volume | PIER Journals

Abstract

The possibility of near-field passive 3-D imaging using the aperture synthesis technique is theoretically proven and highlights the opportunity for imaging the entire human body by an antenna receiving array that surrounds the body. In these scenarios there will be partial obscuration of some regions of the body, by other parts of the body. This results in some receivers in the array being able to measure emission from certain parts of the body, while others are obscured from a measurement. A model is presented which enables the eects of obscuration to be assessed for planar-like, cylindrical-like, and concave-like regions of the human body. The eect the obscuration has on the spatial resolution of the imager is evaluated by examining the 3-D point spread function, as determined by a near-field aperture synthesis imaging algorithm. It is shown that over many areas of the human body, the Abbe microscope resolution of λ/2 (5 mm@30 GHz) in a direction transverse to the human body surface is achievable, an attractive proposition for security screening. However, the spatial resolution in a direction normal to the human body surface is shown to be close to λ(10 mm@30 GHz). In regions of greater obscuration, such as in the armpits, the resolution may fall to λ(10 mm@ 30 GHz) and 5λ (50 mm@30 GHz) in the directions transverse and normal to the human body surface respectively. It is also shown by simulation using a human body solid model and the 3-D aperture synthesis imaging algorithm how the image quality changes with the number of receiving antennas.

1. Luukanen, A., R. Appleby, M. Kemp, and N. A. Salmon, "Millimeter-wave and terahertz imaging in security applications," Terahertz Spectroscopy and Imaging, Springer Berlin Heidelberg, 2013.

2. Nanzer, J. A., "Microwave and Millimeter-wave Remote Sensing for Security Applications," Artech, 2012.

3. Ahmed, S. S., "Microwave imaging in security --- Two decades of innovation," IEEE Journal of Microwaves, Vol. 1, No. 1, 191-201, 2021.
doi:10.1109/JMW.2020.3035790

4. Martin, C. A. and V. G. Kolinko, "Concealed weapons detection with an improved passive millimeter-wave imager," Proc. SPIE --- The International Society for Optical Engineering, Vol. 5410, 252-259, 2004.

5. Salmon, N. A., R. Macpherson, A. Harvey, P. Hall, S. Hayward, P. Wilkinson, and C. Taylor, "First video rate imagery from a 32-channel 22-GHz aperture synthesis passive millimetre wave imager," Proc. SPIE --- Millimetre Wave and Terahertz Sensors and Technology IV, Vol. 8188, 31-42, 2011.

6. Hu, T., Z. Xiao, H. Li, R. Lv, and X. Lu, "Experimental methods of indoor millimeter-wave radiometric imaging for personnel concealed contraband detection," Proc. SPIE --- The International Society for Optical Engineering, Vol. 9275, 201-209, 2014.

7. Zheng, C., X. Yao, A. Hu, and J. Miao, "A passive millimeter-wave imager used for concealed weapon detection," Progress In Electromagnetics Research B, Vol. 46, 379-397, 2012.

8. Heinz, E., T. May, D. Born, G. Zieger, S. Anders, V. Zakosarenko, H. G. Meyer, and C. Schaffel, "Passive 350 GHz video imaging systems for security applications," J. Infrared, Millimeter, Terahertz Waves, Vol. 36, No. 10, 879-895, 2015.
doi:10.1007/s10762-015-0170-8

9. Salmon, N. A., "Indoor full-body security screening: Radiometric microwave imaging phenomenology and polarimetric scene simulation," IEEE Access, Vol. 8, 144621-144637, 2020.
doi:10.1109/ACCESS.2020.3013967

10. Coward, P. R. and R. Appleby, "Development of an illumination chamber for indoor millimeter-wave imaging," Proc. SPIE --- Passive Millimeter-Wave Imaging Technology VI and Radar Sensor Technology VII, Vol. 5077, 54-61, 2003.

11. Doyle, R., B. Lyons, A. Lettington, T. McEnroe, J. Walshe, J. McNaboe, and P. Curtin, "Illumination strategies to achieve effective indoor millimeter wave imaging for personnel screening applications," Proc. SPIE --- Passive Millimeter-Wave Imaging Technology VIII, Vol. 5789, 101-108, 2005.
doi:10.1117/12.603456

12. Thompson, A. R., J. M. Moran, and G. W. Swenson, Interferometry and Synthesis in Radio Astronomy, Springer, 2017.
doi:10.1007/978-3-319-44431-4

13. Zheng, C., X. Yao, A. Hu, and J. Miao, "Initial results of a passive millimeter-wave imager used for concealed weapon detection BHU-2D-U," Progress In Electromagnetics Research C, Vol. 43, 151-163, 2013.
doi:10.2528/PIERC13062801

14. Zhao, Y., A. Hu, W. Si, X. Guo, and J. Miao, "Calibration of visibility samples for real-time passive millimeter wave imaging," IEEE Access, Vol. 9, 106441-106450, 2021.
doi:10.1109/ACCESS.2021.3100102

15. Salmon, N. A. and N. Bowring, "Near-field and three-dimensional aperture synthesis imaging," Proc. SPIE --- Millimetre Wave and Terahertz Sensors and Technology VI, Vol. 8900, 109-117, 2013.

16. Salmon, N. A. and N. Bowring, "Three-dimensional radiometric aperture synthesis microscopy for security screening," Proc. SPIE --- Millimetre Wave and Terahertz Sensors and Technology VII, Vol. 9252, 12-20, 2014.

17. Salmon, N. A. and N. Bowring, "Simulations of three-dimensional radiometric imaging of extended sources in a security screening portal," Proc. SPIE --- Millimetre Wave and Terahertz Sensors and Technology VIII, Vol. 9651, 965106, 2015.
doi:10.1117/12.2197409

18. Salmon, N. A., "3-D radiometric aperture synthesis imaging," IEEE Trans. Microwave Theory Tech., Vol. 63, No. 11, 3579-3587, 2015.
doi:10.1109/TMTT.2015.2481413

19. Goodman, J. W., Statistical Optics, Wiley, 2015.

20. Salmon, N. A., "Spatial resolutions and field-of-views in millimetre wave aperture synthesis security screening imagers," Proc. SPIE --- Millimetre Wave and Terahertz Sensors and Technology XI, Vol. 10800, 1080004, 2018.

21. Lipson, A., S. G. Lipson, and H. Lipson, Optical Physics, Cambridge University Press, 2010.
doi:10.1017/CBO9780511763120

22. Zhang, Z., Microwave Radiometry Technology and Application, Beijing Publishing House of Electronics Industry, 1995.

23. Camps Carmona, A. J., Application of Interferometric Radiometry to Earth Observation, Universitat Politecnica de Catalunya, 1996.

24. Corbella, I., N. Duffo, M. Vall-Llossera, A. Camps, and F. Torres, "The visibility function in interferometric aperture synthesis radiometry," IEEE Trans. Geosci. Electron., Vol. 42, No. 8, 1677-1682, 2004.
doi:10.1109/TGRS.2004.830641

25. Carter, W. H., "Three different kinds of fraunhofer approximations. II. Propagation of the cross-spectral density function," J. Mod. Opt., Vol. 37, No. 1, 109-120, 1990.
doi:10.1080/09500349014550101

26. Carter, W. H., "On refocusing a radio telescope to image sources in the near field of the antenna array," IEEE Trans. Antennas Propag., Vol. 37, No. 3, 314-319, 1989.
doi:10.1109/8.18727

27. Peichl, M., H. Suess, M. Suess, and S. Kern, "Microwave imaging of the brightness temperature distribution of extended areas in the near and far field using two-dimensional aperture synthesis with high spatial resolution," Radio Sci., Vol. 33, No. 3, 781-801, 1998.
doi:10.1029/97RS02398

28. Gonzalez, A. "Measurement of areas on a sphere using Fibonacci and latitude-longitude lattices," Math. Geosci., Vol. 42, No. 1, 49-64, 2010.
doi:10.1007/s11004-009-9257-x

29. MakeHuman: Open Source tool for making 3D characters, http://www.makehumancommunity.org.

30. Salmon, N. A., "Outdoor passive millimeter-wave imaging: Phenomenology and scene simulation," IEEE Trans. Antennas Propag., Vol. 66, No. 2, 897-908, 2017.
doi:10.1109/TAP.2017.2781742

31. Rubinstein, R. Y. and D. P. Kroese, Simulation and the Monte Carlo Method, Wiley, 2016.
doi:10.1002/9781118631980

32. Zhao, Y., W. Si, B. Han, Z. Yang, A. Hu, and J. Miao, IEEE Access, Vol. 10, 32879-32888, 2022.

33. Chen, X., A. Hu, J. Gong, and J. Miao, "Ka band low channel mutual coupling integrated packaged phased array receiver front-end for passive millimeter-wave imaging," Micromachines, Vol. 14, No. 4, 2023.

34. Salmon, N. A., "Polarimetric scene simulation in millimeter-wave radiometric imaging," Proc. SPIE --- Radar Sensor Technology VIII and Passive Millimeter-Wave Imaging Technology VII, Vol. 5410, 260-269, 2004.

35. Kopilovich, L. and L. Sodin, "Multielement system design in astronomy and radio science," Springer Science + Business Media B.V., 2001.

36. Ruf, S. C., "Numerical annealing of low-redundancy linear arrays," IEEE Trans. Antennas Propag., Vol. 41, No. 1, 85-90, 1993.
doi:10.1109/8.210119

Ms. Xuelei Sun

Dr. Neil Anthony Salmon

Dr. Xiaodong Zhuge

Dr. Jungang Miao