Combining depth and intensity images to produce enhanced object detection for use in a robotic colony

Robotic colonies that can communicate with each other and interact with their ambient environments can be utilized for a wide range of research and industrial applications. However amongst the problems that these colonies face is that of the isolating objects within an environment. Robotic colonies that can isolate objects within the environment can not only map that environment in de-tail, but interact with that ambient space. Many object recognition techniques ex-ist, however these are often complex and computationally expensive, leading to overly complex implementations. In this paper a simple model is proposed to isolate objects, these can then be recognize and tagged. The model will be using 2D and 3D perspectives of the perceptual data to produce a probability map of the outline of an object, therefore addressing the defects that exist with 2D and 3D image techniques. Some of the defects that will be addressed are; low level illumination and objects at similar depths. These issues may not be completely solved, however, the model provided will provide results confident enough for use in a robotic colony

Retrieval of vegetative fluid resistance terms for rigid stems using airborne lidar.

Hydraulic resistance of riparian forests is an unknown but important term in flood conveyance modeling. Lidar has proven to be a very important new data source to physically characterize floodplain vegetation. This research outlines a recent campaign that aims to retrieve vegetation fluid resistance terms from airborne laser scanning to parameterize trunk roughness. Information on crown characteristics and vegetation spacing can be extracted for individual trees to aid in the determining of trunk stem morphology. Airborne lidar data were used to explore the potential to characterize some of the prominent tree morphometric properties from natural and planted riparian poplar zones such as tree position, tree height, trunk location, and tree spacing. Allometric equations of tree characteristics extrapolated from ground measurements were used to infer below-canopy morphometric variables. Results are presented from six riparian-forested zones on the Garonne and Allier rivers in southern and central France. The tree detection and crown segmentation (TDCS) method identified individual trees with 85% accuracy, and the TreeVaW method detected trees with 83% accuracy. Tree heights were overall estimated at both river locations with an RMSE error of around 19% for both methods, but crown diameter at the six sites produced large deviations from ground-measured values of above 40% for both methods. Total height-derived trunk diameters using the TDCS method produced the closest roughness coefficient values to the ground-derived roughness coefficients. The stem roughness values produced from this method fell within guideline values

Synchrotron quantification of ultrasound cavitation and bubble dynamics in Al-10Cu melts

Knowledge of the kinetics of gas bubble formation and evolution under cavitation conditions in molten alloys is important for the control casting defects such as porosity and dissolved hydrogen. Using in situ synchrotron X-ray radiography, we studied the dynamic behaviour of ultrasonic cavitation gas bubbles in a molten Al-10 wt% Cu alloy. The size distribution, average radius and growth rate of cavitation gas bubbles were quantified under an acoustic intensity of 800 W/cm2 and a maximum acoustic pressure of 4.5 MPa (45 atm). Bubbles exhibited a log-normal size distribution with an average radius of 15.3 ± 0.5 μm. Under applied sonication conditions the growth rate of bubble radius, R(t), followed a power law with a form of R(t) = αtβ, and α = 0.0021 & β = 0.89. The observed tendencies were discussed in relation to bubble growth mechanisms of Al alloy melts.The work was made possible by the financial support from the ExoMet Project (which is co-funded by the European Commission in the 7th Framework Programme (contract FP7-NMP3-LA-2012-280421), by the European Space Agency and by the individual partner organisations), from the UK EPSRC grants (EP/I02249X/1, EP/K00588X/1, EP/K005804/1) and the Research Complex at Harwell

Development of a Fibre Bragg Grating Sensor for Rock Deformation Monitoring

This thesis examines the theoretical and experimental performance of a fibre Bragg grating sensor for static and dynamic strain measurement in hard rock. A literature review focuses on the fundamental theory of fibre Bragg gratings, various physical demodulation schemes used to interrogate Bragg sensors with an emphasis on charge coupled device spectrometry, as well as the aliasing behaviour of Bragg gratings as sensors. A coupled numerical-analytical analysis is conducted on various sensor configurations designed for borehole deployment in order to establish the response of the strain sensors under various strain conditions. The findings of an experimental investigation of two sensors subjected to uniaxial strain within a grout and a rock specimen are presented. The experimental data confirm the feasibility of using the proposed sensor as a part of an integrated optical strain sensing network.M.A.S