Download or read book Pilot Studies on Object Motion Perception During Linear Self Motion After Long Duration Centrifugation of Human Subjects written by and published by . This book was released on 1993 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four experiments are reported. They were carried out with the purpose of investigating whether we could use and optimize a particular experimental paradigm to investigate the effects of long duration centrifugation of human subjects. The method involved the psychophysical measurement of visual thresholds for perceiving object motion during self-motion on a linear track sled (acquired by the TNO Institute for Perception from the European Space Agency). Since the experiments were of a preliminary nature-we cannot (yet) draw definite conclusions as to their theoretical interpretation. Nevertheless it can be concluded that we have indeed developed an optimal method. In addition, we have arrived at two hypotheses, which can be tested in further research. According to the first hypothesis, long duration centrifugation affects the way in which visual information interacts with otolith reactivity. According to the second hypothesis, subjects who rely largely on visual information for a correct percept of egomotion are more susceptible to centrifuge induced sickness than others.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multisensory Control of Posture written by F. Hlavacka and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: From recent developments in the rapidly growing area of neuroscience it has become increasingly clear that a simplistic description of brain function as a broad collection of simple input-output relations is quite inadequate. Introspection already tells us that our motor behavior is guided by a complex interplay between many inputs from the outside world and from our internal "milieu," internal models of ourselves and the outside world, memory content, directed attention, volition, and so forth. Also, our motor activity normally involves more than a circumscribed group of muscles, even if we intend to move only one effector organ. For example, a reaching movement or a reorientation of a sensory organ almost invariably requires a pattern of preparatory or assisting activities in other parts of the body, like the ones that maintain the body's equilibrium. The present volume is a summary of the papers presented at the symposium "Sensory Interaction in Posture and Movement Control" that was held at Smolenice Castle near Bratislava, Slovakia, as a Satellite Symposium to the ENA Meeting 1994 in Vienna. The focus of this meeting was not only restricted to the "classical" sensory interactions such as between vestibular and visual signals, or between otolith and semicircular canal inputs. Rather, the symposium tried to consider also the interplay between perception and action, between reflexive and volitional motor acts as well as between sensory driven or self-initi ated motor acts and reafferent inputs.
Download or read book Human Self motion Perception During Vertical Linear Oscillation and Virtual Environment Exposure written by William Geoffrey Wright and published by . This book was released on 2002 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1993 with total page 1832 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Perception of Real Motion written by Santo Salvatore and published by . This book was released on 1972 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993 with total page 1168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Perception of Object Motion During Self Motion written by Diederick Christian Niehorster and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Perceptual Processes Underlying Depth Judgements of Moving Objects During Self motion written by Ranran L.. French and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "An important function of the visual system is to represent the 3D structure of the world from the sequence of 2D images projected onto the retinae. During observer translation, relative image motion between stationary objects at different distances (motion parallax, MP) provides potent depth information. However, if an object is moving relative to the scene, this complicates the computation of depth from MP since there will be an additional component of image motion related to object motion. To correctly compute depth from MP, this component should be ignored by the brain. Previous experimental and theoretical work on depth perception from MP has assumed that objects are stationary in the world. How the brain perceives depth of moving objects based on motion parallax has not been examined. This dissertation investigates the perception of depth for moving objects during self-motion in human subjects. First, we ask if human subjects can accurately judge depth of moving objects. Six human subjects were asked to judge the depth of an object relative to the plane of fixation while lateral self-motion was simulated by optic flow. We find that subjects show a robust and systematic depth bias that depends on the object's direction relative to self-motion. Next, we ask whether a subject's belief about whether an object is moving in the world affects their depth judgement. Six subjects were asked to judge the depth of an object relative to the plane of fixation as well as whether the object moves relative to the scene. We find that, on average, subjects show a greater depth bias if they mistake a moving object as "not moving" when object motion information is ambiguous. Finally, we construct three Bayesian inference models with each model implementing a mechanism for depth discrimination. Our model comparison results show that the model which implements subjects' belief about whether an object moves relative to the scene can best explain the perceptual depth biases we observed."--Pages x-xi.
Download or read book Aerospace Medicine and Biology written by and published by . This book was released on 1991 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Perception of Object Motion During Self motion written by Diederick Christian Niehorster and published by . This book was released on 2013 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Motion Perception with Conflicting Or Congruent Visual and Vestibular Cues written by Andrew Alan Rader and published by . This book was released on 2009 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction: We are required on a daily basis to estimate our position and motion in space by centrally combining noisy, incomplete, and potentially conflicting or ambiguous, information from both sensory sources (e.g. vestibular organs, visual, proprioceptive), and non-sensory sources (e.g. efferent copy, cognition)). This "spatial orientation" is normally subconscious, and information from multiple sense organs is automatically fused into perception. As late as the early nineteenth century, very little was known about the underlying mechanisms, and our understanding of some critical factors such as such as how the brain resolves the tilt-translation ambiguity is only now beginning to be understood. The otolith organs function like a three-axis linear accelerometer, responding to the vector difference between gravity and linear acceleration (GIF= g - a). How does the brain separate gravity from linear acceleration? How does the brain combine cues from disparate sensors to derive an overall perception of motion? What happens if these sensors provide conflicting information? Humans routinely perform balance tasks on a daily basis, sometimes in the absence of visual cues. The inherent complexity of the tasks is evidenced by the wide range of balance pathologies and locomotive difficulties experienced by people with vestibular disorders. Maintaining balance involves stabilizing the body's inverted pendulum dynamics where the center of rotation (at the ankles) is below the center of mass and the vestibular sensors are above the center of rotation (for example, swaying above the ground level or balancing during standing or walking). This type of swing motion is also encountered in most fixed-wing aircraft and flight simulators, where the pilot is above the center of roll. Swing motions where the center of mass and sensors are below the center of rotation are encountered on a child's swing, and in some high-wing aircraft and helicopters. Spatial orientation tasks requiring central integration of sensory information are ubiquitous in aerospace. Spatial disorientation, often triggered by unusual visual or flight conditions, is attributed to around 10% of aviation accidents, and many of these are fatal. Simulator training is a key factor in establishing the supremacy of instrument-driven flight information over vestibular and other human sensory cues in the absence of reliable visual information. It therefore becomes important to ensure that simulators re-create motion perceptions as accurately as possible. What cues can safely be ignored or replaced with analogous cues? How realistic and consistent must a visual scene be to maintain perceptual fidelity? Spatial orientation is also a critical human factor in spaceflight. Orientation and navigation are impaired by the lack of confirming gravitation cues in microgravity, as sensory cues are misinterpreted and generate the incorrect motion perceptions. These persist at least until the vestibular or central nervous system pathways adapt to the altered gravity environment, however human navigation never fully adapts to the three dimensional frame. There is a wealth of data describing the difficulties with balance, gait, gaze control, and spatial orientation on return to Earth. Post-flight ataxia (a neurological sign of gross incoordination of motor movements) is a serious concern for all returning space travelers for at least ten days. This would be an even more serious concern for newly arrived astronauts conducting operations extraterrestrial environments after a long space flight. What motion profiles in a lunar landing simulator on Earth will best prepare astronauts for the real task in an altered gravity environment? Far from being a problem restricted to a human operator, the aerospace systems themselves face the same challenge of integrating sensory information for navigation. Modeling how the brain performs multi-sensory integration has analogies to how aircraft and spacecraft perform this task, and in fact modelers have employed similar techniques. Thus, developments in modeling multi-sensory integration improve our understanding of both the operator and the vehicle. Specifically, this research is concerned with how human motion perception is affected during swing motion when vestibular information is incomplete or ambiguous, or when conflicting visual information is provided.
Download or read book A Cybernetic Approach to Self Motion Perception written by Florian Soyka and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-motion describes the motion of our body through the environment and is an essential part of our everyday life. The aim of this thesis is to improve our understanding of how humans perceive self-motion, mainly focusing on the role of the vestibular system. Following a cybernetic approach, this is achieved by systematically gathering psychophysical data and then describing it based on mathematical models of the vestibular sensors. Three studies were performed investigating perceptual thresholds for translational and rotational motions and reaction times to self-motion stimuli. Based on these studies, a model is introduced which is able to describe thresholds for arbitrary motion stimuli varying in duration and acceleration profile shape. This constitutes a significant addition to the existing literature since previous models only took into account the effect of stimulus duration, neglecting the actual time course of the acceleration profile. In the first and second study model parameters were identified based on measurements of direction discrimination thresholds for translational and rotational motions. These models were used in the third study to successfully predict differences in reaction times between varying motion stimuli proving the validity of the modeling approach. This work can allow for optimizing motion simulator control algorithms based on self-motion perception models and developing perception based diagnostics for patients suffering from vestibular disorders.
Download or read book Studies on the Rotation Problem in Self motion Perception written by Jacobus Duijnhouwer and published by . This book was released on 2013 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self motion Perception Through Visual Optic Flow and Vestibular Cues written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1996 with total page 944 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Elementary Movement Vectors in Human Visual System sic written by Aleksander Pulver and published by . This book was released on 1995 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
