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 20 of 25 for “"median filter"”.
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Weighted median filters and related nonlinear filters with applications in image processing
In the last few decades, a number of nonlinear filters were presented, especially in the electrical engineering literature. One of the most popular nonlinear filters is weighted median filtering. The main objective of this thesis is to analyse the statistical and deterministic properties of the …
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Median filtering for target detection in an airborne threat warning system
… background. In this thesis, real time spatial prefiltering algorithms that facilitate the detection of such targets in an airborne threat warning system are investigated. The objective of prefiltering is to pass target signals unattenuated while rejecting background and noise. The use of unsharp …
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System (for) Tracking Equilibrium and Determining Incline (STEADI)
… and classification. For the processing both a median filter and a high pass filter are used. A Median filter is used to amplify/enhance the signal by removing impulsive noise while preserving the signal shape while the High pass filter is used to emphasise transitions in the signal. Then, in …
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Automatic Registration of Imagery to Mobile LiDAR Maps
… intensity values, and reducing noise with a median filter. The SCI is processed with a median filter to remove salt-and-pepper noise from the generation methods while preserving edges. Edgeboxes are adapted to find similar features in both SCIs and camera images. These features are then …
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Fast Registration of Tabular Document Images Using the Fourier-Mellin Transform
… segmentation algorithm, based on the median filter. The background removal algorithm is also demonstrated as a useful tool to remove ambient signal noise during correlation. Common problems with FMIR are eliminated by background removal, meaning that apodization (tapering down to zero …
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Multi-stage processing for effective segmentation of SAR sea ice images
… Inspired by the advantages of the Adaptive Median filter (AMF) and the Wiener filter, the Modified Adaptive Median filter (MAMF) is proposed. The MAMF uses local image statistics to identify speckle regions and the Minimum Mean Square Error (MMSE) estimator to suppress speckle. The MAMF is …
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Efficient design and implementation of image processing algorithms on reconfigurable hardware using Handel-C
… this thesis the image processing algorithms like median filter, basic morphological operators, convolution and edge detection algorithms are implemented on FPGA. A pipelined architecture of these algorithms is presented. The proposed architectures are capable of producing one output on every clock …
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Motion picture restoration
… has been traditionally achieved by the use of median filter structures. A new three dimensional multilevel median structure is presented in this work with the additional use of a detector which limits the distortion caused by the filters . This technique is found to be extremely effective in …
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Gradient-Based Surface Reconstruction and the Application to Wind Waves
… of gradient fields is investigated. Median filter pre-processing offers a computationally efficient method that is robust to outliers. After the reconstruction error analysis, selected reconstruction methods are applied to imaging slope gauge data measured in the wind-wave facility …
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Gradient-Based Surface Reconstruction and the Application to Wind Waves
… of gradient fields is investigated. Median filter pre-processing offers a computationally efficient method that is robust to outliers. After the reconstruction error analysis, selected reconstruction methods are applied to imaging slope gauge data measured in the wind-wave facility …
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Portal Imaging Using a CSI (TL) Scintillator Coupled to a Cooled CCD Camera
… and image enhancement algorithms. An adaptive median filter <br />algorithm for the removal of impulse noise was developed, analyzed and incorporated into the <br />image processing protocol.</p> <p>Results from the theoretical analysis and experimental evaluation have indicated that the …
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A method for the spatial functionalization of the dynamic response of a structure with structural stability considerations
… in laser scan angie coordinates is presented. A filtering process involving a median and edge-median filter algorithm followed by a Discrete Fourier Transform/low-pass spatial frequency domain filter/Inverse Discrete Fourier Transform algorithm is used to reduce the effect of errant data recorded …
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Vehicle tracking and speed estimation for traffic surveillance
… provides comprehensive tools for thresholding, filtering and blob analysis. Optical flow was the image processing technique used to determine the moving vehicles. A median filter was used to remove salt and pepper noise from the thresholded image. Combinations of several morphological operations …
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Robust hardware elements for weightless artificial neural networks
… can form a threshold logic based digital signal filter. Two weightless autoassociative memory based neuro-filters are presented and their filtration properties studied and compared with a traditional median filter. Eachn novel architecture was emulated using weightless numericM ATLAB code prior …
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Computing Two-Dimensional Unambiguous Horizontal Wave Number Spectra From OH Airglow Images
… fielding each image, then removing stars using a median filter, subtracting an estimate of the background continuum, and finally, computing the relative OH intensity perturbations. Each pixel is then mapped onto a 256 x 256 rectilinear grid of geographic coordinates using a 9 x 9 Hamming-weighted …
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A support vector machine embedded weed identification system
… 270 weed plants in the field. With an adaptive median filter to enhance the image quality, the accuracy was raised to 75.9% at the expense of extra image processing time. Both of the laboratory and field tests showed that the SVM method with reasonable accuracy is feasible for weed …
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Analysis of atmospheric delays and asymmetric positioning errors in the global positioning system
… longer than 75 days from the signal using a median filter. The skewness of the station position residuals was subsequently calculated in the north, east and up directions. In the cases examined, typical position outliers are 5-15 mm. In extreme cases, skewed position residuals, not related to …
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Boolean Weightless Neural Network Architectures
… is investigated through simulation of digital filters using a Type 1 Neuroram neuro-filter. Simulations have been performed using MATLAB to compare the results to a conventional median filter. Type 1 Neuroram has been tested on an extended collection of noise types. The importance of the …
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A Field-Wise Retrieval Algorithm for SeaWinds
… ambiguity selection algorithm uses a field-wise median filter to select the field-wise ambiguity closest to the true wind in each region. Point-wise nudging is used to further improve the filed-wise estimate using information from the point-wise estimates. Combined, these two techniques select a …
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The investigation and design of a machine vision system for the detection and control of the separation in a spinal ore concentrator
… edge position signal was smoothed by a filter. Based on periodogram analysis of the edge position signal, a smoothing filter was implemented which incorporates a median filter, followed by a fading-memory polynomial filter. These filters gave sufficient smoothing with little lag to step …
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