| 1. |
- Bengtsson, Tomas, 1983, et al.
(författare)
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Regularized Optimization for Joint Super-Resolution and High Dynamoc Range Image Reconstruction in a Percetually Uniform Domain.
- 2012
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Ingår i: ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings. - 1520-6149. - 9781467300469 ; , s. 1097-1100
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Konferensbidrag (refereegranskat)abstract
- This paper discusses resolution enhancement of a set of images with varying exposure durations, having a high combined dynamic range. So far, little has been said in relation to the Human Visual System when it comes to Super-Resolution and High Dynamic Range fusion, unlike the case for traditional Super-Resolution where errors are measured with respect to human perception in the pixel domain. We propose a Super-Resolution method in the L*a*b* domain to bridge the gap and present some image reconstruction results.
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| 2. |
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| 3. |
- Cerullo, Livia, 1982, et al.
(författare)
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Concurrent estimation of space and frequency variation for dielectrics: a microwave tomography system for process sensing applications
- 2011
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Ingår i: Proceedings of the 9th International Conference on Electromagnetic Wave Interaction with Water and Moist Substances, Kansas City, MO USA, May 31 - June 3, 2011. - 9781629934556 ; , s. 177-184
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Konferensbidrag (refereegranskat)abstract
- In many powder processing operations, the effective complex permittivity of the material under processing yields important information concerning the state of the process. This complex permittivity varies in general with respect to both space and frequency. For an accurate estimation of the process material parameters, it is important to be able to incorporate these dependencies in the estimation algorithm. Here, we present a rather general type of parameterization that is tailored for this type of situation. The parameterization is described in terms of a parameterization mesh, which makes it feasible to refine the computational mesh without influencing the number of degrees of freedom in the estimation problem. A test case demonstrates that our approach can yield accurate reconstructions.
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| 4. |
- Cerullo, Livia, 1982, et al.
(författare)
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Determination of model order for inverse scattering applications
- 2010
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Ingår i: Proceedings of the V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010 J. C. F. Pereira, A. Sequeira and J. M. C. Pereira (Eds) Lisbon, Portugal,14-17 June 2010. - 9789899677814
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Konferensbidrag (refereegranskat)
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| 5. |
- Cerullo, Livia, 1982, et al.
(författare)
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Microwave measurement system for dispersive dielectric properties of densely packed pellets
- 2017
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Ingår i: Measurement: Journal of the International Measurement Confederation. - : Elsevier BV. - 0263-2241. ; 106, s. 179-189
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Tidskriftsartikel (refereegranskat)abstract
- We present a microwave measurement system that is intended for the estimation of the dispersive dielectric properties for densely packed pellets. In particular, we estimate the Debye parameters for the effective permittivity of a mixture of air and densely packed moist microcrystalline cellulose pellets for the frequency band 2.7–5.1 GHz. The Debye parameters are estimated by means of minimizing the misfit between the measured scattering parameters and the corresponding computed response given a model of the measurement system. This minimization is performed by means of a nonlinear iterative optimization procedure, which is supported by continuum sensitivities, and the optimum is found in 10–60 iterations for the cases presented in this article. We find that increasing moisture content yields an increase in the static permittivity and a decrease in the relaxation time.
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| 6. |
- Cerullo, Livia, 1982, et al.
(författare)
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Microwave Measurements for Metal Vessels
- 2013
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Ingår i: 7th European Conference on Antennas and Propagation, EuCAP 2013, Gothenburg, Sweden, 8-12 April 2013. - 2164-3342. - 9781467321877 ; , s. 3869 - 3873
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Konferensbidrag (refereegranskat)abstract
- We present two different measurement techniques intended for closed metal vessels, where the objective is to measure the permittivity inside the metal vessel. This problem is relevant for many applications found in e.g. process industry. The first approach exploits the measurement of resonance frequencies, where the metal vessel is used as a microwave resonator. In the second approach, we let the boundary of the metal vessel be equipped with aperture antennas, where the aperture antennas are implemented in terms of rectangular waveguides. The waveguide apertures loads the cavity significantly and we exploit the scattering matrix parameters for the solution of the inverse problem.
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| 7. |
- Chen, Ming, 1972, et al.
(författare)
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Adaptive Channel Prediction Based on Polynomial Phase Signals
- 2008
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Ingår i: 2008 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP; Las Vegas, NV; United States; 31 March 2008 through 4 April 2008. - 1520-6149. - 9781424414840 ; , s. 2881-2884
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Konferensbidrag (refereegranskat)abstract
- Motivated by recently published physics based scattering SISO and MIMO channel models, a new adaptivechannel prediction using Kalman filter based on non-stationary polynomial phase signals with time-varying amplitudes is proposed. To mitigate the influence of the time-varying amplitudes on parameter estimation, an iterative estimation using the Non-linear instantaneous LS criterion is proposed, where the number of signal components and model orders are known. The new predictoroutperforms the classical Linear Prediction and stationarysinusoidal modeling based prediction in Monte Carlo simulations.
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| 8. |
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| 9. |
- Chen, Ming, 1972, et al.
(författare)
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Long Range Channel Prediction Based on Non-Stationary Parametric Modeling
- 2009
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Ingår i: IEEE Transactions on Signal Processing. - 1941-0476 .- 1053-587X. ; 57:2, s. 622-634
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Tidskriftsartikel (refereegranskat)abstract
- Motivated by the analysis of measured radio channels and recently published physics-based scattering SISO and MIMO channel models, a new approach of long-range channel prediction based on nonstationary multicomponent polynomial phase signals (MC-PPS) is proposed. An iterative and recursive method for detecting the number of signals and the orders of the polynomial phases is proposed. The performance of these detectors and estimators is evaluated by Monte Carlo simulations. The performance of the new channel predictors is evaluated using both synthetic signals and examples of real world channels measured in urban and suburban areas. High-order polynomial phase parameters are detected in most of the measured data sets, and the new methods outperform the classical LP in given examples for long-range prediction for the cases where the estimated model parameters are stable. For the more difficult data sets, the performance of these methods are similar, which provides alternatives for system design when other issues are concerned.
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| 10. |
- Chen, Ming, 1972, et al.
(författare)
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Models and Predictions of Scattered Radio Waves on Rough Surfaces
- 2007
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Ingår i: IEEE ICASSP 2007 (Honolulu, Hawaii, USA, 2007). ; 3, s. 785-788
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Konferensbidrag (refereegranskat)abstract
- Scattering of radio waves on rough surfaces is investigated using ray tracing techniques, which results in a sinusoidal model with time varying amplitudes. An AR(d) model with nonzero mean is proposed to characterize and predict the time variation of the amplitudes. A covariance sequence based method is proposed to estimate the autoregressive coefficients from the channel observations. An adaptive channel predictor using a Kalman filter is proposed to predict the complex amplitudes of the scattering signal. The proposed method outperforms other sinusoidal modeling based channel predictors and Linear Predictors with single scattering scenarios.
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