Using Image Processing Methods to Improve the Detection of Buried Explosive Threats in GPR Data

Current state of the art techniques for landmine detection in ground penetrating radar (GPR) utilize statistical methods to identify characteristics of a landmine response. This research makes use of 2-D slices of data in which subsurface landmine responses have hyperbolic shapes. Various methods from the field of visual image processing are adapted to the 2-D GPR data, producing superior landmine detection results. This research goes on to develop a physics-based GPR augmentation method motivated by current advances in visual object detection. This GPR specific augmentation is used to mitigate issues caused by insufficient training sets. This work shows that augmentation improves detection performance under training conditions that are normally very difficult. Finally, this work introduces the use of convolutional neural networks as a method to learn feature extraction parameters. These learned convolutional features outperform hand-designed features in GPR detection tasks. This work presents a number of methods, both borrowed from and motivated by the substantial work in visual image processing. The methods developed and presented in this work show an improvement in overall detection performance and introduce a method to improve the robustness of statistical classification.

Histories and Historiographies of Juvenile Delinquency in Nineteenth-Century England

This thesis explores the history of juvenile delinquency in England during the decades bracketing the nineteenth century’s turn and how modern historians have analyzed this period. The purported birth of juvenile delinquency during this tumultuous period is widely attributed by both historians and Victorians to the explosive growth in England’s urban population. Contemporary statistics of criminal prosecutions confirmed emergent literary tropes that viewed childhoods spent on city streets as inevitably corrupting. Public policy and private charity for more than a century thereafter would recommend removal from the city’s corrupting cultural influences to a highly romanticized vision of rural space as healing innocence. This thesis challenges the juxtaposition of country and city on which such explanations of juvenile delinquency rest. Utilizing the neglected testimony of magistrates, constables, rural residents, and juvenile criminals themselves, it will demonstrate that rural England also suffered from increasing juvenile crime in this period. It will illuminate the complex social, economic, and political dynamics responsible for the oft-cited statistical gap between rural and urban arrest rates, showing that the latter were in neither case transparent measures of criminal activity. Crime was on the rise in English rural counties as transformed by industrial capitalism as were England’s booming cities, suggesting that historians who continue to emphasize the dichotomy between the city and the country have not only recycled a Victorian narrative but also limited their own understandings of the time.