intentional actions are inherently constrained by the models it has. These models may serve as interfaces between sensing modules and reasoning modules, or in the case of telerobots serve as interface between the human operator and the distant robot. A robot operating in a known restricted environment may have a priori knowledge of its whole possible work domain, which will be assimilated in its World Model. As the information in the World Model is relatively fixed, an Environment Model must be introduced to cope with the changes in the environment and to allow exploring entirely new domains. Introduced here is an algorithm that uses dense range data collected at various positions in the environment to refine and update or generate a 3-D volumetric model of an environment. The model, which is intended for autonomous robot navigation and tele-perception, consists of cubic voxels with the possible attributes: Void, Full, and Unknown. Experimental results from simulations of range data in synthetic environments are given. The quality of the results show great promise for dealing with noisy input data. The performance measures for the algorithm are defined, and quantitative results for noisy data and positional uncertainty are presented.

Roth-Tabak, Y.↗
NASA NTRS1990

Situationally Driven Local Navigation for Mobile Robots

For mobile robots to autonomously accommodate dynamically changing navigation tasks in a goal-directed fashion, they must employ navigation plans. Any such plan must provide for the robot's immediate and continuous need for guidance while remaining highly flexible in order to avoid costly computation each time the robot's perception of the world changes. Due to the world's uncertainties, creation and maintenance of navigation plans cannot involve arbitrarily complex processes, as the robot's perception of the world will be in constant flux, requiring modifications to be made quickly if they are to be of any use. This work introduces navigation templates (NaT's) which are building blocks for the construction and maintenance of rough navigation plans which capture the relationship that objects in the world have to the current navigation task. By encoding only the critical relationship between the objects in the world and the navigation task, a NaT-based navigation plan is highly flexible; allowing new constraints to be quickly incorporated into the plan and existing constraints to be updated or deleted from the plan. To satisfy the robot's need for immediate local guidance, the NaT's forming the current navigation plan are passed to a transformation function. The transformation function analyzes the plan with respect to the robot's current location to quickly determine (a few times a second) the locally preferred direction of travel. This dissertation presents NaT's and the transformation function as well as the needed support systems to demonstrate the usefulness of the technique for controlling the actions of a mobile robot operating in an uncertain world.

Slack, Marc Glenn↗
NASA NTRS1991

An assessment of the Space Station Freedom program's leakage current requirement

The Space Station Freedom Program requires leakage currents to be limited to less than human perception level, which NASA presently defines as 5 mA for dc. The origin of this value is traced, and the literature for other dc perception threshold standards is surveyed. It is shown that while many varying standards exist, very little experimental data is available to support them.

Nagy, Michael↗
NASA NTRS1989

Aircraft noise induced building vibration and effects on human response

The acoustic loads resulting from aircraft noise and sonic booms which can induce vibration in the structure and result in radiation of noise into its interior, rattling of items in contact with the structure, and the perception of the inhabitants that the structure is vibrating, are investigated. In particular, the response of buildings, particularly residential structures, to aircraft noise and the resulting effects on human response have been the subjects of considerable research at the NASA Langley Research Center. These studies are reviewed with particular emphasis on the response of houses to aircraft overflight noise and any increase in noise annoyance caused by the perception of vibration and rattling.

Powell, Clemans A.↗
NASA NTRS1990

Recent research results in stereo 3-D pictorial displays at Langley Research Center

Recent results from a NASA-Langley program which addressed stereo 3D pictorial displays from a comprehensive standpoint are reviewed. The program dealt with human factors issues and display technology aspects, as well as flight display applications. The human factors findings include addressing a fundamental issue challenging the application of stereoscopic displays in head-down flight applications, with the determination that stereoacuity is unaffected by the short-term use of stereo 3D displays. While stereoacuity has been a traditional measurement of depth perception abilities, it is a measure of relative depth, rather than actual depth (absolute depth). Therefore, depth perception effects based on size and distance judgments and long-term stereo exposure remain issues to be investigated. The applications of stereo 3D to pictorial flight displays within the program have repeatedly demonstrated increases in pilot situational awareness and task performance improvements. Moreover, these improvements have been obtained within the constraints of the limited viewing volume available with conventional stereo displays. A number of stereo 3D pictorial display applications are described, including recovery from flight-path offset, helicopter hover, and emulated helmet-mounted display.

Parrish, Russell V.↗
NASA NTRS1991

Telerobotic ground-remote operations

The Telerobotic Ground-Remote Operations task consists of development of a demonstration local-site operator control station that includes a graphical user interface (GUI) for control of a remote robot, and development of operator-assisted perception algorithms and software that will provide flexible and accurate world modeling capabilities. The topics covered are presented in view graph form and include: (1) local site development configuration; (2) system design; (3) operator control station (local site) software block diagram; (4) operator-assisted perception; and (5) program status.

Bon, Bruce↗
NASA NTRS1991

Visually Guided Control of Movement

The papers given at an intensive, three-week workshop on visually guided control of movement are presented. The participants were researchers from academia, industry, and government, with backgrounds in visual perception, control theory, and rotorcraft operations. The papers included invited lectures and preliminary reports of research initiated during the workshop. Three major topics are addressed: extraction of environmental structure from motion; perception and control of self motion; and spatial orientation. Each topic is considered from both theoretical and applied perspectives. Implications for control and display are suggested.

Johnson, Walter W.↗
NASA NTRS1991

The use of activity-based cost estimation as a management tool for cultural change

It will be shown that the greatest barrier to American exploration of the planet Mars is not the development of the technology needed to deliver humans and return them safely to earth. Neither is it the cost of such an undertaking, as has been previously suggested, although certainly, such a venture may not be inexpensive by some measures. The predicted costs of exploration have discouraged serious political dialog on the subject. And, in fact, even optimistic projections of the NASA budget do not contain the resources required, under the existing development and management paradigm, for human space exploration programs. It will be demonstrated that the perception of the costs of such a venture, and the cultural responses to the perceptions are factors inhibiting American exploration of the moon and the planet Mars. Cost models employed in the aerospace industry today correctly mirror the history of past space programs, and as such, are representative of the existing management and development paradigms. However, if, under this current paradigm no major exploration programs are feasible, then cost analysis methods based in the past may not have great utility in exploring the needed cultural changes. This paper explores the use of a new type of model, the activity based cost model, which will treat management style as an input variable, in a sense providing a tool whereby a complete, affordable program might be designed, including both the technological and management aspects.

Mandell, Humboldt↗
NASA NTRS1991

Operator-coached machine vision for space telerobotics

A prototype system for interactive object modeling has been developed and tested. The goal of this effort has been to create a system which would demonstrate the feasibility of high interactive operator-coached machine vision in a realistic task environment, and to provide a testbed for experimentation with various modes of operator interaction. The purpose for such a system is to use human perception where machine vision is difficult, i.e., to segment the scene into objects and to designate their features, and to use machine vision to overcome limitations of human perception, i.e., for accurate measurement of object geometry. The system captures and displays video images from a number of cameras, allows the operator to designate a polyhedral object one edge at a time by moving a 3-D cursor within these images, performs a least-squares fit of the designated edges to edge data detected with a modified Sobel operator, and combines the edges thus detected to form a wire-frame object model that matches the Sobel data.

Bon, Bruce↗