Accurate perception and control of self-motion is vital for human survival. Most animals rely on vision for navigating through complex environments. In this thesis, I investigated how vision influence perception and guide self-motion from two aspects: (1) what visual information humans pick up from the environment to form their perception and guide their self-motion; (2) how the degeneration of the basal ganglia and cerebellum, the two largest subcortical nuclei connecting the visual and motor areas of the brain, affect the controller’s performance. Study 1 examined the condition under which optic-flow information beyond velocity field helps heading perception. I systematically varied the amount of information in velocity field through manipulations of field of view (FOV). The amount of optic-flow information beyond velocity field was manipulated by two types of displays. I found heading bias increased with the reduction of FOV only when optic-flow information beyond velocity field was not available. Study 2 investigated whether the information investigated in Study 1 is sufficient and necessary for active control of heading. I used the similar display simulations as study 1 with the exception that the vehicle orientation was perturbed pseudo-randomly. Participants used a joystick, under both velocity and acceleration control dynamics, to continuously rotate the vehicle orientation back to its heading direction. The results showed that participants’ accurate performance under condition that only provided velocity field information was further improved when optic-flow information beyond velocity field was available. Study 3 examined the relative contributions of three visual cues (i.e., heading from optic flow, bearing, and splay angle) for lane-keeping control. Observers controlled the car’s lateral movement to stay in the center of the lane while facing two random perturbations affecting the use of bearing or splay angle information. I found that performance improved with enriched flow information. In the presence of splay angles, participants ignored bearing angle information. Study 4 investigated the roles of the basal ganglia and cerebellum in motor control task using brain-damaged patients. Participant’s task was to use the joystick to keep a blob in the center of the display while the horizontal position of the blob was perturbed pseudo-randomly. This task is not a self-motion task but mimics real-world lane-keeping control. Both the Parkinson’s disease patients and cerebellar patients showed impaired motor control performance in comparison with the healthy controls. In conclusion, the visual information used for motor control in general depends on the task. For traveling along a curved path, the velocity field contains sufficient information for heading perception and heading control. Optic-flow information beyond velocity field improves heading perception when the velocity field does not contain sufficient information. It also helps heading control when available. For lane-keeping control, adding optic flow information improves participants’ performance. Splay angle information plays a more important role than does bearing angle information. The visual information used for motor control changes when certain brain areas are damaged. Parkinson’s disease patients and cerebellar patients show the inability to process visual input effectively for online motor control. / published_or_final_version / Psychology / Doctoral / Doctor of Philosophy

The premise that mature visual function depends upon the nature of visual experience during development is based primarily on experiments showing that visual deprivation during a 'critical' period early in life causes abnormalities in visual cortex and an enduring loss of spatial vision (amplyopia). There is, however, little evidence that early visual experience atually enables mature vision. Experments in this thesis provide such evidence. The measurement of optomotor responses daily from eye opening permanently enhances optomotor sensitivity and the perception of visual motion. The plasticity allowing this enhancement is transient and peaks in efficacy before the start of the classical 'critical ' period for ocular dominance plasticity. The enhancement is dependent upon optomotor responses generated by the movement of high spatial frequency visual stimuli, and is mediated by the visual cortex. These studies show that a form of experience-dependent plasticity, distinct from that of the critical period, enables mature motion vision. / viii, 107 leaves : ill. (some col.) ; 28 cm.

The reach-to-eat movement, in which a hand is advanced towards a food item, shapes to grasp the food item, and withdrawals to place the food item into the mouth for eating, is a behaviour that is performed daily. The movement is controlled by two sensory systems, vision to guide hand advance and grasping, and somatosensation to guide hand withdrawal and mouth placement. The purpose of the present thesis was to examine how the sensory control of reaching-to-eat develops in infancy and degenerates following neurodegenerative disorder. The tight coupling of vision to hand advance and somatosensation to hand withdrawal has a developmental profile from six months to one year of age. That is, six-month-old infants rely on vision to advance their hand, grasp the target, and withdrawal the target to the mouth. By twelve months of age, infants display the adult pattern of coupling vision to hand advance and grasping. The tight coupling of vision to hand advance degenerates with basal ganglia disease, such that subjects with Parkinson’s disease and Huntington’s disease show an overreliance on vision to guide hand advance for grasping and hand withdrawal for mouth placement. The results of the thesis demonstrate that efficient use of sensory control to guide motor behaviour is an important aspect of development that is disrupted by neurodegenerative disease. / xiv, 286 leaves : ill. ; 29 cm

A number of conducting gesture analysis and performance systems have been developed over the years. However, most of the previous projects either primarily concentrated on tracking tempo and amplitude indicating gestures, or implemented individual mapping techniques for expressive gestures that varied from research to research. There is a clear need for a uniform process that could be applied toward analysis of both indicative and expressive gestures. The proposed system provides a set of tools that contain extensive functionality for identification, classification and performance with conducting gestures. Gesture recognition procedure is designed on the basis of Hidden Markov Model (HMM) process. A set of HMM tools are developed for Max/MSP software. Training and recognition procedures are applied toward both right-hand beat- and amplitude-indicative gestures, and left-hand expressive gestures. Continuous recognition of right-hand gestures is incorporated into a real-time gesture analysis and performance system in Eyesweb and Max/MSP/Jitter environments.

Bibliography: p. 165-184. / xvi, 184 p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis explores the issue of copying natural vision processes with regard to providing sensing information in real-time to the lowest control levels of an autonomous vehicle. It is argued that the interpretation of sensory data should result in a level of perception which is tailored to the requirements of the control system. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1996?

Bibliography: leaves 188-203. / xxii, 203 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / In this thesis insect vision principles are applied to the main mechanism for motion detection. Advanced VLSI technologies are employed for designing smart micro-sensors in which the imager and processor are integrated into one monolithic device. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1996

Thesis (Ph.D.)--Rochester Institute of Technology, 2008. / Typescript. Includes bibliographical references (p. 133-137).

Thesis (M.S.)--Indiana University, 2003. / Includes bibliographical references (leaves 56-64). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (Ed. D.)--Illinois State University, 1972. / Title from title page screen, viewed Sept. 27, 2004. Dissertation Committee: Max R. Rennels (chair), Richard A. Salome, Ronald Halinski, Macon L. Williams, Fred V. Mills. Includes bibliographical references (leaves 75-79). Also available in print.

Thesis (Ph. D.)--Washington State University, May 2009. / Title from PDF title page (viewed on Apr. 21, 2010). "Department of Psychology." Includes bibliographical references (p. 39-43).