This study investigates augmented reality using third person perspective and what precision can be achieved by using this method. There have been prior studies in regards to precision using augmented reality, however studies using third person perspective is scarce. This study presents a solution using a static camera capturing the user as well as the plane to augment from behind. This augmented image is then transferred to a handheld device that is held by the user. Using this method the user will be free to manipulate and work with the plane without removing the device that captures the scene, a common problem when using visual reference markers in augmented reality. The study successfully shows that this can be implemented without compromising user experience as well as achieving a precision below 13 millimeters. The AR-tool has been proven to reduce time consumption of the task by up to four times compared to the manual method using a folding ruler.

Buildings and public infrastructures are crucial to our societies in that they provide habitations, workplaces, commodities and services indispensible to our daily life. As vital parts of facility management, operations and maintenance (O&M) ensure a facility to continuously function as intended, which take up the longest time in a facility’s life cycle and demand great expense. Therefore, computers and information technology have been actively adopted to automate traditional maintenance methods and processes, making O&M faster and more reliable. Augmented reality (AR) offers a new approach towards human-computer interaction through directly displaying information related to real objects that people are currently perceiving. People’s sensory perceptions are enhanced (augmented) with information of interest naturally without deliberately turning to computers. Hence, AR has been proved to be able to further improve O&M task performance. The research motif of this thesis is user evaluations of AR applications in the context of facility maintenance. The studies look into invisible target designation tasks assisted by developed AR tools in both indoor and outdoor scenarios. The focus is to examine user task performance, which is influenced by both AR system performance and human perceptive, cognitive and motoric factors. Target designation tasks for facility maintenance entail a visualization-interaction dilemma. Two AR systems built upon consumer-level hand-held devices using an off-the-shelf AR software development toolkit are evaluated indoors with two disparate solutions to the dilemma – remote laser pointing and the third person perspective (TPP). In the study with remote laser pointing, the parallax effect associated with AR “X-ray vision” visualization is also an emphasis. A third hand-held AR system developed in this thesis overlays infrared information on façade video, which is evaluated outdoors. Since in an outdoor environment marker-based tracking is less desirable, an infrared/visible image registration method is developed and adopted by the system to align infrared information correctly with the façade in the video. This system relies on the TPP to overcome the aforementioned dilemma.

Parkinson’s disease (PD) is a neurodegenerative condition which results in severe motor impairment. Deterioration in multiple domains of cognition is another hallmark of PD. Together, these motor and cognitive impairments impact substantially on language and communication. Co-speech gestures are a form of action and are also part of linguistic processes, yet have rarely been explored in PD. Gestures can provide imagistic depictions of concepts described by speech and contribute to communication in healthy individuals. They rely on visual, spatial, and motor simulations and imagery, which may be impaired in PD. It is therefore of clinical importance to evaluate how co-speech gestures might be impaired to understand the extent of communicative impairment in PD. PD can also provide a useful model to understanding the cognitive basis of co-speech gesture in healthy people. In Chapter 2, participants described isolated actions. Gesture rate did not differ between the two groups, however, the groups differed in terms of the visual perspective they adopted when depicting actions in gesture. Controls preferred a “character viewpoint” or first-person perspective where their hands represented the hands of the actor, whereas PD patients preferred an “observer viewpoint” or third-person perspective, where their hand represented a whole person. This finding was replicated and extended in Chapter 3 where low-motion and high-motion actions were described in a longer narrative task. PD patients produced fewer character viewpoint gestures when describing high-motion action events, suggesting a difficulty in simulating these events from a first-person perspective. In addition, PD patients had difficult depicting “manner” (how an action is performed) features in gesture during high but not low motion. Extending the findings of Chapter 2, whilst overall rate of gesture production was not affected, PD patients produced action gestures at a significantly lower rate than controls. Chapter 4 took a different focus by investigating gesture depictions of static spatial (rather than dynamic action) features via a house description task. Gesture rate did not differ, but the groups depicted different types of spatial properties to a different extent. Whilst both groups predominantly gestured about location and relative position information, PD patients gestured more about directions whereas controls gestures more about shape and size information. This suggests that different strategies were being employed by the two groups. Finally, testing young adults’ comprehension of these spatial gestures in Chapter 5 revealed that gestures did not significantly improve comprehension of either PD patients’ or controls’ spoken messages, though there may have been ceiling effects. However, both PD patients and controls were viewed as more competent when their messages were viewed with gestures. The findings suggest a selective action-gesture deficit in PD which complements work demonstrating action-verb impairments in these patients, and supports gesture production theories which hypothesise a role for motor simulations and imagery. Overall gesture rate appears to be largely unaffected. The effects of PD can be felt beyond changes to goal-directed action, in the realms of language and social behaviour, but gestures may be able to improve listeners’ social perceptions of PD patients.