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dc.contributor.advisorCree, Michael J.
dc.contributor.advisorDorrington, Adrian A.
dc.contributor.advisorKünnemeyer, Rainer
dc.contributor.authorGodbaz, John Peter
dc.date.accessioned2012-06-05T02:23:32Z
dc.date.available2015-09-29T21:18:51Z
dc.date.issued2012
dc.identifier.citationGodbaz, J. P. (2012). Ameliorating Systematic Errors in Full-Field AMCW Lidar (Thesis, Doctor of Philosophy (PhD)). University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/6385en
dc.identifier.urihttps://hdl.handle.net/10289/6385
dc.description.abstractThis thesis presents an analysis of systematic error in full-field amplitude modulated continuous wave range-imaging systems. The primary focus is on the mixed pixel/multipath interference problem, with digressions into defocus restoration, irregular phase sampling and the systematic phase perturbations introduced by random noise. As an integral part of the thesis, a detailed model of signal formation is developed, that models noise statistics not included in previously reported models. Prior work on the mixed pixel/multipath interference problem has been limited to detection and removal of perturbed measurements or partial amelioration using spatial information, such as knowledge of the spatially variant scattering point spread function, or raytracing using an assumption of Lambertian reflection. Furthermore, prior art has only used AMCW range measurements at a single modulation frequency. In contrast, in this thesis, by taking multiple measurements at different modulation frequencies with known ratio-of-integers frequency relationships, a range of new closed-form and lookup table based inversion and bounding methods are explored. These methods include: sparse spike train deconvolution based multiple return separation, a closed-form inverse using attenuation ratios and a normalisation based lookup table method that uses a new property we term the characteristic measurement. Other approaches include a Cauchy distribution based model for backscattering sources which are range-diffuse, like fog or hair. Novel bounding methods are developed using the characteristic measurement and attenuation ratios on relative intensity, relative phase and phase perturbutation. A detailed noise and performance analysis is performed of the characteristic measurement lookup table method and the bounding methods using simulated data. Experiments are performed using the University of Waikato Heterodyne range-imager, the Canesta XZ-422 and the Mesa Imaging Swissranger 4000 in order to demonstrate the performance of the lookup table method. The lookup table method is found to provide an order of magnitude improvement in ranging accuracy, albeit at the expense of ranging precision.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherUniversity of Waikato
dc.rightsAll items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectTime of Flight
dc.subjectAMCW
dc.subjectLidar
dc.subjectMixed Pixels
dc.subjectMultipath Interference
dc.subjectRange Imaging
dc.subjectAliasing
dc.subjectCharacteristic Measurement
dc.titleAmeliorating Systematic Errors in Full-Field AMCW Lidaren
dc.typeThesis
thesis.degree.grantorUniversity of Waikato
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (PhD)
dc.date.updated2012-05-21T02:20:31Z
pubs.place-of-publicationHamilton, New Zealanden_NZ


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