Bibliographies thématiques / Distortion estimation

Littérature scientifique sur le sujet « Distortion estimation »

Auteur : Grafiati
Publié le 11 mars 2023

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Articles de revues sur le sujet "Distortion estimation"

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Peng, Z. K., G. Meng et F. L. Chu. « Improved Wavelet Reassigned Scalograms and Application for Modal Parameter Estimation ». Shock and Vibration 18, no 1-2 (2011) : 299–316. http://dx.doi.org/10.1155/2011/590741.

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The present work carries out a comprehensive investigation into the border distortion deficiency for the conventional scalogram and the reassigned scalogram. The reasons for this deficiency are analyzed, and a simple way is suggested to determine the border distortion ranges. New methods are proposed to reduce the border distortions in both the scalograms. The practical meanings of the border distortion improvement method are demonstrated by applying both the scalograms with and without border distortion improvements to estimate the modal parameters for a 2-DOF linear system. The estimation results indicate that, in the presence of noise, which is inevitable in practice, for the mode with weak amplitude, the reassigned scalogram can perform better than the conventional scalogram in estimating the modal parameters. In addition, for the mode with short effective duration, its frequency components at the border distortion ranges are of great importance for the modal parameter estimation purpose, and the border distortion improvement method can greatly increase the estimation accuracy.
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Chin, Sin Chee, Chee-Onn Chow, Jeevan Kanesan et Joon Huang Chuah. « A Study on Distortion Estimation Based on Image Gradients ». Sensors 22, no 2 (14 janvier 2022) : 639. http://dx.doi.org/10.3390/s22020639.

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Image noise is a variation of uneven pixel values that occurs randomly. A good estimation of image noise parameters is crucial in image noise modeling, image denoising, and image quality assessment. To the best of our knowledge, there is no single estimator that can predict all noise parameters for multiple noise types. The first contribution of our research was to design a noise data feature extractor that can effectively extract noise information from the image pair. The second contribution of our work leveraged other noise parameter estimation algorithms that can only predict one type of noise. Our proposed method, DE-G, can estimate additive noise, multiplicative noise, and impulsive noise from single-source images accurately. We also show the capability of the proposed method in estimating multiple corruptions.
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Zhang, Qiuwen, Liang Tian, Lixun Huang, Xiaobing Wang et Haodong Zhu. « Rendering Distortion Estimation Model for 3D High Efficiency Depth Coding ». Mathematical Problems in Engineering 2014 (2014) : 1–7. http://dx.doi.org/10.1155/2014/940737.

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A depth map represents three-dimensional (3D) scene geometry information and is used for depth image based rendering (DIBR) to synthesize arbitrary virtual views. Since the depth map is only used to synthesize virtual views and is not displayed directly, the depth map needs to be compressed in a certain way that can minimize distortions in the rendered views. In this paper, a modified distortion estimation model is proposed based on view rendering distortion instead of depth map distortion itself and can be applied to the high efficiency video coding (HEVC) rate distortion cost function process for rendering view quality optimization. Experimental results on various 3D video sequences show that the proposed algorithm provides about 31% BD-rate savings in comparison with HEVC simulcast and 1.3 dB BD-PSNR coding gain for the rendered view.
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Liao, Kang, Chunyu Lin et Yao Zhao. « A Deep Ordinal Distortion Estimation Approach for Distortion Rectification ». IEEE Transactions on Image Processing 30 (2021) : 3362–75. http://dx.doi.org/10.1109/tip.2021.3061283.

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Sankisa, Arun, Katerina Pandremmenou, Peshala V. Pahalawatta, Lisimachos P. Kondi et Aggelos K. Katsaggelos. « SSIM-Based Distortion Estimation for Optimized Video Transmission over Inherently Noisy Channels ». International Journal of Multimedia Data Engineering and Management 7, no 3 (juillet 2016) : 34–52. http://dx.doi.org/10.4018/ijmdem.2016070103.

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The authors present two methods for examining video quality using the Structural Similarity (SSIM) index: Iterative Distortion Estimate (IDE) and Cumulative Distortion using SSIM (CDSSIM). In the first method, three types of slices are iteratively reconstructed frame-by-frame for three different combinations of packet loss and the resulting distortions are combined using their probabilities to give the total expected distortion. In the second method, a cumulative measure of the overall distortion is computed by summing the inter-frame propagation impact to all frames affected by a slice loss. Furthermore, the authors develop a No-Reference (NR) sparse regression framework for predicting the CDSSIM metric to circumvent the real-time computational complexity in streaming video applications. The two methods are evaluated in resource allocation and packet prioritization schemes and experimental results show improved performance and better end-user quality. The accuracy of the predicted CDSSIM values is studied using standard performance measures and a Quartile-Based Prioritization (QBP) scheme.
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MA, LILI, YANGQUAN CHEN et KEVIN L. MOORE. « RATIONAL RADIAL DISTORTION MODELS OF CAMERA LENSES WITH ANALYTICAL SOLUTION FOR DISTORTION CORRECTION ». International Journal of Information Acquisition 01, no 02 (juin 2004) : 135–47. http://dx.doi.org/10.1142/s0219878904000173.

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The common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires estimation of these distortion parameters. The task of estimating radial distortion is to find a radial distortion model that allows easy undistortion as well as satisfactory accuracy. This paper presents a new class of rational radial distortion models with easy analytical undistortion formulae. Experimental results are presented to show that with this class of rational radial distortion models, satisfactory and comparable accuracy can be achieved.
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Tsukahara, H. « Estimation of Distortion Risk Measures ». Journal of Financial Econometrics 12, no 1 (19 mars 2013) : 213–35. http://dx.doi.org/10.1093/jjfinec/nbt005.

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Guo, Kai, Hu Ye, Honglin Chen et Xin Gao. « A New Method for Absolute Pose Estimation with Unknown Focal Length and Radial Distortion ». Sensors 22, no 5 (25 février 2022) : 1841. http://dx.doi.org/10.3390/s22051841.

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Estimating the absolute pose of a camera is one of the key steps for computer vision. In some cases, especially when using a wide-angle or zoom lens, the focal length and radial distortion also need to be considered. Therefore, in this paper, an efficient and robust method for a single solution is proposed to estimate the absolute pose for a camera with unknown focal length and radial distortion, using three 2D–3D point correspondences and known camera position. The problem is decomposed into two sub-problems, which makes the estimation simpler and more efficient. The first sub-problem is to estimate the focal length and radial distortion. An important geometric characteristic of radial distortion, that the orientation of the 2D image point with respect to the center of distortion (i.e., principal point in this paper) under radial distortion is unchanged, is used to solve this sub-problem. The focal length and up to four-order radial distortion can be determined with this geometric characteristic, and it can be applied to multiple distortion models. The values with no radial distortion are used as the initial values, which are close to the global optimal solutions. Then, the sub-problem can be efficiently and accurately solved with the initial values. The second sub-problem is to determine the absolute pose with geometric linear constraints. After estimating the focal length and radial distortion, the undistorted image can be obtained, and then the absolute pose can be efficiently determined from the point correspondences and known camera position using the undistorted image. Experimental results indicate this method’s accuracy and numerical stability for pose estimation with unknown focal length and radial distortion in synthetic data and real images.
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Ayof, Mohamad Nizam, Ruzaini Mohd Nawi, Nur Izan Syahriah Hussein et Nor Zulaikha Zainol. « Distortion Prediction of Welded Thin Plate Lap Joints by Finite Element Analysis and Experiment ». Key Engineering Materials 796 (mars 2019) : 175–82. http://dx.doi.org/10.4028/www.scientific.net/kem.796.175.

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Welding process is an efficient joining process of metals that is achieved by gas metal arc welding (GMAW) process. Localized heating during welding process can result in distortion of the welded plate. The estimation of magnitude and distribution of distortion are important to maintain the quality of products. Finite element method is implemented to investigate the distortions behavior of thin steel plate, cold rolled (SPCC) material in lap joint using GMAW process. A three-dimensional, two-step thermomechanical finite element model study was applied to analyze and evaluate distortion behavior in lap joint. The result of distortion from finite element analysis (FEA) was compared to experimental data to validate the accuracy of the method.
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Tong, Jonathan, Robert S. Allison et Laurie M. Wilcox. « The Impact of Radial Distortions in VR Headsets on Perceived Surface Slant ». Journal of Imaging Science and Technology 63, no 6 (1 novembre 2019) : 60409–1. http://dx.doi.org/10.2352/j.imagingsci.technol.2019.63.6.060409.

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Abstract Modern virtual reality (VR) headsets use lenses that distort the visual field, typically with distortion increasing with eccentricity. While content is pre-warped to counter this radial distortion, residual image distortions remain. Here we examine the extent to which such residual distortion impacts the perception of surface slant. In Experiment 1, we presented slanted surfaces in a head-mounted display and observers estimated the local surface slant at different locations. In Experiments 2 (slant estimation) and 3 (slant discrimination), we presented stimuli on a mirror stereoscope, which allowed us to more precisely control viewing and distortion parameters. Taken together, our results show that radial distortion has significant impact on perceived surface attitude, even following correction. Of the distortion levels we tested, 5% distortion results in significantly underestimated and less precise slant estimates relative to distortion-free surfaces. In contrast, Experiment 3 reveals that a level of 1% distortion is insufficient to produce significant changes in slant perception. Our results highlight the importance of adequately modeling and correcting lens distortion to improve VR user experience.
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Thèses sur le sujet "Distortion estimation"

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Mitikiri, Praveen Kumar. « Rate distortion analysis for conditional motion estimation ». Thesis, Wichita State University, 2008. http://hdl.handle.net/10057/2010.

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Rate Distortion analysis is a branch of information theory that predicts the tradeoffs between rate and distortion in source coding. In this thesis, we present the rate distortion analysis for conditional motion estimation, a process that estimates motion based on a criterion that affects coding rate, complexity of coding scheme and quality of the reconstructed video. In order to guide the rate distortion analysis, we use a conditional motion estimation scheme that estimates motion for certain blocks selected based on significant changes. We begin by explaining the conditional motion estimation technique and the effect of decision criteria on the technique. We then model the motion vectors as Gaussian-Markov process and study the rate distortion tradeoffs in the video encoding scheme. The rate distortion bound derived in this manner is also validated with a practical approach.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering
Includes bibliographic references (leaves 28-31)
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Mitikiri, Praveen Kumar Namuduri Kamiswara. « Rate distortion analysis for conditional motion estimation ». A link to full text of this thesis in SOAR, 2008. http://hdl.handle.net/10057/2010.

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Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering.
Copyright 2008 by Praveen Kumar Mitikiri. All Rights Reserved. Includes bibliographical references (leaves 28-31).
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Smith, Katherine Nicole. « New Methodology for the Estimation of StreamVane Design Flow Profiles ». Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/82039.

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Inlet distortion research has become increasingly important over the past several years as demands for aircraft flight efficiency and performance has increased. To accommodate these demands, research progression has shifted the emphasis onto airframe-engine integration and improved understanding of engine operability in less than ideal conditions. Swirl distortion, which is considered a type of non-uniform inflow inlet distortion, is characterized by the presence of swirling flow in an inlet. The presence of swirling flow entering an engine can affect the compression systems performance and operability, therefore it is an area of current research. A swirl distortion generation device created by Virginia Tech, identified as the StreamVane, has the ability to produce various swirl distortion flow profiles. In its current state, the StreamVane methodology generates a design swirl distortion at the trailing edge of the device. However, in many applications the plane at which the researcher wants a desired distortion is downstream of the StreamVane trailing edge. After the distortion is discharged from the StreamVane it develops as it moves downstream. Therefore, to more accurately replicate a desired swirl distortion at a given downstream plane, distortion development downstream of the StreamVane must be considered. Currently Virginia Tech utilizes a numerical modeling design tool, designated StreamFlow, that generates predictions of how a StreamVane-generated distortion propagates downstream. However, due to the non-linear physics of the flow problem, StreamFlow cannot directly calculate an accurate inverse solution that can predict upstream conditions from a downstream boundary, as needed to design a StreamVane. To solve this problem, in this research, an efficient estimation process has been created, combining the use of the StreamFlow model with a Markov Chain Monte Carlo (MCMC) parameter estimation tool to estimate upstream flow profiles that will produce the desired downstream profiles. The process is designated the StreamFlow-MC2 Estimation Process. The process was tested on four fundamental types of swirl distortions. The desired downstream distortion was input into the estimation process to predict an upstream profile that would create the desired downstream distortion. Using the estimated design profiles, 6-inch diameter StreamVanes were designed then wind tunnel tested to verify the distortion downstream. Analysis and experimental results show that using this method, the upstream distortion needed to create the desired distortion was estimated with excellent accuracy. Based on those results, the StreamFlow-MC2 Estimation Process was validated.
Master of Science
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Kakarala, Avinash. « Hardware Implementation Of Conditional Motion Estimation In Video Coding ». Thesis, University of North Texas, 2011. https://digital.library.unt.edu/ark:/67531/metadc103341/.

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This thesis presents the rate distortion analysis of conditional motion estimation, a process in which motion computation is restricted to only active pixels in the video. We model active pixels as independent and identically distributed Gaussian process and inactive pixels as Gaussian-Markov process and derive the rate distortion function based on conditional motion estimation. Rate-Distortion curves for the conditional motion estimation scheme are also presented. In addition this thesis also presents the hardware implementation of a block based motion estimation algorithm. Block matching algorithms are difficult to implement on FPGA chip due to its complexity. We implement 2D-Logarithmic search algorithm to estimate the motion vectors for the image. The matching criterion used in the algorithm is Sum of Absolute Differences (SAD). VHDL code for the motion estimation algorithm is verified using ISim and is implemented using Xilinx ISE Design tool. Synthesis results for the algorithm are also presented.
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Zhao, Zhanlue. « Performance Appraisal of Estimation Algorithms and Application of Estimation Algorithms to Target Tracking ». ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/394.

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This dissertation consists of two parts. The first part deals with the performance appraisal of estimation algorithms. The second part focuses on the application of estimation algorithms to target tracking. Performance appraisal is crucial for understanding, developing and comparing various estimation algorithms. In particular, with the evolvement of estimation theory and the increase of problem complexity, performance appraisal is getting more and more challenging for engineers to make comprehensive conclusions. However, the existing theoretical results are inadequate for practical reference. The first part of this dissertation is dedicated to performance measures which include local performance measures, global performance measures and model distortion measure. The second part focuses on application of the recursive best linear unbiased estimation (BLUE) or lineae minimum mean square error (LMMSE) estimation to nonlinear measurement problem in target tracking. Kalman filter has been the dominant basis for dynamic state filtering for several decades. Beyond Kalman filter, a more fundamental basis for the recursive best linear unbiased filtering has been thoroughly investigated in a series of papers by Dr. X. Rong Li. Based on the so-called quasirecursive best linear unbiased filtering technique, the constraints of the Kalman filter Linear-Gaussian assumptions can be relaxed such that a general linear filtering technique for nonlinear systems can be achieved. An approximate optimal BLUE filter is implemented for nonlinear measurements in target tracking which outperforms the existing method significantly in terms of accuracy, credibility and robustness.
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Bavikadi, Sathwika, et Venkata Bharath Botta. « Estimation and Correction of the Distortion in Forensic Image due to Rotation of the Photo Camera ». Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-15965.

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Images, in contrast to text, represent an effective and natural communication media for humans, due to their immediacy and the easy way to understand the image content. Shape recognition and pattern recognition are one of the most important tasks in the image processing. Crime scene photos should always be in focus and there should always be a ruler be present, this will allow the investigators the ability to resize the image to accurately reconstruct the scene. Therefore, the camera must be on a grounded platform such as tripod. Due to the rotation of the camera around the camera center there exist the distortion in the image which must be minimized. The distorted image should be corrected using transformation method. Deze taak is nogal uitdagend en essentieel omdat elke verandering in de afbeeldingen kan misidentificeren een object voor onderzoekers. Forensic image processing can help the analyst extract information from low quality, noisy image or geometrically distorted. Obviously, the desired information must be present in the image although it may not be apparent or visible. Considering challenges in complex forensic investigation, we understand the importance and sensitivity of data in a forensic images.The HT is an effective technique for detecting and finding the images within noise. It is a typical method to detect or segment geometry objects from images. Specifically, the straight-line detection case has been ingeniously exploited in several applications. The main advantage of the HT technique is that it is tolerant of gaps in feature boundary descriptions and is relatively unaffected by image noise. The HT and its extensions constitute a popular and robust method for extracting analytic curves. HT   attracted a lot of research efforts over the decades. The main motivations behind such interest are the noise immunity, the ability to deal with occlusion, and the expandability of the transform. Many variations of it have evolved. They cover a whole spectrum of shape detection from lines to irregular shapes. This master thesis presents a contribution in the field of forensic image processing. Two different approaches, Hough Line Transformation (HLT), Hough Circular Transformation (HCT) are followed to address this problem. Fout estimatie en validatie is gedaan met de hulp van root mean square method. De prestatie van beide methoden is geëvalueerd door ze te vergelijken. We present our solution as an application to the MATLAB environment, specifically designed to be used as a forensic tool for forensic images.
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ZANAJ, BLERINA. « Estimation of vital parameters through the usage of UWB radars ». Doctoral thesis, Università Politecnica delle Marche, 2013. http://hdl.handle.net/11566/242700.

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Il principale obiettivo della tesi è stato lo sviluppo di un insieme di algoritmi per la valutazione di parametri vitali, come il respiro ed il battito cardiaco, utilizzando un radar UWB. La ricerca fa parte di un progetto più esteso, denominato NIMURRA (Non Invasive Monitoring by Ultra Wide Band Radar of Respiratory Activity of people inside a spatial environment), che il Dipartimento di Ingegneria dell’Informazione dell’Università Politecnica delle Marche ha messo a punto per conto dell’Agenzia Spaziale Italiana (ASI). Al progetto hanno contribuito anche gruppi di ricerca provenienti da altre università e alcune aziende che operano nel settore aerospaziale. Ne sistema basato su radar UWB, l’antenna trasmette una sequenza di impulsi ultracorti verso il soggetto monitorato e l’informazione cercata viene ottenuta attraverso opportuna elaborazione del segnale ricevuto. Quest’ultimo contiene anche segnali riflessi dovuti agli altri oggetti nell’ambiente simulato (clutter). Di essi si tiene conto attraverso un’adeguata caratterizzazione della risposta impulsiva del sistema. L’algoritmo deve eliminare i contributi dovuti al clutter, isolando l’eco generato dal torace umano. Dopo l’eliminazione del clutter, l’algoritmo identifica i punti di massimo dell’energia del segnale. E’ in corrispondenza di questi istanti, infatti, che risulta conveniente effettuare un’analisi in frequenza, basata sulla trasformata di Fourier o di sue versioni ottimizzate. Tale metodo consente di identificare la frequenza di respirazione dalla semplice rivelazione del picco dello spettro. La procedura è stata analizzata ed implementata sia dal punto di vista della modellizzazione analitica che della simulazione numerica. Oltre alla frequenza di respirazione, risulta anche auspicabile poter ricostruire lo spostamento della cavità toracica. Anche questo risultato può essere ottenuto attraverso lo sviluppo di opportuni algoritmi di elaborazione dei segnali. Tra le tecniche utilizzabili allo scopo, si rivela particolarmente efficace eseguire la correlazione tra il segnale ricevuto ed un segnale locale opportunamente scelto. La ricostruzione dello spostamento toracico richiede, ovviamente, un incremento dei tempi di elaborazione, anche se, come sottoprodotto, essa consente di ottenere anche la stima della frequenza di respirazione. La valutazione della frequenza cardiaca è, di norma, molto più complessa, in quanto le armoniche dovute al battito cardiaco sono “mascherate” dalla frequenza di respirazione (ed i suoi multipli) e dai prodotti di intermodulazione. Nell’ambito della tesi, sono comunque state messe a punto opportune operazioni di filtraggio, e valutata la loro efficacia in funzione dei valori relativi delle frequenze di interesse. Come accennato più sopra, una parte rilevante dell’attività di ricerca ha riguardato la messa a punto di programmi, in ambiente Matlab© per la simulazione e l’elaborazione dei segnali negli scenari di interesse. Accanto allo schema più convenzionale (e normalmente adottato, ad esempio nell’ambito del progetto NIMURRA) che prevede l’utilizzo di un radar esterno (a parete) si è anche studiato, pur con minor dettaglio, il caso di radar impiantato negli indumenti del soggetto sotto misura (e dunque solidale con la cavità toracica). Le caratteristiche essenziali del problema restano immutate, ma occorre tener conto del fatto che in questo caso il segnale utile è fornito dagli oggetti presenti nell’ambiente. Infine, si fatto il caso di soggetto sotto misura che si muove, in accordo con leggi deterministiche o aleatorie, compiendo brevi spostamenti nell’intorno della posizione di riferimento. In questo ulteriore scenario, il problema principale consiste nell’eliminazione del contributo nel segnale riflesso dovuto al movimento, e per raggiungere questo obiettivo l’algoritmo di elaborazione del segnale è stato opportunamente modificato. Gli algoritmi sono stati verificati anche a partire da misure reali effettuate presso i laboratori dell’Università La Sapienza di Roma, mostrando, in gran parte dei casi, un’ottima corrispondenza con i risultati di misure convenzionali (Es.: spirometro, per la valutazione della frequenza di respirazione).
This work purpose is the building of an algorithm that estimate the vital parameters from the received signal of an UWB antenna. The research was part of a large project found by the Italian Space Agency, where are included different research groups from different universities in Italy beside the group at Università Politecnica delle Marche. The algorithm was thought to measure the vital parameters of the astronauts before, during and after their mission. The project was entitled NIMURRA (Non Invasive Monitoring by Ultra wide band Radar of Respiratory Activity of people inside a spatial environment). The antenna transmits toward the person and due to the lack of directivity of it we will have the reflected waves also from the other objects. The environment and person reflected signals will be modeled firstly by the impulsive response. By performing a convolution with the reflected pulse we create the simulation matrix. The reflected signal from the human chest reaches the antenna attenuated by the propagation of it in air and distorted by the multiple reflections of the inner tissues of human body. The receiving antenna will gather also the other contributions from the static objects. These last contributions create the static clutter. The algorithm needs to eliminate these other contributions in order to let only the human chest echo. After elimination of the clutter it searches for the maximum of the energy of the signal. Performing a transformation of the column that holds the maximum of energy we find that the harmonic with the highest peak is that of the breath frequency. Another vital parameter of interest is the amplitude of the chest displacement. To make an estimation of the amplitude of the chest movement we need to reconstruct the chest movement form from the received signal. It can be done by performing a correlation between the received signal and a chosen signal that we call as reference signal. The estimation of breath frequency can be estimated also by making the transformation of the chest movement reconstructed and the peak with the highest energy belong to breath frequency. Heart frequency was another parameter of interest for us but its detection comes out a little difficult as it is hidden by the breath harmonics and intermodulation harmonics. The analytical study and modeling were transferred into Matlab code. This algorithm estimates the breath frequency and reconstructs the chest movement. It is possible to choose between the different scenarios of realization of measurements with UWB radar. The scenarios developed were two other beside the main branch with which we started. These other scenarios were when the antenna is on the person body and moves with the chest, it transmits toward the other objects around the person that holds it. The last scenario was when the person under observation with UWB performs small movements. The estimation of breath in this case will follow another path when firstly now we need to estimate the movement of the person. Then this movement is subtracted, by doing so we leave only the moving of the chest during respiration. The estimation of the breath follows after the same algorithm developed for the case of a standing person while the antenna radiates toward him.
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Toivonen, T. (Tuukka). « Efficient methods for video coding and processing ». Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514286957.

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Abstract This thesis presents several novel improvements to video coding algorithms, including block-based motion estimation, quantization selection, and video filtering. Most of the presented improvements are fully compatible with the standards in general use, including MPEG-1, MPEG-2, MPEG-4, H.261, H.263, and H.264. For quantization selection, new methods are developed based on the rate-distortion theory. The first method obtains locally optimal frame-level quantization parameter considering frame-wise dependencies. The method is applicable to generic optimization problems, including also motion estimation. The second method, aimed at real-time performance, heuristically modulates the quantization parameter in sequential frames improving significantly the rate-distortion performance. It also utilizes multiple reference frames when available, as in H.264. Finally, coding efficiency is improved by introducing a new matching criterion for motion estimation which can estimate the bit rate after transform coding more accurately, leading to better motion vectors. For fast motion estimation, several improvements on prior methods are proposed. First, fast matching, based on filtering and subsampling, is combined with a state-of-the-art search strategy to create a very quick and high-quality motion estimation method. The successive elimination algorithm (SEA) is also applied to the method and its performance is improved by deriving a new tighter lower bound and increasing it with a small constant, which eliminates a larger part of the candidate motion vectors, degrading quality only insignificantly. As an alternative, the multilevel SEA (MSEA) is applied to the H.264-compatible motion estimation utilizing efficiently the various available block sizes in the standard. Then, a new method is developed for refining the motion vector obtained from any fast and suboptimal motion estimation method. The resulting algorithm can be easily adjusted to have the desired tradeoff between computational complexity and rate-distortion performance. For refining integer motion vectors into half-pixel resolution, a new very quick but accurate method is developed based on the mathematical properties of bilinear interpolation. Finally, novel number theoretic transforms are developed which are best suited for two-dimensional image filtering, including image restoration and enhancement, but methods are developed with a view to the use of the transforms also for very reliable motion estimation.
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Barr, Michael. « The Influence of the Projected Coordinate System on Animal Home Range Estimation Area ». Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5343.

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Animal home range estimations are important for conservation planning and protecting the habitat of threatened species. The accuracy of home range calculations is influenced by the map projection chosen in a geographic information system (GIS) for data analysis. Different methods of projection will distort spatial data in different ways, so it is important to choose a projection that meets the needs of the research. The large number of projections in use today and the lack of distortion comparison between the various types make selecting the most appropriate projection a difficult decision. The purpose of this study is to quantify and compare the amount of area distortion in animal home range estimations when projected into a number of projected coordinate systems in order to understand how the chosen projection influences analysis. The objectives of this research are accomplished by analyzing the tracking data of four species from different regions in North and South America. The home range of each individual from the four species datasets is calculated using the Characteristic Hull Polygon method for home range estimation and then projected into eight projected coordinate systems of various scales and projection type, including equal area, conformal, equidistant, and compromise projections. A continental Albers Equal Area projection is then used as a baseline area for the calculation of a distortion measurement ratio and magnitude of distortion statistic. The distortion measurement ratio and magnitude calculations provide a measurement of the quantity of area distortion caused by a projection. Results show the amount distortion associated with each type of projection method and how the amount of distortion changes for a projection based on geographic location. These findings show how the choice of map projection can have a large influence on data analysis and illustrate the importance of using an appropriate PCS for the needs of a given study. Distorted perceptions can influence decision-making, so it is important to recognize how a map projection can influence the analysis and interpretation of spatial data.
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Li, Junlin. « Distributed estimation in resource-constrained wireless sensor networks ». Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26633.

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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Ghassan AlRegib; Committee Member: Elliot Moore; Committee Member: Monson H. Hayes; Committee Member: Paul A. Work; Committee Member: Ying Zhang. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Livres sur le sujet "Distortion estimation"

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Leland, R. P. Wind profile estimation from point to point laser distortion data. [Washington, DC : National Aeronautics and Space Administration, 1989.

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Daniel Távora de Queiroz Cobra. Estimation and correction of geometric distortions in side-scan sonar design. Woods Hole, MA : WHOI, 1990.

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G, Williams J. Estimating engine airflow in gas-turbine powered aircraft with clean and distorted inlet flows. Edwards, Calif : National Aeronautics and Space Administration, Dryden Flight Research Center, 1996.

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Chapitres de livres sur le sujet "Distortion estimation"

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Weng, Li, et Bart Preneel. « Image Distortion Estimation by Hash Comparison ». Dans Lecture Notes in Computer Science, 62–72. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-17832-0_7.

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Schuster, Guido M., et Aggelos K. Katsaggelos. « Optimal Motion Estimation and Motion Compensated Interpolation for Video Compression ». Dans Rate-Distortion Based Video Compression, 123–50. Boston, MA : Springer US, 1997. http://dx.doi.org/10.1007/978-1-4757-2566-7_5.

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Pável, Szabolcs, Csanád Sándor et Lehel Csató. « Distortion Estimation Through Explicit Modeling of the Refractive Surface ». Dans Lecture Notes in Computer Science, 17–28. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-30508-6_2.

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Tavakoli, Hamed Rezazadegan, et Hamid Reza Pourreza. « Automated Center of Radial Distortion Estimation, Using Active Targets ». Dans Computer Vision – ACCV 2009, 325–34. Berlin, Heidelberg : Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12304-7_31.

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Tang, Zhenhua, Sunguo Huang et Hongbo Jiang. « Source Distortion Estimation for Wyner-Ziv Distributed Video Coding ». Dans MultiMedia Modeling, 277–88. Cham : Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73600-6_24.

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Devos, Thomas, et François Malrait. « Embedded Estimation of Variable Speed Drive Input Current Distortion ». Dans Springer Proceedings in Energy, 633–48. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69799-0_45.

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Lund, Hannu, Sakari Penttilä et Tuomas Skriko. « Experimental Verification of Knowledge-Based Welding Distortion Estimation Method ». Dans Lecture Notes in Mechanical Engineering, 54–61. Cham : Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-17629-6_7.

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Patel, Shrey, Dhaval Shah, Shashikant Joshi et Kaushik Patel. « Estimation of Distortion for CFRP Antenna Reflector During Autoclave Processing ». Dans Lecture Notes on Multidisciplinary Industrial Engineering, 657–67. Singapore : Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9072-3_55.

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Roy, Aniket, et Rajat Subhra Chakraborty. « Optimal Distortion Estimation for Prediction Error Expansion Based Reversible Watermarking ». Dans Digital Forensics and Watermarking, 265–79. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-53465-7_20.

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Steele, R. Matt, et Christopher Jaynes. « Overconstrained Linear Estimation of Radial Distortion and Multi-view Geometry ». Dans Computer Vision – ECCV 2006, 253–64. Berlin, Heidelberg : Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11744023_20.

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Actes de conférences sur le sujet "Distortion estimation"

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Kim, Jong-Ho, Byung-Gyu Kim et Chang-Sik Cho. « Distortion-Based Partial Distortion Search for Fast Motion Estimation ». Dans Multimedia and Expo, 2007 IEEE International Conference on. IEEE, 2007. http://dx.doi.org/10.1109/icme.2007.4284971.

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Cho, Woon, Minjung Lee, Hyungtae Kim et Joonki Paik. « Automatic estimation of distortion coefficient for correcting radial distortion ». Dans 2018 International Conference on Electronics, Information, and Communication (ICEIC). IEEE, 2018. http://dx.doi.org/10.23919/elinfocom.2018.8330606.

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Hartley, R. I., et Sing Bing Kang. « Parameter-free radial distortion correction with centre of distortion estimation ». Dans Tenth IEEE International Conference on Computer Vision (ICCV'05) Volume 1. IEEE, 2005. http://dx.doi.org/10.1109/iccv.2005.184.

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Hassebrook, Laurence G., Michael E. Lhamon, Mao Wang et Jyoti P. Chatterjee. « Distortion parameter estimation using complex distortion-invariant correlation filter bank responses ». Dans SPIE's 1995 Symposium on OE/Aerospace Sensing and Dual Use Photonics, sous la direction de David P. Casasent et Tien-Hsin Chao. SPIE, 1995. http://dx.doi.org/10.1117/12.205807.

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Tai, Wei-Cheng, Gwo-Long Li et Tian-Sheuan Chang. « Bandwidth-rate-distortion optimized motion estimation ». Dans 2009 IEEE International Conference on Multimedia and Expo (ICME). IEEE, 2009. http://dx.doi.org/10.1109/icme.2009.5202461.

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Young, Sean I., et David Taubman. « Rate-distortion optimized optical flow estimation ». Dans 2015 IEEE International Conference on Image Processing (ICIP). IEEE, 2015. http://dx.doi.org/10.1109/icip.2015.7351086.

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Mehta, Divya, A. Bagubali, Alex Noel Joseph, Vipan Kumar, Vinod Karar et Shashi Poddar. « Radial distortion estimation using analytical technique ». Dans 2017 2nd IEEE International Conference on Recent Trends in Electronics, Information & Communication Technology (RTEICT). IEEE, 2017. http://dx.doi.org/10.1109/rteict.2017.8256866.

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Zeng, Wei, Mayank Goswami, Feng Luo et Xianfeng Gu. « Geometric Registration Based on Distortion Estimation ». Dans 2013 IEEE International Conference on Computer Vision (ICCV). IEEE, 2013. http://dx.doi.org/10.1109/iccv.2013.327.

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Gee, Trevor, Wei Li, Patrice Delmas, Heide Friedrich et Georgy Gimel'farb. « Distortion estimation to improve tsai calibration for cameras with large optical distortion ». Dans 2017 International Conference on Image and Vision Computing New Zealand (IVCNZ). IEEE, 2017. http://dx.doi.org/10.1109/ivcnz.2017.8402507.

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Caron, Andre-Louis, Pierre-Mar Jodoin et Christophe Charrier. « Search Strategies for Image Multi-distortion Estimation ». Dans 2010 20th International Conference on Pattern Recognition (ICPR). IEEE, 2010. http://dx.doi.org/10.1109/icpr.2010.692.

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