A stereo vision technique based on the multi-positioned camera criterion

A modified feature based stereo vision [sic] technique is described in this thesis. The technique uses the curve-segments as the feature primitives in the matching process. The local characteristics of the curve-segments are extracted by the, Generalized Hough Transform. A set of images of a scene, which are taken by a multi-positioned camera satisfying the parallelism criterion, are first filtered by the Laplacian of a Gaussian operator in different widths, i.e. coarse to fine channels. At each channel, the Generalized Hough Transform is applied to the curve-segments in each image. The curve position, the curve-length, the curve centroid, the average gradient of the curve-segment and the R-table are, used as the local features in representing the distinctive characteristics of the curve-segment. These features of all the curve-segments, in an image are used as the constraints to find the corresponding curve-segments in the different images. The epipolar constraint oil the centroid of the curve-segment is used to limit the search window ill the images. Since the multi-images of one view are used, there exist more information about the scene than the two relational images criterion. Its performance compares to the other matching techniques, for example, the point, matching or twin image matching that the mismatching and the calculation are greatly reduced. Although the algorithm is not feasible for the realization of the real-time implementation of stereo vision [sic], it is a more economic way of finding the depth of all object or a view

Development and evaluation of a digital tool for virtual reconstruction of historic Islamic geometric patterns

For the purpose of cultural heritage preservation, the task of recording and reconstructing visually complicated architectural geometrical patterns is facing many practical challenges. Existing traditional technologies rely heavily on the subjective nature of our perceptual power in understanding its complexity and depicting its color differences. This study explores one possible solution, through utilizing digital techniques for reconstructing detailed historical Islamic geometric patterns. Its main hypothesis is that digital techniques offer many advantages over the human eye in terms of recognizing subtle differences in light and color. The objective of the study is to design, test and evaluate an automatic visual tool for identifying deteriorated or incomplete archaeological Islamic geometrical patterns captured in digital images, and then restoring them digitally, for the purpose of producing accurate 2D reconstructed metric models. An experimental approach is used to develop, test and evaluate the specialized software. The goal of the experiment is to analyze the output reconstructed patterns for the purpose of evaluating the digital tool in respect to reliability and structural accuracy, from the point of view of the researcher in the context of historic preservation. The research encapsulates two approaches within its methodology; Qualitative approach is evident in the process of program design, algorithm selection, and evaluation. Quantitative approach is manifested through using mathematical knowledge of pattern generation to interpret available data and to simulate the rest based on it. The reconstruction process involves induction, deduction and analogy. The proposed method was proven to be successful in capturing the accurate structural geometry of the deteriorated straight-lines patterns generated based on the octagon-square basic grid. This research also concluded that it is possible to apply the same conceptual method to reconstruct all two-dimensional Islamic geometric patterns. Moreover, the same methodology can be applied to reconstruct many other pattern systems. The conceptual framework proposed by this study can serve as a platform for developing professional softwares related to historic documentation. Future research should be directed more towards developing artificial intelligence and pattern recognition techniques that have the ability to suplement human power in accomplishing difficult tasks

Parallel architectures for image analysis

This thesis is concerned with the problem of designing an architecture specifically for the application of image analysis and object recognition. Image analysis is a complex subject area that remains only partially defined and only partially solved. This makes the task of designing an architecture aimed at efficiently implementing image analysis and recognition algorithms a difficult one. Within this work a massively parallel heterogeneous architecture, the Warwick Pyramid Machine is described. This architecture consists of SIMD, MIMD and MSIMD modes of parallelism each directed at a different part of the problem. The performance of this architecture is analysed with respect to many tasks drawn from very different areas of the image analysis problem. These tasks include an efficient straight line extraction algorithm and a robust and novel geometric model based recognition system. The straight line extraction method is based on the local extraction of line segments using a Hough style algorithm followed by careful global matching and merging. The recognition system avoids quantising the pose space, hence overcoming many of the problems inherent with this class of methods and includes an analytical verification stage. Results and detailed implementations of both of these tasks are given

On kiwi (Apteryx mantelli) vocal behaviour and activity : relations to population densities and applications to conservation : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Zoology at Massey University, Manawatū, Aotearoa New Zealand

According to the International Union for the Conservation of Nature (IUCN), over 38,500 species of living organisms assessed (27.8%) are currently threatened with extinction. Reducing this startling percentage requires cost–effective monitoring of populations of many and varied species. Information regarding population trends is crucial to allow decision makers to judiciously allocate unavoidably limited resources. Acoustic monitoring has long been employed to document the presence and estimate populations of vocal species for conservation purposes. Determining populations trends without the need of sighting or capturing animals can drastically reduce costs and improve welfare. However, as with many other indirect monitoring practices, acoustic surveys impose a series of assumptions about the detectability of the observed animals and their vocal behaviour. Whereas the variability in detection distances and other observer–induced effects can be minimised using acoustic recorders, enabling the delivery of animal abundances using acoustic monitoring requires detailed knowledge of the target species’ behaviours to relate numbers of detected acoustic cues to those of animals in an area. The iconic North Island Brown Kiwi (Apteryx mantelli, Bartlett 1851) is a flightless nocturnal bird species endemic to Aotearoa New Zealand, fragmentedly distributed across its mainland range and some of its offshore islands. North Island Brown Kiwi are known for their characteristic vocalisations which differ between sexes, with males emitting series of whistle-like syllables, and females producing series of hoarser and lower frequency syllables. Indeed, acoustic surveys are routinely employed by conservation groups and the Department of Conservation Te Papa Atawhai to monitor North Island Brown Kiwi. These surveys, known as Kiwi Call Counts, require observers to annotate sex, direction of arrival, and distance of the detected Kiwi vocalisations over a set period of time. However, little is known of North Island Brown Kiwi vocal behaviour and how this may relate to animal abundance and the development of more accurate and objective monitoring practices is included among the objectives of the Kiwi Recovery Plan (Germano et al., 2018). This thesis aimed to investigate North Island Brown Kiwi vocal behaviour and activity to build more objective and accurate acoustic monitoring protocols. Firstly, results from an extensive literature review on the acoustic playback technique — which has been shown to have the potential to enhance acoustic surveys in other species — led to the development of a set of recommendations to enable reproducibility when using playback. Secondly, results from playback experiments showed how single microphone acoustic recording units (ARUs) can be used to localise sound sources with reasonable degrees of uncertainty. This enables the potential transition of Kiwi Call Counts from relying on human observers to ARUs, which would allow for objective interpretation of the data while creating a potentially perpetual record. One of the thesis aims was to ascertain the potential of using playback to standardise the response of Kiwi populations. The results of experiments testing the effect of playback and environmental factors on kiwi vocal response show that there is no real relationship between the vocal activity of the target Kiwi community and playback. However, they corroborate and add to existing knowledge of Kiwi vocal behaviour by identifying relationships between the latter and external factors, such as lunar illumination and weather conditions. This thesis finally concentrated on the issue of relating vocal activity to animal abundance by developing and trialling the use of animal-borne acoustic recorders in conjunction to fixed ARUs. Since using animal-borne acoustic recorders entails handling target animals, we first performed an experiment on post–handling vocal behaviour to ascertain whether the vocal activity of handled birds of our target community differed from that of birds that had never been handled. The results from this experiment showed that the vocal activity recorded from a gully inhabited by never handled Kiwi did not differ from that of a gully inhabited by birds that were handled during the survey — and have been regularly handled over the last 17 years — in any detectable way. This is encouraging both for animal welfare purposes, and for comparing acoustic surveys from both managed and more wild Kiwi populations. Finally, the results from employing the animal-borne acoustic recorders to inform density estimates showed how information about individual vocal activity informs more realistic and consistent population estimates than methods based only on community–level vocalisations. On all the occasions sampled, results of population estimates only accounting for environmentally recorded vocalisations delivered lower abundance expectations for both males and females. Repeated sampling results show how estimates that account for individual vocal activity are both more consistent and closer to real densities than traditional methods, as estimated by paired sampling with a specialised dog survey. Lastly, information from individual vocal activity in some populations informed more accurate estimates for other populations without individually tagged animals. Taking advantage of having multiple populations with tagged individuals, we estimated abundances of a target population with three different models: unmarked, tagged with animal-borne acoustic recorders, and with information from other populations’ tagged individuals. This last estimate was in between the unmarked and with animal-borne acoustic recorders and apparently more accurate than the unmarked model. This thesis provides methods and shows encouraging results to eventually employ passive acoustic monitoring to infer Kiwi abundance in a cost-effective and non–invasive fashion at large scale, and invites further employment of animal-borne acoustic recorders to confidently deliver abundance estimates, crucial information for conservation decision makers. Using animal-borne acoustic recorders and ARUs together as a way to estimate populations does involve some invasive trials, but has the potential to lead to fully non–invasive robust abundance estimates though passive acoustic monitoring

A Neurophysiologic Study Of Visual Fatigue In Stereoscopic Related Displays

Two tasks were investigated in this study. The first study investigated the effects of alignment display errors on visual fatigue. The experiment revealed the following conclusive results: First, EEG data suggested the possibility of cognitively-induced time compensation changes due to a corresponding effect in real-time brain activity by the eyes trying to compensate for the alignment. The magnification difference error showed more significant effects on all EEG band waves, which were indications of likely visual fatigue as shown by the prevalence of simulator sickness questionnaire (SSQ) increases across all task levels. Vertical shift errors were observed to be prevalent in theta and beta bands of EEG which probably induced alertness (in theta band) as a result of possible stress. Rotation errors were significant in the gamma band, implying the likelihood of cognitive decline because of theta band influence. Second, the hemodynamic responses revealed that significant differences exist between the left and right dorsolateral prefrontal due to alignment errors. There was also a significant difference between the main effect for power band hemisphere and the ATC task sessions. The analyses revealed that there were significant differences between the dorsal frontal lobes in task processing and interaction effects between the processing lobes and tasks processing. The second study investigated the effects of cognitive response variables on visual fatigue. Third, the physiologic indicator of pupil dilation was 0.95mm that occurred at a mean time of 38.1min, after which the pupil dilation begins to decrease. After the average saccade rest time of 33.71min, saccade speeds leaned toward a decrease as a possible result of fatigue on-set. Fourth, the neural network classifier showed visual response data from eye movement were identified as the best predictor of visual fatigue with a classification accuracy of 90.42%. Experimental data confirmed that 11.43% of the participants actually experienced visual fatigue symptoms after the prolonged task

Rocket exhaust plume computer program improvement. Volume 1: Summary: Method of characteristics nozzle and plume programs

A summary is presented of the various documents that discuss and describe the computer programs and analysis techniques which are available for rocket nozzle and exhaust plume calculations. The basic method of characteristics program is discussed, along with such auxiliary programs as the plume impingement program, the plot program and the thermochemical properties program