Non-contact vital sign detection using radar is relevant for many applications. In search and rescue missions in disaster-stricken areas, this technology can be used to non-invasively detect live survivors on the ground. However, in a very large disaster area, a fast and effective detection approach is required. This need has suggested radar mounted on a flying platform such as a drone as the most feasible approach. This task is challenging, since human respiration is weak, and the signal recorded is easily affected by disturbances such as noise and movement of the platform. Therefore, in this study, we propose a signal processing technique to deal with this problem. Human respiration signals modulate a hyperbolic pattern recorded by moving radar because of distance projection, leading us to applying sequential image processing steps and hyperbolic pattern reconstruction to extract respiration signals. A Fourier transform is then applied to seek the respiration frequency component. The results of laboratory experiments show that the proposed method can detect human respiration. As an important note, the flying speed of the platform should be determined carefully to cope with slow human respiration.
1. Ralf, B., et al., "UAV-based polarimetric synthetic aperture radar for mine detection," 2019 IEEE International Geosciences and Remote Sensing Symposium, 9208-9211, IEEE, 2019.
2. Feng, Q., J. Liu, and J. Gong, "UAV remote sensing for urban vegetation mapping using random forest and texture analysis," Remote Sensing, Vol. 7, No. 1, 1074-1094, 2015. doi:10.3390/rs70101074
3. Rohman, B. P. A., et al., "Multisensory surveillance drone for survivor detection and geolocalization in complex post-disaster environment," 2019 International Geosciences and Remote Sensing Symposium 2019, 9368-9371, IEEE, 2019. doi:10.1109/IGARSS.2019.8899804
4. Andra, M. B., B. P. A. Rohman, and T. Usagawa, "Feasibility evaluation for keyword spotting system using mini microphone array on UAV," 2019 International Geosciences and Remote Sensing Symposium 2019, 2264-2267, IEEE, 2019. doi:10.1109/IGARSS.2019.8899304
5. Xu, Y., et al., "Vital sign detection method based on multiple higher order cumulant for ultrawideband radar," IEEE Transactions on Geoscience and Remote Sensing, Vol. 50, No. 4, 1254-1265, 2013. doi:10.1109/TGRS.2011.2164928
6. Naishadham, K., et al., "Estimation of cardiopulmonary parameters from ultra wideband radar measurements using the state space method," IEEE Transactions on Biomedical Circuits and Systems, Vol. 10, No. 6, 1037-1046, 2016. doi:10.1109/TBCAS.2015.2510652
7. Wu, S., et al., "Study on a novel UWB linear array human respiration model and detection method," IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, Vol. 9, No. 1, 125-140, 2016. doi:10.1109/JSTARS.2016.2519760
8. Li, C. and J. Lin, "Complex signal demodulation and random body movement cancellation techniques for non-contact vital sign detection," 2008 IEEE MTT-S International Microwave Symposium Digest, 567-570, IEEE, 2008.
9. Nakata, R. H., et al., "Motion compensation for an unmanned aerial vehicle remote radar life sensor," IEEE Journal on Emerging and Selected Topics in Circuits and Systems, Vol. 8, No. 2, 329-337, 2018. doi:10.1109/JETCAS.2018.2821624
10. Selesnick, I. W., "The double density discrete wavelet transform," Wavelets in Signal and Image Analysis: From Theory to Practice, Springer, Netherlands, 2001.
11. Baili, J., et al., "Application of the discrete wavelet transform to denoise GPR signals," 2nd International Symposium on Communications, Control and Signal Processing, 2006.
12. Lagarias, J. C., J. A. Reeds, M. H. Wright, and P. E. Wright, "Convergence properties of the Nelder-Mead simplex method in low dimensions," SIAM Journal of Optimization, Vol. 9, No. 1, 112-147, 1998. doi:10.1137/S1052623496303470
13. Nelder, J. A. and R. Mead, "A simplex method for function minimization," The Computer Journal, Vol. 7, 308-313, 1965. doi:10.1093/comjnl/7.4.308
14. Cayenne Radar Development Kit — Bow Tie, , Available online: https://store.flatearthinc.com/products/cayenne-radar-development-kit (accessed on 26 September 2019).
15. Lindh, W. Q., et al., Delmar’s Comprehensive Medical Assisting: Administrative and Clinical Competencies, Cengage Learning, New York, 2013.
16. Kondo, T., et al., "Laser monitoring of chest wall displacement," European Respiratory Journal, Vol. 10, No. 8, 1865-1869, 1997. doi:10.1183/09031936.97.10081865