Coloration and colour vision in a parrot ring species

Ring species, in which reproductively isolated forms are connected by a chain of intermediate populations, provide valuable insights into the maintenance of trait variability, divergence in sympatry, and the how small changes can lead to species level differences. The parrot Platycercus elegans of eastern Australia is highly variable in plumage coloration in the wild, ranging from pale yellow to deep crimson in the chest, rump and head. It has been suggested as the only known parrot ring species worldwide, and one of less than ~25 ring species amongst all organisms. We test hypotheses for the information signalled by the colour variation, and for the maintenance of the variability.

Seeing the light : diet related variation in the vision of Platycercus elegans

 Poster Presentation

Primary mental health care reform in Australia : the vision and the reality

Reports on primary mental health care reform in Australia 1991-2001 and the involvement of general practioners as the key providers. Investigates the degree to which the vision of policy makers and key stakeholders for a more integrated and effective system had been achieved. Findings suggested there is a considerable mismatch between the policy vision and the implementation reality and that the current system falls short of providing the support and systemic changes necessary for GPs to provide effective mental health care.

3D depth estimation using wavelet analysis based stereo vision approach

A complete and highly robust 3D reconstruction algorithm based on stereo vision is presented. The developed system is capable of reconstructing dimensionally accurate 3D models of the objects and is very simple and cost effective due to its prominent software dependency and minimal hardware involvevment unlike existing systems.

Apprehending vision

This thesis explores the contexts, conditions and implications of postmodern "visuality" through a body of films that display a critical preocupation with vision, visual technologies and violence, and which promote the demystification of visual cultures and the expansion of perception and subjectivity.

Mobility and vision for mobile robots in non-deterministic, competitive environments

Develops an award winning design for an omnidirectional mobile robot that is both lightweight and extremely maneuverable. Two methods of robot vision, one using rotating lasers and a second using color video cameras were also developed and the merits of both explored.

Vision-based target tracking and surveillance with robust set-valued state estimation

Tracking a target from a video stream (or a sequence of image frames) involves nonlinear measurements in Cartesian coordinates. However, the target dynamics, modeled in Cartesian coordinates, result in a linear system. We present a robust linear filter based on an analytical nonlinear to linear measurement conversion algorithm. Using ideas from robust control theory, a rigorous theoretical analysis is given which guarantees that the state estimation error for the filter is bounded, i.e., a measure against filter divergence is obtained. In fact, an ellipsoidal set-valued estimate is obtained which is guaranteed to contain the true target location with an arbitrarily high probability. The algorithm is particularly suited to visual surveillance and tracking applications involving targets moving on a plane.

A robust set-valued state estimation approach to the problem of vision based SLAM for mobile robots

The problem of visual simultaneous localization and mapping (SLAM) is examined in this paper using ideas and algorithms from robust control and estimation theory. Using a stereo-vision based sensor, a nonlinear measurement model is derived which leads to nonlinear measurements of the landmark coordinates along with optical flow based measurements of the relative robot-landmark velocity. Using a novel analytical measurement transformation, the nonlinear SLAM problem is converted into the linear filter is guaranteed stable and the ALAM state estimation error is bounded within an ellipsoidal set. No similar results are available for the commonly employed extended Kalman filter which is known to exhibit divergent and inconsistency characteristics in practice.

A method for stereo-vision-based tracking for robotic applications

Vision-based tracking of an object using perspective projection inherently results in non-linear measurement equations in the Cartesian coordinates. The underlying object kinematics can be modelled by a linear system. In this paper we introduce a measurement conversion technique that analytically transforms the non-linear measurement equations obtained from a stereo-vision system into a system of linear measurement equations.We then design a robust linear filter around the converted measurement system. The state estimation error of the proposed filter is bounded and we provide a rigorous theoretical analysis of this result. The performance of the robust filter developed in this paper is demonstrated via computer simulation and via practical experimentation using a robotic manipulator as a target. The proposed filter is shown to outperform the extended Kalman filter (EKF).