Bi-objective bundle adjustment: towards large-scale visual sea-floor mapping with a minimal sensor suite

Visual sea-floor mapping is a rapidly growing application for Autonomous Underwater Vehicles (AUVs). AUVs are well-suited to the task as they remove humans from a potentially dangerous environment, can reach depths human divers cannot, and are capable of long-term operation in adverse conditions. The output of sea-floor maps generated by AUVs has a number of applications in scientific monitoring: from classifying coral in high biological value sites to surveying sea sponges to evaluate marine environment health.

Global flash multifocal electroretinogram : early detection of local functional changes and its correlations with optical coherence tomography and visual field loss in diabetic eyes

Purpose: To investigate the correlations of the global flash multifocal electroretinogram (MOFO mfERG) with common clinical visual assessments – Humphrey perimetry and Stratus circumpapillary retinal nerve fiber layer (RNFL) thickness measurement in type II diabetic patients. Methods: Forty-two diabetic patients participated in the study: ten were free from diabetic retinopathy (DR) while the remainder suffered from mild to moderate non-proliferative diabetic retinopathy (NPDR). Fourteen age-matched controls were recruited for comparison. MOFO mfERG measurements were made under high and low contrast conditions. Humphrey central 30-2 perimetry and Stratus OCT circumpapillary RNFL thickness measurements were also performed. Correlations between local values of implicit time and amplitude of the mfERG components (direct component (DC) and induced component (IC)), and perimetric sensitivity and RNFL thickness were evaluated by mapping the localized responses for the three subject groups. Results: MOFO mfERG was superior to perimetry and RNFL assessments in showing differences between the diabetic groups (with and without DR) and the controls. All the MOFO mfERG amplitudes (except IC amplitude at high contrast) correlated better with perimetry findings (Pearson’s r ranged from 0.23 to 0.36, p<0.01) than did the mfERG implicit time at both high and low contrasts across all subject groups. No consistent correlation was found between the mfERG and RNFL assessments for any group or contrast conditions. The responses of the local MOFO mfERG correlated with local perimetric sensitivity but not with RNFL thickness. Conclusion: Early functional changes in the diabetic retina seem to occur before morphological changes in the RNFL.

Visual sensitivity loss in the central thirty degrees of visual field is associated with diabetic peripheral neuropathy

Aims/hypothesis: Impaired central vision has been shown to predict diabetic peripheral neuropathy (DPN). Several studies have demonstrated diffuse retinal neurodegenerative changes in diabetic patients prior to retinopathy development, raising the prospect that non-central vision may also be compromised by primary neural damage. We hypothesise that type 2 diabetic patients with DPN exhibit visual sensitivity loss in a distinctive pattern across the visual field, compared with a control group of type 2 diabetic patients without DPN. Methods: Increment light sensitivity was measured by standard perimetry in the central 30 degree of visual field for two age-matched groups of type 2 diabetic patients, with and without neuropathy (n=40/30). Neuropathy status was assigned using the neuropathy disability score. Mean visual sensitivity values were calculated globally, for each quadrant and for three eccentricities (0-10 degree , 11-20 degree and 21-30 degree ). Data were analysed using a generalised additive mixed model (GAMM). Results: Global and quadrant between-group visual sensitivity mean differences were marginally but consistently lower (by about 1 dB) in the neuropathy cohort compared with controls. Between-group mean differences increased from 0.36 to 1.81 dB with increasing eccentricity. GAMM analysis, after adjustment for age, showed these differences to be significant beyond 15 degree eccentricity and monotonically increasing. Retinopathy levels and disease duration were not significant factors within the model (p=0.90). Conclusions/interpretation: Visual sensitivity reduces disproportionately with increasing eccentricity in type 2 diabetic patients with peripheral neuropathy. This sensitivity reduction within the central 30 degree of visual field may be indicative of more consequential loss in the far periphery.

Visual servoing approach to collision avoidance for aircraft

This paper presents a reactive Sense and Avoid approach using spherical image-based visual servoing. Avoidance of point targets in the lateral or vertical plane is achieved without requiring an estimate of range. Simulated results for static and dynamic targets are provided using a realistic model of a small fixed wing unmanned aircraft.

Rotorcraft collision avoidance using spherical image-based visual servoing and single point features

This paper presents a reactive collision avoidance method for small unmanned rotorcraft using spherical image-based visual servoing. Only a single point feature is used to guide the aircraft in a safe spiral like trajectory around the target, whilst a spherical camera model ensures the target always remains visible. A decision strategy to stop the avoidance control is derived based on the properties of spiral like motion, and the effect of accurate range measurements on the control scheme is discussed. We show that using a poor range estimate does not significantly degrade the collision avoidance performance, thus relaxing the need for accurate range measurements. We present simulated and experimental results using a small quad rotor to validate the approach.

Visual motion perception predicts driving hazard perception ability

PURPOSE: To examine the basis of previous findings of an association between indices of driving safety and visual motion sensitivity and to examine whether this association could be explained by low-level changes in visual function. METHODS: 36 visually normal participants (aged 19 – 80 years), completed a battery of standard vision tests including visual acuity, contrast sensitivity and automated visual fields. and two tests of motion perception including sensitivity for movement of a drifting Gabor stimulus, and sensitivity for displacement in a random-dot kinematogram (Dmin). Participants also completed a hazard perception test (HPT) which measured participants’ response times to hazards embedded in video recordings of real world driving which has been shown to be linked to crash risk. RESULTS: Dmin for the random-dot stimulus ranged from -0.88 to -0.12 log minutes of arc, and the minimum drift rate for the Gabor stimulus ranged from 0.01 to 0.35 cycles per second. Both measures of motion sensitivity significantly predicted response times on the HPT. In addition, while the relationship involving the HPT and motion sensitivity for the random-dot kinematogram was partially explained by the other visual function measures, the relationship with sensitivity for detection of the drifting Gabor stimulus remained significant even after controlling for these variables. CONCLUSION: These findings suggest that motion perception plays an important role in the visual perception of driving-relevant hazards independent of other areas of visual function and should be further explored as a predictive test of driving safety. Future research should explore the causes of reduced motion perception in order to develop better interventions to improve road safety.

Engaging Noemi Lakmeier's living installations : the ethics of embarrassment

In Exercise in Losing Control (2007) and We Are for You Because We are Against Them (2010), Austrian-born artist Noemi Lakmaier represents Otherness – and, in particular, the experience of Otherness as one of being vulnerable, dependent or visibly different from everyone else in a social situation – by placing first herself then a group of participants in big circular balls she calls ‘Weebles’. In doing so, Lakmaier depicts Otherness as an absurd, ambiguous or illegible element in otherwise everyday ‘living installations’ in which people meet, converse, dine and connect with spectators and passersby on the street. In this paper I analyse the way spectators and passersby respond to the weeble-wearers. Not surprisingly, responses vary – from people who hurry away, to people who try to talk to the weeble-wearer, to people who try to kick or tip the weeble to test its reality. The not-quite-normal situation, and the visibility of the spectators in the situation, asks spectators to rehearse their response to corporeal differences that might be encountered in day-to-day life. As the range of comments, confrontations and struggles show, the situation transfers the ill-at-ease, embarrassed and awkward aspects of dealing with corporeal difference from the disabled performer to the able spectator-become-performer. In this paper, I theorise some of the self-conscious spectatorial responses this sort of work can provoke in terms of an ethics of embarrassment. As the Latin roots of the word attest, embarrassment is born of a block, barrier or obstacle to move smoothly through a social or communicative encounter. In Lakmaier’s work, a range of potential blocks present themselves. The spectators’ responses – from ignoring the weeble, to querying the weeble, to asking visual, verbal or physical questions about how the weeble works, and so on – are ways of managing the interruption and moving forward. They are, I argue, strategies for moving from confusion to comprehension, or from what Emmanuel Levinas would call an encounter with the unknown to back into the horizon of the known, classified and classifiable. They flag the potential for what Levinas would call an ethical face-to-face encounter with the Other in which spectators and passersby may unexpectedly find themselves in a vulnerable position.

Compass points : the locations, landscapes and coordinates of identities in contemporary performance making : proceedings of the Australasian Association for Theatre, Drama & Performance Studies (ADSA) Conference 2012

Compass Points: The Locations, Landscapes and Coordinates of Identities' the Australasian Association for Theatre, Drama and Performance Studies (ADSA) Conference 2012 was held at Queensland University of Technology, July 3-6 2012. The Conference was sponsored by the Australasian Association for Theatre, Drama and Performance Studies (ADSA), Queensland University of Technology (QUT), Ian Potter Foundation, Arts Queensland, La Boite Theatre Company and Queensland Theatre Company. The papers selected for this collection represent a small sample of the scope, depth and diversity of scholarship presented at the conference - they cover a range of genres, cultures and contexts in contemporary performance making from autobiography, to playwrighting, to public space performance and beyond. The papers collected have been peer-reviewed to Australia’s Department of Education, Science and Training (DEST) standards - each has been subject to two blind reviews, followed by acceptance, rejection or revision, and editing of accepted papers - by colleagues from Australasia and overseas. The review process for the conference publication was separate from the review process for acceptance of abstracts for the actual conference presentations. The conference convenors, Bree Hadley and Caroline Heim, edited the collection, and would like to thank all those who gave their time to advise on the peer review process and act as reviewers - Tom Burvill, Christine Comans, Sean Edgecomb, Angela Campbell, Natalie Lazaroo, Jo Loth, Meg Mumford, Ulrike Garde, Laura Ginters, Andre Bastian, Sam Trubridge, Delyse Ryan, Georgia Seffrin, Gillian Arrighi, Rand Hazou, Rob Pensalfini, Sue Fenty-Studham, Mark Radvan, Rob Conkie, Kris Plummer, Lisa Warrington, Kate Flaherty, Bryoni Tresize, Janys Hayes, Lisa Warrington, Teresa Izzard, Kim Durban, Veronica Kelly, Adrian Keirnander, James Davenport, Julie Robson and others. We, and the authors, appreciate the rigour and care with which peers have approached the scholarship presented here. This collection was published in final form on July 3rd 2012, the first day of the ADSA Conference 2012.

A visual language for the collaborative visualization of integrated conceptual models in product development scenarios

In various industrial and scientific fields, conceptual models are derived from real world problem spaces to understand and communicate containing entities and coherencies. Abstracted models mirror the common understanding and information demand of engineers, who apply conceptual models for performing their daily tasks. However, most standardized models in Process Management, Product Lifecycle Management and Enterprise Resource Planning lack of a scientific foundation for their notation. In collaboration scenarios with stakeholders from several disciplines, tailored conceptual models complicate communication processes, as a common understanding is not shared or implemented in specific models. To support direct communication between experts from several disciplines, a visual language is developed which allows a common visualization of discipline-specific conceptual models. For visual discrimination and to overcome visual complexity issues, conceptual models are arranged in a three-dimensional space. The visual language introduced here follows and extends established principles of Visual Language science.

Identities and transformational experiences for quantitative problem solving : gender comparisons of first-year university science students

Women are underrepresented in science, technology, engineering and mathematics (STEM) areas in university settings; however this may be the result of attitude rather than aptitude. There is widespread agreement that quantitative problem-solving is essential for graduate competence and preparedness in science and other STEM subjects. The research question addresses the identities and transformative experiences (experiential, perception, & motivation) of both male and female university science students in quantitative problem solving. This study used surveys to investigate first-year university students’ (231 females and 198 males) perceptions of their quantitative problem solving. Stata (statistical analysis package version 11) analysed gender differences in quantitative problem solving using descriptive and inferential statistics. Males perceived themselves with a higher mathematics identity than females. Results showed that there was statistical significance (p<0.05) between the genders on 21 of the 30 survey items associated with transformative experiences. Males appeared to have a willingness to be involved in quantitative problem solving outside their science coursework requirements. Positive attitudes towards STEM-type subjects may need to be nurtured in females before arriving in the university setting (e.g., high school or earlier). Females also need equitable STEM education opportunities such as conversations or activities outside school with family and friends to develop more positive attitudes in these fields.

Visual sea-floor mapping from low overlap imagery using bi-objective bundle adjustment and constrained motion

In most visual mapping applications suited to Autonomous Underwater Vehicles (AUVs), stereo visual odometry (VO) is rarely utilised as a pose estimator as imagery is typically of very low framerate due to energy conservation and data storage requirements. This adversely affects the robustness of a vision-based pose estimator and its ability to generate a smooth trajectory. This paper presents a novel VO pipeline for low-overlap imagery from an AUV that utilises constrained motion and integrates magnetometer data in a bi-objective bundle adjustment stage to achieve low-drift pose estimates over large trajectories. We analyse the performance of a standard stereo VO algorithm and compare the results to the modified vo algorithm. Results are demonstrated in a virtual environment in addition to low-overlap imagery gathered from an AUV. The modified VO algorithm shows significantly improved pose accuracy and performance over trajectories of more than 300m. In addition, dense 3D meshes generated from the visual odometry pipeline are presented as a qualitative output of the solution.

Student or scholar? Transforming identities through a research writing group

This article explores the role a writing group played in influencing the scholarly identities of a group of doctoral students by fostering their writing expertise. While the interest in writing groups usually centres on their potential to support doctoral students to publish, few studies have been conducted and written by the students themselves. Using a situated learning perspective on identity, we explore the connection that emerged between our perceptions of ourselves as developing expertise as scholarly writers and the function of the writing group as a dynamic space for transforming our identities. Findings show that our writing group served as a flexible and interactive Community of Practice (CoP) that shaped critical and durable shifts in identity amongst members.

MAVwork : a framework for unified interfacing between micro aerial vehicles and visual controllers

Debugging control software for Micro Aerial Vehicles (MAV) can be risky out of the simulator, especially with professional drones that might harm people around or result in a high bill after a crash. We have designed a framework that enables a software application to communicate with multiple MAVs from a single unified interface. In this way, visual controllers can be first tested on a low-cost harmless MAV and, after safety is guaranteed, they can be moved to the production MAV at no additional cost. The framework is based on a distributed architecture over a network. This allows multiple configurations, like drone swarms or parallel processing of drones' video streams. Live tests have been performed and the results show comparatively low additional communication delays, while adding new functionalities and flexibility. This implementation is open-source and can be downloaded from github.com/uavster/mavwork

Multi-device key management using visual side channels in pervasive computing environments

In the modern connected world, pervasive computing has become reality. Thanks to the ubiquity of mobile computing devices and emerging cloud-based services, the users permanently stay connected to their data. This introduces a slew of new security challenges, including the problem of multi-device key management and single-sign-on architectures. One solution to this problem is the utilization of secure side-channels for authentication, including the visual channel as vicinity proof. However, existing approaches often assume confidentiality of the visual channel, or provide only insufficient means of mitigating a man-in-the-middle attack. In this work, we introduce QR-Auth, a two-step, 2D barcode based authentication scheme for mobile devices which aims specifically at key management and key sharing across devices in a pervasive environment. It requires minimal user interaction and therefore provides better usability than most existing schemes, without compromising its security. We show how our approach fits in existing authorization delegation and one-time-password generation schemes, and that it is resilient to man-in-the-middle attacks.