Active microwave imaging techniques are aimed at reconstructing an unknown region under test by means of suitable inversion algorithms starting from the measurement of the scattered electromagnetic field. Within such a framework, this paper focuses on an innovative strategy that fully exploits the information arising from the illumination of the investigation domain with different configurations as well as radiation patterns of the probing sources. The proposed approach can be easily integrated with multiview techniques and, unlike multifrequency methods, it does not require additive a-priori information on the dielectric nature of the scatterer under test. A large number of numerical simulations concerned with 2D geometries confirms the effectiveness of the inversion strategy as well as its robustness with respect to noise on data. Moreover, the results of a comparative study with single-source methodologies further point out the advantages and potentialities of the new approach.
2. Yu, Y., T. Yu, and L. Carin, "Three-dimensional inverse scattering of a dielectric target embedded in a lossy half-space," IEEE Trans. Geosci. Remote Sensing, Vol. 42, 957-973, 2004.
3. Hoole, S. R. H., S. Subramaniam, R. Saldanha, J.-L. Coulomb, and J.-C. Sabonnadiere, "Inverse problem methodology and finite elements in the identifications of cracks, sources, materials, and their geometry in inaccessible locations," IEEE Trans. Magn., Vol. 27, 3433-3443, 1991.
4. Bolomey, J. C., Frontiers in Industrial Process Tomography, Engineering Foundation, 1995.
5. Bolomey, J. C., "Recent European developments in active microwave imaging for industrial, scientific, and medical applications," IEEE Trans. Microwave Theory Tech., Vol. 37, 2109-2117, 1991.
6. Louis, K., "Medical imaging: State of the art and future development," Inverse Problems, Vol. 8, 709-738, 1992.
7. Caorsi, S., A. Massa, M. Pastorino, and A. Rosani, "Microwave medical imaging: Potentialities and limitations of a stochastic optimization technique," IEEE Trans. Microwave Theory Tech., Vol. 52, 1909-1916, 2004.
8. Colton, D. and R. Kress, Inverse Acoustics and Electromagnetic Scattering Theory, Springer-Verlag, Berlin, Germany, 1992.
9. Bertero, M. and P. Boccacci, Introduction to Inverse Problem in Imaging, IoP Publishing, Philadelphia, 1998.
10. Denisov, A. M., Elements of Theory of Inverse Problems, VSP, Utrecht, The Netherlands, 1999.
11. Belkebir, K., J. M. Elissalt, J. M. Geffrin, and C. Pichot, "Newton-Kantorovich and modified gradient --- Inversion algorithms applied to Ipswich data," IEEE Antennas Propag. Mag., Vol. 38, 41-43, 1996.
12. Franchois, A. and C. Pichot, "Microwave imaging-complex permittivity reconstruction with a Levenberg-Marquardt method," IEEE Trans. Antennas Propagat., Vol. 45, 203-215, 1997.
13. Pastorino, M., A. Massa, and S. Caorsi, "A microwave inverse scattering technique for image reconstruction based on a genetic algorithm," IEEE Trans. Instrum. Meas., Vol. 49, No. 3, 573-578, Jun. 2000.
14. Van den Berg, P. M. and A. Abubakar, "Contrast source inversion method: State of art," Progress In Electromagnetics Research, Vol. 34, 189-218, 2001.
15. Caorsi, S., M. Donelli, A. Lommi, and A. Massa, "Location and imaging of two-dimensional scatterers by using a particle swarm algorithm," Journal of Electromagnetic Waves and Applications, Vol. 18, 481-494, 2004.
16. Caorsi, S., G. L. Gragnani, and M. Pastorino, "An approach to microwave imaging using a multiview moment method solution for a two-dimensional infinite cylinder," IEEE Trans. Microwave Theory Tech., Vol. 39, 1062-1067, 1991.
17. Bucci, O. M. and T. Isernia, "Electromagnetic inverse scattering: retrievable information and measurements strategies," Radio Science, 2123-2138, 1997.
18. Belkebir, K., R. Kleinman, and C. Pichot, "Microwave imaging --- Location and shape reconstruction from multifrequency scattering data," IEEE Trans. Microwave Theory Tech., Vol. 45, 469-475, 1997.
19. Bucci, O. M., L. Crocco, T. Isernia, and V. Pascazio, "Inverse scattering problems with multifrequency data: Reconstruction capabilities and solution strategies," IEEE Trans. Geosci. Remote Sensing, Vol. 38, 1749-1756, 2000.
20. Franceschini, D., M. Donelli, R. Azaro, and A. Massa, "Dealing with multifrequency scattering data through the IMSA," IEEE Trans. Antennas Propagat., Vol. 55, 2412-2417, 2007.
21. Zhang, W., L. Li, and F. Li, "Multifrequency imaging from intensity-only data using the phaseless data distorted Rytov iterative method," IEEE Trans. Antennas Propagat., Vol. 57, 290-295, 2009.
22. Chew, W. C. and J.-H. Lin, "A frequency-hopping approach for microwave imaging of large inhomogeneous bodies," IEEE Microwave Guided Wave Lett., Vol. 5, 439-441, 1995.
23. Caorsi, S., M. Donelli, D. Franceschini, and A. Massa, "A new methodology based on an iterative multi-scaling for microwave imaging," IEEE Trans. Microwave Theory Tech., Vol. 51, 1162-1173, 2003.
24. Donelli, M., D. Franceschini, P. Rocca, and A. Massa, "Three-dimensional microwave imaging problems solved through an efficient multi-scaling particle swarm optimization," IEEE Trans. Geosci. Remote Sens., Vol. 47, 1467-1481, 2009.
25. Franceschini, D., M. Donelli, G. Franceschini, and A. Massa, "Iterative image reconstruction of two-dimensional scatterers illuminated by TE waves," IEEE Trans. Microwave Theory Techn., Vol. 54, 1484-1494, Apr. 2006.
26. Kaas, M., W. Rieger, C. Huber, G. Lehner, and W. M. Rucker, "Improvement of inverse scattering results by combining TM-and TE-polarized probing waves using an iterative adaptation technique," IEEE Trans. Magn., Vol. 35, 1574-1577, 1999.
27. Chou, C.-P. and Y.-W. Kiang, "Inverse scattering of dielectric cylinders by a cascaded TE-TM method," IEEE Trans. Microwave Theory Techn., Vol. 47, 1923-1930, 1999.
28. Poli, L. and P. Rocca, "Exploitation of TE-TM scattering data for microwave imaging through the multi-scaling reconstruction strategy," Progress In Electromagnetics Research, Vol. 99, 245-260, 2009.
29. Isernia, T., V. Pascazio, and R. Pierri, "On the local minima in a tomographic imaging technique," IEEE Trans. Geosci. Remote Sensing, Vol. 39, 1596-1607, 2001.
30. Jones, D. S., The Theory of Electromagnetism, Pergamon Press, Oxford, UK, 1964.
31. Richmond, J. H., "Scattering by a dielectric cylinder of arbitrary cross section shape," IEEE Trans. Antennas Propagat., Vol. 13, 334-341, 1965.
32. Caorsi, S., A. Massa, and M. Pastorino, "Numerical assessment concerning a focused microwave diagnostic method for medical applications," IEEE Trans. Antennas Propagat., Vol. 48, 1815-1830, 2000.
33. Kohn, R. V. and A. McKenney, "Numerical implementation of a variational method for electrical impedance tomography," Inverse Problems, Vol. 6, 389-414, 1990.
34. Caorsi, S., A. Massa, and M. Pastorino, "A computational technique based on a real-coded genetic algorithm for microwave imaging purposes," IEEE Trans. Geosci. Remote Sens., Vol. 38, 1697-1708, 2000.
35. Caorsi, S., A. Massa, M. Pastorino, and A. Randazzo, "Electromagnetic detection of dielectric scatterers using phaseless synthetic and real data and the memetic algorithm," IEEE Trans. Geosci. Remote Sens., Vol. 41, 2745-2753, 2003.
36. Donelli, M. and A. Massa, "A computational approach based on a particle swarm optimizer for microwave imaging of two-dimensional dielectric scatterers," IEEE Trans. Microwave Theory Techn., Vol. 53, 1761-1776, 2004.
37. Rocca, P., M. Benedetti, M. Donelli, D. Franceschini, and A. Massa, "Evolutionary optimization as applied to inverse problems," Inverse Problems | 25th Year Special Issue of Inverse Problems, Invited Topical Review, Vol. 25, 2009.
38. Van den Berg, P. M. and R. E. Kleinman, "A contrast source inversion method," Inverse Problems, Vol. 13, 1607-1620, 1997.
39. Caorsi, S., M. Donelli, and A. Massa, "Detection, location and imaging of multiple scatterers by means of the iterative multiscaling method," IEEE Trans. Microwave Theory Techn., Vol. 52, 1217-1228, 2004.
40. Caorsi, S., M. Donelli, and A. Massa, "Analysis of the stability and robustness of the iterative multi-scaling approach for microwave imaging applications," Radioscience, Vol. 39, 2004.
41. Franceschini, G., D. Franceschini, and A. Massa, "Full-vectorial three-dimensional microwave imaging through the iterative multi-scaling strategy --- A preliminary assessment," IEEE Geosci. Remote Sens. Lett., Vol. 2, 428-432, 2005.
42. Donelli, M., G. Franceschini, A. Martini, and A. Massa, "An integrated multi-scaling strategy based on a particle swarm algorithm for inverse scattering problems," IEEE Trans. Geosci. Remote Sens., Vol. 44, 298-312, 2006.
43. Benedetti, M., D. Lesselier, M. Lambert, and A. Massa, "A multi-resolution technique based on shape optimization for the reconstruction of homogeneous dielectric objects," Inverse Problems, Vol. 25, 1-26, 2009.
44. Donelli, M., D. Franceschini, G. Franceschini, and A. Massa, "E®ective exploitation of multi-view data through the iterative multi-scaling method --- An experimental assessment," Progress In Electromagnetics Research, Vol. 54, 137-154, 2005.
45. Franceschini, G., M. Donelli, R. Azaro, and A. Massa, "Inversion of phaseless total field data using a two-step strategy based on the iterative multi-scaling approach," IEEE Trans. Geosci. Remote Sens., Vol. 44, 3527-3539, 2006.
46. Benedetti, M., A. Casagranda, M. Donelli, and A. Massa, "An adaptive multi- scaling imaging technique based on a fuzzy-logic strategy for dealing with the uncertainty of noisy scattering data," IEEE Trans. Antennas Propagat., Vol. 55, 3265-3278, 2007.
47. Balanis, C. A., Antenna Theory: Analysis and Design, Wiley, New York, 1997.
48. Duchene, B., D. Lesselier, and R. E. Kleinman, "Inversion of the 1996 Ipswich data using binary specialization of modified gradient methods," IEEE Antennas Propag. Mag., Vol. 39, 9-12, 1997.
49. Massa, A., D. Franceschini, G. Franceschini, M. Raffetto, M. Pastorino, and M. Donelli, "Parallel GA-based approach for microwave imaging applications," IEEE Trans. Antennas Propagat., Vol. 53, 3118-3127, 2005.