When spatial updating tasks are performed in a real-world setting, participants usually complete it with ease (e.g., Klatzky et al., 1998). However, in virtual reality (VR), when tasks are presented using optic flow, participants tend to exhibit one of two response patterns, with some participants correctly updating their headings (“turners”) and others pointing consistently in the opposite direction (“non-turners”) (e.g., Gramann et al., 2005). While research has looked at the stability and pointing characteristics of these two groups (e.g., Gramann et al., 2012; Riecke, 2008), we still do not know why non-turners exist. The following thesis studied two potential sources of cue conflict—stationary versus central visual information and sensorimotor interference—that could impact participants’ strategies using the Starfield task (Gramann et al., 2012). Occluding stationary peripheral information increased pointing errors, especially for turners. It is thus possible that turners require the peripheral information to correctly parse and process the central optic flow. Alternatively, manipulating body orientation to decrease sensorimotor interference seemed to decrease error and increase strategy consistency for both turners and non-turners. It is possible that the orientation changes allowed participants to ignore the stationary body- based cues, thereby improving spatial updating. Although these manipulations did not remove the non-turner group altogether, they provided important insights into how cue conflicts may play a role in spatial updating for VR tasks. / Thesis / Master of Science (MSc)

In this thesis, a novel Object Tracking Algorithm is proposed which tracks objects on Apple iPhone 4 platform in real-time. The system utilizes the colorspace of the frames provided by iPhone camera, in parallel with the motion data provided by iPhone motion sensors, to cancel the effect of iPhone rotations during tracking and matching different candidate tracks. The proposed system also adapts to changes in target appearance and size, thus leading to an object tracking robust to such changes. Several experiments conducted on actual video sequences are used to illustrate the functionality of the proposed approach.

In this thesis, a novel Object Tracking Algorithm is proposed which tracks objects on Apple iPhone 4 platform in real-time. The system utilizes the colorspace of the frames provided by iPhone camera, in parallel with the motion data provided by iPhone motion sensors, to cancel the effect of iPhone rotations during tracking and matching different candidate tracks. The proposed system also adapts to changes in target appearance and size, thus leading to an object tracking robust to such changes. Several experiments conducted on actual video sequences are used to illustrate the functionality of the proposed approach.

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Thesis (Ph. D.)--Miami University, Dept. of Psychology, 2009. / Title from second page of PDF document. Includes bibliographical references (p. 42-49).

Thesis (M.A.)--Miami University, Dept. of Psychology, 2005. / Title from first page of PDF document. Document formatted into pages; contains [1], iv, 35 p. : ill. Includes bibliographical references (p. 32-35).

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<p>Successful navigation requires an accurate mental spatial representation of the environment that can be updated during movement. Experiments with animals and humans have demonstrated the existence of two forms of spatial representation: egocentric (observer-centered) and allocentric (environment-centered). Unfortunately, specifically how humans use these two systems is not well understood. The current dissertation was focused on providing evidence differentiating human use of egocentric and allocentric spatial reference frames, specifically examining the characteristics and contributions from body-based sources. Two empirical chapters are presented that include experiments involving two common spatial tasks. In Chapter 2, updating of feature relations within a room-sized environment was examined by having observers provide directional judgments to learned features with respect to an imagined orientation that was either congruent or incongruent with their physical orientation. The information available for updating the physical orientation was manipulated across experiments. Performance differences between congruent and incongruent conditions demonstrated the reliance on egocentric representations for updating, and differentiated body- and knowledge-based components of the egocentric updating process. The specificity of the body-based component was examined in Chapter 3 by having observers detect changes made to a tabletop spatial scene following a viewpoint shift resulting from their movement, scene rotation or both. The relation between the extent of observer movement and the magnitude of the experienced viewpoint shift was manipulated. Change detection performance was best when the extent of observer movement most closely matched the viewpoint shift, and declined as the match declined. Thus, body-based cues contributed specific information for updating self-to-feature relations that facilitated scene recognition. Throughout the course of the research program it has become clear that humans rely on egocentric representations to complete these tasks, and sensory and motor modalities involved in self-motion are integrated for updating spatial relations of novel environments.</p> / Doctor of Philosophy (PhD)