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Full-Text Articles in Engineering
Electrical Capacitance Measurements To Assess European Corn Borer Infestation In Maize, Mavrik D. Thomas
Electrical Capacitance Measurements To Assess European Corn Borer Infestation In Maize, Mavrik D. Thomas
Theses and Dissertations
The European Corn Borer (ECB), Ostrinia nubilalis, is an agricultural pest which bores small holes in the rind of maize stalks and then proceeds to consume the pith. Because most of the damage to the stalk is internal, it is difficult to quantify the damage to an individual stalk without time-consuming, manual examination. This work explored the hypothesis that internal damage could be detected and quantified using non-destructive, electromagnetic measurements. Laboratory experiments and numerical simulation studies predicted changes in capacitance of stalks due to hollow core ECB damage. A guarded probe device to measure electrical impedance from 500 Hz to …
Inverse Scattering Image Quality With Noisy Forward Data, Thomas J. Sorensen
Inverse Scattering Image Quality With Noisy Forward Data, Thomas J. Sorensen
Theses and Dissertations
Image quality metrics for several inverse scattering methods and algorithms are presented. Analytical estimates and numerical simulations provide a basis for poor image quality diagnostics. The limitations and noise behavior of reconstructed images are explored analytically and empirically using a contrast ratio. Theoretical contrast ratio estimates using the canonical PEC circular cylinder are derived. Empirical studies are conducted to confirm theoretical estimates and to provide examples of image quality vs SNR for more complex scatterer profiles. Regularized sampling is shown to be more noise sensitive than tomographic reconstructive methods.