Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"Autofocus"”.
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Implementation of Range Autofocus for SAR Radar Imaging
… must be corrected for. This paper describes an autofocus technique used to correct for phase error due to non-linearities in the components of a FMCW radar. Also described here is the algorithm used in calculating the phase error and application of the phase correction with triangle modulation. …
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The Phase Gradient Autofocus Algorithm with Range Dependent Stripmap SAR
<p>The Phase Gradient Autofocus (PGA) algorithm is widely used in spotlight mode SAR for motion compensation. The Maximum Likelihood PGA (ML PGA) algorithm has been shown to be a superior autofocus method. The PGA is restricted to high altitude aircraft. Since lower altitude SARs have significant …
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The development of a predictive autofocus algorithm using a general image formation model
… of a general imaging model for use in autofocus, astigmatism correction, and resolution analysis. The model is based on the modulation transfer function of the imaging system in the presence of aberrations, in particular defocus. The extension of the model to include astigmatism is also …
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Multichannel Methods for Restoration in Computed Imaging
… on problems in two imaging modalities: the autofocus problem in synthetic aperture radar (SAR), and the problem of estimating coil sensitivities in parallel magnetic resonance imaging (PMRI). A common thread in both problems is their inherent multichannel nature, i.e., both exhibit special …
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Translation and rotational motion compensation techniques for Inverse Synthetic Aperture Radar (ISAR) Imaging of sea vessels
This dissertation covers range alignment, autofocus, and time window length optimisation for ISAR imaging of sea vessels. The rationale behind the study was to review the range alignment, autofocus, and time window length optimisation techniques found in the literature and to assess the strengths …
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Sampling in Computational Cameras
… study on image processing, we turn to the camera autofocus con- trol. With the demonstration of a DL-based autofocus pipeline and saliency de- tection network, we show that AI achieves 5 - 10x faster autofocus compared to traditional contrast maximization and allows content-based autofocus …
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Toward a compact underwater structured light 3-D imaging system
… and a higher resolution camera board module with autofocus. Satisfactory 3-D scanning validated the performance of structured light scanning above water. However, contaminants in the water hindered accurate rendering by the system while submerged due to light scattering. Future development of a …
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Physical Designs in Artificial Neural Imaging
… designs play. In all-in-focus imaging, we see autofocus, sampling and fusion algorithms are redefined for optimizing the image quality of a camera with limited depth of field. Image-based neural autofocus acts 5-10x faster than traditional algorithms. The focus control based on the rule or …
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Laser-induced breakdown spectroscopy applied to pasture, titanium, and bioplastics
… measuring the reduction in carbon emissions. An autofocus system, based on the triangulation method, was used to minimise variations caused by lens-to-sample distance (LTSD). With the success of sintering titanium, LIBS was used to investigate non-aqueous organic systems. Employing LIBS to …
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PARALLEL ARCHITECTURES FOR REAL-TIME SAR RANGE-DOPPLER PROCESSING AND QUALITY AUTOMATIC FOCUSING ALGORITHM
… of the large pool, the Quality Phase-Gradient Autofocus (QPGA) solution achieves near convergence quality without iteration. The focusing quality of QPGA has been shown to be better than the conventional PGA. Comparing in terms of computational speed (Pentium 200 platform), QPGA is 3 times …
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Development of an ultrafast laser ultra-precision machining platform
… provides methods for automatic tilt correction, autofocus for the laser, angular ablation machining methods and other diagnostic tools. The interface is setup to capture the required data to provide traceability and diagnostics on the laser machining process. This aided the research carried out …
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Entwicklung, Kalibrierung und Erprobung eines kameraunterstützten Hängetachymeters
Trotz aller technischen Weiterentwicklungen in der Vergangenheit unterscheiden sich moderne elektronische Tachymeter in ihrer Grundkonstruktion nicht wesentlich von ihren analogen Vorgängern. Ihnen allen ist gemeinsam, dass eine Visur um den Nadir nicht möglich ist. Dies bedeutet, dass Punkte, …