A new perspective of storm bite on sandy beaches using unmanned aerial vehicles

Aerial imagery collected before and after major storm events is ideal for the assessment of coastal landscape change driven by individual high-magnitude events. Using traditional satellite sensors and manned aerial systems can be challenging due to issues related to cloud cover, mobilization expenses and resolution. Rapid advances in unmanned aerial vehicle (UAV) technology allow for the cost-effective collection of aerial imagery and topography at centimetre resolution suitable for assessing change in coastal ecosystems. In this study we demonstrate the utility of UAV-based photogrammetry to quantify storm-driven sediment dynamics on a sandy beach on the open-coast shoreline of Victoria, Australia. UAV-based aerial photography was collected before and after a major storm event. High-resolution (< 5 cm) aerial imagery and digital surface models were acquired and change-detection techniques were applied to quantify changes in the beachface. An average beach erosion of 12.24 m3/m with a maximum of 28.05 m3/m was observed, and the volume of sand cut from the beachface and retreat of the foredune are clearly illustrated. Following the storm event, erosion was estimated at 7259.94 ± 503.69 m3 along 550 m of beach. By combining the aerial imagery and derived topographic datasets we demonstrate the advantage of UAV-based photogrammetry techniques for rapid high-resolution data collection in semi-remote locations. Its utility in setting unlimited virtual vantage points is also illustrated and the valuable perspective it provides for tracking landscape change discussed.

Vision, ambiguity and perceptual possibility : why pictures matter in the critique of stereo-immersive VR

The acquisition of three-dimensional immersive space through advanced digitial imaging technology, suggests a profound shift from the relatively impoverished representational stratgies of two-dimensional pictorial imagery.  This entails an epistemological shift from pictorial representation, to the presentation of actual three-dimensional space through stereoscopic (3D) imagery.  Moreover, it suggests that visuality rather than 'virtuality' is the core issue in understanding the nature of the epistemological shift associated with stereo-immersive VR.

A shift in visual epistemology from 'flat' pictorial representation to three-dimensional stereo-immersion suggests a gainful move toward a visuality imbued with spatial possibilities.  In quantitative terms, these visual-spatial gains may seem self-evident.  However, certain aspects peculiar to pictorial representation are missing from stereo-immersive imaging.  That is lost in stereo-immersive imaging, and how it can be measured?

This thesis proposes that the inherent ambiguity of two-dimensional representations of three-dimensional spatial structure in pictures, invokes a perceptual response in which pictorial spaces elicit 'perceptual possibility'.  The robust three-dimentional spatiality of stereo-immersvie VR foreclosures such possibility.  Through examining stereo-immersive VR in terms of its visuality, the thesis develops a new appraoch to understanding VR that solves some of the issues associated with the problematic concept of 'virtuality'.  In addition, the thesis finds that by placing stereo-immersive VR and pictures within the shared paradigm of 'the visual', an important dimension of pictures that has been overlooked in past analyses re-emerges : the thesis proposes the concept of 'artifactuality' to account for the way pictures are fundamentally, and in the first instance, aesthetic objects for visual perception.  It is in their manner of appearing as pictures, that they are perceived as pictures of something.  It is from this fundamental basis that their many levels of meaning and signification - their manifold 'realisms' - can arise.

This thesis therefore addresses two intersecting problems within the paradigm of the visual: it proposes 1) that analyses of 'the virtual' be grounded in the 'artifactuality' of pictorial perception, and 2) that the spatiality of stereo-immersive VR be reinvigorated by purposefully 'under-contraining' its key percept - the robust, 'solid' stereoscopic structuring of visual space.  This approach opens up the discourse of stereo-immersive VR to new visual paradigms.  The thesis proposes that these be modelled not on the impossibility of 'the virtual', but on the possibilities of visual ambiguity drawn from the analysis of pictorial perception.

Conceptual design for fully autonomous aerial and ground system for precision agriculture

There are few regulatory restrictions involving the use of fully autonomous unmanned aerial systems in unpopulated, farming areas of Australia. The combination of a fully autonomous aerial and ground systems would provide efficient and cost effective retrieval of soil and vegetation data for use in precision agriculture. The aerial system will survey the site and collect spectral imagery to analyse plant density, stress and nutrition. The ground sensors will collect soil moisture content readings throughout the site. The data from both systems will be collated at a central base station. The base station will also provide housing and interface with the aerial system.

Experimental study of ostensibly shamanic journeying imagery in naďve participants I: antecedents

The purpose of the present study was to investigate experimentally the antecedents of ostensibly shamanic journeying imagery associated with the Lower World in naïve participants. Forty six participants completed a composite questionnaire consisting of demographic items and the Tellegen Absorption Scale (Tellegen and Atkinson 1974). Participants were randomly assigned to one of five conditions: Harner's (1990) shamanic journeying to the Lower World instructions coupled with monotonous percussion drumming at either 4 or 8 beats-per-second for either 10 or 15 minutes; and sitting quietly with eyes closed for 15 minutes. Participants' phenomenology was retrospectively assessed using the Phenomenology of Consciousness Inventory (Pekala 1991) and a mental imagery checklist. The results indicated that there was a statistically significant difference between conditions with regards to the number of ostensibly shamanic journeying images. After adjusting for Harner's (1990) instructions, a significant main effect was found for both beats-per-second and time with regards to the number of ostensibly shamanic journeying images reported. There was a statistically significant relationship between condition and the tendency to report mental imagery associated with rocky ravines, predatory creatures, and rivers. Religious devotion was found to be a significant predictor of the number of ostensibly shamanic journeying images reported. Religious exposure and trait absorption were significant predictors of altered experience. Implications of the findings are discussed and suggestions for future research advanced.

Shamanic journeying imagery, constructivism and the affect bridge technique

Shamanic journeying imagery arguably occurs across cultures and historical epochs. However, to what extent is the content of the journeying imagery a construction of the shaman's cultural milieu, belief structures, autobiographical memories, and so forth. The present article finds the literature inconclusive on this question. It is suggested that attempts to answer it face a fundamental methodological problem: how to detect contextual influences on imagery that the shaman cannot report on because they are outside his/her present consciousness and memory. The authors propose a partial solution: Watkins' (1971) Affect Bridge, a memory “uncovering” technique used in hypnosis. A non-hypnotic version of the technique developed by one of the authors for inquiry into shamanic journeying imagery is then described.

Phenomenological analysis of experimentally induced visual mental imagery associated with shamanic journeying to the lower world

This study explored ostensibly shamanic journeying imagery by (a) assessing visual images across induction techniques (i.e., sonic driving, Ganzfeld, relaxation, and sitting with eyes open); (b) determining combination(s) of induction technique and instructions most associated with religious imagery; and (c) investigating the origins of visual imagery. Six participants were randomly assigned to factorial combinations of a 3 x 4 mixed design (levels of instruction x levels of induction) and were administered the Modified Affect Bridge to explore the origins of mental imagery reported during the experimental conditions. Phenomenological analysis yielded comprehensive constituent themes. Harner’s (1990) shamanic journeying, coupled with religious, instructions were associated with the highest religious imagery, while visual images associated with shamanic journeying were derived primarily from autobiographical memories.

Experimental study of ostensibly shamanic journeying imagery in naďve participants II: phenomenological mapping and modified affect bridge

This study develops the methodological framework advanced in Rock, Baynes, and Casey's (2005) experimental study of ostensibly shamanic journeying imagery in naïve participants. Specifically, the present study experimentally investigates the impact of the word landscape, featured in Harner's (1990) shamanic journeying to the Lower World instructions, on the number of landscape-related images reported; examines the origins of ostensibly shamanic journeying images; and maps the phenomenological state effects of shamanic journeying to the Lower World. Sixtyeight naïve participants were randomly assigned to one of three conditions: either the original or a revised version of Harner's (1990) instructions coupled with monotonous percussion drumming at 8 beats-per-second for 15 minutes, or sitting quietly with eyes open for 15 minutes. Each participant's subjective experience was retrospectively assessed using the Phenomenology of Consciousness Inventory (PCI) (Pekala 1991) and a mental imagery checklist. Subsequently, participants were administered the Modified Affect Bridge for the purpose of exploring the origins of mental imagery experienced during the experimental conditions. The results indicated that there was a statistically significant difference between conditions with regard to the number of ostensibly shamanic journeying images reported, but not between treatment conditions with regard to the number of landscaperelated images reported. There were no significant relationships between condition and mental imagery derived from autobiographical memories. There were statistically significant differences between conditions with regard to the PCI dimensions of fear, altered state of awareness, and arousal.

An active stereo vision-based learning approach for robotic tracking, fixating and grasping control

In this paper, an active stereo vision-based learning approach is proposed for a robot to track, fixate and grasp an object in unknown environments. First, the functional mapping relationships between the joint angles of the active stereo vision system and the spatial representations of the object are derived and expressed in a three-dimensional workspace frame. Next, the self-adaptive resonance theory-based neural networks and the feedforward neural networks are used to learn the mapping relationships in a self-organized way. Then, the approach is verified by simulation using the models of an active stereo vision system which is installed in the end-effector of a robot. Finally, the simulation results confirm the effectiveness of the present approach.

The rough sets feature selection for trees recognition in color aerial images using genetic algorithms

Selecting a set of features which is optimal for a given task is the problem which plays an important role in a wide variety of contexts including pattern recognition, images understanding and machine learning. The concept of reduction of the decision table based on the rough set is very useful for feature selection. In this paper, a genetic algorithm based approach is presented to search the relative reduct decision table of the rough set. This approach has the ability to accommodate multiple criteria such as accuracy and cost of classification into the feature selection process and finds the effective feature subset for texture classification . On the basis of the effective feature subset selected, this paper presents a method to extract the objects which are higher than their surroundings, such as trees or forest, in the color aerial images. The experiments results show that the feature subset selected and the method of the object extraction presented in this paper are practical and effective.

A multi-wavelet based technique for calculating dense 2D disparity maps from stereo

A vision based approach for calculating accurate 3D models of the objects is presented. Generally industrial visual inspection systems capable of accurate 3D depth estimation rely on extra hardware tools like laser scanners or light pattern projectors. These tools improve the accuracy of depth estimation but also make the vision system costly and cumbersome. In the proposed algorithm, depth and dimensional accuracy of the produced 3D depth model depends on the existing reference model instead of the information from extra hardware tools. The proposed algorithm is a simple and cost effective software based approach to achieve accurate 3D depth estimation with minimal hardware involvement. The matching process uses the well-known coarse to fine strategy, involving the calculation of matching points at the coarsest level with consequent refinement up to the finest level. Vector coefficients of the wavelet transform-modulus are used as matching features, where wavelet transform-modulus maxima defines the shift invariant high-level features with phase pointing to the normal of the feature surface. The technique addresses the estimation of optimal corresponding points and the corresponding 2D disparity maps leading to the creation of accurate depth perception model.

What are the origins of shamanic journeying imagery? The modification of a hypnoanalytic technique to address an enduring methodological problem

Shamanic journeying imagery arguably transcends geographical space and historical time. However, to what extent is the content of the journeying imagery a construction of the shaman's cultural cosmology, belief systems, autobiographical memories, etc? It is suggested that attempts to answer this question are hampered by a fundamental methodological obstacle: how to detect contextual influences on imagery that the shaman cannot report on because they are outside his/her present awareness and memory. A partial solution is presented: Watkins' (1971) Affect Bridge, a hypnoanalytic technique used to uncover the origin of an affect. A nonhypnotic version of the technique developed for inquiry into shamanic journeying imagery is then explicated. Two recent empirical studies conducted by Rock (2006) and Rock, Casey and Baynes (2006), illustrating the utility of the Modified Affect Bridge with regards to investigating experimentally the origin of ostensibly shamanic journeying imagery reported by naive participants, are summarized. A tentative ostensibly shamanic journeying imagery origin typology is formulated and suggestions for future research are advanced.

Stereo-vision-based moving object tracking via robust linear filtering

Vision-based tracking sensors typically provide nonlinear measurements
of the targets Cartesian position and velocity state components. In this paper we derive linear measurements using an analytical measurement conversion technique which can be used with two (or more) vision sensors. We derive
linear measurements in the target’s Cartesian position and velocity components and we derive a robust version of a linear Kalman filter. We show that our linear robust filter significantly outperforms the extended Kalman Filter. Moreover, we prove that the state estimation error is bounded.

Depth estimation using multi-wavelet analysis based stereo vision approach

The problem of dimensional defects in aluminum die- casting is widespread throughout the foundry industry and their detection is of paramount importance in maintaining product quality. Due to the unpredictable factory environment and metallic, with highly reflective, nature of aluminum die-castings, it is extremely hard to estimate true dimensionality of the die-casting, autonomously. In this work, we propose a novel robust 3D reconstruction algorithm capable of reconstructing dimensionally accurate 3D depth models of the aluminum die-castings. The developed system is very simple and cost effective as it consists of only a stereo cameras pair and a simple fluorescent light. The developed system is capable of estimating surface depths within the tolerance of 1.5 mm. Moreover, the system is invariant to illuminative variations and orientation of the objects in the input image space, which makes the developed system highly robust. Due to its hardware simplicity and robustness, it can be implemented in different factory environments without a significant change in the setup.