Millimeter wave (MMW) imaging has found rapid adoption in security applications such as concealed object detection under clothing. However, the imaging quality is often degraded due to resolution limit and low signal level. This study addresses shape feature analysis following concealed object detection. The object region is extracted by multi-level segmentation. Shape features are composed of several descriptors which are object area, perimeter, major and minor axes of the basic rectangle, rectangularity, compactness, and eccentricity. In the experiments, three objects (gun, hand ax, and plastic bottle containing liquid skin aid) concealed under clothing are captured by the passive MMW imaging system. The extracted shape features are compared with the true features from the object model showing good accuracy.
2. Appleby, R. and R. N. Anderton, "Millimeter-wave and submillimeter-wave imaging for security and surveillance," Proc. IEEE, Vol. 95, No. 8, 1683-1690, 2007.
3. Chen, H.-M., S. Lee, R. M. Rao, M.-A. Slamani, and P. K. Varshney, "Imaging for concealed weapon detection: A tutorial overview of development in imaging sensors and processing," IEEE Signal Processing Magazine, Vol. 22, 52-61, 2005.
4. Kim, W.-G., N.-W. Moon, H.-K. Kim, and Y.-H. Kim, "Linear polarization sum imaging in passive millimeter-wave imaging system for target recognition," Progress In Electromagnetics Research, Vol. 136, 175-193, 2013.
5. Demirci, S., H. Cetinkaya, E. Yigit, C. Ozdemir, and A. A. Vertiy, "A study on millimeter-wave imaging of concealed objects: Application using back-projection algorithm," Progress In Electromagnetics Research, Vol. 128, 457-477, 2012.
6. Sato, H., K. Sawaya, K. Mizuno, J. Uemura, M. Takeda, J. Takahashi, K. Yamada, K. Morichika, T. Hasegawa, H. Hirai, H. Nikura, T. Matsuzaki, S. Kato, and J. Nakada, "Passive millimeter-wave imaging for security and safety applications," Proc. of SPIE, Vol. 7671, 76710V, 2010.
7. Shen, X., C. R. Dietlein, E. Grossman, Z. Popovic, and F. G. Meyer, "Detection and segmentation of concealed objects in Terahertz images," IEEE Trans. on Image Processing, Vol. 17, No. 12, 2465-2475, 2008.
8. Haworth, C. D., Y. De Saint-Pern, D. Clark, E. Trucco, and Y. R. Petillot, "Detection and tracking of multiple metallic objects in millimeter-wave images," International Journal of Computer Vision, Vol. 71, 183-196, 2007.
9. Yeom, S., D. Lee, J.-Y. Son, M. Jung, Y. Jang, S. Jung, and S. Lee, "Real-time outdoor concealed-object detection with passive millimeter wave imaging," Opt. Express, Vol. 19, No. 3, 2530-2536, 2011.
10. Yeom, S., D. Lee, and J.-Y. Son, "Multi-level segmentation of passive millimeter wave images for hidden object detection," Optical Engineering, Vol. 51, 091613, 2012.
11. Li, L. C., J. Y. Yang, G. L. Cui, Z. M. Jiang, and X. Zheng, "Method of passive MMW image detection and identification for close target," J. Infrared, Millimeter Terahertz Waves, Vol. 32, No. 102-115, 2011.
12. Jacobs, E. L. and O. Furxhi, "Target identification and navigation performance modeling of a passive millimeter wave imager," Appl. Opt., Vol. 49, E94-E105, 2010.
13. Belongie, S., J. Malik, and J. Puzicha, "Shape matching and object recognition using shape contexts," IEEE PAMI, Vol. 24, 509-521, 2002.
14. Yeom, S., D. Lee, Y. Jang, M. Lee, and S. Jung, "Real-time outdoor concealed-object detection with passive millimeter wave imaging," Opt. Express, Vol. 20, No. 9, 9371-9381, 2012.
15. Gonzalez, R. C., Digital Image Processing 2/E, Prentice-Hall Inc., 2003.
16. Pitas, I., Digital Image Processing Algorithms and Applications, John Wiley & Sons, Inc., 2000.
17. Mingqiang, Y., K. Kidiyo, and R. Joseph, Pattern Recognition Techniques, Technology and Applications. Ch. 3: A Survey of Shape Feature Extraction Techniques, InTech, 2008.
18. Gersho, A. and R. M. Gray, Vector Quantization and Signal Compression, Kluwer Academic Publishers, Boston, MA, 1992.
19. Bishop, C. M., Neural Networks for Pattern Recognition, Oxford, 1995.
20. Yeom, S., D. Lee, H. Lee, J. Son, and V. P. Gushin, "Vector clustering of passive millimeter wave images with linear polarization for concealed object detection," Progress In Electromagnetics Research Letters, Vol. 39, 169-180, 2013.