Three-Dimensional Terahertz Coded-Aperture Imaging Based on Back Projection

Terahertz coded-aperture imaging (TCAI) can overcome the difficulties of traditional radar in forward-looking and high-resolution imaging. Three-dimensional (3D) TCAI relies mainly on the reference-signal matrix (RSM), the large size and poor accuracy of which reduce the computational efficiency and imaging ability, respectively. According to the previous research on TCAI, traditional TCAI cannot reduce the heavy computational burden while the improved TCAI achieve reconstructing the target parts of different ranges in parallel. However, large-sized RSM still accounts for the computational complexity of traditional TCAI and the improved TCAI. Therefore, this paper proposes a more efficient imaging method named back projection (BP)-TCAI (BP-TCAI). Referring to the basic principle of BP, BP-TCAI can not only divide the scattering information in different ranges but also project the range profiles into different imaging subareas. In this way, the target parts in different subareas can be reconstructed simultaneously to synthesize the whole 3D target and thus decomposes the computational complexity thoroughly. During the pulse compression and projection processes, the signal-to-noise ratio (SNR) of BP-TCAI is also improved. This present the imaging method, model and procedures of traditional TCAI, the improved TCAI and the proposed BP-TCAI. Numerical experimental results prove BP-TCAI to be more effective and efficient than previous imaging methods of TCAI. Besides, BP-TCAI can also be seen as synthetic aperture radar (SAR) imaging with coding technology. Therefore, BP-TCAI opens a future gate combining traditional SAR and coded-aperture imaging.

[1]  Xiang Li,et al.  The Geometry of Signal Detection with Applications to Radar Signal Processing , 2016, Entropy.

[2]  Bin Deng,et al.  Three-Dimensional Terahertz Coded-Aperture Imaging Based on Matched Filtering and Convolutional Neural Network , 2018, Sensors.

[3]  Michael E. Tipping.  Sparse Bayesian Learning and the Relevance Vector Machine , 2001, J. Mach. Learn. Res..

[4]  Mohammed Reza M. Hashemi,et al.  Electronically-Controlled Beam-Steering through Vanadium Dioxide Metasurfaces , 2016, Scientific Reports.

[5]  Gabriel Virbila,et al.  Coded aperture subreflector array for high resolution radar imaging , 2017, Defense + Security.

[6]  Shensheng Han,et al.  Fourier-Transform Ghost Imaging with Hard X Rays. , 2016, Physical review letters.

[7]  V. Krozer,et al.  THz Active Imaging Systems With Real-Time Capabilities , 2011, IEEE Transactions on Terahertz Science and Technology.

[8]  Hongqiang Wang,et al.  Geometric means and medians with applications to target detection , 2017, IET Signal Process..

[9]  Bin Deng,et al.  Three-Dimensional Terahertz Coded-Aperture Imaging Based on Geometric Measures , 2018, Sensors.

[10]  Eran Socher,et al.  Design and Measurements of 100 GHz Reflectarray and Transmitarray Active Antenna Cells , 2017, IEEE Transactions on Antennas and Propagation.

[11]  Zhishen Tong,et al.  Spectral Camera based on Ghost Imaging via Sparsity Constraints , 2015, Scientific Reports.

[12]  Patrick Lj Valdez,et al.  Standoff concealed weapon detection using a 350-GHz radar imaging system , 2010, Defense + Commercial Sensing.

[13]  Xiang Li,et al.  Radar Coincidence Imaging under Grid Mismatch , 2014 .

[14]  Thomas Fromenteze,et al.  Experimental Synthetic Aperture Radar With Dynamic Metasurfaces , 2017, IEEE Transactions on Antennas and Propagation.

[15]  Guillaume Ginolhac,et al.  Back Projection Version of Subspace Detector SAR Processors , 2011, IEEE Transactions on Aerospace and Electronic Systems.

[16]  Lars M. H. Ulander,et al.  Synthetic-aperture radar processing using fast factorized back-projection , 2003 .

[17]  Xiang Wan,et al.  Transmission-Type 2-Bit Programmable Metasurface for Single-Sensor and Single-Frequency Microwave Imaging , 2016, Scientific Reports.

[18]  Bin Deng,et al.  Three-Dimensional Terahertz Coded-Aperture Imaging Based on Single Input Multiple Output Technology , 2018, Sensors.

[19]  George Eastman House,et al.  Sparse Bayesian Learning and the Relevance Vector Machine , 2001 .

[20]  Xiaoli Zhou,et al.  Radar coincidence imaging with phase error using Bayesian hierarchical prior modeling , 2016, J. Electronic Imaging.

[21]  David R. Smith,et al.  Design and Analysis of a W-Band Metasurface-Based Computational Imaging System , 2017, IEEE Access.

[22]  David R. Smith,et al.  Large Metasurface Aperture for Millimeter Wave Computational Imaging at the Human-Scale , 2017, Scientific Reports.

[23]  W. R. Tribe,et al.  Hidden object detection: security applications of terahertz technology , 2004, SPIE OPTO.

[24]  David R. Smith,et al.  Terahertz compressive imaging with metamaterial spatial light modulators , 2014, Nature Photonics.

[25]  Xiang Li,et al.  Radar Coincidence Imaging: an Instantaneous Imaging Technique With Stochastic Signals , 2014, IEEE Transactions on Geoscience and Remote Sensing.